Intensity-modulated radiotherapy reduces gastrointestinal toxicity in pelvic radiation therapy with moderate dose

Application of Recombinant Human Superoxide Dismutase in Radical Concurrent Chemoradiotherapy for Cervical Cancer to Prevent and Treat Radiation-induced Acute Rectal Injury: A Multicenter, Randomized, Open-label, Prospective Trial

PURPOSE

The purpose of this study was to evaluate the efficacy of recombinant human superoxide dismutase (rhSOD) enemas in radiation-induced acute rectal injury (RARI) in patients with locally advanced cervical cancer.

METHODS AND MATERIALS

In this phase 3, randomized, open-label trial (NCT04819685) conducted across 14 medical centers in China from June 2021 to August 2023, all patients received concurrent chemoradiation therapy (CCRT). The experimental group was treated with a rhSOD enema during chemoradiation therapy, and the control group had no enema. The Common Terminology Criteria for Adverse Events (version 5.0) was used to evaluate radiation therapy-induced side effects. Endoscopic appearance was assessed using the Vienna Rectoscopy Score. The primary endpoint in the acute phase was the occurrence rate and duration of grade ≥1 (≥G1) diarrhea during CCRT. Secondary endpoints included the occurrence rate and duration of ≥G2 and ≥G3 diarrhea, ≥G1 and ≥G2 diarrhea lasting at least 3 days, and damage to the rectal mucosa due to radiation therapy measured by endoscopy.

RESULTS

Two hundred and eighty-three patients were randomly divided into the experimental (n = 141) or control group (n = 142). The mean number of ≥G1 and ≥G2 diarrhea days were significantly lower in the experimental group than in the control group (3.5 and 0.8 days vs 14.8 and 4.5 days, respectively; P < .001). The incidence of ≥G2 diarrhea decreased from 53.6% to 24.1% when rhSOD enemas were used. Use of antidiarrheals was lower in the experimental group (36.2% vs 55.7%, P < .001). Three patients felt intolerable or abdominal pain after rhSOD enema. RARI grades in the experimental group tended to be lower than those in the control group (P = .061). Logistic regression analysis revealed that rhSOD enema was associated with a lower occurrence rate of ≥G1/2 diarrhea for at least 3 days (P < .001).

CONCLUSIONS

The results of this study suggest that rhSOD enema is safe and significantly reduces the incidence, severity, and duration of RARI, protecting the rectal mucosa.

Racecadotril Versus Loperamide in Acute Radiation Enteritis: A Randomized, Double-Masked, Phase 3, Noninferiority Trial

PURPOSE

There is currently no gold standard for the management of acute radiation enteritis. We compared the efficacy and safety of Racecadotril, an anti-hypersecretory drug, versus Loperamide, an anti-motility agent, in acute radiation enteritis.

METHODS AND MATERIALS

We conducted a randomized, double-masked, non-inferiority trial at a single research institute. Patients receiving curative radiation for pelvic malignancies, who developed grade 2 or 3 diarrhea (as per Common Terminology Criteria for Adverse Events, v 4.0) were included in the study. Patients in the intervention arm received Racecadotril and placebo. Patients in the control arm received Loperamide and placebo. The primary outcome was the resolution of diarrhea, 48 hours after the start of treatment.

RESULTS

162 patients were randomized between 2019 and 2022. On intention-to-treat analysis, 68/81 patients, 84%, (95% CI, 74.1%-91.2%) in the Racecadotril arm and 70/81, 86.4%, (95% CI, 77.0%-93.0%) in the Loperamide arm improved from grade 2 or 3 diarrhea to grade 1 or 0, (P= .66, χ2 test). The difference in proportion was 2.4% (95% CI: -8.5% to 13.4%). Since the upper boundary of the 95% CI crossed our non-inferiority margin of 10% (13.4%) we could not prove the non-inferiority of Racecadotril over Loperamide. Rebound constipation was more in the Loperamide arm compared to Racecadotril (17.3% vs 6.2%; P = .028) CONCLUSIONS: The non-inferiority of Racecadotril to Loperamide in acute radiation enteritis could not be demonstrated. However, Racecadotril can be the preferred drug of choice in acute radiation enteritis because Racecadotril does not affect bowel motility, achieved a high clinical success rate similar to that of Loperamide, and was associated with lesser side effects.

