Normal tissue complication probability modeling of acute hematologic toxicity in cervical cancer patients treated with chemoradiotherapy

The Role of Lymphocyte Recovery Index in Prognosis Prediction for Locally Advanced Cervical Cancer With Radiation-Induced Lymphopenia

BACKGROUND

In patients with locally advanced cervical cancer (LACC) undergoing concurrent chemoradiotherapy (CCRT), the high incidence of radiation-induced lymphopenia significantly affects prognosis. There are significant variations in lymphocyte count (ALC) recovery patterns among patients, and their impact on prognosis remains unclear. This study aims to quantify the lymphocyte recovery patterns by the lymphocyte recovery index (LRI) and evaluate its prognostic value.

METHODS

This study reviewed patients with LACC who had ALCs available within 6 months post-CCRT. Lymphopenia was graded using CTCAE 5.0, and lymphocyte recovery patterns were quantified using LRI (the ratio of ALCs at 6 months post-treatment to baseline ALCs). Cox regression analysis was conducted to assess the correlation between LRI, other clinical factors, and survival. The dose-volume of bone marrow (BM) following pelvic radiotherapy was collected, and measurements of spleen standardized uptake value (SUV) and spleen-to-liver SUVmax ratio (SLR) were obtained from pre-treatment 18F-FDG PET/CT. Logistic regression analysis was used to identify independent risk factors for LRI.

RESULTS

A total of 180 patients were included retrospectively. During CCRT, 53 patients (29.4%) experienced G4 lymphopenia. The median LRI was 53.4% (range 13.2%-159.4%). Multivariable analysis revealed that LRI, G4 lymphopenia, and FIGO stage were associated with progression-free survival (PFS) and overall survival (OS). Subgroup analysis revealed that the degree of lymphopenia (G4 and G1-3) did not affect the correlation between LRI and PFS (P: 0.001 and 0.011) or OS (P: 0.003 and 0.043). Regarding FIGO stage, the impact of LRI on PFS (p < 0.001) and OS (p < 0.001) was primarily observed in patients with FIGO stage > II. Logistic analysis identified BM-V10 > 96.0% and SLR > 0.90 as independent risk factors for LRI.

CONCLUSION

In patients with LACC after CCRT, the LRI is associated with prognosis. Splenic metabolism and BM irradiation are associated with lymphocyte recovery.

Predicting grade II-IV bone marrow suppression in patients with cervical cancer based on radiomics and dosiomics

Objective

The objective of this study is to develop a machine learning model integrating clinical characteristics with radiomics and dosiomics data, aiming to assess their predictive utility in anticipating grade 2 or higher BMS occurrences in cervical cancer patients undergoing radiotherapy.

Methods

A retrospective analysis was conducted on the clinical data, planning CT images, and radiotherapy planning documents of 106 cervical cancer patients who underwent radiotherapy at our hospital. The patients were randomly divided into training set and test set in an 8:2 ratio. The radiomic features and dosiomic features were extracted from the pelvic bone marrow (PBM) of planning CT images and radiotherapy planning documents, and the least absolute shrinkage and selection operator (LASSO) algorithm was employed to identify the best predictive characteristics. Subsequently, the dosiomic score (D-score) and the radiomic score (R-score) was calculated. Clinical predictors were identified through both univariate and multivariate logistic regression analysis. Predictive models were constructed by intergrating clinical predictors with DVH parameters, combining DVH parameters and R-score with clinical predictors, and amalgamating clinical predictors with both D-score and R-score. The predictive model's efficacy was assessed by plotting the receiver operating characteristic (ROC) curve and evaluating its performance through the area under the ROC curve (AUC), the calibration curve, and decision curve analysis (DCA).

Results

Seven radiomic features and eight dosiomic features exhibited a strong correlation with the occurrence of BMS. Through univariate and multivariate logistic regression analyses, age, planning target volume (PTV) size and chemotherapy were identified as clinical predictors. The AUC values for the training and test sets were 0.751 and 0.743, respectively, surpassing those of clinical DVH R-score model (AUC=0.707 and 0.679) and clinical DVH model (AUC=0.650 and 0.638). Furthermore, the analysis of both the calibration and the DCA suggested that the combined model provided superior calibration and demonstrated a higher net clinical benefit.

Conclusion

The combined model is of high diagnostic value in predicting the occurrence of BMS in patients with cervical cancer during radiotherapy.

Hematological changes in women with cervical cancer before and after cancer treatment: retrospective cohort study

Hematological changes is one of the most common complications occurred in cancer patients. Therefore, the current study aimed to assess the hematological toxicity of cervical cancer patients before and after the initiation of treatment. The retrospective cohort study was conducted from 2015 to 2022 at the University of Gondar Comprehensive Specialized Hospital. The hematological profile and sociodemographic and clinical data of the cervical cancer patients were collected using data extraction sheets. The Epidata version 3.1 and SPSS version 25 were used for data entry and analysis, respectively. Descriptive statistics were employed to summarize the data. To compare the median differences in hematological parameters before and after treatment, the Wilcoxon rank test was used. In addition, to assess the presence of an independent association between hematological abnormalities and the independent variables, logistic regression models were used. A p value less than 0.05 was considered to indicate statistical significance for all tests. In current study, the median (Interquartile range) of hemoglobin levels, white blood cell counts, and platelet counts, before treatment were 13.2 (12.1, 15) g/dl, 7.5 (5.8, 11.8) *109/L, and 330 (252, 383) *109/L, respectively. However, after treatment the median (Interquartile range) value of hemoglobin levels, white blood cell counts, and platelet counts were significantly lowered. On the other hand, red cell distribution width was significantly greater after treatment. At baseline, the magnitude of leucocytosis, anemia, and thrombocytosis were 27.9%, 24.6%, and 18.7%, respectively. After the treatment, anemia increased to 44.3%, but leucocytosis and thrombocytosis were replaced by leucopenia 18.3% and thrombocytopenia 17.8%, respectively. Hematological abnormalities such as anemia, leucopenia and thrombocytopenia were high after chemo-radiotherapy, and surgery. As the stage of cancer advances, the risk of developing anemia, leucocytosis, and thrombocytosis increased in 7.6, 6.9 and 9 times, respectively. Furthermore, being HIV patients and rural resident increased the risk of developing anemia about twofold. In conclusion hematological abnormalities were observed before and after cervical cancer treatment, with significance increment after chemo-radiotherapy and surgery. As the stage of cancer advances, the risk of developing hematological abnormalities increases. Therefore, routine monitoring of hematological changes before and after treatment and screening for major risk factors are important for improved patients' management.

Evaluating the Effects of Prostate Radiotherapy Intensified with Pelvic Nodal Radiotherapy and Androgen Deprivation Therapy on Myelosuppression: Single-Institution Experience

BACKGROUND

Prostate cancer (PCa) management commonly involves the utilization of prostate radiotherapy (PRT), pelvic nodal radiotherapy (PNRT), and androgen deprivation therapy (ADT). However, the potential association of these treatment modalities with bone marrow (BM) suppression remains inadequately reported in the existing literature. This study is designed to comprehensively evaluate the risk of myelosuppression associated with PRT, shedding light on an aspect that has been underrepresented in prior research.

MATERIALS AND METHODS

We conducted a retrospective analysis of 600 patients with prostate cancer (PCa) treated with prostate radiotherapy (PRT) at a single oncology center between 2007 and 2017. Patients were categorized into four cohorts: PRT alone (n = 149), PRT + ADT, (n = 91), PRT + PNRT (n = 39), and PRT + PNRT + ADT (n = 321). To assess the risk of myelosuppression, we scrutinized specific blood parameters, such as hemoglobin (HGB), white blood cells (WBCs), neutrophils (NEUT), lymphocytes (LYM), and platelets (PLT) at baseline, mid-treatment (mRT), immediately post-RT (pRT), 1 month post-RT (1M-pRT), and 1 year post-RT (1Y-pRT). The inter-cohort statistical significance was evaluated with further stratification based on the utilized RT technique {3D conformal radiotherapy (3D-CRT), and intensity-modulated radiation therapy (IMRT)}.

RESULTS

Significant statistical differences at baseline were observed in HGB and LYM values among all cohorts (p < 0.05). Patients in the PRT + PNRT + ADT cohort had significantly lower HGB at baseline and 1M-pRT. In patients undergoing ADT, BMS had a significant impact at 1M-pRT {odds ratio (OR) 9.1; 95% Confidence Interval (CI) 4.8-17.1} and at 1Y-pRT (OR 2.84; CI 1.14-7.08). The use of 3D-CRT was linked to reduced HGB levels in the PRT + PNRT + ADT group at 1 month pRT (p = 0.015). Similarly, PNRT significantly impacted BMS at 1M-pRT (OR 6.7; CI 2.6-17.2). PNRT increased the odds of decreased WBC counts at 1Y-pRT (OR 6.83; CI: 1.02-45.82). Treatment with any RT techniques (3D-CRT or IMRT), particularly in the PRT + PNRT and PRT + PNRT + ADT groups, significantly increased the odds of low LYM counts at all time points except immediately pRT (p < 0.05). Furthermore, NEUT counts were considerably lower at 1M-pRT (p < 0.05) in the PRT + PNRT + ADT group. PLT counts were significantly decreased by PRT + PNRT + ADT at mRT (OR 2.57; 95% CI: 1.42-4.66) but were not significantly impacted by the RT technique.

CONCLUSIONS

Treatment with PRT, ADT, PNRT, and 3D-CRT is associated with BMS. Despite this statistically significant risk, no patient required additional interventions to manage the outcome. While its clinical impact appears limited, its importance cannot be underestimated in the context of increased integration of novel systemic agents with myelosuppressive properties. Longer follow-up should be considered in future studies.

Prevention and management of radiotherapy-related toxicities in gynecological malignancies. Position paper on behalf of AIRO (Italian Association of Radiotherapy and Clinical Oncology)

Multi-modal therapies for gynecological cancers management may determine a wide range of side effects which depend on therapy-related factors and patient characteristics and comorbidities. Curative or adjuvant pelvic radiotherapy is linked with acute and late toxicity due to irradiation of organs at risk, as small and large bowel, rectum, bladder, pelvic bone, vagina and bone marrow. Successful toxicity management varies with its severity, Radiation Centre practice and experience and skills of radiation oncologists. This position paper was designed by the Italian Association of Radiation and Clinical Oncology Gynecology Study Group to provide radiation oncologists with evidence-based strategies to prevent and manage acute and late toxicities and follow-up recommendations for gynecological cancer patients submitted radiotherapy. Six workgroups of radiation oncologists with over 5 years of experience in gynecologic cancers were setup to investigate radiotherapy-related toxicities. For each topic, PubMed database was searched for relevant English language papers from January 2005 to December 2022. Titles and abstracts of results were checked to verify suitability for the document. Reference lists of selected studies and review papers were added if pertinent. Data on incidence, etiopathogenesis, prevention, treatment and follow-up of acute and late side effects for each organ at risk are presented and discussed.

Bone marrow toxicity in patients with locally advanced cervical cancer undergoing multimodal treatment with VMAT/IMRT: are there dosimetric predictors for toxicity?

