Minimum absolute lymphocyte count during radiotherapy as a new prognostic factor for nasopharyngeal cancer

The predictors of lymphopenia and its effects on survival in locally advanced esophageal squamous cell carcinoma

To investigate the impact of the effective radiation dose to immune cells (EDIC) and gross tumor volume (GTV) on lymphopenia and survival in patients with locally advanced esophageal squamous cell carcinoma (LAESCC). Between January 2013 and December 2020, 272 LAESCC patients were treated with definitive radiotherapy in two institutions. Based on radiation doses to the lungs, heart, and body region scanned, EDIC was calculated as an equal uniform dose to the total blood considering blood flow and fraction effect. The radiotherapy plan was used to calculate the GTVs. Lymphopenia was graded based on the lowest lymphocyte count during RT. The overall survival (OS), progress-free survival (PFS), and local recurrence-free survival (LRFS) were analyzed statistically. The lowest lymphocyte count was significantly correlated with EDIC (r= -0.389, p < .001) and GTV (r= -0.211, p < .001). Lymphopenia, EDIC, and GTV are risk factors for patients with ESCC. In a Kaplan-Meier analysis with EDIC and GTV as stratification factors, lymphopenia was not associated with OS in the EDIC>12.9 Gy group (p = .294)and EDIC ≤ 12.9 Gy group, and it was also not associated with OS in GTV>68.8 cm3 group (p = .242) and GTV ≤ 68.8 cm3 group(p = .165). GTV and EDIC had an impact on the relationship between lymphopenia and OS in patients with LAESCC undergoing definitive RT. Poorer OS, PFS, and LRFS are correlated with lymphopenia, higher EDIC, and larger GTV.

Machine learning-derived prognostic signature for progression-free survival in non-metastatic nasopharyngeal carcinoma

BACKGROUND

Early detection of high-risk nasopharyngeal carcinoma (NPC) recurrence is essential. We created a machine learning-derived prognostic signature (MLDPS) by combining three machine learning (ML) models to predict progression-free survival (PFS) in patients with non-metastatic NPC.

METHODS

A cohort of 653 patients with non-metastatic NPC was divided into a training (n = 457) and validation (n = 196) dataset (7:3 ratio). The study included clinicopathological characteristics, hematologic markers, and MRI findings in three machine learning models-random forest (RF), extreme gradient boosting (XGBoost), and least absolute shrinkage and selection operator (LASSO)-to predict progression-free survival (PFS). A Venn diagram identified the overlapping signatures from the three ML algorithms. Cox proportional hazard analysis determined the MLDPS for PFS.

RESULTS

The RF, XGBoost, and LASSO algorithms identified six consensus factors from the 33 signatures. Cox proportional hazards analysis showed that the MLDPS includes age, lymphocyte count, number of positive lymph nodes, and regional lymph node density. Additionally, MLDPS effectively stratified prognosis, with low-risk individuals showing better PFS than high-risk individuals (p < 0.001).

CONCLUSION

MLDPS, based on clinicopathological characteristics, hematologic markers, and MRI findings, is crucial for guiding clinical management and personalizing treatments for patients with non-metastatic NPC.

Nomograms containing body dose parameters for predicting survival in patients with nasopharyngeal carcinoma

PURPOSE

To assess the impact of body dose on survival outcomes in nasopharyngeal carcinoma (NPC) patients and to create novel nomograms incorporating body dose parameters for predicting survival.

METHODS

594 of non-metastasis NPC patients (training group, 396; validation group, 198) received intensity-modulated radiation therapy at our institution from January 2012 to December 2016. Patient characteristics, body dose parameters in dose-volume histogram (DVH) and hematology profiles were collected for predicting overall survival (OS) and progression-free survival (PFS). Nomograms for OS and PFS were developed using the selected predictors. Each nomogram was evaluated based on its C-index and calibration curve.

RESULTS

Body dose-based risk score for OS (RSOS), N stage, age, and induction chemotherapy were independent predictors for OS, with a C-index of 0.784 (95% CI 0.749-0.819) in the training group and 0.763 (95% CI 0.715-0.810) in the validation group for the nomogram. As for PFS, the most important predictors were the body dose-based risk score for PFS (RSPFS), N stage, and induction chemotherapy. C-index of PFS nomogram was 0.706 (95% CI 0.681-0.720) in the training group and 0.691 (95% CI 0.662-0.711) in the validation group. The two models outperformed the TNM staging system in predicting outcomes.

CONCLUSIONS

Body dose coverage is a useful predictor of prognosis in clinical routine patients. The novel nomograms integrating body dose parameters can precisely predict OS and PFS in NPC patients.

Dosimetric Effect of Thymus and Thoracic Duct on Radiation-Induced Lymphopenia in Patients With Primary Lung Cancer Who Received Thoracic Radiation

Purpose

Radiation-induced lymphopenia is a well-recognized factor for tumor control and survival in patients with cancer. This study aimed to determine the role of radiation dose to the thymus and thoracic duct on radiation-induced lymphopenia.

Methods and Materials

Patients with primary lung cancer treated with thoracic radiation therapy between May 2015 and February 2020 with whole blood count data were eligible. Clinical characteristics, including age, gender, histology, stage, chemotherapy regimen, radiation dosimetry, and absolute lymphocyte count (ALC) were collected. The thymus and thoracic duct were contoured by one investigator for consistency and checked by one senior physician. The primary endpoint was radiation-induced decrease in lymphocytes, defined as the difference in ALC (DALC) before and after radiation therapy.

Results

The data of a total of 116 consecutive patients were retrospectively retrieved. Significant correlations were found between DALC and several clinical factors. These factors include stage, chemotherapy or concurrent chemoradiation, biologically effective dose (BED), mean lung dose, mean body dose, effective dose to immune cells (EDIC), mean thymus dose (MTD), and mean thoracic duct dose (MTDD) (all P < .05). Ridge regression showed that DALC = 0.0063 × BED + 0.0172 × EDIC + 0.0002 × MTD + 0.0147 × MTDD + 0.2510 (overall P = .00025 and F = 5.85). The combination model has the highest area under the curve of 0.77 (P < .001) when fitting the logistic regression model on DALC categorized as binary endpoint. The sensitivity and specificity of the combined model were 89% and 58%, respectively.

Conclusions

This study demonstrated for the first time that radiation doses to the thymus and thoracic duct are strongly associated with radiation-induced lymphopenia patients with lung cancer. Further validation studies are needed to implement thymus and thoracic duct as organs at risk.

CT-based dosiomics and radiomics model predicts radiation-induced lymphopenia in nasopharyngeal carcinoma patients

Purpose

This study aims to develop and validate a model predictive for the incidence of grade 4 radiation-induced lymphopenia (G4RIL), based on dosiomics features and radiomics features from the planning CT of nasopharyngeal carcinoma (NPC) treated by radiation therapy.

Methods

The dataset of 125 NPC patients treated with radiotherapy from August 2018 to March 2019 was randomly divided into two sets-an 85-sample training set and a 40-sample test set. Dosiomics features and radiomics features of the CT image within the skull bone and cervical vertebrae were extracted. A feature selection process of multiple steps was employed to identify the features that most accurately forecast the data and eliminate superfluous or insignificant ones. A support vector machine learning classifier with correction for imbalanced data was trained on the patient dataset for prediction of RIL (positive classifier for G4RIL, negative otherwise). The model's predictive capability was gauged by gauging its sensitivity (the likelihood of a positive test being administered to patients with G4RIL) and specificity in the test set. The area beneath the ROC curve (AUC) was utilized to explore the association of characteristics with the occurrence of G4RIL.

Results

Three clinical features, three dosiomics features, and three radiomics features exhibited significant correlations with G4RIL. Those features were then used for model construction. The combination model, based on nine robust features, yielded the most impressive results with an ACC value of 0.88 in the test set, while the dosiomics model, with three dosiomics features, had an ACC value of 0.82, the radiomics model, with three radiomics features, had an ACC value of 0.82, and the clinical model, with its initial features, had an ACC value of 0.6 for prediction performance.