Evaluation of PTV margins with daily iterative online adaptive radiotherapy for postoperative treatment of endometrial and cervical cancer: a prospective single-arm phase 2 study

BACKGROUND

To determine the optimal planning target volume (PTV) margins for adequate coverage by daily iterative cone-beam computed tomography (iCBCT)-guided online adaptive radiotherapy (oART) in postoperative treatment of endometrial and cervical cancer and the benefit of reducing PTV margins.

METHODS

Fifteen postoperative endometrial and cervical cancer patients treated with daily iCBCT-guided oART were enrolled in this prospective phase 2 study. Pre- and posttreatment iCBCT images of 125 fractions from 5 patients were obtained as a training cohort, and clinical target volumes (CTV) were contoured separately. Uniform three-dimensional expansions were applied to the PTVpre to assess the minimum margin required to encompass the CTVpost. The dosimetric advantages of the proposed online adaptive margins were compared with conventional margin plans (7-15 mm) using an oART emulator in another cohort of 125 iCBCT scans. A CTV-to-PTV expansion was verified on a validation cohort of 253 fractions from 10 patients, and further margin reduction and acute toxicity were studied.

RESULTS

The average time from pretreatment iCBCT to posttreatment iCBCT was 22 min. A uniform PTV margin of 5 mm could encompass nodal CTVpost in 100% of the fractions (175/175) and vaginal CTVpost in 98% of the fractions (172/175). The margin of 5 mm was verified in our validation cohort, and the nodal PTV margin could be further reduced to 4 mm if ≥ 95% CTV coverage was predicted to be achieved. The adapted plan with a 5 mm margin significantly improved pelvic organ-at-risk dosimetry compared with the conventional margin plan. Grade 3 toxicities were observed in only one patient with leukopenia, and no patients experienced acute urinary toxicity.

CONCLUSION

In the postoperative treatment of endometrial and cervical cancer, oART could reduce PTV margins to 5 mm, which significantly decrease the dose to critical organs at risk and potentially lead to a lower incidence of acute toxicity.

Dosimetry and acute radiation enteritis comparison between prone and supine position in IMRT for gynecological cancers

PURPOSE

To probe the differences of dosimetry and acute radiation enteritis between prone and supine position in gynecological cancer patients treated with intensity-modulate radiotherapy (IMRT).

METHODS

Gynecologic tumor patients who received IMRT from January 2020 to July 2021 were analyzed. 60 patients were enrolled and divided into the supine or prone position group according to different radiotherapy positions, including 34 patients in prone position and 26 patients in supine position. The dose-volume histogram of organs at risk (OARs) and the incidence of acute radiation enteritis were compared between the two groups. Multivariate logistic regression analysis was conducted to show the clinical characteristics and dose volume metrics to the association of acute radiation enteritis.

RESULTS

The percentage of volume receiving 5 Gy, 10 Gy, 15 Gy, 20 Gy, 30 Gy, 40 Gy, and 45 Gy doses for the small intestine were 79.0%, 67.4%, 59.6%, 44.3%, 17.0%, 8.9%, and 6.0%, respectively in the prone group, which were lower than those in the supine group (P < 0.05). The mean radiation dose (Dmean ) of the small intestine exposure in prone group was decreased (P < 0.001). Compared with the supine group, the prone group who suffered from acute radiation enteritis were much less. The probability of indigestion, nausea, vomiting, diarrhea, and abdominal pain in the prone position were 35.29%, 29.41%, 17.65%, 38.24%, and 5.88%, respectively. The differences in indigestion, nausea, and diarrhea between the two groups were statistically significant (P = 0.012, P = 0.029, and P = 0.041). Multivariate logistic regression analysis was shown that prone position was found to be protective against indigestion (P = 0.002), nausea (P = 0.013), vomiting (P = 0.035), and abdominal pain (P = 0.021).

CONCLUSION

Prone position in IMRT for gynecological cancers could significantly reduce radiation dose to the small bowel and colon, which would decrease the occurrence and severity of acute intestinal side effects possibly.