PURPOSE

For women with locoregionally advanced cervical cancer, the standard of care treatment is the curatively intended chemoradiation therapy (CRT). A relationship between bone marrow (BM) dose-volume histograms (DVHs) and acute hematological toxicity (HT) has been debated recently. Aim of this study was the evaluation of BM dose constraints and HT in a contemporary patient cohort.

METHODS

Radiation treatment plans of 31 patients with cervical cancer (FIGO stage IIB-IVB) treated with intensity-modulated radiotherapy and simultaneous chemotherapy were explored retrospective. Pelvic bones (PB) and femoral heads (FH) were contoured and DVHs were correlated with white blood cells (WBC), hemoglobin levels and platelets.

RESULTS

Comparing the absolute blood levels with the dose volumes of both FH and PB the data showed a significant correlation between WBC and the median dose of the FH and the median dose, V30Gy, V40Gy and V50Gy of the PB. A correlation between the toxicity grade of anemia and mean dose, maximum dose and V5Gy of the PB was found. Counting the highest grade of HT of all three blood levels of each patient, significant correlations were found for the mean and median dose, V30Gy, V40Gy and V50Gy of the PB.

CONCLUSION

The results show that blood levels may correlate with distinct dosimetric subvolumes of critical bone marrow compartments with a potential impact on therapeutic outcome and treatment-related toxicity. The data presented are in line with the previous findings on the relevance of dosimetric exposure of pelvic bony subvolumes.

Probability of normal tissue complications for hematologic and gastrointestinal toxicity in postoperative whole pelvic radiotherapy for gynecologic malignancies using intensity-modulated proton therapy with robust optimization

This retrospective treatment-planning study was conducted to determine whether intensity-modulated proton therapy with robust optimization (ro-IMPT) reduces the risk of acute hematologic toxicity (H-T) and acute and late gastrointestinal toxicity (GI-T) in postoperative whole pelvic radiotherapy for gynecologic malignancies when compared with three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated X-ray (IMXT) and single-field optimization proton beam (SFO-PBT) therapies. All plans were created for 13 gynecologic-malignancy patients. The prescribed dose was 45 GyE in 25 fractions for 95% planning target volume in 3D-CRT, IMXT and SFO-PBT plans and for 99% clinical target volume (CTV) in ro-IMPT plans. The normal tissue complication probability (NTCP) of each toxicity was used as an in silico surrogate marker. Median estimated NTCP values for acute H-T and acute and late GI-T were 0.20, 0.94 and 0.58 × 10-1 in 3D-CRT; 0.19, 0.65 and 0.24 × 10-1 in IMXT; 0.04, 0.74 and 0.19 × 10-1 in SFO-PBT; and 0.06, 0.66 and 0.15 × 10-1 in ro-IMPT, respectively. Compared with 3D-CRT and IMXT plans, the ro-IMPT plan demonstrated significant reduction in acute H-T and late GI-T. The risk of acute GI-T in ro-IMPT plan is equivalent with IMXT plan. The ro-IMPT plan demonstrated potential clinical benefits for reducing the risk of acute H-T and late GI-T in the treatment of gynecologic malignances by reducing the dose to the bone marrow and bowel bag while maintaining adequate dose coverage to the CTV. Our results indicated that ro-IMPT may reduce acute H-T and late GI-T risk with potentially improving outcomes for postoperative gynecologic-malignancy patients with concurrent chemotherapy.

Acute hematologic toxicity prediction using dosimetric and radiomics features in patients with cervical cancer: does the treatment regimen matter?

Background

Acute hematologic toxicity (HT) is a prevalent adverse tissue reaction observed in cervical cancer patients undergoing chemoradiotherapy (CRT), which may lead to various negative effects such as compromised therapeutic efficacy and prolonged treatment duration. Accurate prediction of HT occurrence prior to CRT remains challenging.

Methods

A discovery dataset comprising 478 continuous cervical cancer patients (140 HT patients) and a validation dataset consisting of 205 patients (52 HT patients) were retrospectively enrolled. Both datasets were categorized into the CRT group and radiotherapy (RT)-alone group based on the treatment regimen, i.e., whether chemotherapy was administered within the focused RT duration. Radiomics features were derived by contouring three regions of interest (ROIs)-bone marrow (BM), femoral head (FH), and clinical target volume (CTV)-on the treatment planning CT images before RT. A comprehensive model combining the radiomics features as well as the demographic, clinical, and dosimetric features was constructed to classify patients exhibiting acute HT symptoms in the CRT group, RT group, and combination group. Furthermore, the time-to-event analysis of the discriminative ROI was performed on all patients with acute HT to understand the HT temporal progression.

Results

Among three ROIs, BM exhibited the best performance in classifying acute HT, which was verified across all patient groups in both discovery and validation datasets. Among different patient groups in the discovery dataset, acute HT was more precisely predicted in the CRT group [area under the curve (AUC) = 0.779, 95% CI: 0.657-0.874] than that in the RT-alone (AUC = 0.686, 95% CI: 0.529-0.817) or combination group (AUC = 0.748, 95% CI: 0.655-0.827). The predictive results in the validation dataset similarly coincided with those in the discovery dataset: CRT group (AUC = 0.802, 95% CI: 0.669-0.914), RT-alone group (AUC = 0.737, 95% CI: 0.612-0.862), and combination group (AUC = 0.793, 95% CI: 0.713-0.874). In addition, distinct feature sets were adopted for different patient groups. Moreover, the predicted HT risk of BM was also indicative of the HT temporal progression.

Conclusions

HT prediction in cervical patients is dependent on both the treatment regimen and ROI selection, and BM is closely related to the occurrence and progression of HT, especially for CRT patients.

Hematologic Toxicity and Bone Marrow-Sparing Strategies in Chemoradiation for Locally Advanced Cervical Cancer: A Systematic Review

The standard treatment for locally advanced cervical cancer typically includes concomitant chemoradiation, a regimen known to induce severe hematologic toxicity (HT). Particularly, pelvic bone marrow dose exposure has been identified as a contributing factor to this hematologic toxicity. Chemotherapy further increases bone marrow suppression, often necessitating treatment interruptions or dose reductions. A systematic search for original articles published between 1 January 2006 and 7 January 2024 that reported on chemoradiotherapy for locally advanced cervical cancer and hematologic toxicities was conducted. Twenty-four articles comprising 1539 patients were included in the final analysis. HT of grade 2 and higher was observed across all studies and frequently exceeded 50%. When correlating active pelvic bone marrow and HT, significant correlations were found for volumes between 10 and 45 Gy and HT of grade 3 and higher. Several dose recommendations for pelvic bone and pelvic bone marrow sparing to reduce HT were established, including V10 < 90-95%, V20 < 65-86.6% and V40 < 22.8-40%. Applying dose constraints to the pelvic bone/bone marrow is a promising approach for reducing HT, and thus reliable implementation of therapy. However, prospective randomized controlled trials are needed to define precise dose constraints and optimize clinical strategies.

Effects of bone marrow sparing radiotherapy on acute hematologic toxicity for patients with locoregionally advanced cervical cancer: a prospective phase II randomized controlled study

OBJECTIVE

To evaluate effects of bone marrow sparing (BMS) radiotherapy on decreasing the incidence of acute hematologic toxicity (HT) for locoregionally advanced cervical cancer (LACC) patients treated by pelvic irradiation.

MATERIALS AND METHODS

LACC patients were recruited prospectively from May 2021 to May 2022 at a single center and were evenly randomized into the BMS group and the control group. All patients received pelvic irradiation with concurrent cisplatin (40 mg/m2 weekly), followed by brachytherapy and BM V40 < 25% in the BMS group was additionally prescribed. Acute HT was assessed weekly. Binary logistic regression model and receiver operating characteristic (ROC) curve were used for predictive value analysis. The trial was registered with Chinese clinical trial registry (ChiCTR2200066485).

RESULTS

A total of 242 patients were included in the analysis. Baseline demographic, disease and treatment characteristics were balanced between the two groups. In the intention-to-treat population, BMS was associated with a lower incidence of grade ≥ 2 and grade ≥ 3 acute HT, leukopenia and neutropenia s(72.70% v 90.90%, P < 0.001*; 16.50% vs. 65.30%, P < 0.001*; 66.10% vs. 85.10%, P = 0.001*; 13.20% vs. 54.50%, P < 0.001*; 37.20% vs. 66.10%, P < 0.001*; 10.70% vs. 43.80%, P < 0.001*). BMS also resulted in decreased dose delivered to the organs at risk (OARs) including rectum, bladder and left and right femoral head. Univariate and multivariate analyses showed that BM V40 was an independent risk factor for grade ≥ 3 acute HT (odds ratio [OR] = 2.734, 95% confidence interval [CI] = 1.959-3.815, P < 0.001*). Cutoff value was 25.036% and area under the curve (AUC) was 0.786. The nomogram was constructed, which was rigorously evaluated and internally cross-validated, showing good predictive performance.

CONCLUSIONS

Receiving BMS pelvic irradiation could reduce the incidence of acute HT in LACC patients, and BM V40 < 25% may be a significant factor in reducing the risks of acute HT.

Intensity-Modulated Radiation Therapy for Uterine Cervical Cancer to Reduce Toxicity and Enhance Efficacy - an Option or a Must?: A Narrative Review

Radiotherapy (RT) is a fundamental modality in treatment of cervical cancer. With advancement of technology, conventional RT used for external beam radiotherapy (EBRT) for over half a century has been rapidly replaced with intensity-modulated radiation therapy (IMRT) especially during the last decade. This newer technique is able to differentiate the intensity of radiation within the same field, thus reduces the inevitable exposure of radiation to normal organs and enables better dose delivery to tumors. Recently, the American Society for Radiation Oncology has released a guideline for RT in cervical cancer. Although a section of the guideline recommends IMRT for the purpose of toxicity reduction, a thorough review of the literature is necessary to understand the current status of IMRT in cervical cancer. This narrative review updates the recent high-level evidences regarding the efficacy and toxicity of IMRT and provides a better understanding of the most innovative techniques currently available for EBRT enabled by IMRT.