Conclusion

The findings show that radiomics and dosiomics features are correlated with the G4RIL of NPC patients. The model incorporating radiomics features and dosiomics features from planning CT can predict the incidence of G4RIL in NPC patients.

[Radiation-induced lymphopenia: Lymphocytes as a new organ at risk]

Taking the immune system into account in the fight against tumors has upset the cancer treatment paradigm in the 21st century. Combination treatment strategies associating radiotherapy with immunotherapy are being increasingly implemented in clinical practice. In this context, lymphocytes, whether lymphocytes infiltrating the tumour, circulating blood lymphocytes or lymphocytes residing within the lymph nodes, are key players in cellular and humoral anti-tumor immunity. The significant radiosensitivity of lymphocytes was demonstrated in the early 1990s. Along with the cells of the digestive mucosa, lymphocytes are thus among the most radiosensitive cell types in the body. Compared to the old practices of external radiotherapy, current intensity modulated treatments have allowed a considerable improvement in acute and late toxicity, at the cost of a significant increase in the volume irradiated at low doses. This is not without consequence on the incidence of radiation-induced lymphopenia, with prognostic implications for many tumor types. Thus, in order not to hinder the action of antitumor immunity and the efficacy of immunotherapy, it is essential to consider lymphocytes as a new organ at risk in its own right. In this development, based on current data from the literature, we will begin by justifying the necessary prevention of radiation-induced lymphopenia, before providing the tools currently known to apprehend lymphocytes as a new multicompartments. Finally, we will broaden the perspective by outlining ways to develop research in this area.

Pericardial irradiation dose may be strongly associated with grade 4 lymphopenia and affect prognosis in patients with locally advanced esophageal cancer receiving definitive concurrent chemoradiotherapy

BACKGROUND

The immune system may influence prognosis, and lymphopenia is a frequent side effect of concurrent chemoradiotherapy (CCRT). Radical irradiation for locally advanced esophageal cancer (LA-EC) exposes significant vascular and heart volumes. In this study, we hypothesized that lymphopenia is linked to cardiac and pericardial doses and affects patient prognosis.

METHODS AND MATERIALS

We identified 190 LA-EC patients who received radical CCRT. Multivariate analysis (MVA) was performed to correlate clinical factors and dosimetric parameters with overall survival (OS). We collected lymphocyte-related variables and ratios before and during CCRT. MVA was performed to correlate hematologic toxicity with OS. The relationship between dosimetric parameters and G4 lymphopenia was determined using logistic stepwise regression. Finally, a nomogram of G4 lymphopenia was developed and validated externally.

RESULTS

Median follow-up time for all patients was 27.5 months. On MVA for OS, higher pericardial V30 (PV30 ) was linked to worse survival (HR: 1.013, 95% CI: 1.001-1.026, p = 0.039). The median OS stratified by PV30  > 55.3% and PV30  ≤ 55.3% was 24.0 months and 54.0 months, respectively (p = 0.004). G4 lymphopenia was shown to be linked with worse OS in the MVA of hematological toxicity with OS (HR: 2.042, 95% CI: 1.335-3.126, p = 0.001). Thirty of the 100 patients in the training set had G4 lymphopenia. Logistic stepwise regression was used to identify variables associated with G4 lymphopenia, and the final model consisted of stage-IVA (p = 0.017), platelet-to-lymphocyte ratio during CCRT (p = 0.008), Heart V50 (p = 0.046), and PV30 (p = 0.048). Finally, a nomogram predicting G4 lymphocytopenia were constructed and externally validated. The ROC curve showed an AUC for internal validation of 0.775 and external validation of 0.843.

CONCLUSION

Higher doses of pericardial radiation might affect LA-EC patients' prognosis by inducing G4 lymphopenia during CCRT. Further prospective studies are warranted to confirm these findings, especially in the era of immune-checkpoint inhibitor treatment.

Nomogram incorporating potent inflammatory indicators for overall survival estimation of patients with primary oral squamous cell carcinoma

Background

Inflammation has been recognized to be a factor that substantially influences tumorigenesis and tumor prognosis. Hence, this study was aimed to investigate an inflammatory marker with the most potent prognostic ability and to evaluate the survival estimation capability of dynamic change in this marker for patients suffered from oral squamous cell carcinoma (OSCC).

Methods

469 patients' inflammatory indicators including lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic inflammatory response index (SIRI), were calculated. Their predictive abilities for overall survival (OS) were evaluated by Kaplan-Meier curves to screen for the one with the most potent prognostic value. The predictive ability of dynamic changes in this marker was verified and a predictive nomogram incorporating inflammatory indicators was developed.

Results

A high LMR was identified to be an indicator of a satisfactory survival rate. Compared with that of other inflammatory markers, area under the receiver operating characteristics (ROC) curve (AUC) of LMR for 1-year and 3-year OS was significantly larger (P<0.001). Dynamic LMR change remained an significant parameter for predicting OS (OR: 2.492, 95% CI: 1.246-4.981, p = 0.010). The nomogram incorporating LMR exhibited a superior prognostic significance than the TNM system, as suggested by the C-index (0.776 vs 0.651 in primary cohort; 0.800 vs 0.707 in validation cohort, P<0.001) and AUC.

Conclusions

LMR was demonstrated to possess a more potent survival estimation capability than the other three inflammatory parameters. Dynamic changes in LMR serves as a significant parameter for overall survival estimation of primary OSCC patients. The established nomogram incorporating inflammatory markers showed more accuracy and sensitivity for survival estimation of primary OSCC patients.

Prognostic Significance of the Post-Treatment Neutrophil-to-Lymphocyte Ratio in Pharyngeal Cancers Treated with Concurrent Chemoradiotherapy

BACKGROUND

Even though the pre-treatment neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are well-established prognosticators in various cancers including head and neck cancers, there have been relatively few studies on the clinical significance of the post-treatment values. This study aimed to investigate the changes in NLR and PLR after concurrent chemoradiotherapy (CCRT) and to evaluate their prognostic significance in pharyngeal cancers.

METHODS

This study was retrospectively conducted on 461 consecutive patients with primary pharyngeal cancer who had received definitive CCRT. Blood test results before and after CCRT were obtained, and the pre- and post-treatment NLR and PLR were calculated. Patient prognosis was evaluated based on overall survival (OS) and relapse-free survival (RFS).

RESULTS

After CCRT, the NLR increased from 2.01 (interquartile range (IQR), 1.53-2.62) to 2.69 (IQR, 1.93-3.81), and the PLR increased from 118.84 (IQR, 92.61-151.63) to 193.19 (IQR, 146.28-262.46). Along with high pre-treatment NLR and high pre-treatment PLR, high post-treatment NLR was also significantly associated with worse OS and RFS (p = 0.013 and p = 0.026). In addition, patients with a high ΔNLR (i.e., the difference between pre- and post-treatment NLRs) had significantly worse OS and RFS (p = 0.013 and p = 0.026). However, only a high pre-treatment NLR (hazard ratio (HR), 2.19; 95% confidence interval (CI), 1.17-4.08; p = 0.014), age (HR, 2.16; 95% CI, 1.14-4.08; p = 0.018), and stage IV (HR, 2.11; 95% CI, 1.15-3.89; p = 0.017) were independent prognostic factors for OS in the multivariate analysis.

CONCLUSIONS

In patients with pharyngeal cancers, following CCRT, the NLR and PLR increased significantly from pre-treatment values. Like the pre-treatment NLR and PLR, a high post-treatment NLR and a significant increase in NLR were also associated with poor prognosis. Further prospective studies are required to prove the independent significance of the post-treatment NLR and PLR.

Effect of lymphoid volume irradiation on radiation-induced lymphopenia in head and neck cancers

PURPOSE

Radiotherapy induces significant and prolonged lymphopenia in head and neck cancer patients with poorer outcomes and reduced survival. Irradiated volumes may be correlated with lymphopenia with a potential impact on immunotherapy efficacy. We assessed associations between volumes treated with radiotherapy and the nadir of the lymphocyte count in patients with head and neck cancer.

MATERIALS AND METHODS

We conducted a monocentric retrospective study in patients with head and neck cancer treated with radiation. Univariate analysis used regression analysis to model nadir lymphocyte count and radiotherapy volumes; multivariate analysis then modelled factors associated with nadir lymphocyte count.