Comparison of Acute Gastrointestinal Toxicity of Intensity-Modulated Radiotherapy Versus Three-Dimensional Conformal Radiotherapy in Patients of Carcinoma Cervix

Introduction Cervical cancer is the most common gynaecological malignancy worldwide, with a higher prevalence in middle- and low-income countries. Chemoradiotherapy, followed by intracavitary brachytherapy, is the treatment of choice in locally advanced cervical cancer. The most common acute side effect of external beam radiotherapy (EBRT) is bowel toxicity in the form of diarrhoea and abdominal cramps. The treatment techniques of EBRT were revolutionised with the advent of intensity modulation. This study aims to prospectively analyse whether the dosimetric advantage of intensity-modulated radiotherapy (IMRT) over three-dimensional conformal radiotherapy (3DCRT) is translated clinically into a decrease in acute toxicity. Method Twenty-four patients were randomised into two groups: the 3DCRT and the IMRT. Acute gastrointestinal (GI) toxicity was assessed during treatment using radiation therapy oncology group grading. The factors under consideration were age, stage of the disease, treatment technique, chemotherapy, and the intention of therapy (radical or adjuvant). The mean bowel bag dose of the two techniques was analysed. Result Among the factors under consideration, it was found that the treatment technique was the only factor that had a significant association with acute bowel toxicity in both univariate (p = 0.036) and multivariate analyses (p = 0.028). The mean V25 (the volume receiving 25 Gy), V45, and V50 of the bowel bag in the IMRT arm were significantly less than the 3DCRT arm. Grades 2 and 3 acute bowel toxicities were also higher in the 3DCRT arm. Conclusion The treatment technique is essential to determining acute GI toxicity during pelvic radiotherapy. With IMRT, the dose to the bowel bag and, in turn, the acute bowel toxicity can be reduced.

Use of specific duodenal dose constraints during treatment planning reduces toxicity after definitive para-aortic radiotherapy for cervical cancer

PURPOSE

To validate the safety of paraaortic nodal (PAN) radiation therapy (RT) for patients with cervical cancer when the duodenal dose is limited to V₅₅<15 cm³ and V₆₀<2 cm³.

METHODS AND MATERIALS

Ninety-seven patients who were treated with RT for cervical cancer between 2010 and 2018, received at least 56 Gy to grossly involved PANs. Patients were treated with concurrent chemoradiation (n=88, 91%), with 93% (n=90) receiving intensity-modulated RT (IMRT) to the initial PAN field, and 98% (n=95) receiving IMRT to a sequential PAN boost. V₅₅<15 cm³ and V₆₀ <2 cm³ criteria were implemented in 2014. Normal tissues were contoured on CT simulation datasets; the duodenum was contoured from the gastric outlet to the duodenojejunal flexure. Sixty-six patients (68%) had a resimulation scan after approximately 20 fractions. Composite duodenal doses were calculated using the initial CT for 50 patients (52%) and the resimulation CT for 47 patients (48%) depending on anatomic changes throughout treatment.

RESULTS

The median duodenal V₅₅ was 3.5 cm³ (interquartile range [IQR] 0.2-8.1 cm³) and the median V₆₀ was 0.3 cm³ (IQR 0.0-1.8). Constraints were exceeded in 18 patients, 16 (89%) of whom had been treated before 2014. Treatment for the 2 patients treated after 2014 had been complicated by significant weight loss and reduced anterior-posterior diameter, which likely overestimated the true dose on the composite plan. Only 1 patient experienced grade 3 duodenal toxicity (stricture requiring endoscopic balloon dilation 3 months after treatment); however, the stricture was outside the high-dose boost volume and the patient had a history of gastritis. Six patients (6%) had a first recurrence within the PAN region.

CONCLUSIONS

Limiting duodenal dose to V₅₅<15 cm³ and V₆₀<2 cm³ for patients with cervical cancer and PAN involvement is feasible and minimizes duodenal toxicity while maintaining acceptable local control rates.

Patterns of Care and Outcomes for Non-Metastatic Prostate Cancer in the United States: Results of the CancerMPact® Survey 2018

Purpose

We describe patterns of care and treatment outcomes for non-metastatic PCa (nmPCA), either hormone-sensitive or castration-resistant, in the United States of America (USA) in 2018.

Methods

A survey (CancerMPact^®) recruited physicians nationwide to answer an online questionnaire about how they treated patients with nmPCA. Questions covered aspects of treatment at all disease stages. Board-certified urologists and oncologists with at least five years of clinical practice and who treated at least 30 PCa patients monthly were included.

Results

The survey included responses from ninety-four physicians with an average of 17.5 years of clinical practice, who had treated a combined average of 4415 patients with nmPCA per month in 2018. Approximately 40% of patients in stage I were managed with either active surveillance or observation/no therapy, decreasing to 20%, 8% and 6% in stages II, III and IV(M0), respectively. Intensity-modulated radiotherapy was favored over other radiotherapy modalities, with rates of use ranging between 60% and 69% depending on disease stage. Leuprolide as monotherapy or in combination with enzalutamide, abiraterone or bicalutamide were the most common systemic treatment options for non-metastatic hormone-sensitive PCa (nmHSPC) patients with the first or second recurrence. Only 16.5% of non-metastatic castration-resistant PCa (nmCRPC) patients did not relapse within five years of initial therapy for nmCRPC.