Bone Marrow Sparing by Intensity Modulated Proton Beam Therapy in Postoperative Irradiation of Gynecologic Malignancies

Purpose: The aim of this matched-pair cohort study was to evaluate the potential of intensity-modulated proton therapy (IMPT) for sparring of the pelvic bone marrow and thus reduction of hematotoxicity compared to intensity-modulated photon radiotherapy (IMRT) in the setting of postoperative irradiation of gynaecological malignancies. Secondary endpoint was the assessment of predictive parameters for the occurrence of sacral insufficiency fractures (SIF) when applying IMPT. Materials and Methods: Two cohorts were analyzed consisting of 25 patients each. Patients were treated with IMPT compared with IMRT and had uterine cervical (n = 8) or endometrial cancer (n = 17). Dose prescription, patient age, and diagnosis were matched. Dosimetric parameters delivered to the whole pelvic skeleton and subsites (ilium, lumbosacral, sacral, and lower pelvis) and hematological toxicity were evaluated. MRI follow-up for evaluation of SIF was only available for the IMPT group. Results: In the IMPT group, integral dose to the pelvic skeleton was significantly lower (23.4GyRBE vs 34.3Gy; p < 0.001), the average V5Gy, V10Gy, and V20Gy were reduced by 40%, 41%, and 28%, respectively, compared to the IMRT group (p < 0.001). In particular, for subsites ilium and lower pelvis, the low dose volume was significantly lower. Hematotoxicity was significantly more common in the IMRT group (80% vs 32%; p = 0009), especially hematotoxicity ≥ CTCAE II (36% vs 8%; p = 0.037). No patient in the IMPT group experienced hematotoxicity > CTCAE II. In the IMPT cohort, 32% of patients experienced SIF. Overall SIF occurred more frequently with a total dose of 50.4 GyRBE (37.5%) compared to 45 GyRBE (22%). No significant predictive dose parameters regarding SIF could be detected aside from a trend regarding V50Gy to the lumbosacral subsite. Conclusion: Low-dose exposure to the pelvic skeleton and thus hematotoxicity can be significantly reduced by using IMPT compared to a matched photon cohort. Sacral insufficiency fracture rates appear similar to reported rates for IMRT in the literature.

Comparative Analysis of VMAT and IMRT Techniques: Evaluation of Dose Constraints and Bone Marrow Sparing in Cervical Cancer Patients Undergoing Chemoradiotherapy

BACKGROUND

Carcinoma of the cervix is a globally significant cause of morbidity and mortality among women. Concurrent chemoradiotherapy, a standard approach for locally advanced cervical cancer, invariably involves pelvic irradiation. Although this strategy is effective, it inevitably affects the pelvic bone marrow, a crucial hematopoietic site, and leads to hematological toxicity The potential of IMRT to spare bone marrow in pelvic irradiation settings has been an area of significant interest, with the aim to mitigate the hematological toxicity associated with pelvic radiotherapy. Radiotherapy techniques have evolved in terms of conformity and normal tissue sparing. Our study intends to explore the use of BM sparing techniques among patients of carcinoma cervix.

PATIENTS AND METHODS

Twenty patients of carcinoma cervix FIGO Stage IIIB treated with concurrent chemoradiotherapy were selected for this study. The external contour of bones was delineated on planning CT as a surrogate for BM. We generated three plans on a single patient:1. without BM as the dose constraint, namely N-IMRT plan; 2. with BM constraint, namely BMS-IMRT plan; 3. VMAT plan in which BM constraint was given. The dose volume histogram (DVH) for planning target volume (PTV) and organs at risk (OAR) were analyzed. BM parameters: V10, V20, V30, V40, mean, maximum and minimum dose were compared.  Results: PTV coverage was comparable in all techniques. VMAT plans resulted in superior BM sparing compared with N-IMRT plan (P-<0.001) and BMS-IMRT plan (P-<0.001, 0.021 and 0.001 respectively for V20, V30 and V40). VMAT plans had better CI compared with BMS-IMRT (P-0.002) and N-IMRT (P-0.001) plans.

CONCLUSION

Our study adds to the growing evidence that VMAT might be the preferred technique for patients with carcinoma of the cervix undergoing concurrent chemoradiotherapy, as it provides comparable target coverage and better sparing of bone marrow compared to IMRT.

A prospective single-arm study on the relationship between dose-volume parameters of pelvic functional bone marrow and acute hematological toxicities during intensity-modulated radiotherapy with or without concurrent chemotherapy for uterine cervical/endometrial cancer

BACKGROUND

FLT-PET/CT can accurately identify and locate functional bone marrow (FBM) with hematopoietic capability, the FBM were divided into two levels as FBM1 (strongest hemopoietic ability region)and FBM2 (moderate hemopoietic ability region) via FLT-PET/CT. The purpose of this study was to explore the relationship between dose-volume parameters of pelvic FBM and hematologic toxicity (HT) during radiotherapy with or without concurrent chemotherapy for uterine cervical/endometrial cancer.

METHODS

From December 2016 to September 2021, ninety-seven uterine cervical/endometrial cancer patients received intensity-modulated radiation therapy were prospectively recruited in this single-arm, prospective, phase II trial. Blood counts were reviewed weekly during radiotherapy. Single- and multifactor regression methods were used to analyze the relationships between dose-volume parameters of FBM1/2 and grade ≥ 2 HT. ROC curves were used to determine the cutoff values for the dose-volume parameters of FBM1/2.

RESULTS

The incidence of grade ≥ 2 leukopenia, neutropenia, thrombocytopenia and anemia in patients during radiotherapy was 63.9%, 45.4%, 19.6% and 38.8% respectively, and the median occurrence time was the 29th, 42th, 35th and 31th day, respectively. Multivariate regression analysis showed that the Dmax of FBM1 was significantly related to grade ≥ 2 leukopenia (OR = 1.277 95% CI 1.067-1.528, P = 0.008), Dmean of FBM2 was significantly related to grade ≥ 2 thrombocytopenia (OR = 1.262 95% CI 1.066-1.494, P = 0.007), and V10 of FBM1 was significantly related to grade ≥ 2 anemia (OR = 1.198 95% CI 1.003-1.431, P = 0.046). The incidence of grade ≥ 2 leukopenia for patients with FBM1 Dmax < 53 Gy was lower than that for patients with FBM1 Dmax ≥ 53 Gy (53.4% vs. 95.8%, P < 0.001). The incidence of grade ≥ 2 thrombocytopenia in patients with FBM2 Dmean < 33 Gy was lower than that in patients with FBM2 Dmean ≥ 33 Gy (0 vs. 28.4%, P < 0.001). The incidence of grade ≥ 2 anemia for patients with FBM1 V10 < 95% was lower than that in patients with FBM1 V10 ≥ 95% (24.4% vs. 57.1%, P = 0.003).

CONCLUSIONS

Grade ≥ 2 HT usually occurs in the 4th week of radiotherapy for patients with uterine cervical/endometrial cancer. The Dmax and V10 of FBM1 and the Dmean of FBM2 were significantly associated with the occurrence of grade ≥ 2 HT. The recommended optimal dose constraints were FBM1 Dmax < 53 Gy, V10 < 95%, and FBM2 Dmean <33 Gy.

Acute hematologic toxicity of radiation therapy - a comprehensive analysis and predictive nomogram

To investigate radiation-induced cytopenia and establish predictive nomograms for hematological toxicity, we reviewed 3786 patients aged 18 or older who received radiation monotherapy between 2010 and 2021 for non-hematologic malignancies. We collected data on patient background, treatment content and hematologic toxicities for 12 weeks after the start of radiotherapy. The patients were randomly divided into training and test groups in 7:3 ratio. In the training group, we conducted ordered logistic regression analysis to identify predictive factors for neutropenia, lymphocytopenia, anemia and thrombocytopenia. Nomograms to predict Grade 2-4 cytopenia were generated and validated in the test group. Grade 3 or higher hematologic toxicities were observed in 9.7, 44.6, 8.3 and 3.1% of patients with neutropenia, lymphocytopenia, anemia and thrombocytopenia, respectively. We identified six factors for neutropenia grade, nine for lymphocytopenia grade and six for anemia grade with statistical significance. In the analysis of thrombocytopenia, the statistical model did not converge because of a small number of events. Nomograms were generated using factors with high predictive power. In evaluating the nomograms, we found high area under the receiver operating characteristic curve values (neutropenia; 0.75-0.85, lymphopenia; 0.89-0.91 and anemia; 0.85-0.86) in predicting Grade 2-4 cytopenia in the test group. We established predictive nomograms for neutropenia, leukocytopenia and anemia and demonstrated high reproducibility when validated in an independent cohort of patients.

Deep learning-based dose map prediction for high-dose-rate brachytherapy

Background. Creating a clinically acceptable plan in the time-sensitive clinic workflow of brachytherapy is challenging. Deep learning-based dose prediction techniques have been reported as promising solutions with high efficiency and accuracy. However, current dose prediction studies mainly target EBRT which are inappropriate for brachytherapy, the model designed specifically for brachytherapy has not yet well-established.Purpose. To predict dose distribution in brachytherapy using a novel Squeeze and Excitation Attention Net (SE_AN) model.Method. We hypothesized the tracks of192Ir inside applicators are essential for brachytherapy dose prediction. To emphasize the applicator contribution, a novel SE module was integrated into a Cascaded UNet to recalibrate informative features and suppress less useful ones. The Cascaded UNet consists of two stacked UNets, with the first designed to predict coarse dose distribution and the second added for fine-tuning 250 cases including all typical clinical applicators were studied, including vaginal, tandem and ovoid, multi-channel, and free needle applicators. The developed SE_AN was subsequently compared to the classic UNet and classic Cascaded UNet (without SE module) models. The model performance was evaluated by comparing the predicted dose against the clinically approved plans using mean absolute error (MAE) of DVH metrics, includingD2ccandD90%.Results. The MAEs of DVH metrics demonstrated that SE_AN accurately predicted the dose with 0.37 ± 0.25 difference for HRCTVD90%, 0.23 ± 0.14 difference for bladderD2cc, and 0.28 ± 0.20 difference for rectumD2cc. In comparison studies, UNet achieved 0.34 ± 0.24 for HRCTV, 0.25 ± 0.20 for bladder, 0.25 ± 0.21 for rectum, and Cascaded UNet achieved 0.42 ± 0.31 for HRCTV, 0.24 ± 0.19 for bladder, 0.23 ± 0.19 for rectum.Conclusion. We successfully developed a method specifically for 3D brachytherapy dose prediction. Our model demonstrated comparable performance to clinical plans generated by experienced dosimetrists. The developed technique is expected to improve the standardization and quality control of brachytherapy treatment planning.

Radiation hematologic toxicity prediction for locally advanced rectal cancer using dosimetric and radiomics features

BACKGROUND

Hematologic toxicity (HT) is a common adverse tissue reaction during radiotherapy for rectal cancer patients, which may lead to various negative effects such as reduced therapeutic effect, prolonged treatment period and increased treatment cost. Therefore, predicting the occurrence of HT before radiotherapy is necessary but still challenging.

PURPOSE

This study proposes a hybrid machine learning model to predict the symptomatic radiation HT in rectal cancer patients using the combined demographic, clinical, dosimetric, and Radiomics features, and ascertains the most effective regions of interest (ROI) in CT images and predictive feature sets.

METHODS

A discovery dataset of 240 rectal cancer patients, including 145 patients with HT symptoms and a validation dataset of 96 patients (63 patients with HT) with different dose prescription were retrospectively enrolled. Eight ROIs were contoured on patient CT images to derive Radiomics features, which were then, respectively, combined with the demographic, clinical, and dosimetric features to classify patients with HT symptoms. Moreover, the survival analysis was performed on risky patients with HT in order to understand the HT progression.

RESULTS

The classification models in ROIs of bone marrow and femoral head exhibited relatively high accuracies (accuracy = 0.765 and 0.725) in the discovery dataset as well as comparable performances in the validation dataset (accuracy = 0.758 and 0.714). When combining the two ROIs together, the model performance was the best in both discovery and validation datasets (accuracy = 0.843 and 0.802). In the survival analysis test, only the bone marrow ROI achieved statistically significant performance in accessing risky HT (C-index = 0.658, P = 0.03). Most of the discriminative features were Radiomics features, and only gender and the mean dose in Irradvolume was involved in HT.