RESULTS

Of the 77 included patients, 97% presented lymphopenia during radiotherapy with an average nadir of 431 cells/mm³ at a median of 40 days after the beginning of treatment. The volume of high-risk radiotherapy and gross tumour volume were correlated with nadir lymphocyte count with a Spearman coefficient of -0.267 (P=0.019) and -0.387 (P=0.001), respectively. After multivariate linear regression, high-risk radiotherapy was significantly associated with nadir lymphocyte count with a regression coefficient of -0.32 (per cubic centimetre) [95% CI=-0.60; -0.03] (P=0.028).

CONCLUSION

High-risk radiotherapy was significantly associated with nadir lymphocyte count in patients with head and neck cancer treated with radiation. Sparing lymphoid volumes from irradiation by elective nodal irradiation or proton therapy may limit lymphopenia and needs to be investigated in combination with immunotherapy.

Establishment of a prognostic nomogram for patients with locoregionally advanced nasopharyngeal carcinoma incorporating clinical characteristics and dynamic changes in hematological and inflammatory markers

Background

This study aims to investigate the prognostic value of changes in hematological and inflammatory markers during induction chemotherapy (IC) and concurrent chemo-radiation (CCRT), thus construct nomograms to predict progression free survival (PFS) of patients with locally advanced nasopharyngeal carcinoma (LANPC).

Methods

130 patients were included in this prospective analysis. Univariate and multivariate cox regression analyses were conducted to identify prognostic factors. Three multivariate analyses integrating different groups of variables were conducted independently. Concordance indexes (c-index), calibration plots and Kaplan-Meier curves were used to evaluate the nomograms. Bootstrap validation was performed to determine the accuracy of the nomogram using 1000 resamples. The performances of proposed nomograms and TNM staging system were compared to validate the prognostic value of hematological and inflammatory markers.

Results

Pretreatment gross tumor volume of nodal disease (GTVn), Δe/bHGB (hemoglobin count at end of treatment/baseline hemoglobin count), and stage were selected as predictors for 3-year PFS in first multivariate analysis of clinical factors. The second multivariate analysis of clinical factors and all hematological variables demonstrated that ΔminLYM (minimum lymphocyte count during CCRT/lymphocyte count post-IC), pretreatment GTVn and stage were associated with 3-year PFS. Final multivariate analysis, incorporating all clinical factors, hematological variables and inflammatory markers, identified the following prognostic factors: pretreatment GTVn, stage, ΔmaxPLR (maximum platelet-to-lymphocyte ratio (PLR) during CCRT/PLR post-IC), and ΔminPLT (minimum platelet count during CCRT/platelet count post-IC). Calibration plots showed agreement between the PFS predicted by the nomograms and actual PFS. Kaplan–Meier curves demonstrated that patients in the high-risk group had shorter PFS than those in the low-risk group (P ≤ 0.001). The c-indexes of the three nomograms for PFS were 0.742 (95% CI, 0.639-0.846), 0.766 (95% CI, 0.661-0.871) and 0.815 (95% CI,0.737-0.893) respectively, while c-index of current TNM staging system was 0.633 (95% CI, 0.531-0.736).

Conclusion

We developed and validated a nomogram for predicting PFS in patients with LANPC who received induction chemotherapy and concurrent chemo-radiation. Our study confirmed the prognostic value of dynamic changes in hematological and inflammatory markers. The proposed nomogram outperformed the current TNM staging system in predicting PFS, facilitating risk stratification and guiding individualized treatment plans.

Impact of hematologic toxicities during concurrent chemoradiation for cervical cancer

Objective

To evaluate the prognostic significance of hematological toxicities during cervical cancer treatment.

Methods

Patients treated for cervical carcinoma with definitive chemoradiation were identified. Toxicities were assessed during weeks 1 to 6 of concurrent external beam radiation and chemotherapy. Outcomes were analyzed using Cox regression analysis.

Results

One hundred twenty-one patients with Federation of Gynecology and Obstetrics stage I–III disease were eligible for analysis. Median age at diagnosis was 45 years (interquartile range, 40–52) with median follow-up time of 34 months (95% confidence interval, 30.8–37.2). All patients experienced some grade of hematologic toxicity. The most common grade 3+ toxicities were low absolute lymphocyte count (n=115, 95%), low white blood cell count (n=21, 17%), and anemia (n=11, 9%). The most common grade 4 toxicity was lymphopenia, experienced by 36% of patients (n=44). Grade 4 lymphopenia was associated with reduced overall survival (hazard ratio [HR], 4.5; P=0.005), progression-free survival (HR, 3.4; P=0.001), and local control (HR, 4.1; P=0.047). Anemia grade 3, 4 was also associated with reduced overall survival (HR, 4.1; P=0.014). After controlling for disease and treatment variables, grade 4 lymphopenia remained significantly associated with reduced overall survival (HR, 9.85; P=0.007). The association with grade 4 lymphopenia only remained significant in women of Hispanic ethnicity.

Conclusion

Severe lymphopenia was associated with reduced overall survival and progression-free survival in Hispanic women undergoing definitive chemoradiation for cervical cancer, but not associated with outcomes in non-Hispanic women.

Treatment-related lymphopenia impairs the treatment response of anti-PD-1 therapy in esophageal squamous cell carcinoma

PURPOSE

Great interest has been focused on radiotherapy (RT) with immunotherapy. We sought to investigate the significance of treatment-related lymphopenia (TRL) in esophageal squamous cell carcinoma (ESCC) patients receiving anti-PD-1 therapy and the factors associated with TRL, especially RT.

METHODS

167 patients with ESCC that received anti-PD-1 therapy wereidentified, 72 of them received RT. TRL was defined as absolute lymphocyte count (ALC) < 0.50 × 10⁹ cells/L at the start of immunotherapy and/or during immunotherapy. Depending on the presence of TRL, patients were divided into two groups.

RESULTS

At median follow-up of 6.5 months, the ORR of patients without TRL (n = 65; 38.9%) reached 29.4% while patients (n = 102; 61.1%) with TRL was 23.1%, DCR was 81.4% and 75.4% respectively. Patients with TRL showed shorter progression-free survival (PFS) compared with patients without TRL (median PFS: 4.8 vs. 7.0 months, P = 0.009). Multivariate analyses confirmed TRL is an independent prognostic factor for poorer PFS (HR, 1.855; P = 0.008). RT significantly increased the occurrence of TRL (OR = 0.502, P = 0.035). Patients receiving ICIs < 33.5 days after RT showed a poorer PFS compared to that ≥ 33.5 days (median PFS: 4.1 vs 7.3 months, P = 0.008). The explanation is that patients with shorter time interval had a higher incidence of TRL (P = 0.028).

CONCLUSION

TRL was an independent predictor of poor outcomes in ESCC patients receiving anti-PD-1 therapy. RT was a key factor affecting TRL. A shorter time interval of < 33.5 days between RT and anti-PD-1 therapy can lead to a poor prognosis by increasing the occurrence of TRL.

Shortened Radiation Time Promotes Recovery From Radiation-induced Lymphopenia in Early-Stage Non-small Cell Lung Cancer Patients Treated With Stereotactic Body Radiation Therapy

Background: To evaluate the potential impact of radiation time on radiation-induced lymphopenia (RIL) and subsequently recovery after stereotactic body radiation therapy (SBRT) and to examine the associations between radiation time and with patient outcomes in early-stage non-small cell lung cancer (NSCLC). Methods: Clinical and laboratory records of subjects consisted of 115 patients who had received SBRT for early-stage NSCLC. Clinical and laboratory records were retrospective reviewed to assess the changes in total lymphocyte counts (TLCs) following SBRT. Associations of TLCs kinetics with the clinical and treatment features, and outcomes were analyzed. Results: Most patients (100/115, 86.96%) experienced significantly decreased median TLCs following SBRT (1700 vs 1100 cells/µL; P < .001), and 52 patients (45.21%) met the criteria for lymphopenia. Six months after SBRT, 44 patients (38.26%) had recovered. A negative correlation between TLCs reduction and radiation time was observed (r = −0.381, P < .001). According to the receiver-operating characteristic curve analysis, the optimal cut-off value for radiation time to was 3950 s to predict lymphocyte count recovery (LR) following RIL was 3950 s (P < .001). Multivariate analyses demonstrated that radiation time was significantly associated with LR (odds ratio [OR], 0.113; 95% confidence interval [CI], 0.029-0.432; P = .001) but not TLCs reduction (P = .575). LR within 6 months after SBRT was associated with improved progression-free survival in patients without non-lymphopenia (P = .034), but had little effect in patients with lymphopenia (P = .405). Conclusion: A longer radiation time was associated with a lower rate of LR within 6 months after SBRT in patients with early-stage NSCLC. Given the association of severe and persistent RIL with survival in NSCLC, further study of the effect of radiation time on immune status is warranted.