Conclusion

While PCa treatment recommendations are rapidly changing due to advances in treatment, we observed great concordance between their most current versions and real-world data treatment patterns reported by US physicians.

DEVIATION BETWEEN THE PLANNED DOSE AND THE IN VIVO DOSIMETRY RESULTS DURING POSTOPERATIVE IRRADIATION IN PATIENTS WITH UTERINE CANCER DEPENDING ON ANTHROPOMETRIC DATA

Topometry is an integral part of irradiation whose task is to repeat the position of the patient set by the simulator to repeat the PTV and the spatial relationship between the radiation field and the risk organs that were identified during planning. The dose distribution formulated in the plan is only an ideal model. There is some gap between the actual and planned dose distribution, especially in overweight patients.

OBJECTIVE

evaluate the effect of anthropometric data on the deviation between the planned dose and the results of dosimetry in vivo in patients with uterine cancer during postoperative irradiation.

MATERIALS AND METHODS

The authors analyzed the results of treatment of 110 patients with stage IB-II uterine can- cer who were treated at the Department of Radiation Therapy of the Institute of Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine from 2016 to 2019. The technique of classical fractionation was used with a single focal dose of 2.0 Gy 5 times a week, the total focal dose was 42.0-50.0 Gy. To assess the effect of the patient's anthropometric data on the difference between the actual and calculated dose, the authors per- formed in vivo dosimetry after the first session and in the middle of the postoperative course of external beam radi- ation therapy.

RESULTS

Рatients with BSA < 1.92 m2, had the median relative deviation at the first session -4.12 %, after 20.0 Gy - 3.61 %, patients with BSA > 1.92 m2: -2.06 % and -1.55 % respectively. After 20 Gy 34.8 % of patients with BSA < 1.92 m2 there was an increase in deviation from the planned dose, 65.2 % a decrease, while in 56.1 % of patients with BSA > 1.92 m2 there was an increase, and in 43.9 % - its reduction. With increasing BMI, the actual dose received on the rectal mucosa in the tenth session of irradiation is approaching the calculated one.

CONCLUSIONS

When irradiated on the ROKUS-AM device, we did not find a probable dependence of the influence of the constitutional features of patients between the received and planned radiation dose. When treated with a Clinac 600 C, only body weight and body mass index at the tenth irradiation session have a likely effect on the dose differ- ence. Therefore, issues related to the individual approach to the treatment of uterine cancer, depending on anthro- pometric data is an urgent problem of modern radiotherapy.

Indigenous Groin Board Immobilization Reduces Planning Target Volume Margins in Groin Radiotherapy

Purpose:

To quantify the relative motion of pelvic and groin lymph nodes (PLN and GLN) and define indicative margins for image-guided radiotherapy based on bony anatomy for the frog-leg position (FLP) and groin immobilization board (GIB).

Materials and Methods:

Twenty patients with planning computed tomography (CT) scan and on treatment cone beam CTs (median = 8) for groin and pelvic radiotherapy were included in the study. Of these nine were treated with FLP and eleven with GIB. The PLN and GLN regions on the left and right were outlined in each scan. Systematic and random uncertainties were determined along with correlations between the motions of these regions. The clinical target volume to planning target volume (PTV) margins required to take motion into account was calculated for each immobilization.

Results:

The mean shifts for PLN and GLN were lesser but not statistically lower using GIB over FLP. There was significant concordance in the vertical, longitudinal and lateral motion of the pelvis and right groin (P = 0.015, 0.09 and 0.049, respectively), pelvis and left groin (P = 0.001, 0.048, and 0.006, respectively) and between left and right groin (P = 0.013, 0.01 and 0.07, respectively) for FLP and not GIB. The PTV margins required by Van Herk and Stroom's formula were reduced from 11 mm and 9 mm to 6 mm and 5 mm for pelvis; 12 mm and 11 mm to 7 mm and 6 mm for groin, respectively, using FLP over GIB.

Conclusions:

GIB brings concordance in shifts between pelvis and groin and between bilateral groins, thereby reducing the required PTV margins.