CONCLUSION

The results reflect that the Radiomics features of bone marrow are significantly correlated with HT occurrence and progression in rectal cancer. The proposed Radiomics-based model may help the early detection of radiotherapy induced HT in rectal cancer patients and thus improve the clinical outcome in future.

Dosimetric correlation of bone marrow irradiation with acute hematological toxicity in concurrent chemoradiation of cervical carcinoma patients

Background

Many acute toxicities are associated with concurrent chemoradiation in cervical carcinoma, which includes burning micturition, burning defecation, pain lower abdomen, increased frequency of stools along with Acute Hematological Toxicity (AHT). AHT is often an expected adverse effect, which can lead to treatment interruptions and decreased response rates. The purpose of this study is to analyze if there are any dosimetric constraints on the volume of bone marrow irradiated with AHT in cervical carcinoma patients treated with concurrent chemoradiation.

Material and Methods

In this retrospective study of 215 patients, a total of 180 patients were eligible for analysis. Multiple parameters of bone marrow volumes (whole pelvis bone marrow and its sub-volumes--ilium, lower pelvis, and lumbosacral spine) which were contoured individually for all patients were assessed to have any statistically significant association with AHT.

Results

The median age of the cohort was 57 years and majority of cases were locally advanced (stage IIB-IVA: 88.3%). Grade I, II, III leukopenia was seen in 44, 25, and 6 patients, respectively. A statistically significant correlation between grade 2+ and 3+ leukopenia was seen if bone marrow V10, V20, V30, and V40 were more than 95%, 82%, 62%, and 38%, respectively. In subvolume analysis, volumes of lumbosacral spine V20, V30, and V40 more than 95%, 90%, and 65%, respectively, were statistically significant for AHT.

Conclusion

Bone marrow volumes should also be given a constraint and should be tried to be achieved so that it leads to minimal treatment breaks due to AHT.

Is it time for bone marrow sparing radiation therapy to be standard of care in cervical cancer?

Evaluating a recent prospective trial of active bone marrow sparing defined by 99mTc‐single‐photon emission computed tomography imaging in the landscape of the existing literature.

The impact of bone marrow sparing on organs at risk dose for cervical cancer: a Pareto front analysis

Background and purpose

To quantify the increase in bladder and rectum dose of a bone marrow sparing (BMS) VMAT strategy for primary treatment of locally advanced cervical cancer (LACC).

Materials and methods

Twenty patients with stage IB-IVA cervical cancer were selected for this study. The whole Pelvic Bones (PB) was taken as substitute for bone marrow. For every patient, Pareto-optimal plans were generated to explore the trade-off between rectum, bladder, and PB mean dose. The PB mean dose was decreased in steps of 1 Gy. For each step, the increase in rectum and bladder mean dose was quantified. The increase in mean dose of other OAR compared to no BMS was constrained to 1 Gy.

Results

In total, 931 plans of 19 evaluable patients were analyzed. The average [range] mean dose of PB without BMS was 22.8 [20.7-26.2] Gy. When maximum BMS was applied, the average reduction in mean PB dose was 5.4 [3.0-6.8] Gy resulting in an average mean PB dose of 17.5 [15.8-19.8] Gy. For <1 Gy increase in both the bladder and the rectum mean dose, the PB mean dose could be decreased by >2 Gy, >3 Gy, >4 Gy, and >5 Gy for 19/19, 13/19, 5/19, and 1/19 patients, respectively.

Conclusion

Based on the comprehensive three-dimensional Pareto front analysis, we conclude that 2-5 Gy BMS can be implemented without a clinically relevant increase in mean dose to other OAR. If BMS is too dominant, it results in a large increase in mean dose to other OAR. Therefore, we recommend implementing moderate BMS for the treatment of LACC patients with VMAT.

The impact of bone marrow irradiation dose on acute haematologic toxicity in cervical cancer patients treated with concurrent chemoradiotherapy

OBJECTIVE

To evaluate the impact of bone marrow (BM) irradiation dose on acute haematologic toxicity (HT) in concurrent chemoradiotherapy for cervical cancer.

METHODS

Sixty-nine patients with cervical cancer treated with curative or postoperative adjuvant therapy received weekly cisplatin concurrent chemotherapy (CCT) and intensity-modulated radiation therapy (IMRT). The whole pelvic bone marrow (PBM) was delineated and divided into three subsites: ilium (IL), lower pelvis (LP), and lumbosacral spine (LS). Associations between clinical variables, dose volume of BM, including PBM, IL, LP, and LS in the form of x-Vy (volume receiving y Gy for x), and blood cell count nadir were tested using linear regression models. Receiver operating characteristic (ROC) curve analysis was further used to analyse the cutoff values of the variables with p < 0.05 in the multivariate analysis.

RESULTS

In 69 patients, the haemoglobin nadir was positive correlated with baseline haemoglobin (p < 0.001), negative correlated with relative LP-V10 (p = 0.005), relative LP-V25 (p = 0.002), relative LP-V50 (p = 0.007), relative LP-mean (p = 0.003), absolute LP-V15 (p = 0.049), absolute LP-V25 (p = 0.004) and absolute LP-V30 (p = 0.009). The platelet nadir was positive correlated with baseline platelets (p = 0.048) and negative correlated with relative LP-V40 (p = 0.028), but there was no significant variable in absolute radiation volume by multivariate analysis. No variables related to the neutrophil nadir were found, and the 69 patients were divided into group A (43 cases) receiving 3-4 cycles of CCT and group B (26 cases) receiving 5-6 cycles of CCT. In group A, the relative IL-V15 (p = 0.014), the relative IL-V50 (p = 0.010) and the absolute LP-V50 (p = 0.011) were negative correlated with the neutrophil nadir. No significant variable was found in group B. No significant variables related to the lymphocyte nadir were found, and the neutrophil-to-lymphocyte ratio (NLR) was analysed. Age (p < 0.05), relative LP-V15 (p = 0.037) and absolute PBM-mean (p < 0.001) were found to be negative related to NLR.

CONCLUSION

The dosimetric parameters of relative irradiated volume of BM have more statistically significant datas on acute HT than absolute irradiated volume. The nadir of haemoglobin and platelets and the vertice of NLR were more affected by the irradiation dose to LP, while neutrophils were more affected by the dose to IL. Acute HT was negative related to both low-dose irradiation (V10-30) and high-dose irradiation (V40, V50). For more than 4 cycles of CCT, the effect of BM irradiation on the neutrophils nadir was masked by chemotherapy.

MAD-Net: Multi-attention dense network for functional bone marrow segmentation

Radiotherapy is the main treatment modality for various pelvic malignancies. However, high intensity radiation can damage the functional bone marrow (FBM), resulting in hematological toxicity (HT). Accurate identification and protection of the FBM during radiotherapy planning can reduce pelvic HT. The traditional manual method for contouring the FBM is time-consuming and laborious. Therefore, development of an efficient and accurate automatic segmentation mode can provide a distinct leverage in clinical settings. In this paper, we propose the first network for performing the FBM segmentation task, which is referred to as the multi-attention dense network (named MAD-Net). Primarily, we introduce the dense convolution block to promote the gradient flow in the network as well as incite feature reuse. Next, a novel slide-window attention module is proposed to emphasize long-range dependencies and exploit interdependencies between features. Finally, we design a residual-dual attention module as the bottleneck layer, which further aggregates useful spatial details and explores intra-class responsiveness of high-level features. In this work, we conduct extensive experiments on our dataset of 3838 two-dimensional pelvic slices. Experimental results demonstrate that the proposed MAD-Net transcends previous state-of-the-art models in various metrics. In addition, the contributions of the proposed components are verified by ablation analysis, and we conduct experiments on three other datasets to manifest the generalizability of MAD-Net.

A radiomics approach for predicting acute hematologic toxicity in patients with cervical or endometrial cancer undergoing external-beam radiotherapy

PURPOSE

This study is purposed to establish a predictive model for acute severe hematologic toxicity (HT) during radiotherapy in patients with cervical or endometrial cancer and investigate whether the integration of clinical features and computed tomography (CT) radiomics features of the pelvic bone marrow (BM) could define a more precise model.

METHODS

A total of 207 patients with cervical or endometrial cancer from three cohorts were retrospectively included in this study. Forty-one clinical variables and 2226 pelvic BM radiomic features that were extracted from planning CT scans were included in the model construction. Following feature selection, model training was performed on the clinical and radiomics features via machine learning, respectively. The radiomics score, which was the output of the final radiomics model, was integrated with the variables that were selected by the clinical model to construct a combined model. The performance of the models was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

The best-performing prediction model comprised two clinical features (FIGO stage and cycles of postoperative chemotherapy) and radiomics score and achieved an AUC of 0.88 (95% CI, 0.81-0.93) in the training set, 0.80 (95% CI, 0.62-0.92) in the internal-test set and 0.85 (95% CI, 0.71-0.94) in the external-test dataset.

CONCLUSION

The proposed model which incorporates radiomics signature and clinical factors outperforms the models based on clinical or radiomics features alone in terms of the AUC. The value of the pelvic BM radiomics in chemoradiotherapy-induced HT is worthy of further investigation.

The relationship between the radiation dose of pelvic-bone marrow and lymphocytic toxicity in concurrent chemoradiotherapy for cervical cancer

OBJECTIVE

The purpose of this study is to verify the correlation between medium and low radiation doses of the pelvic-bone marrow and the incidence of lymphocytic toxicity during concurrent chemoradiotherapy for cervical cancer.

MATERIALS AND METHODS

This research included 117 cervical cancer patients, who received concurrent chemoradiotherapy. Radiotherapy included external-beam radiation therapy and brachytherapy. The dosimetry parameters include the Volume receiving 5 Gy (V5), 10 Gy (V10), 20 Gy (V20), 30 Gy (V30), 40 Gy (V40), 50 Gy (V50), and the mean dose (D mean) of the bone marrow. Lymphocytic toxicity was calculated from lowest lymphocytic count after two cycles of concurrent chemotherapy.

RESULTS

During concurrent chemoradiotherapy, the incidence of lymphocytic toxicity is 94.88%. The incidence of grade 3-4 toxicity is 68.38%. Multivariate analysis findings show that the dosimetry parameters V5, V10, V20, and V30 are significantly correlated with lymphocytic toxicity. The patients are divided into small-volume subgroups and large-volume subgroups based on the cutoff values. The relative risk of both grade 1-4 and grade 3-4 lymphocytic toxicity is significantly lower in the small-volume subgroups than in the large-volume subgroups (P < 0.05). Kaplan-Meier analysis shows that the incidence of both grade 1-4 and grade 3-4 lymphocytic toxicity of the small-volume subgroups is significantly lower than that of the large-volume subgroups (P < 0.05).

CONCLUSION

There is a significant correlation between a medium and low dose of pelvic-bone-marrow radiation and incidence of lymphocytic toxicity. Reducing the volume of medium and low radiation doses could effectively reduce incidence of lymphocytic toxicity.