Aberrant Alteration of Circulating Lymphocyte Subsets in Small Cell Lung Cancer Patients Treated with Radiotherapy

Purpose: The role of different circulating lymphocyte subsets, as well as their correlation with clinical characteristics of small cell lung cancer patients have not yet been fully understood. This study aims to evaluate the influence of the fluctuating absolute numbers of lymphocyte subpopulations in peripheral blood of patients with small cell lung cancer. Methods: The absolute counts and percentages of lymphocyte subsets in peripheral blood of 329 patients with small cell lung cancer were retrospectively analyzed. The numbers of CD3⁺, CD3⁺CD4⁺, and CD3⁺CD8⁺ T lymphocytes, CD3^-CD19⁺ B lymphocytes, and CD3^-CD16⁺CD56⁺ NK cells were evaluated by flow cytometry. Their relationship with the patients' clinical characteristics were statistically evaluated. Results: The CD4/CD8 values derived from the absolute number and percentage of CD3⁺CD4⁺ cells divided by CD3⁺CD8⁺ cells were identical (1.86  ±  0.99). There was no association between any of the lymphocyte subsets levels and age/sex of the 329 patients with small cell lung cancer. The patients with advanced stage had a reduction in CD3⁺ and CD3⁺CD4⁺ T cell counts and a decreased CD4/CD8 ratio. The levels of CD3⁺CD4⁺ T cells, CD3^-CD19⁺ B cells, CD3^-CD16⁺CD56⁺ NK cells, and CD4/CD8 ratio were associated with advanced tumor-node-metastasis stage. Patients who had undergone radiotherapy were characterized by lymphopenia with lower numbers of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺ T lymphocyte, B lymphocyte, NK cell, and CD4/CD8 ratio. The evaluation of individual CD4/CD8 ratio should be combined with other clinical parameters. Conclusions: Patients with small cell lung cancer have altered lymphocyte homeostasis. Lymphopenia was a long-lasting feature of the enrolled patients who were treated with radiotherapy. The available lymphocyte subsets levels might be used to manage the clinical treatment scheme.

Can Rational Combination of Ultra-high Dose Rate FLASH Radiotherapy with Immunotherapy Provide a Novel Approach to Cancer Treatment?

FLASH radiotherapy (FLASH-RT) delivers radiation treatment at an ultra-high dose rate that is several orders of magnitude higher than current clinical practice. In multiple preclinical studies, FLASH-RT has shown consistent normal tissue sparing effects while preserving equivalent antitumour activity in comparison with conventional dose rate radiation treatment. This is known as the 'FLASH effect'. Given the recent research interest in combining hypofractionated radiotherapy with immunotherapy to try to improve clinical outcomes, there is an intriguing clinical question as to whether FLASH irradiation may be a rational partner to combine with immune modulating drugs? To better predict the synergistic effect of both modalities, here we review the biological mechanisms of how FLASH differentially impacts the immune landscape, including circulating immune cells, tumour microenvironment and the inflammatory response. In order to make recommendations for future research, we summarise all published studies that investigated the immune modulatory effects of FLASH-RT and further explore the scientific reasons for combining FLASH with immunotherapy for potential clinical applications.

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.

[Effects of neoadjuvant chemoradiotherapy on infiltrating immune cells in the tumor microenvironment of rectal cancer]

OBJECTIVE

To detect the changes in the number and phenotype of tumor infiltrating immune cells in rectal cancer tissues before and after neoadjuvant concurrent chemoradiotherapy (CRT) and analyze their correlation with the clinicopathological parameters of the patients.

METHODS

The protein expressions of CD3, CD4, CD8, CD56 and Foxp3 in biopsy specimens and postoperative pathological specimens collected from 20 rectal cancer patients before and after neoadjuvant CRT were detected using Elivision^TM Plus immunohistochemistry, and the results were statistically analyzed.

RESULTS

Compared with the measurements before the therapy, neoadjuvant CRT resulted in significant increments in CD3 (21.8% vs 48.8%, P < 0.001), CD4(16.5% vs 42.2%, P < 0.001), CD8(8.3% vs 33.4%, P < 0.001)and CD56(0 vs 7.6%, P=0.012), obvious reduction in Foxp3 expression(26.0% vs 15.3%, P=0.005), but no significant changes in CD4/CD8 ratio of(2.7 vs 5.1).Multivariate analysis showed that the increase of CD3-positive cells(HR=0.16, P=0.028)and CD8-positive cells(HR=0.03, P=0.001)was positively correlated with the disease-free survival of the patients after the operation.

CONCLUSION

Neoadjuvant CRT can significantly increase the proportions of infiltrating immune cells positive for CD3, CD4, CD8 and CD56 and decrease the proportion of Treg lymphocytes in the tumor tissues in patients with rectal cancer.The patients with increased CD3-and CD8-positive T lymphocytes may have longer disease-free survival after the surgery.

Comparative prognostic value of different preoperative complete blood count cell ratios in patients with oral cavity cancer treated with surgery and postoperative radiotherapy

Background

We sought to compare the prognostic significance of different preoperative complete blood count cell ratios in patients with oral cavity squamous cell carcinoma (OSCC) treated with surgery and postoperative radiotherapy (PORT).

Methods

We retrospectively reviewed the clinical records of 890 patients with OSCC who were treated with surgery and PORT. The following preoperative complete blood count cell ratios were collected: neutrophil‐to‐lymphocyte ratio (NLR), platelet‐to‐lymphocyte ratio (PLR), and lymphocyte‐to‐monocyte ratio (LMR). Overall survival (OS), local control, regional control, and distant control (DC) served as the main outcomes of interest.

Results

The results of multivariate analysis in the entire study cohort revealed that a low NLR was the only independently favorable marker of both OS (adjusted hazard ratio [HR]: 0.794, 95% confidence interval (CI): 0.656–0.961, bootstrap p = 0.028) and DC (adjusted HR: 0.659, 95% CI: 0.478–0.909, bootstrap p = 0.015). Both LMR and PLR were not retained in the model as independent predictors. Subgroup analyses in high‐risk patients (i.e., those bearing T4 disease, N3 disease, or poor differentiation) revealed that a high NLR was a significant adverse risk factor for both OS and DC (all p < 0.03)—with a borderline significance being evident for DC in patients with T4 disease (p = 0.058).

Conclusions

A high pretreatment NLR was an independent unfavorable risk factor for both OS and DC in patients with OSCC who underwent surgery and PORT. No other preoperative complete blood count parameters and cell ratios were found to have prognostic significance.