Late Changes in the Extracellular Matrix of the Bladder after Radiation Therapy for Pelvic Tumors

Radiation therapy is one of the cardinal approaches in the treatment of malignant tumors of the pelvis. It leads to the development of radiation-induced complications in the normal tissues. Thus, the evaluation of radiation-induced changes in the extracellular matrix of the normal tissue is deemed urgent, since connective tissue stroma degradation plays a crucial role in the development of Grade 3-4 adverse effects (hemorrhage, necrosis, and fistula). Such adverse effects not only drastically reduce the patients' quality of life but can also become life-threatening. The aim of this study is to quantitatively analyze the bladder collagen state in patients who underwent radiation therapy for cervical and endometrial cancer and in patients with chronic bacterial cystitis and compare them to the normal bladder extracellular matrix.

MATERIALS AND METHODS

One hundred and five patients with Grade 2-4 of radiation cystitis, 67 patients with bacterial chronic cystitis, and 20 volunteers without bladder pathology were enrolled. Collagen changes were evaluated depending on its hierarchical level: fibrils and fibers level by atomic force microscopy; fibers and bundles level by two-photon microscopy in the second harmonic generation (SHG) mode; general collagen architectonics by cross-polarization optical coherence tomography (CP OCT).

RESULTS

The main sign of the radiation-induced damage of collagen fibrils and fibers was the loss of the ordered "basket-weave" packing and a significant increase in the total area of ruptures deeper than 1 µm compared to the intact sample. The numerical analysis of SHG images detected that a decrease in the SHG signal intensity of collagen is correlated with the increase in the grade of radiation cystitis. The OCT signal brightness in cross-polarization images demonstrated a gradual decrease compared to the intact bladder depending on the grade of the adverse event.

CONCLUSIONS

The observed correspondence between the extracellular matrix changes at the microscopic level and at the level of the general organ architectonics allows for the consideration of CP OCT as a method of "optical biopsy" in the grading of radiation-induced collagen damage.

Management of Long-Term Toxicity From Pelvic Radiation Therapy

Pelvic radiation therapy is an integral component in the treatment of various gastrointestinal, gynecologic, and genitourinary cancers. As survival rates from these malignancies improve, the prevalence of toxicity secondary to pelvic radiation has increased. Gastrointestinal toxicities are the most common complications and greatly impact quality of life. Toxicities can present in acute or late stages; although symptoms may be similar during both, the management may differ. Acute toxicities represent an inflammatory reaction in response to the radiation exposure, whereas late toxicities may arise as a result of small vessel disease, ischemia, and fibrosis. Currently, there are no large clinical trials and only limited guidelines on the management of late gastrointestinal radiation toxicities. Therapy is generally approached in a stepwise manner from medical to endoscopic to surgical methods. Several endoscopic therapies, such as the treatment of radiation proctitis with argon plasma coagulation and dilation of radiation bowel strictures, may prevent the need for surgical intervention, which may be associated with high morbidity and mortality. Given that late toxicities can occur years after radiation therapy, they are often difficult to recognize and diagnose. Successful management of late toxicities requires recognition, an understanding of the underlying pathophysiology, and a multidisciplinary approach. More dedicated research could clarify the prevalence of gastrointestinal pelvic radiation toxicities, permit a better understanding of the efficacy and safety profile of current therapies, and allow for the development of novel therapeutic approaches.

Assessing the Effect of Radiotherapy in Addition to Surgery in Colon Adenocarcinomas: a Systematic Review and Meta-analysis of Contemporary Evidence

PURPOSE

This study aims to review the contemporary evidence investigating radiotherapy (RT) in addition to surgery for colon adenocarcinomas.

METHODS

We searched the following databases: PubMed, Science Direct, Scopus, ASCOpubs, the Cochrane Library, and Google Scholar. Studies (since January 2005) comparing outcomes of high-risk colon adenocarcinomas who underwent RT in addition to surgery versus no RT were eligible. Pooling of outcomes from published results or from analysis of survival curves was done. Subgroup analysis was conducted to determine if the efficacy of RT varies with RT timing.

RESULTS

Eight studies were included (five retrospective cohorts, three population-based studies). Pooled analysis from retrospective cohorts showed a reduction in 5-year LR (OR 0.41; 95% CI 0.21-0.79; p = 0.007) in the RT group. A benefit in 3-year (OR 1.81; 95% CI 1.15-2.87; p = 0.01) and 5-year (OR 2.10; 95% CI 1.21-3.63; p = 0.008) DFS and in 3-year (OR 2.55; 95% CI 1.43-4.54; p = 0.001) and 5-year (OR 2.00; 95% CI 1.17-3.41; p = 0.01) OS was seen in the RT group. The OS benefit was demonstrated in the subgroup analysis of neoadjuvant RT, but not with adjuvant RT. The improvement in OS with neoadjuvant RT was supported by a population-based study from NCDB, while results from two population-based studies investigating adjuvant RT were conflicting.