The effect of radiotherapy time and dose on acute hematologic toxicity during concurrent postoperative chemoradiotherapy for early high-risk cervical cancer

Objective: This study aims to analyze the characteristics and factors that influence acute hematological toxicity (HT) during concurrent chemoradiotherapy (CCRT) for cervical cancer, as well as to provide reference data for clinical practice. Methods: Patients with FIGO IB1-IIA2 cervical cancer who underwent CCRT from May 2018 to August 2020 were included in this study retrospectively. All patients had received external beam radiation therapy and platinum-based concurrent chemotherapy. HT was assessed according to CTCAE 5.0. The pelvic bone marrow was redrawn on the original CT images and divided into four parts: the whole pelvic bone marrow (WP-BM), iliac bone marrow (IL-BM), lower pelvic bone marrow (LP-BM), and lumbosacral bone marrow (LS-BM). The radiation dose and volume of each part of the pelvic bone marrow were recalculated in a new plan created using the original planning parameters. The corresponding dose-volume histogram (DVH) was generated to obtain the bone marrow volumes receiving 10Gy, 20Gy, 30Gy, 40Gy, 45Gy, and 50Gy. Results: In 112 patients, the incidences of grade 2 or higher leukopenia, anemia, thrombocytopenia, and neutropenia were 49.1%, 2.7%, 1.8%, and 20.5%, respectively. Leukopenia was linked to LS-V20 (r = -0.310; P = 0.006) and radiotherapy treatment lengths (days) (r = -0.416; P = 0.013). Anemia was associated with WP-V30, WP-V40, WP-V45, WP-V50, IL-V20, IL-V40, ILV45, IL-V50, LP-V30, LP-V40, LP-V45, and LP-V50 (P <0.05). Thrombocytopenia (r = -0.304, P = 0.007) and neutropenia (r = -0.368, P = 0.009) was associated only with the length of radiotherapy treatment (day). Multiple regression analysis showed that only anemia was negatively correlated with WP-V30, IL-V40, and LP-V40 (P <0.05). Conclusions: Acute HT during CCRT in early-stage high-risk cervical cancer may be related to the duration of radiotherapy and the volume of different radiotherapy doses received at different parts in the pelvic bone marrow.

Dosimetric evaluation of bone marrow sparing in proton radiotherapy for cervical cancer guided by MR functional imaging

BACKGROUND

To segment the pelvic active bone marrow (PABM) using magnetic resonance (MR) functional imaging and investigate the feasibility and dosimetric characteristics of cervical cancer proton radiotherapy for active bone marrow (ABM) sparing.

METHODS

We collected CT and MR simulation images of 33 patients with cervical cancer retrospectively. The PBM was contoured on the MRI FatFrac images; the PBM was divided into high-active bone marrow (ABM-_high) and low-active bone marrow based on the fat content of the PBM. Four radiotherapy plans were created for each patient, which included intensity-modulated photon therapy (IMRT), bone marrow sparing IMRT (IMRT-BMS), intensity-modulated proton therapy (IMPT), and bone marrow sparing IMPT (IMPT-BMS). The dosimetric differences among the four plans were compared.

RESULTS

The ABM-_high volume in the enrolled patients accounted for 45.2% of the total ABM volume. The target coverage was similar among the four radiotherapy plans. IMRT-BMS, IMPT, and IMPT-BMS reduced the D_mean of ABM-_high by 16.6%, 14.2%, and 44.5%, respectively, compared to the D_mean of IMRT (p < 0.05). IMPT-BMS had the best protective effect on the bone marrow. Compared to IMRT, the volume of ABM-_high receiving an irradiation dose of 5-40 Gy decreased by 10.2%, 36.8%, 58.8%, 67.4%, 64.9%, and 44.5%, respectively (p < 0.001).

CONCLUSIONS

The MR functional imaging technique helped in the grading and segmentation of PABM. MR functional image-guided proton radiotherapy for cervical cancer can achieve optimal BMS.

Functional MRI radiomics-based assessment of pelvic bone marrow changes after concurrent chemoradiotherapy for cervical cancer

Objectives

To quantify the dose-response relationship of changes in pelvic bone marrow (PBM) functional MR radiomic features (RF) during concurrent chemoradiotherapy (CCRT) for patients with cervical cancer and establish the correlation with hematologic toxicity to provide a basis for PBM sparing.

Methods

A total of 54 cervical cancer patients who received CCRT were studied retrospectively. Patients underwent MRI IDEAL IQ and T2 fat suppression (T2fs) scanning pre- and post-CCRT. The PBM RFs were extracted from each region of interest at dose gradients of 5–10 Gy, 10–15 Gy, 15–20 Gy, 20–30 Gy, 30–40 Gy, 40–50 Gy, and > 50 Gy, and changes in peripheral blood cell (PBC) counts during radiotherapy were assessed. The dose-response relationship of RF changes and their correlation with PBC changes were investigated.

Results

White blood cell, neutrophils (ANC) and lymphocyte counts during treatment were decreased by 49.4%, 41.4%, and 76.3%, respectively. Most firstorder features exhibited a significant dose-response relationship, particularly FatFrac IDEAL IQ, which had a maximum dose-response curve slope of 10.09, and WATER IDEAL IQ had a slope of − 7.93. The firstorder-Range in FAT IDEAL IQ and firstorder-10Percentile in T2fs, showed a significant correlation between the changes in ANC counts under the low dose gradient of 5–10 Gy (r = 0.744, -0.654, respectively, p < 0.05).

Conclusion

Functional MR radiomics can detect microscopic changes in PBM at various dose gradients and provide an objective reference for bone marrow sparing and dose limitation in cervical cancer CCRT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10254-7.

Development of a nomogram for predicting grade 2 or higher acute hematologic toxicity of cervical cancer after the pelvic bone marrow sparing radiotherapy

Background

Acute hematologic toxicity (HT) is a common complication during radiotherapy of cervical cancer which may lead to treatment delay or interruption. Despite the use of intensity-modulated radiation therapy (IMRT) with the pelvic bone marrow (PBM) sparing, some patients still suffer from acute HT. We aimed to identify predictors associated with HT and develop a nomogram for predicting grade 2 or higher (G2+) acute HT in cervical cancer following the PBM sparing strategy.

Methods

This study retrospectively analyzed 125 patients with cervical cancer who underwent IMRT with the PBM sparing strategy at our institution. Univariate and multivariate logistic regression, best subset regression, and least absolute shrinkage and selection operator (LASSO) regression, respectively, were used for predictor screening, and Akaike information criterion (AIC) was used to determine the best model for developing the nomogram. Finally, we quantified the risk of G2+ acute HT based on this model to establish a risk stratification.

Results

The independent predictors used to develop the nomogram were histological grade, pre-radiotherapy chemotherapy, pre-radiotherapy HT, and radiotherapy [IMRT alone vs. concurrent chemoradiotherapy (CCRT)] which were determined by the univariate and multivariate logistic regression with the minimum AIC of 125.49. Meanwhile, the heat map showed that there is no multicollinearity among the predictors. The nomogram was well-calibrated to reality, with a Brier score of 0.15. The AUC value was 0.82, and the median Brier score and AUC in 1000 five-fold cross-validation were 0.16 and 0.80, respectively. The web version developed together was very easy to use. The risk stratification indicated that high-risk patients (risk point > 195.67) were more likely to develop G2+ acute HT [odds ratio (OR) = 2.17, 95% confidence interval (CI): 1.30-3.05].

Conclusion

This nomogram well-predicted the risk of G2+ acute HT during IMRT in cervical cancer after the PBM sparing strategy, and the constructed risk stratification could assist physicians in screening high-risk patients and provide a useful reference for future prevention and treatment strategies for acute HT.

Lymphocyte-sparing pelvic radiotherapy for prostate cancer: An in-silico study

•

Lymphocyte-sparing planning was developed for prostate cancer pelvic radiotherapy.

•

A significant dose reduction to the bone marrow was successfully demonstrated.

•

An Effective Dose to Immune Cells (EDIC) model was proposed for pelvic irradiation.

Background and Purpose

Evidence regarding radiation-induced lymphopenia and its negative impact on oncological outcome is incrementing. Therefore, the aim of this study is to evaluate the feasibility of lymphocyte-rich organs at risk (LOAR) sparing in pelvic irradiation for localized prostate cancer and to estimate its impact on the effective dose to circulating immune cells (EDIC).

Materials and Methods

Twenty patients with pelvic nodal and prostate or prostate bed irradiation were included. The following bone marrow (BM) structures were delineated as LOARs using semi-automatic segmentation: lumbosacral spine (Ls-BM), ilium (Il-BM), lower pelvis (Lp-BM), and the combined whole-pelvis (Wp-BM). Twenty new lymphocyte sparing treatment plans (LS plans) were calculated, optimizing doses to LOARs while maintaining strict coverage of the targets and respecting standard OARs dose constraints. Finally, we elaborated an EDIC calculation model for pelvic irradiation.

Results

LS plans showed a statistically significant dose decrease for LOAR compared to standard of care plans without compromising target coverage nor classic OAR dose constraints: in prostate plans, the V40Gy for Ls-BM, Il-BM, and Lp-BM was decreased by 23 %, 36 %, 52 % respectively. For prostate bed plans, the V40Gy for Ls-BM, Il-BM, and Lp-BM was decreased by 25 %, 59 %, 56 %, respectively. For Wp-BM, the V10Gy, V20Gy, and Dmean have been decreased by 3 %, 14 %, 15 %, and by 5 %, 15 %, 17 %, respectively for prostate and prostate bed plans. A statistically significant decrease in EDIC was seen for LS plans in both groups.

Conclusions

We successfully demonstrated the feasability of lympocyte-sparing treatment planning in pelvic irradiation, also proposing a model for EDIC calculation.

ECOG-ACRIN Guideline for Contouring and Treatment of Early Stage Anal Cancer Using IMRT/IGRT

PURPOSE

Previous anal cancer guidelines delineate target volumes similarly for all patients with squamous cell carcinoma of the anal canal and/or perianal skin (SCCA), regardless of disease stage. The purpose of this guideline is to provide customized radiation treatment recommendations for early stage (T1-2 N0 M0) anal cancer treated with intensity modulated and image guided radiation therapy (RT).

METHODS AND MATERIALS

A contouring atlas and radiation treatment recommendations for the ongoing, randomized phase II trial of deintensified chemoradiation for early stage SCCA (EA2182) was created by an expert panel of radiation oncologists. A literature search was conducted to update and expand these recommendations into a guideline for routine clinical use.

RESULTS

For the majority of cases, we recommend treatment in the supine, frog leg position with the use of a customized immobilization device and daily image guided RT to ensure optimal bone and soft tissue alignment. Vaginal dilators can be used daily during RT to maximize genitalia sparing. We recommend use of a 10-mm margin on the gross tumor plus including the anal complex to create the primary clinical target volume. To define the elective lymph node clinical target volume, we recommend starting with a 7-mm expansion on blood vessels, but then further refining these volumes based on the anatomic location. A 5- to 10-mm planning target volume (PTV) margin is suggested based on institutional setup and patient-specific factors. When using a simultaneous integrated boost technique, a dose of 50.4 Gy to primary PTV and 42 Gy to lymph node PTV, both delivered over 28 fractions, with chemotherapy is appropriate for early stage anal cancer.