Use of Multi-Site Radiation Therapy for Systemic Disease Control

Metastatic cancer is a heterogeneous entity, some of which could benefit from local consolidative radiation therapy (RT). Although randomized evidence is growing in support of using RT for oligometastatic disease, a highly active area of investigation relates to whether RT could benefit patients with polymetastatic disease. This article highlights the preclinical and clinical rationale for using RT for polymetastatic disease, proposes an exploratory framework for selecting patients best suited for these types of treatments, and briefly reviews potential challenges. The goal of this hypothesis-generating review is to address personalized multimodality systemic treatment for patients with metastatic cancer. The rationale for using high-dose RT is primarily for local control and immune activation in either oligometastatic or polymetastatic disease. However, the primary application of low-dose RT is to activate distinct antitumor immune pathways and modulate the tumor stroma in efforts to better facilitate T cell infiltration. We explore clinical cases involving high- and low-dose RT to demonstrate the potential efficacy of such treatment. We then group patients by extent of disease burden to implement high- and/or low-dose RT. Patients with low-volume disease may receive high-dose RT to all sites as part of an oligometastatic paradigm. Subjects with high-volume disease (for whom standard of care remains palliative RT only) could be treated with a combination of high-dose RT to a few sites for immune activation, while receiving low-dose RT to several remaining lesions to enhance systemic responses from high-dose RT and immunotherapy. We further discuss how emerging but speculative concepts such as immune function may be integrated into this approach and examine therapies currently under investigation that may help address immune deficiencies. The review concludes by addressing challenges in using RT for polymetastatic disease, such as concerns about treatment planning workflows, treatment times, dose constraints for multiple-isocenter treatments, and economic considerations.

Significance of lymphocyte recovery from treatment-related lymphopenia in locally advanced pancreatic cancer

BACKGROUND AND PURPOSE

Radiation-induced lymphopenia is associated with poor prognosis in resected pancreatic cancer and locally advanced pancreatic cancer. However, whether lymphocyte recovery contributes to pancreatic cancer prognosis has not been well-investigated.

MATERIALS AND METHODS

We evaluated 497 locally advanced pancreatic cancer patients who underwent concurrent chemoradiotherapy (CCRT). Complete blood counts of patients were obtained before, during, and after CCRT until the 12-month follow-up visit. Patients were categorized into 3 groups according to the development of and recovery from acutte severe lymphopenia (ASL): no ASL (group A, n = 198), recovery from ASL (group B, n = 141), and no recovery from ASL (group C, n = 89). Prognostic factors of overall survival (OS) and progression-free survival (PFS) were determined using Cox regression analyses.

RESULTS

In groups A, B, and C, the 2-year OS rates were 40.4%, 31.9%, and 14.6%, respectively, and the 2-year PFS rates were 23.7%, 18.4%, and 10.1%, respectively. OS and PFS were comparable between Groups A and B, while group C had poor OS and PFS (p < 0.001). Recovery from ASL was associated with superior OS (HR 0.42, 95% CI: 0.32-0.55, p < 0.001) and PFS (HR 0.53, 95% CI: 0.41-0.70, p < 0.001). The baseline lymphocyte counts and target volume independently predicted development and recovery from ASL.

CONCLUSION

Recovery from ASL was associated with both superior OS and PFS in patients who received CCRT for locally advanced pancreatic cancer. Baseline lymphocyte counts and target volume were associated with both the development of and recovery from treatment-related ASL.

[Mechanisms of radiation-induced lymphopenia and therapeutic impact]

Radiation induced lymphopenia is frequent and can be severe and durable. Although lymphocytes have long been known as highly radiosensitive cells, it is poorly characterized. Radiation-induced lymphopenia seems to affect lymphocyte subpopulations differently and seems to be influenced by radiation modalities. The depth and duration of lymphopenia depend on the location of the irradiation and the volumes of treatment. Importantly, radiation-induced lymphopenia has been associated with poorer prognosis in several tumor types. The knowledge about radiation-induced lymphopenia might lead to a rethinking of the modalities of radiotherapy and new approaches to restore lymphocytes counts.

Mean cardiopulmonary dose and vertebral marrow dose differentially predict lineage-specific leukopenia kinetics during radiotherapy for esophageal cancer

BACKGROUND AND PURPOSE

Lymphopenia is associated with poor outcomes in esophageal cancer (EC) patients undergoing chemoradiotherapy (CRT). We hypothesized that radiation dose to marrow (central) vs. circulating (peripheral) leukocytes (WBCs) may have unique effects on WBC counts and clinical outcomes in EC.

MATERIALS AND METHODS

Weekly and 90-day post-CRT blood cell counts were evaluated for 46 patients with stage II-III EC treated with CRT. Thoracic vertebral volume spared (TVS) radiation was extracted from dose volume histograms (DVH). Mean cardiopulmonary dose (mCPD) was calculated as mean dose to the volumetric sum of heart, lungs, and great vessels as a surrogate for circulating blood pool. Linear and logistic regression identified associations between dosimetric variables and hematologic toxicities (HT). Repeated measures ANOVA tested associations between cell count trends and clinical predictors.

RESULTS

WBCs and platelets reached nadir at week 6 of CRT. On multivariate analysis, mCPD was associated with lower WBC and neutrophil nadirs (p < 0.05). TVS5-40 Gy were associated with higher lymphocyte nadirs (all p < 0.05). Repeated measures ANOVA revealed an interaction effect of sex on absolute lymphocyte trend as well as age (<67 vs. >67) and diabetes on normalized lymphocyte trend (all p < 0.015).

CONCLUSIONS

mCPD and volume of thoracic marrow spared radiation differentially predict lineage-specific leukopenias during CRT for EC. mCPD is significantly associated with lower total WBC and neutrophil nadirs. In contrast, greater thoracic marrow spared radiation is associated with mitigation of lymphopenia during CRT. Clinical factors such as sex, age, and diabetes may be associated with a more rapid decline in hematologic counts during treatment.

The impact of the effective dose to immune cells on lymphopenia and survival of esophageal cancer after chemoradiotherapy

PURPOSE

To test the hypothesis that effective dose to circulating immune cells (EDIC) impacts the severity of radiation-induced lymphopenia and clinical outcomes of esophageal cancer patients treated with concurrent chemoradiotherapy (CCRT).

MATERIAL AND METHODS

488 esophageal cancer patients treated with CCRT with and without surgery were analyzed. The EDIC model considers the exposure of circulating immune cells as the proportion of blood flow to lung, heart, liver, and the volume of the exposed area of the body, with the basis of mean lung dose (MLD), mean heart dose (MHD), mean liver dose (MlD), and integral dose (ITD) of the body region scanned, calculated as: EDIC=0.12∗MLD+0.08∗MHD+0.15∗0.85∗MlD∗n45^1/2+0.45+0.35∗0.85∗nk^1/2∗ITD62∗10³ Where n is the fraction number. Correlations of EDIC with overall survival (OS), progression free survival (PFS), distant metastasis free survival (DMFS), and locoregional control (LRC) rates were analyzed using both univariable and multivariable Cox models. Lymphopenia during CCRT was graded according to Common Terminology Criteria for Adverse Events version 4.0.

RESULTS

Grade 4 lymphopenia resulted in inferior clinical outcomes, including OS, PFS, and DMFS. The median EDIC was 3.6 Gy (range, 0.8-6.0 Gy). Higher EDIC was strongly associated with severe lymphopenia, particularly when EDIC was above 4 Gy. Patients with EDIC > 4.0 Gy had more G4 lymphopenia than those with EDIC ≤ 4.0 Gy (67.3% vs. 40.8%; P < 0.001). On multivariate analysis, increasing EDIC was independently and inversely associated with worse OS, PFS, and DMFS.

CONCLUSION

EDIC can be recommended as a useful tool to predict lymphopenia and inferior clinical outcomes, and it should be minimized below 4 Gy.

Radiation-induced lymphopenia correlates with survival in nasopharyngeal carcinoma: impact of treatment modality and the baseline lymphocyte count

Background and purpose

We evaluated the relationship between patient-, tumor-, and treatment-related features and radiation-induced lymphopenia (RIL) and evaluated the correlation between RIL and survival outcome in NPC patients to help improve the treatment strategy.

Methods

This retrospective study included 374 patients with stage II-IVa NPC who had been treated with definitive RT and were enrolled from 2004 to 2015; The associations between the G3–4 RIL (absolute lymphocyte count, ALC <  0.5 × 10⁹ cells/L) during RT and patient-, tumor-, and treatment-related factors were assessed using Cox regression analyses. The correlation between ALC nadir and survival was examined using a Kaplan-Meier analysis, compared with the log-rank test, and confirmed by a Cox proportional hazards analysis.