CONCLUSION

Taking into account the limitations of the studies, our review of evidence suggests a possible role of RT in improving oncologic outcomes of select colon adenocarcinomas. Prospective studies are needed to definitively assess the value of RT for colon cancer.

Rectal Dose Is the Other Dosimetric Factor in Addition to Small Bowel for Prediction of Acute Diarrhea during Postoperative Whole-Pelvic Intensity-Modulated Radiotherapy in Gynecologic Patients

Simple Summary

Although the small bowel volume effect for acute diarrhea during radiotherapy has been investigated, no study has reported the influence of rectal dose. We analyzed 108 patients undergoing intensity-modulated radiotherapy after hysterectomy. Acute diarrhea was defined as onset during radiotherapy based on Common Terminology Criteria for Adverse Events (CTCAE) version 3. Both small bowel and rectum dosimetric parameters affected Grade 2 to 3 diarrhea. The high-dose volume effects on the small bowel still play an important role in postoperative intensity-modulated radiotherapy. This is the first large cohort study to demonstrate the role of both IMRT dosimetric factors of the rectum and the small bowel in acute diarrhea in gynecological patients with a previous hysterectomy. A small bowel volume of 39.6 Gy < 60 mL and a mean rectal dose of <32.75 Gy are suggested as constraints to treatment planning.

Abstract

We studied the association of rectal dose with acute diarrhea in patients with gynecologic malignancies undergoing whole-pelvic (WP) intensity-modulated radiotherapy (IMRT). From June 2006 to April 2019, 108 patients with previous hysterectomy who underwent WP IMRT were enrolled in this cohort study. WP irradiation of 39.6–45 Gy/22–25 fractions was initially delivered to the patients. Common Terminology Criteria for Adverse Events (CTCAE) version 3 was used to evaluate acute diarrhea during radiotherapy. Small bowel volume at different levels of isodose curves (Vn%) and mean rectal dose (MRD) were measured for statistical analysis. The multivariate analysis showed that the MRD ≥ 32.75 Gy (p = 0.005) and small bowel volume of 100% prescribed (V100%) ≥ 60 mL (p = 0.008) were independent factors of Grade 2 or higher diarrhea. The cumulative incidence of Grade 2 or higher diarrhea at 39.6 Gy were 70.5%, 42.2%, and 15.0% (p < 0.001) in patients with both high (V100% ≥ 60 mL and MRD ≥ 32.75 Gy), either high, and both low volume-dose factors, respectively. Strict constraints for the rectum/small bowel or image-guided radiotherapy to reduce these doses are suggested.

Radioprotection and Radiomitigation: From the Bench to Clinical Practice

The development of protective agents against harmful radiations has been a subject of investigation for decades. However, effective (ideal) radioprotectors and radiomitigators remain an unsolved problem. Because ionizing radiation-induced cellular damage is primarily attributed to free radicals, radical scavengers are promising as potential radioprotectors. Early development of such agents focused on thiol synthetic compounds, e.g., amifostine (2-(3-aminopropylamino) ethylsulfanylphosphonic acid), approved as a radioprotector by the Food and Drug Administration (FDA, USA) but for limited clinical indications and not for nonclinical uses. To date, no new chemical entity has been approved by the FDA as a radiation countermeasure for acute radiation syndrome (ARS). All FDA-approved radiation countermeasures (filgrastim, a recombinant DNA form of the naturally occurring granulocyte colony-stimulating factor, G-CSF; pegfilgrastim, a PEGylated form of the recombinant human G-CSF; sargramostim, a recombinant granulocyte macrophage colony-stimulating factor, GM-CSF) are classified as radiomitigators. No radioprotector that can be administered prior to exposure has been approved for ARS. This differentiates radioprotectors (reduce direct damage caused by radiation) and radiomitigators (minimize toxicity even after radiation has been delivered). Molecules under development with the aim of reaching clinical practice and other nonclinical applications are discussed. Assays to evaluate the biological effects of ionizing radiations are also analyzed.