CONCLUSIONS

This guideline provides anatomic, clinical, and technical instructions to guide radiation oncologists in the planning and delivery of intensity modulated and image guided RT for early stage SCCA.

Pelvic bones ADC could help to predict severe hematologic toxicity in patients undergoing concurrent chemoradiotherapy for cervical cancer

BACKGROUND

Hematologic toxicity (HT) during concurrent chemoradiotherapy (CCRT) for cervical cancer can lead to treatment breaks and compromise efficacy.

PURPOSE

To evaluate the association between severe hematologic toxicity (HT) and clinical factors and pelvic apparent diffusion coefficient (ADC) during CCRT of cervical cancer patients.

METHODS

Data from 120 patients with cervical cancer who were treated with CCRT from January 2016 and December 2018 were retrospectively analyzed. The clinical data (age, menopausal status, clinical stage, body mass index, chemotherapy regimen and chemotherapy cycle) of the patients were collected, and the cohort were divided into two groups based on the HT grade: HT3+ group (HT grade ≥ 3; 66 patients) and HT3- group (HT grade<3; 54 patients). All patients performed MRI before CCRT, and pelvic (ilium, pubis, ischium) ADC value was measured on ADC map. The correlation between severe HT and clinical parameters and pelvic ADC value were analyzed by univariate analysis, and the diagnostic performance was further assessed by receiver operating characteristic (ROC) analysis.

RESULTS

In univariate analysis, the menopausal status (p = 0.012) and chemotherapy regimen (p = 0.011) were significantly correlated with severe HT in overall patients, and menopausal patients or patients receiving paclitaxel plus cisplatin (TP) regimen were more likely to develop severe HT. HT3+ group showed a significantly lower pelvic ADC value than HT3- group. The ADC value cut-offs derived from our study for predicting severe HT was 0.317 × 10^-3 mm²/s in overall patients. Neither clinical parameters or pelvic ADCs were associated with severe HT in menopausal patients when analyzed separately (p > 0.05).

CONCLUSIONS

Severe HT was significantly associated with menopausal status and chemotherapy regimen in patients with cervical cancer treated with CCRT, and HT3+ group showed a lower pelvic ADC value.

Comparing dosimetric and cancer control outcomes after intensity‑modulated radiation therapy and tomotherapy for advanced cervical cancer

Concurrent chemoradiation therapy (CCRT) is the standard treatment for locally advanced cervical cancer. The present study aimed to compare the therapeutic responses, toxicities and dosimetric parameters between intensity-modulated radiation therapy (IMRT) and tomotherapy (TOMO) in patients with advanced cervical cancer. This retrospective study included 310 patients with stage IIB-IIIB cervical cancer who underwent CCRT, with 155 patients in each group. Intracavitary brachytherapy was performed after a course of external beam radiation therapy (EBRT), or in the last week of pelvic EBRT. The treatment planning aim at point A (defined as a reference location 2 cm above the vaginal fornix and 2 cm beside the mid axis of the uterus) was >85 Gy in an equivalent dose at 2 Gy. There was no statistical difference with regard to clinicopathological characteristics between the two groups (P>0.05). Improved dose conformity and dose homogeneity (P<0.05) were observed in TOMO planning. TOMO provided more efficacious critical organ sparing than IMRT when assessing the percentage of normal tissue receiving at least 20 Gy (V20) for the bladder, the percentage of normal tissue receiving at least 40 Gy (V40) for the femoral head, and the V40 and V20 for the rectum (P<0.05). TOMO demonstrated a greater ability to protect the ovary (P<0.05). The acute radiation toxicity of proctitis and leukopenia were significantly lower in the TOMO group (P<0.05). The chronic radiation toxicity of radiation enterocolitis and cystitis was lower in the TOMO group (P<0.05). Thus, TOMO provided better critical organ sparing than IMRT. The radiation toxicities were acceptable. Therefore, TOMO appears to be a good option for the treatment of stage IIB-IIIB cervical cancer.

Correlation between changes of pelvic bone marrow fat content and hematological toxicity in concurrent chemoradiotherapy for cervical cancer

Objectives

To quantify the pelvic bone marrow (PBM) fat content changes receiving different radiation doses of concurrent chemoradiotherapy for cervical cancer and to determine association with peripheral blood cell counts.

Methods

The data of 54 patients were prospectively collected. Patients underwent MRI iterative decomposition of water and fat with echo asymmetrical and least squares estimation (IDEAL IQ) scanning at RT-Pre, RT mid-point, RT end, and six months. The changes in proton density fat fraction (PDFF%) at 5–10 Gy, 10–15 Gy, 15–20 Gy, 20–30 Gy, 30–40 Gy, 40–50 Gy, and > 50 Gy doses were analyzed. Spearman’s rank correlations were performed between peripheral blood cell counts versus the differences in PDFF% at different dose gradients before and after treatment.

Results

The lymphocytes (ALC) nadirs appeared at the midpoint of radiotherapy, which was only 27.6% of RT-Pre; the white blood cells (WBC), neutrophils (ANC), and platelets (PLT) nadirs appeared at the end of radiotherapy which was 52.4%, 65.1%, and 69.3% of RT-Pre, respectively. At RT mid-point and RT-end, PDFF% increased by 46.8% and 58.5%, respectively. Six months after radiotherapy, PDFF% decreased by 4.71% under 5–30 Gy compared to RT-end, while it still increased by 55.95% compared to RT-Pre. There was a significant positive correlation between PDFF% and ANC nadirs at 5–10 Gy (r = 0.62, P = 0.006), and correlation was observed between PDFF% and ALC nadirs at 5–10 Gy (r = 0.554, P = 0.017).

Conclusion

MRI IDEAL IQ imaging is a non-invasive approach to evaluate and track the changes of PBM fat content with concurrent chemoradiotherapy for cervical cancer. The limitation of low-dose bone marrow irradiation volume in cervical cancer concurrent chemoradiotherapy should be paid more attention to.

Dosimetric parameters and absolute monocyte count can predict the prognosis of acute hematologic toxicity in cervical cancer patients undergoing concurrent chemotherapy and volumetric-modulated arc therapy

Purpose

To explore clinical and dosimetric predictors of acute hematologic toxicity (HT) in cervical cancer patients treated with concurrent chemotherapy and volumetric-modulated arc therapy (VMAT).

Methods and materials

We retrospectively reviewed the clinical data of 184 cervical cancer patients who had concurrent chemotherapy and VMAT. Hematological parameters were collected during the treatment period. The total pelvic bone (TPB) was delineated retrospectively for dose-volume calculations. To compare the differences between two groups, the normality test findings were used to run a paired-samples t-test or Wilcoxon signed-rank test. Pearson's correlation analysis or Spearman's correlation was used to testing the correlation between the two variables. Binary logistic regression analysis was used to analyze associations between HT and possible risk factors. The receiver operating characteristic curve(ROC) was used to evaluate the best cut-off point for dosimetric planning constraints.

Results

The nadir of absolute monocyte count (AMC) was found to be positively correlated with the nadir of absolute white blood cells (WBC) count (r = 0.5378, 95% CI 0.4227–0.6357, P < 0.0001) and the nadir of absolute neutrophil count(ANC) (r = 0.5000, 95% CI 0.3794–0.6039, P < 0.0001). The AMC decreased and increased before the ANC and WBC. In multivariate logistic regression analysis, the chemotherapy regimens and the TPB_V20 were independent risk factors for developing grade ≥ 3 HT. The optimal TPB_V20 cut-off value identified by ROC curves and the Youden test was 71% (AUC = 0.788; 95% CI 0.722–0.845; P value < 0.001).

Conclusions

The changing trend of AMC can be used as an effective predictor for the timing and severity of the ANC/WBC nadirs and prophylactic G-CSF administration. Maintain TPB_V20 < 71% and selecting single-agent cisplatin or carboplatin could significantly reduce grade ≥ 3 HT in cervical cancer patients undergoing concurrent chemoradiotherapy.

Advances in Radiation Oncology for the Treatment of Cervical Cancer

Background: Over the past two decades, there has been significant advancement in the management of cervical cancer, particularly in the domain of definitive chemoradiotherapy for locally advanced cervical cancer (LACC). Indeed, radiation treatment paradigms have shifted from a two-dimensional (2D) approach solely based on anatomical bony landmarks, to an image-guided three-dimensional (3D) approach, with the goal of delivering doses more precisely to clinical targets with an increased sparing of organs-at-risk. Methods: This is a narrative review on the advances in radiation technologies for the treatment of cervical cancer. Using the PubMed database, we identified articles published in English up until November 18, 2021 on the treatment of LACC with external beam radiotherapy (EBRT) and brachytherapy. A search of the Clinicaltrials.gov and Clinicaltrialsregister.eu retrieved information on ongoing clinical trials on the topic of combined immunotherapy and radiotherapy in cervical cancer. Results: We highlight the historical evolution from the use of 2D radiotherapy to 3D-conformal radiotherapy, and then intensity modulated radiotherapy (IMRT) for the delivery of EBRT. We also discuss advances in brachytherapy, notably the transition to 3D image-guided adaptive brachytherapy (3D-IGABT). In this context, we highlight large cohort studies that were recently constructed and have shown significant improvement in local control and treatment-related toxicities with 3D-IGABT. Finally, we discuss other advances in the field, notably the use of stereotactic body radiotherapy (SBRT) as a substitute to brachytherapy, and the addition of immunotherapy to chemoradiation. Conclusions: The use of IG-IMRT and 3D-IGABT have considerably improved treatment outcomes and toxicity profiles for patients with LACC, and are now considered the gold standard in many countries. The use of SBRT boost as a replacement for brachytherapy has been associated with increased toxicity and decreased efficacy and should be used with caution in the context of clinical trials. New experimental approaches include the addition of immunotherapy to chemoradiation regimens.

Positron Emission Tomography-Guided Bone Marrow-Sparing Radiation Therapy for Locoregionally Advanced Cervix Cancer: Final Results From the INTERTECC Phase II/III Trial

PURPOSE

To test effects of positron emission tomography (PET)-based bone marrow-sparing (BMS) image-guided intensity modulated radiation therapy (IG-IMRT) on efficacy and toxicity for patients with locoregionally advanced cervical cancer.

METHODS AND MATERIALS

In an international phase II/III trial, patients with stage IB-IVA cervical carcinoma were treated with either PET-based BMS-IG-IMRT (PET-BMS-IMRT group) or standard image-guided IMRT (IMRT group), with concurrent cisplatin (40 mg/m2 weekly), followed by brachytherapy. The phase II component nonrandomly assigned patients to PET-BMS-IMRT or standard IMRT. The phase III trial randomized patients to PET-BMS-IMRT versus IMRT, with a primary endpoint of progression-free survival (PFS) but was closed early for futility. Phase III patients were analyzed separately and in combination with phase II patients, comparing acute hematologic toxicity, cisplatin delivery, PFS, overall survival (OS), and patterns of failure. In a post-hoc exploratory analysis, we investigated the association between pretreatment absolute lymphocyte count (ALC) and OS.