Results

In the multivariate analysis, lower baseline ALC and intensity modulated radiation therapy (IMRT) (vs. 2 dimensional-conformal radiation therapy,2D-CRT) were identified as 2 independent factors that were associated with G3–4 RIL. In the multivariate survival analysis, patients with G3–4 ALC nadir had longer local recurrence-free survival durations (LRFS) (vs. G0–2 nadir, HR = 0.548, P = 0.005) and longer progression-free survival durations (PFS) (vs. G0–2 nadir, HR = 0.676, P = 0.022), while patients with G4 ALC nadir had a shorter distant-metastasis-free survival duration (DMFS) (vs. G0–2 nadir, hazard ratio [HR] = 2.567, P = 0.037).

Conclusions

In the study, lymphopenia during RT were affected by baseline ALC and RT modality independently. Moreover, G3–4 ALC nadir was independently linked with longer PFS and LRFS durations, while G4 ALC nadir was independently linked with a shorter DMFS duration.

Radiation-Induced Lymphopenia Predicts Poorer Prognosis in Patients With Breast Cancer: A Post Hoc Analysis of a Randomized Controlled Trial of Postmastectomy Hypofractionated Radiation Therapy

PURPOSE

The aim of this study was to determine whether radiation-induced lymphopenia affects the survival of patients with breast cancer.

METHODS AND MATERIALS

Post hoc analysis was conducted on data from 598 patients with breast cancer from a randomized controlled trial comparing postmastectomy hypofractionated radiation therapy (HFRT; 43.5 Gy in 15 fractions over 3 weeks) with conventional fractionated radiation therapy (CFRT; 50 Gy in 25 fractions over 5 weeks). Mean peripheral lymphocyte count (PLC) at different time points in the 2 groups was compared by the t test. Disease-free survival and overall survival were analyzed by the Kaplan-Meier method and compared between groups by the log-rank test.

RESULTS

Baseline PLC (pre-PLC) was comparable between HFRT and CFRT patients (1.60 ± 0.57 × 10⁹/L vs 1.56 ± 0.52 × 10⁹/L; P = .33). In both groups, the PLC declined steadily during the course of radiation therapy but started to recover at 1 month after radiation therapy. Incidence of lymphopenia was significantly lower in HFRT patients (45.4% vs 55.7%; P = .01). Nadir-PLC was significantly higher in HFRT patients (1.08 ± 0.37 × 10⁹/L vs 0.97 ± 0.31× 10⁹/L; P < .001), as was the nadir-PLC/pre-PLC ratio (0.72 ± 0.28 vs 0.67 ± 0.28; P = .02). Median follow-up was 57.6 months (interquartile range, 38.5-81.4). The 5-year disease-free survival was significantly lower in patients with a nadir-PLC/pre-PLC ratio <0.8 than in those with a ratio ≥0.8 (71.8% vs 82.6%; P = .01); however, overall survival was comparable between the groups (85.8% vs 90.6%; P = .24).

CONCLUSIONS

The risk of radiation-induced lymphopenia in patients with breast cancer is lower with HFRT than with CFRT. A low nadir-PLC/pre-PLC ratio may predict poor prognosis.

A novel deep learning model using dosimetric and clinical information for grade 4 radiotherapy-induced lymphopenia prediction

Radiotherapy-induced lymphopenia has increasingly been shown to reduce cancer survivorship. We developed a novel hybrid deep learning model to efficiently integrate an entire set of dosimetric parameters of a radiation treatment plan with a patient's pre- and mid-treatment information to improve the prediction of grade 4 radiotherapy-induced lymphopenia. We proposed a two-input channel hybrid deep learning model to process dosimetric information using a stacked bi-directional long-short term memory structure and non-dosimetric information using a multilayer perceptron structure independently before integrating the dosimetric and non-dosimetric information for final prediction. The model was trained from 505 patients and tested in 216 patients. We compared our model with other popular predictive models, including logistic regression (with and without elastic-net regularization) random forest, support vector machines, and artificial neural network. Our hybrid deep learning model out-performed other predictive models in various evaluation metrics. It achieved the highest area under the curve at 0.831, accuracy at 0.769, F1 score at 0.631, precision at 0.670, and recall at 0.610. The hybrid deep learning model also demonstrated robustness in exploiting the value of dosimetric parameters in predictive modeling. We demonstrated that our hybrid deep learning model with a two-input channel structure, which addressed the sequential and inter-correlated nature of dosimetric parameters, could potentially improve the prediction of radiotherapy-induced lymphopenia. Our proposed deep learning framework is flexible and transferable to other related radiotherapy-induced toxicities.

Association Between Circulating Lymphocyte Populations and Outcome After Stereotactic Body Radiation Therapy in Patients With Hepatocellular Carcinoma

Background and Objective: Radiation-induced lymphopenia has a tangible impact on overall survival (OS) in multiple solid tumors. We investigated the association between circulating lymphocyte populations (CLPs) before and after stereotactic body radiation therapy (SBRT) and OS in patients with hepatocellular carcinoma (HCC).

Materials and Methods: Seventy-eight HCC patients treated with SBRT between January 2013 and June 2017 were retrospectively analyzed. Baseline and post-treatment total peripheral lymphocyte counts (TPLCs) and values of different CLPs were obtained and analyzed for clinical outcomes. Univariate and multivariate Cox regression analyses were used to explore the independent prognostic factors for patient survival.

Results: The one-, two- and three-year OS rates were 94.8, 75.9, and 63.3%, respectively. The mean TPLCs before and 10 days after SBRT were 1.4 × 10⁹/L and 0.7 × 10⁹/L, respectively. The TPLC recovered to its baseline value 1 year after SBRT. Multivariate analysis results revealed that variables, including tumor necrosis factor-alpha (TNF-α) level <5.5 ng/mL and post-treatment TPLC <0.45 × 10⁹/L were independent factors for inferior OS. Further analysis showed that the values of CLPs, including CD3⁺, CD4⁺, CD8⁺, CD19⁺, and CD16⁺56⁺ cells dropped profoundly 10 days after SBRT, among which CD19⁺ B cell count was mostly depleted and gradually recovered after 2 months. Univariate analysis showed that both baseline and post-treatment TPLC and CLP (except post-treatment B cell) counts were significantly associated with patient OS (p < 0.05 for each). Further stratified analysis performed according to OS at 2 years demonstrated that the CD16⁺CD56⁺ NK cell counts remained significantly elevated in patients with better survival (OS > 2 years) compared to those in short-term survivors at 10 days, 1 month, and 2 months after SBRT (p < 0.05 for each). In addition, there were significant differences in TPLC and CD8⁺ T cell counts in patients with long-term and short-term OS at 2 months after SBRT (p < 0.05).

Conclusions: Peripheral lymphopenia after SBRT might be an independent prognostic factor for poorer outcome in HCC patients. Post-treatment lymphocyte subsets, including CD8⁺ T cell and NK cell counts were also associated with 2-year OS rates.

Baseline Low Prognostic Nutritional Index Predicts Poor Survival in Locally Advanced Nasopharyngeal Carcinomas Treated With Radical Concurrent Chemoradiotherapy

BACKGROUND

To retrospectively assess the impact of prognostic nutritional index (PNI) on survival outcomes of patients with locoregionally advanced nasopharyngeal carcinoma (LA-NPC) treated with concurrent chemoradiotherapy (CCRT).

METHODS

This study incorporated 154 patients with LA-NPC who received exclusive cisplatinum-based CCRT. Receiver operating characteristic (ROC) curve analysis was utilized for accessibility of pretreatment PNI cutoffs influencing survival results. The primary end point was the interaction between the overall survival (OS) and PNI values, while cancer-specific survival (CSS) locoregional progression-free survival (LR-PFS), distant metastasis-free survival (DMFS), and PFS were the secondary end points.