Simple calculation using anatomical features on pre-treatment verification CT for bladder volume estimation during radiation therapy for rectal cancer

Background

Despite detailed instruction for full bladder, patients are unable to maintain consistent bladder filling during a 5-week pelvic radiation therapy (RT) course. We investigated the best bladder volume estimation procedure for verifying consistent bladder volume.

Methods

We reviewed 462 patients who underwent pelvic RT. Biofeedback using a bladder scanner was conducted before simulation and during treatment. Exact bladder volume was calculated by bladder inner wall contour based on CT images (V_ctsim). Bladder volume was estimated either by bladder scanner (V_scan) or anatomical features from the presacral promontory to the bladder base and dome in the sagittal plane of CT (V_ratio). The feasibility of V_ratio was validated using daily megavoltage or kV cone-beam CT before treatment.

Results

Mean V_ctsim was 335.6 ± 147.5 cc. Despite a positive correlation between V_ctsim and V_scan (R² = 0.278) and between V_ctsim and V_ratio (R² = 0.424), V_ratio yielded more consistent results than V_scan, with a mean percentage error of 26.3 (SD 19.6, p < 0.001). The correlation between V_ratio and V_ctsim was stronger than that between V_scan and V_ctsim (Z-score: − 7.782, p < 0.001). An accuracy of V_ratio was consistent in megavoltage or kV cone-beam CT during treatment. In a representative case, we can dichotomize for clinical scenarios with or without bowel displacement, using a ratio of 0.8 resulting in significant changes in bowel volume exposed to low radiation doses.

Conclusions

Bladder volume estimation using personalized anatomical features based on pre-treatment verification CT images was useful and more accurate than physician-dependent bladder scanners.

Trial registration

Retrospectively registered.

Trimodality Therapy for Muscle-Invasive Bladder Cancer: Recent Advances and Unanswered Questions

PURPOSE OF REVIEW

Bladder-sparing trimodality therapy (TMT) has become an accepted alternative to cystectomy for selected muscle invasive bladder cancer (MIBC) patients unfit for cystectomy or opting for bladder preservation. This review will summarize recent advances in TMT for MIBC.

RECENT FINDINGS

A growing body of literature has emerged which supports the use of TMT. However, its delivery is yet to be standardized. The role of chemotherapy and predictive biomarkers remain to be elucidated. Novel bladder-sparing approaches, drug combinations including immunotherapy and targeted therapies are under investigation in clinical trials, with the goal of ultimately enhancing survival and quality of life outcomes. Recent advances in TMT have made bladder preservation possible for MIBC patients seeking an alternative local therapy to cystectomy. With careful patient selection, TMT offers comparable survival outcomes to cystectomy, and improved quality of life as patients are able to successfully retain their bladder.

Standard (8 weeks) vs long (12 weeks) timing to minimally-invasive surgery after NeoAdjuvant Chemoradiotherapy for rectal cancer: a multicenter randomized controlled parallel group trial (TiMiSNAR)

BACKGROUND

The optimal timing of surgery in relation to chemoradiation is still controversial. Retrospective analysis has demonstrated in the recent decades that the regression of adenocarcinoma can be slow and not complete until after several months. More recently, increasing pathologic Complete Response rates have been demonstrated to be correlated with longer time interval. The purpose of the trial is to demonstrate if delayed timing of surgery after neoadjuvant chemoradiotherapy actually affects pathologic Complete Response and reflects on disease-free survival and overall survival rather than standard timing.

METHODS

The trial is a multicenter, prospective, randomized controlled, unblinded, parallel-group trial comparing standard and delayed surgery after neoadjuvant chemoradiotherapy for the curative treatment of rectal cancer. Three-hundred and forty patients will be randomized on an equal basis to either robotic-assisted/standard laparoscopic rectal cancer surgery after 8 weeks or robotic-assisted/standard laparoscopic rectal cancer surgery after 12 weeks.

DISCUSSION

To date, it is well-know that pathologic Complete Response is associated with excellent prognosis and an overall survival of 90%. In the Lyon trial the rate of pCR or near pathologic Complete Response increased from 10.3 to 26% and in retrospective studies the increase rate was about 23-30%. These results may be explained on the relationship between radiation therapy and tumor regression: DNA damage occurs during irradiation, but cellular lysis occurs within the next weeks. Study results, whether confirmed that performing surgery after 12 weeks from neoadjuvant treatment is advantageous from a technical and oncological point of view, may change the current pathway of the treatment in those patient suffering from rectal cancer.