RESULTS

In total, 101 patients were enrolled on the phase II/III trial, including 29 enrolled in phase III (PET-BMS-IMRT group: 16; IMRT group: 13) before early closure. Median follow-up was 33 months for phase III patients and 39 months for all patients. PFS and OS at 5 years for all patients were 73.6% (95% confidence interval [CI], 64.9%-84.3%) and 84% (95% CI, 76%-92.9%]), respectively. There were no differences in number of cisplatin cycles, OS, PFS, or patterns of failure between groups for the combined cohort. The incidence of acute grade ≥ 3 neutropenia was significantly lower in the PET-BMS-IMRT group compared with IMRT for randomized patients (19% vs 54%, χ2P = .048) and in the combined cohort (13% vs 35%, χ2P = .01). Patients with pretreatment ALC ≤ 1.5 k/µL had nonsignificantly worse OS on multivariable analysis (HR 2.85; 95% CI, 0.94-8.62; adjusted P = .216), compared with patients with ALC > 1.5 k/µL. There was no difference in posttreatment ALC by treatment group.

CONCLUSIONS

PET-BMS-IMRT significantly reduced acute grade ≥3 neutropenia, but not treatment-related lymphopenia, compared with standard IMRT. We found no evidence that PET-BMS-IMRT affected chemotherapy delivery or long-term outcomes, and weak evidence of an association between pretreatment ALC and OS.

Peripheral Lymphocyte Counts and Lymphocyte-Related Inflammation Indicators During Radiotherapy for Pelvic Malignancies: Temporal Characterization and Dosimetric Predictors

Purpose: To identify the dosimetric predictors of lymphocytopenia and retrospectively analyze the changing trend of peripheral lymphocyte counts and lymphocyte-related inflammatory indicators in patients with simple pelvic radiotherapy. Methods and Materials: We retrospectively reviewed the clinical data of 188 patients with pelvic malignancies undergoing pelvic radiotherapy. The absolute count of neutrophils, lymphocytes, monocytes, and platelets at each time point was collected, and lymphocyte-related inflammation indicators were obtained, including neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), and the systemic immune-inflammation index (SII). The total pelvic bone (TPB) and the body within the 5 Gy coverage were retrospectively delineated for each patient. Dose-volume histograms corresponding to the delivered volumetric arc therapy plan were used to assess the dose volumes received by the TPB and body. A paired-samples t-test or Wilcoxon signed-rank test for matched pairs was applied for pairwise comparisons. We also established a stepwise multiple linear regression model for the peripheral lymphocyte count (PLC) value at the end of radiotherapy. Results: The PLC and lymphocyte-related inflammatory indicators changed significantly after the start of radiotherapy and persisted for 3-6 months after radiotherapy. The nadirs of PLC occurred at RT-End, and the PLC was still significantly lower than the baseline value at RT-3 months and RT-6 months. NLR, PLR, and SII at RT-End are about 3.5 times the value at RT-Baseline, while LMR is one-fourth of the basal value. In a further multiple stepwise linear regression analysis, the basal PLC (β = 0.156, p ≤ .001), gender (β = 0.096, p = .005), and TPB-V5 (β = −0.016, p ≤ .001) turned out to be the predictor of the absolute value of lymphocytes at the end of radiotherapy. Conclusions: The impact of pelvic radiotherapy on PLC and lymphocyte-related inflammatory indicators is considerable and long-lasting. Minimizing pelvic bone radiation exposure dose (5 Gy) may help to avoid severe cases of lymphocytopenia.

Comparison of survival, acute toxicities, and dose-volume parameters between intensity-modulated radiotherapy with or without internal target volume delineation method and three-dimensional conformal radiotherapy in cervical cancer patients: A retrospective and propensity score-matched analysis

BACKGROUND

To evaluate whether the use of the internal target volume (ITV) delineation method improves the performance of intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) in terms of survival, acute toxicities, and dose-volume parameters.

METHODS

A total number of 477 cervical cancer patients who received concurrent chemoradiotherapy (CCRT) from January 2012 to December 2016 were retrospectively analyzed. They were divided into four groups: the non-ITV (N-ITV) + IMRT, ITV + IMRT, N-ITV + 3DCRT, and ITV + 3DCRT groups, with 76, 41, 327, and 33 patients, respectively. Survival analysis was performed with the Kaplan-Meier and the log-rank tests, and acute toxicity analysis was performed with the chi-squared test and the binary logistic regression test. Using the propensity score matching (PSM) method, 92 patients were matched among the four groups, and their dose-volume parameters were assessed with the Kruskal-Wallis method.

RESULTS

The median follow-up time was 49 months (1-119) for overall survival (OS). The 5-year OS rate was 66.4%. The ITV delineation method was an independent prognostic factor for OS (HR [95% CI]: 0.52 [0.27, 0.98], p = 0.044) and progression-free survival (PFS) (HR [95% CI]: 0.59 [0.36, 0.99], p = 0.045). The ITV + IMRT group had the lowest incidence rate (22%) and the N-ITV + IMRT group had the highest incidence rate of grade ≥3 hematological toxicity (HT) (46.1%) among the four groups. The pelvic bone marrow relative V10, V20, and V30 in the N-ITV + IMRT group was higher than those in the ITV + IMRT and N-ITV + 3DCRT groups (p < 0.05).

CONCLUSIONS

The use of ITV for IMRT treatment planning was associated with improved overall survival and progression-free survival, with lower HT rate.

Feasibility of bone marrow sparing volumetric modulated arc therapy to spare active bone marrow in cervical and vaginal cancer patients: a retrospective dosimetric analysis

INTRODUCTION

Chemoradiotherapy (CRT) is the standard treatment for locally advanced cervical and vaginal cancer. It is associated with high haematological toxicity (HT) that can lead to treatment interruptions and cancelled chemotherapy cycles, reducing the potential effectiveness of this regimen. Bone marrow sparing (BMS) utilising volumetric modulated arc therapy (VMAT) is one method to reduce dose to the active bone marrow (ABM) so that HT rates are reduced. The aim of this paper was to assess whether BMS-VMAT can effectively spare the ABM whilst maintaining clinically acceptable target and organ-at-risk (OAR) doses.

METHODS

Twenty gynaecological cancer patients treated with definitive CRT at the Liverpool/Macarthur Cancer Therapy centres between 2015 and 2020 were retrospectively included. ABM was delineated based on fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. Weekly blood tests and ABM dose parameters at the V10Gy, V20Gy, V30Gy, V40Gy and Dmean were assessed on original plans for any potential correlation with grade 2+ HT. Replanned with VMAT for BMS, various dose parameters were compared with the original plan to assess for any significant differences.

RESULTS

Active bone marrow doses were significantly reduced (P < 0.001 for all parameters) in BMS-VMAT plans, and significant improvements in target and OAR coverage were found compared with the original plans. Compared with VMAT only, target and OARs were comparable. No significant correlations between HT and ABM doses were found.

CONCLUSION

Bone marrow sparing volumetric modulated arc therapy can significantly reduce dose to the active bone marrow whilst maintaining acceptable target and OAR doses. Future prospective trials are needed to evaluate the clinical impact of BMS on toxicity and compliance.

Pelvic bone marrow sparing radiotherapy for cervical cancer: A systematic review and meta-analysis

BACKGROUNDS

Concurrent chemo-radiotherapy in patients with locally advanced cervical cancer has significant hematologic toxicities (HT), leading to treatment disruption and affecting patient prognosis. We performed the meta-analysis to assess the clinical benefit of pelvic (active) bone marrow (BM) sparing radiotherapy.

METHODS

A systematic methodological search of six primary electronic databases was performed. This systematic review mainly assessed the differences in pelvic (active) BM dose-volume parameters (DVP), hematologic toxicity of pelvic (active) BM sparing versus non-sparing radiotherapy plans. The secondary objective was to explore optimal dose limitation regimens and evaluate other radiation-induced toxicities (gastrointestinal and urological toxicity (GT/UT)). Random-effects models were used for meta-analysis.

RESULTS

Final 65 publications that met inclusion criteria were included in the meta-analysis and descriptive tables. Meta-analysis of mean pelvic BM-DVP differences showed that pelvic BM-V_10,20,40,50 (Vx: volume of BM receiving ≥ X Gy) were reduced by -4.6% [95% CI: -6.6, -2.6], -10.9% [-13.2, -8.6], -7.3% [-9.5, -5.2] and -3.4% [-4.3, -2.4] in pelvic BM-sparing plans. Pelvic BM sparing radiotherapy decreased G2/3+ HT [odds ratio (OR) 0.31, (0.23, 0.41)/0.42, (0.28, 0.63)], without increasing GT [G2/3+: OR 0.76, (0.51, 1.14)/0.90, (0.47, 1.74)] and UT [G2/3+: OR 0.91, (0.57, 1.46)/0.54, (0.25, 1.17)]. Pelvic active BM sparing radiotherapy also reduced HT [G2/3+ HT: OR 0.42, (0.23, 0.77)/0.34, (0.16, 0.72)]. There were significant variations between publications in dose restriction regimens.

CONCLUSION

The pelvic BM protection radiotherapy can decrease BM dose and HT. Moreover, it does not increase GT and UT. The clinical benefit of pelvic active BM protection needs to be further validated in randomized controlled trials.

The Impact of Pelvic Nodal Radiotherapy on Hematologic Toxicity: A Systematic Review with Focus on Leukopenia, Lymphopenia and Future Perspectives in Prostate Cancer Treatment

INTRODUCTION

Hematologic toxicity (HT), particularly leukopenia, is a common side-effect of oncologic treatments for pelvic malignancies. Pelvic nodal radiotherapy (PNRT) has been associated with HT development mainly through incidental bone marrow (BM) irradiation; however, several questions remain about the clinical impact of radiotherapy-related HT. Herein, we perform a systematic review of the available evidence on PNRT and HT.

MATERIALS AND METHODS

A comprehensive systematic literature search was performed through EMBASE. Hand searching and clinicaltrials.gov were also used.

RESULTS

While BM-related dose-volume parameters and BM-sparing techniques have been more thoroughly investigated in pelvic malignancies such as cervical, anal, and rectal cancers, the importance of BM as an organ-at-risk has received less attention in prostate cancer treatment.

CONCLUSIONS

We examined the available evidence regarding the impact of PNRT on HT, with a focus on prostate cancer treatment. We suggest that BM should be regarded as an organ-at-risk for patients undergoing PNRT.

PROTECT: Prospective Phase-II-Trial Evaluating Adaptive Proton Therapy for Cervical Cancer to Reduce the Impact on Morbidity and the Immune System

Simple Summary

Chemoradiation with photon radiotherapy is very effective as a locally advanced cervical cancer (LACC) treatment. However, the majority of women with LACC experience treatment-related toxicity involving the gastrointestinal and urogenital tracts and the immune system. Compared to that of photon therapy, proton therapy substantially reduces undesired dose to the organs around the tumor, leading to a decrease in radiotherapy-related side-effects. At present, few studies on proton therapy in patients with LACC will be conducted. The PROTECT trial aims to evaluate the differences in side effects between photon therapy and proton therapy, both combined with chemotherapy, for LACC. Fifteen patients will be enrolled per treatment group. Information will be collected on the differences in dose to the organs around the tumor, treatment-related side effects, and the impact on the immune system. This information will be used to assess the potential of proton therapy as an innovative treatment for LACC.