RESULTS

A rounded PNI cutoff value of 51 was identified in ROC curve analyses to exhibit significant link with CSS, OS, DMFS, and PFS outcomes, but not LR-PFS. Patients grouping per PNI value (≥51 [N = 95] vs <51 [N = 49]) revealed that PNI < 51 group had significantly shorter median CSS (P < .001), OS (P < .001), DMFS (P < .001), and PFS (P < .001) times than the PNI ≥ 51 group, and the multivariate results confirmed the PNI < 51 as an independent predictor of poor outcomes for each end point (P < .05 for each). The unfavorable impact of the low PNI was also continued at 10-year time point with survival rates of 77.9% versus 42.4%, 73.6% versus 33.9%, 57.9% versus 27.1%, and 52.6% versus 23.7% for CSS, OS, DMFS, and PFS, respectively. Additionally, we found that PNI < 51 was significantly associated with higher rates of weight loss >5% over past 6 months (49.2% versus 11.6%; P = .002) compared to PNI < 51 group.

CONCLUSION

Low pre-CCRT PNI levels were independently associated with significantly reduced CSS, OS, DMFS, and PFS outcomes in patients with LA-NPC treated with definitive CCRT.

Spleen Dose-Volume Parameters as a Predictor of Treatment-related Lymphopenia During Definitive Chemoradiotherapy for Esophageal Cancer

AIM

Our study sought to identify dosimetric predictors of treatment-related lymphopenia during chemoradiotherapy for esophageal cancer.

MATERIALS AND METHODS

Patients with esophageal cancer who had received definitive chemoradiotherapy at our Institution were retrospectively assessed. The absolute volume of the spleen, body, and bone marrow that had received 5, 10, 20, and 30 Gy and the mean splenic dose were recorded.

RESULTS

Multivariate linear regression analysis revealed that docetaxel use and spleen dose-volume parameters (V5, V10, V20, V30, and mean splenic dose) were significant independent factors negatively influencing the absolute lymphocyte count at nadir. An increase of 1 Gy in mean splenic dose predicted a 2.9% decrease in nadir absolute lymphocyte count. Univariable logistic regression analysis showed that the mean splenic dose was a significant predictor of grade 4 lymphopenia. None of the body or bone marrow dose-volume parameters significantly predicted lymphopenia.

CONCLUSION

Higher spleen dose-volume parameters were associated with severe lymphopenia during chemoradiotherapy.

Absolute Lymphocyte Count in Preoperative Chemoradiotherapy for Rectal Cancer: Changes Over Time and Prognostic Significance

We analyzed the changes in absolute lymphocyte count and its changes over time in 139 patients treated with preoperative chemoradiotherapy for locally advanced rectal cancer. The baseline absolute lymphocyte count was defined as the median of absolute lymphocyte count levels measured during 30 days before preoperative chemoradiotherapy. Absolute lymphocyte count at 1 month, 0.5 to 1 year, 1 to 2 years, and 2 to 3 years were determined by the median values of the absolute lymphocyte counts during the respective periods. Absolute lymphocyte count decreased after delivering preoperative chemoradiotherapy, reached minimum level at 1 month, and then gradually increased after the completion of chemoradiotherapy. Baseline absolute lymphocyte count had significant correlations with the absolute lymphocyte count of every period (range of coefficient, 0.41-0.64, P < .001). The overall survival of the group with high baseline absolute lymphocyte count was significantly higher than that of the group with low baseline absolute lymphocyte count (5-year overall survival: 82.4% vs 62.9%, P = .012). In multivariable analyses, the baseline absolute lymphocyte count remained as a significant prognostic factor for overall survival, favoring the group with a high baseline absolute lymphocyte count (hazard ratio = 0.405, P = .017). This study showed that the level of baseline absolute lymphocyte count was an independent prognostic factor, and it correlated with the absolute lymphocyte counts across varying periods of treatments and follow-up in patients treated with preoperative chemoradiotherapy for rectal adenocarcinoma.

Prognostic significance of combined pretreatment lymphocyte counts and body mass index in patients with head and neck cancer treated with radiation therapy

We aimed to investigate the prognostic significance of combined pretreatment lymphocyte counts (LCs) and body mass index (BMI) in patients with head and neck cancer (HNC) treated with radiation therapy (RT). Nine hundred and twelve patients with HNC who were treated with RT were retrospectively reviewed. Survival was analyzed by stratifying the patients according to pretreatment LCs and BMI. Patients with low pretreatment LCs and BMI were characterized by a more advanced T stage, fewer nasopharyngeal subsites, less smoking and drinking, and fewer comorbidities. Patients with low pretreatment LCs and BMI had a significantly poorer overall and distant metastasis-free survival than those with high pretreatment LCs and BMI. No significant differences were observed in terms of local or regional recurrence-free survival. Combined pretreatment LCs and BMI may be more effective at predicting overall and distant metastasis-free survival in patients with HNC treated with RT.

[Inflammatory and immune biomarkers of radiation response]

In radiotherapy, the treatment is adapted to each individual to protect healthy tissues but delivers most of time a standard dose according to the tumor histology and site. The only biomarkers studied to individualize the treatment are the HPV status with radiation dose de-escalation strategies, and tumor hypoxia with dose escalation to hypoxic subvolumes using FMISO- or FAZA-PET imaging. In the last decades, evidence has grown about the contribution of the immune system to radiation tumor response. Many preclinical studies have identified some of the mechanisms involved. In this context, we have realised a systematic review to highlight potential inflammatory and immune biomarkers of radiotherapy response. Some are inside the tumor microenvironment, as lymphocyte infiltration or PD-L1 expression, others are circulating biomarkers, including different types of hematological cells, cytokines and chemokines.

High lymphocyte count during neoadjuvant chemoradiotherapy is associated with improved pathologic complete response in esophageal cancer

BACKGROUND AND PURPOSE

Neoadjuvant chemoradiation (nCRT) can reduce tumor infiltrating lymphocytes. We examined absolute lymphocyte count (ALC) nadir during nCRT for esophageal cancer (EC) and pathologic complete response (pCR).

MATERIALS AND METHODS

Patients with stage I-IVA EC (n = 313) treated 2007-2013 with nCRT followed by surgery were analyzed. ALC was obtained before, during/weekly, and one month after CRT. pCR was defined as no viable tumor cells at surgery. High ALC was defined as nadir of ≥0.35 × 10³/μL (highest tertile). Comparison of continuous and categorical variables by pCR was assessed by ANOVA and Pearson's chi-square. Univariate/multivariate logistic regression was used to assess predictors of pCR and high ALC nadir.

RESULTS

Eighty-nine patients (27.8%) achieved a complete pathological response (pCR). For patients with pCR, median ALC nadir was significantly higher than those without (0.35 × 10³/μL vs 0.29 × 10³/μL, p = 0.007). Patients maintaining high ALC nadir had a higher pCR rate (OR1.82, 95%CI 1.08-3.05, p = 0.024). Predictors of high ALC included treatment with proton therapy vs. IMRT (OR4.18, 95%CI 2.34-7.47, p < 0.001), smoking at diagnosis (OR2.80, 95%CI 1.49-5.25, p = 0.001), early stage I-II disease (OR2.33, 95%CI 1.32-4.17, p = 0.005), and SCC histology (OR3.70, 95%CI 1.01-14.29, p = 0.048). Mean body dose (MBD) was inversely related to high ALC nadir (OR0.77 per Gy, 95%CI 0.70-0.84, p < 0.001).

CONCLUSION

A higher ALC level during nCRT is associated with a higher rate of pCR for esophageal cancer patients undergoing trimodality therapy.

Combining Immunotherapy and Radiotherapy for Cancer Treatment: Current Challenges and Future Directions

Since the approval of anti-CTLA4 therapy (ipilimumab) for late-stage melanoma in 2011, the development of anticancer immunotherapy agents has thrived. The success of many immune-checkpoint inhibitors has drastically changed the landscape of cancer treatment. For some types of cancer, monotherapy for targeting immune checkpoint pathways has proven more effective than traditional therapies, and combining immunotherapy with current treatment strategies may yield even better outcomes. Numerous preclinical studies have suggested that combining immunotherapy with radiotherapy could be a promising strategy for synergistic enhancement of treatment efficacy. Radiation delivered to the tumor site affects both tumor cells and surrounding stromal cells. Radiation-induced cancer cell damage exposes tumor-specific antigens that make them visible to immune surveillance and promotes the priming and activation of cytotoxic T cells. Radiation-induced modulation of the tumor microenvironment may also facilitate the recruitment and infiltration of immune cells. This unique relationship is the rationale for combining radiation with immune checkpoint blockade. Enhanced tumor recognition and immune cell targeting with checkpoint blockade may unleash the immune system to eliminate the cancer cells. However, challenges remain to be addressed to maximize the efficacy of this promising combination. Here we summarize the mechanisms of radiation and immune system interaction, and we discuss current challenges in radiation and immune checkpoint blockade therapy and possible future approaches to boost this combination.