TRIAL REGISTRATION

ClinicalTrials.gov NCT3465982.

High precision radiotherapy including intensity-modulated radiation therapy and pulsed-dose-rate brachytherapy for cervical cancer: a retrospective monoinstitutional study

Purpose

To analyse the survival outcomes and toxicity profile of patients treated with pulsed-dose-rate (PDR) brachytherapy (BT) after intensity-modulated radiation therapy (IMRT) for uterine cervical cancer in a single institution.

Material and methods

Between March 2011 and December 2014, 50 patients with histologically proven stages IB1-IVB cervical cancer were treated with IMRT followed by PDR-BT boost. Radiation treatment consisted of IMRT to pelvic with or without paraaortic lymph nodes to a total dose of 45-50.4 Gy. Weekly concomitant chemotherapy was administered to 45 patients. PDR-BT boost was delivered with a median dose of 30 Gy to the high-risk clinical target volume (HR-CTV) after a median time of 14 days since IMRT. Acute and late toxicity were evaluated by Radiation Therapy Oncology Group (RTOG) - European Organization for Research and Treatment of Cancer (EORTC) scoring criteria and Subjective Objective Management Analytic-Late Effects of Normal Tissues (SOMA-LENT) criteria.

Results

Two patients had tumour persistence at 6 months after the end of BT. After a median follow-up of 33 months, 6 distant metastases with or without regional relapse were observed. The 1- and 5-year progression-free survival was 83% (95% CI: 69-91%) and 76% (95% CI: 61-86%), whereas the 3- and 5-year overall survival was 91% (95% CI: 78-97%) and 76% (95% CI: 56-88%), respectively. Urinary and rectal toxicity higher than grade 2 was observed in 6.3% and 17% of patients, respectively. Five patients (10.6%) had grade 4 gastrointestinal toxicity requiring colostomy.

Conclusions

Our study confirms that the combination of IMRT and PDR-BT can be considered an effective treatment for cervical cancer, ensuring high local control, despite the high percentage of locally advanced disease.

Impact of VMAT-IMRT compared to 3D conformal radiotherapy on anal sphincter dose distribution in neoadjuvant chemoradiation of rectal cancer

Background

Neoadjuvant radio- or chemoradiation (nIRT) therapy is the standard treatment for loco-regional advanced rectal cancer patients of the lower or middle third. Currently, intensity modulated radiation therapy (IMRT) is not the recommended radiation technique even though IMRT has advantages compared to 3D-radiation regarding dose sparing to organs at risk like small bowel and urinary bladder. So far, the benefit of IMRT concerning the anal sphincter complex is not examined. With this study we intended to evaluate the dose distribution on the anal sphincters of rectal cancer patients treated with IMRT in comparison with 3D-techniques.

Methods

We selected 16 patients for the IMRT-group and 16 patients for the 3D-group with rectal cancer of the middle third who were treated in our institute. All patients received 45 Gy in a chemoradiation protocol. Patients in both groups were matched regarding stage, primary tumor distance to the anal verge and size of the tumor. We delineated the internal and external anal sphincters, the addition of both sphincters and the levator ani muscle in all patients. Subsequently, we evaluated and compared dose parameters of the different sphincters in both groups and analysed the configuration of the isodoses in the area of the caudal radiation field, respectively.

Results

Most of the relevant dose parameters of the caudal sphincters (Dmean, Dmedian, V10–V40) were significantly reduced in the IMRT-group compared to the 3D-group. Accordingly, the isodoses at the caudal edge of the target volume in the IMRT group demonstrated a steep dose fall. The levator ani muscle always was included into the planned target volumes and received the full dose in both groups.

Conclusions

The modern VMAT-IMRT can significantly reduce the dose to the anal sphincters for rectal cancer patients of the middle third who were treated with conventional chemoradiation therapy.

Chemotherapy and molecular therapy in cervical cancer

In recent years, the treatment of locally-advanced and metastatic cervical cancer has improved greatly due to the introduction of targeted therapies, new chemotherapy combinations, and emerging treatments. Candidates for potentially curative treatment are those patients with good functional status without associated comorbidities. Numerous trials have demonstrated that chemotherapy prolongs survival versus supportive care alone. In addition, polychemotherapy schemes are superior to single agent regimens. Targeted molecular agents have proven beneficial in the treatment of cervical cancer. Second-line treatment should be considered standard practice in patients with good functional status. Finally, given the poor survival outcomes in patients with metastatic disease, participation in clinical studies should always be considered the best option.