Abstract

External beam radiation therapy (EBRT) with concurrent chemotherapy followed by brachytherapy is a very effective treatment for locally advanced cervical cancer (LACC). However, treatment-related toxicity is common and reduces the patient’s quality of life (QoL) and ability to complete treatment or undergo adjuvant therapies. Intensity modulated proton therapy (IMPT) enables a significant dose reduction in organs at risk (OAR), when compared to that of standard intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT). However, clinical studies evaluating whether IMPT consequently reduces side effects for LACC are lacking. The PROTECT trial is a nonrandomized prospective multicenter phase-II-trial comparing clinical outcomes after IMPT or IMRT/VMAT in LACC. Thirty women aged >18 years with a histological diagnosis of LACC will be included in either the IMPT or IMRT/VMAT group. Treatment includes EBRT (45 Gy in 25 fractions of 1.8 Gy), concurrent five weekly cisplatin (40 mg/m²), and 3D image (MRI)-guided adaptive brachytherapy. The primary endpoint is pelvic bones D_mean and mean bowel V_15Gy. Secondary endpoints include dosimetric parameters, oncological outcomes, health-related QoL, immune response, safety, and tolerability. This study provides the first data on the potential of IMPT to reduce OAR dose in clinical practice and improve toxicity and QoL for patients with LACC.

Correlations between bone marrow radiation dose and hematologic toxicity in locally advanced cervical cancer patients receiving chemoradiation with cisplatin: a systematic review

Patients with locally advanced cervical cancer (LACC) treated with chemoradiation often experience hematologic toxicity (HT), as chemoradiation can induce bone marrow (BM) suppression. Studies on the relationship between BM dosimetric parameters and clinically significant HT might provide relevant indices for developing BM sparing (BMS) radiotherapy techniques. This systematic review studied the relationship between BM dose and HT in patients with LACC treated with primary cisplatin-based chemoradiation. A systematic search was conducted in Embase, Medline, and Web of Science. Eligibility criteria were treatment of LACC-patients with cisplatin-based chemoradiation and report of HT or complete blood cell count (CBC). The search identified 1346 papers, which were screened on title and abstract before two reviewers independently evaluated the full-text. 17 articles were included and scored according to a selection of the TRIPOD criteria. The mean TRIPOD score was 12.1 out of 29. Fourteen studies defining BM as the whole pelvic bone contour (PB) detected significant associations with V10 (3/14), V20 (6/14), and V40 (4/11). Recommended cut-off values were V10 > 95-75%, V20 > 80-65%, and V40 > 37-28%. The studies using lower density marrow spaces (PBM) or active bone marrow (ABM) as a proxy for BM only found limited associations with HT. Our study was the first literature review providing an overview of articles evaluating the correlation between BM and HT for patients with LACC undergoing cisplatin-based chemoradiation. There is a scarcity of studies independently validating developed prediction models between BM dose and HT. Future studies may use PB contouring to develop normal tissue complication probability models.

Knowledge-Based Planning for Intact Cervical Cancer

Cervical cancer radiotherapy is often complicated by significant variability in the quality and consistency of treatment plans. Knowledge-based planning (KBP), which utilizes prior patient data to correlated achievable optimal dosimetry with patient-specific anatomy, has demonstrated promise as a quality control tool for controlling this variability, with consequences for patient outcomes, as well as for the reliability of data from multi-institutional clinical trials. In this article we highlight the application of KBP-based quality control to cervical cancer radiotherapy. We discuss the potential impact of KBP on multi-institutional clinical trials to standardize cervical cancer treatment planning across diverse clinics, and discuss challenges and progress in the implementation of KBP for brachytherapy treatment planning. Additionally, we briefly discuss secondary applications of KBP for cervical cancer. The emerging picture from these studies indicates several exciting opportunities for increasing the utilization of KBP in day-to-day cervical cancer radiotherapy.

Bone marrow dosimetric analysis of lymphopenia in patients with esophageal squamous cell carcinoma treated with chemoradiotherapy

BACKGROUND

We analyzed the relationship among peripheral blood lymphocytes, exposed sternum and vertebra body bone marrow (BM), and overall survival (OS) to find BM dosimetric parameters of lymphopenia during chemoradiotherapy (CRT) for patients with esophageal squamous cell carcinoma (ESCC).

METHODS

We examined 476 ESCC patients from January 2012 to January 2015, all of whom received concurrent or sequential CRT. Absolute lymphocyte counts (ALC) during radiotherapy (RT) of each patient were collected from the routine workup at the following RT times: pretreatment ALC (ALC0), at 1-5, 6-10, 11-15, 16-20, and 21-25, and more than 26 sessions (called ALC1-6, respectively). The sternum and vertebral body BM were delineated in accordance with uniform standards, and the irradiated volumes were calculated by dose-volume histograms (DVH). The Kaplan-Meier method and Cox proportional hazards regression were used to analyze the survival of the patients. Comparisons of DVH were performed using the Mann-Whitney U test or two-sample t-test where appropriate.

RESULTS

A relative volume of sternum BM irradiated by more than 20 Gy could clearly affect the peripheral blood lymphocytes. The V20 of sternum BM and V50 of vertebra body BM were related to the OS of the patients, and the level of ALC2 (at 6-10 times of RT) could predict the outcomes of patients. The Cox regression analyses showed that the 218 patients with ALC2 ≥ 0.8 × 109 /L had a significantly higher OS (47.0 months vs. 30.9 months, p < 0.0001) than the 258 patients with ALC2 < 0.8×109 /L.

CONCLUSION

In patients with ESCC, the relative volume of sternum BM irradiated by more than 20 Gy was associated with lymphocytes. Patients with ALC2 ≥ 0.8 × 109 /L had a significantly higher OS. The V20 of the sternum BM, the V50 of the vertebra body BM, and the level of ALC2 were significant prognostic factors in patients with ESCC.

Advances in External Beam Radiation Therapy and Brachytherapy for Cervical Cancer

The standard of care for the definitive treatment of locoregionally advanced cervical cancer is external beam radiation therapy (EBRT) with concurrent chemotherapy followed by a brachytherapy boost. Historically, EBRT was delivered via a two-dimensional technique based primarily on bony landmarks. This gave way to three-dimensional conformal radiation therapy, which allows for dose calculation and adjustment based on individual tumour and patient anatomy. Further technological advances have established intensity-modulated radiation therapy (IMRT) as a standard treatment modality, given the ability to maintain tumoricidal doses to target volumes while reducing unwanted radiation dose to nearby critical structures, thereby reducing toxicity. Routine image guidance allows for increased confidence in patient alignment prior to treatment, and the ability to visualise the daily position of the targets and organs at risk has been instrumental in allowing safe reductions in treated volumes. Additional EBRT technologies, including proton therapy and stereotactic body radiation therapy, may further improve the therapeutic index. In the realm of brachytherapy, a shift from point-based dose planning to image-guided brachytherapy has been associated with improved local control and reduced toxicity, with additional refinement ongoing. Here we will discuss these advances, the supporting data and future directions.

Bone Marrow Suppression during Postoperative Radiation for Bladder Cancer and Comparative Benefit of Proton Therapy—Phase 2 Trial Secondary Analysis

Purpose

For patients with high-risk bladder cancer (pT3⁺ or N⁺), local regional failure remains a challenge after chemotherapy and cystectomy. An ongoing prospective phase 2 trial (NCT01954173) is examining the role of postoperative photon radiation therapy for high-risk patients using volumetric modulated arc therapy. Proton beam therapy (PBT) may be beneficial in this setting to reduce hematologic toxicity. We evaluated for dosimetric relationships with pelvic bone marrow (PBM) and changes in hematologic counts before and after pelvic radiation therapy and explored the potential of PBT treatment plans to achieve reductions in PBM dose.

Materials and Methods

All enrolled patients were retrospectively analyzed after pelvic radiation per protocol with 50.4 to 55.8 Gy in 28 to 31 fractions. Comparative PBT plans were generated using pencil-beam scanning and a 3-beam multifield optimization technique. Changes in hematologic nadirs were assessed using paired t test. Correlation of mean nadirs and relative PBM dose levels were assessed using the Pearson correlation coefficient (CC).

Results

Eighteen patients with a median age of 70 were analyzed. Mean cell count values after radiation therapy decreased compared with preradiation therapy values for white blood cells (WBCs), absolute neutrophil count (ANC), absolute lymphocyte count (all P < .001), and platelets (P = .03). Increased mean PBM dose was associated with lower nadirs in WBC (Pearson CC −0.593, P = .02), ANC (Pearson CC −0.597, P = .02), and hemoglobin (Pearson CC −0.506, P = .046), whereas the PBM V30 to V40 correlated with lower WBC (Pearson CC −0.512 to −0.618, P < .05), and V20 to V30 correlated with lower ANC (Pearson CC −0.569 to −0.598, P < .04). Comparative proton therapy plans decreased the mean PBM dose from 26.5 Gy to 16.1 Gy (P < .001) and had significant reductions in the volume of PBM receiving doses from 5 to 40 Gy (P < .001).

Conclusion

Increased PBM mean dose and V20 to V40 were associated with lower hematologic nadirs. PBT plans reduced PBM dose and may be a valuable strategy to reduce the risk of hematologic toxicity in these patients.

Evaluation of acute hematological toxicity by machine learning in gynecologic cancers using postoperative radiotherapy

Background

The aim of the study is to investigate the factors affecting acute hematologic toxicity (HT) in the adjuvant radiotherapy (RT) of gynecologic cancers by machine learning.

Methods

Between January 2015 and September 2018, 121 patients with endometrium and cervical cancer who underwent adjuvant RT with volumetric-modulated arc therapy (VMAT) were evaluated. The relationship between patient and treatment characteristics and acute HT was investigated using machine learning techniques, namely Logistic Regression, XGBoost, Artificial Neural Network, Random Forest, Naive Bayes, Support Vector Machine (SVM), and Gaussian Naive Bayes (GaussianNB) algorithms.

Results

No HT was observed in 11 cases (9.1%) and at least one grade of HT was observed in 110 cases. There were 55 (45.5%) cases with ≤grade 2 HT (mild HT) and 66 (54.5%) cases with grade ≥3 HT (severe HT). None of the patients developed grade 5 HT. Of 24 variables that could affect acute HT, nine were determined as important variables. According to the results, the best machine learning technique for acute HT estimation was SVM (accuracy 70%, area under curve (AUC): 0.65, sensitivity 71.4%, specificity 66.6%). Parameters affecting hematologic toxicity were evaluated also by classical statistical methods and there was a statistically significant relationship between age, RT, and bone marrow (BM) maximum dose.

Conclusion

It is important to predict the patients who will develop acute HT in order to minimize the side effects of treatment. If these cases can be identified in advance, toxicity rates can be reduced by taking necessary precautions. These cases can be predicted with machine learning algorithms.