A systematic review of the influence of radiation-induced lymphopenia on survival outcomes in solid tumors

Lymphopenia is a common accompaniment of multimodal cancer therapy. As the most radiosensitive cells of the hematopoietic system, lymphocytes residing within or circulating through a radiation portal are frequently depleted by radiation therapy. The recognition that radiation-induced reduction of circulating lymphocyte counts and eventual lymphocyte infiltration of tumors have a tangible impact on overall survival outcomes has revived the interest in understanding the causes of treatment-associated lymphopenia and developing strategies to predict, prevent and ameliorate this well-documented phenomenon. In this systematic review, we have performed a comprehensive search of the literature to elucidate the studies that document a correlation between radiation-associated lymphopenia and survival outcomes in solid malignancies. We also summarize potential unifying paradigms that account for radiation-induced lymphopenia across studies and lay the groundwork for attempting to explain and/or counter this phenomenon.

Lymphocyte Nadir and Esophageal Cancer Survival Outcomes After Chemoradiation Therapy

PURPOSE

Host immunity may affect the outcome in patients with esophageal cancer. We sought to identify factors that influenced absolute lymphocyte count (ALC) nadir during chemoradiation therapy (CRT) for esophageal cancer (EC) and looked for clinically relevant associations with survival.

METHODS AND MATERIALS

504 patients with stage I-III EC (2007-2013) treated with neoadjuvant or definitive CRT with weekly ALC determinations made during treatment were analyzed. Grade of lymphopenia from ALC nadir during CRT was based on Common Terminology Criteria for Adverse Events version 4.0. Associations of ALC nadir with survival were examined using multivariate Cox proportional hazards analysis (MVA) and competing risks regression analysis.

RESULTS

The median follow-up time was 36 months. The incidences of grade 1, 2, 3, and 4 ALC nadir during CRT were 2%, 12%, 59%, and 27%, respectively. The impact was lymphocyte-specific because this was not seen for monocyte or neutrophil count. On MVA, grade 4 ALC nadir (G4 nadir) was significantly associated with worse overall and disease-specific survival outcomes. Predictors of G4 nadir included distal tumor location, definitive CRT, taxane/5-fluorouracil chemotherapy, and photon-based radiation type (vs proton-based). Radiation type strongly influenced the mean body dose exposure, which was a strong predictor for G4 nadir (odds ratio 1.22 per Gray, P<.001).

CONCLUSIONS

G4 nadir during CRT for EC was associated with poor outcomes, suggesting a role of host immunity in disease control. This observation provides a rationale to prospectively test chemotherapeutic and radiation treatment strategies that may have a lower impact on host immunity.

Radiation-related lymphopenia is associated with spleen irradiation dose during radiotherapy in patients with hepatocellular carcinoma

BACKGROUND

The decrease in peripheral blood lymphocytes induced by radiation lessens the antitumour effect of the immune response, which might cause immunosuppression. We aimed to investigate the correlation between the decrease in peripheral blood lymphocytes during radiotherapy (RT) and the spleen irradiation dose in patients with hepatocellular carcinoma (HCC).

METHODS

The subjects were 59 patients with HCC who had received RT from 2005 to 2014. The Min ALC (minimum value of absolute counts for peripheral blood lymphocytes) was collected from the routine workup for each patient prior to RT and weekly during RT. Spleen dose-volume variables, including the percentage of the organ volume receiving ≥ n Gy (Vn) and the mean spleen dose (MSD), were calculated using Eclipse treatment planning. Potential associations between dosimetric variables and the Min ALC were assessed by multiple linear regression analysis.

RESULTS

Peripheral lymphocytes decreased during RT (P < 0.001). The Min ALC correlated with the MSD (P = 0.005), spleen V5 (P = 0.001), spleen V25 (P = 0.026) and spleen V30 (P = 0.018). Controlling for the Karnofsky performance status (KPS), sex, age, Child-Pugh grade, total dose and tumour stage, a multiple linear regression model with bootstrap analysis of 1000 replicates showed that only the spleen V5 was correlated with the decrease in the Min ALC (P < 0.05). According to the receiver-operating characteristic (ROC) curve analysis, the predictive cutoff values of the MSD, V5, V25 and V30 of the spleen for the Min ALC were 227.72 cGy, 17.84, 0.98 and 0.42%, respectively (P = 0.002, P = 0.004, P = 0.007 and P = 0.002, respectively). Furthermore, an MSD ≥ 227.72 cGy (OR = 14.39; 95% CI, 12.18 to 16.60) and V5 (OR = 7.99; 95% CI, 6.91 to 9.07) of the spleen significantly predicted the Min ALC.

CONCLUSIONS

Higher spleen irradiation doses were significantly correlated with lower Min ALC during RT for HCC. V5 should be limited in clinical practice. Maximum sparing for spleen irradiation during RT is recommended to preserve peripheral blood lymphocytes, which may decrease immunosuppression.

The Prognostic Value of Treatment-Related Lymphopenia in Nasopharyngeal Carcinoma Patients

Purpose

This study was conducted to evaluate the prognostic value of treatment-related lymphopenia in patients with nasopharyngeal carcinoma (NPC).

Materials and Methods

A total of 413 consecutive stage II-IVb NPC patients treated with concurrent chemoradiotherapy (CCRT) were enrolled. The overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) were calculated with the Kaplan-Meier method, and differences were compared using the log-rank test.

Results

A minimum (mini)–absolute lymphocyte counts (ALC) of < 390 cells/μL or ALC after 3 months of CCRT (post3m-ALC) < 705 cells/μL was significantly associated with worse outcome than mini-ALC ≥ 390 cells/μL (OS, p=0.002; PFS, p=0.005; DMFS, p=0.004) or post3m-ALC ≥ 705 cells/μL (OS, p < 0.001; PFS, p < 0.001; DMFS, p=0.001). Patients with lymphopenia (mini-ALC < 390 cells/μL and post3m-ALC < 705 cells/μL) had a worse prognosis than those without lymphopenia (mini-ALC ≥ 390 cells/μL and post3m-ALC ≥ 705 cells/μL) (OS, p < 0.001; PFS, p < 0.001; DMFS, p < 0.001). Multivariate analysis revealed that post3m-ALC was an independent prognostic factor for OS (hazard ratio [HR], 1.76; 95% confidence interval [CI], 1.12 to 2.78; p=0.015), PFS (HR, 1.86; 95% CI, 1.23 to 2.82; p=0.003), and DMFS (HR, 1.87; 95% CI, 1.13 to 3.08; p=0.014). Multivariate analysis also revealed that patients with lymphopenia had a high risk of death (HR, 3.79; 95% CI, 1.75 to 8.19; p=0.001), disease progression (HR, 2.93; 95% CI, 1.59 to 5.41; p=0.001), and distant metastasis (HR, 3.89; 95% CI, 1.67 to 9.10; p=0.002). Multivariate analysis performed with time dependent Cox regression demonstrated ALC was an independent prognostic factor for OS (HR, 0.995; 95% CI, 0.991 to 0.999; p=0.025) and PFS (HR, 0.993; 95% CI, 0.988 to 0.998; p=0.006).

Conclusion

Treatment-related lymphopenia was a poor prognostic factor in NPC patients.

The prognostic value of preoperative neutrophils, platelets, lymphocytes, monocytes and calculated ratios in patients with laryngeal squamous cell cancer

This study was aimed to examine the prognostic value of preoperative neutrophils, platelets, lymphocytes, monocytes and calculated ratios in patients with laryngeal squamous cell cancer (LSCC). From January 2007 to December 2011, 979 patients with LSCC were enrolled in our study. Preoperative neutrophils, platelets, lymphocytes, monocytes, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) were analyzed. Besides well-established clinicopathological prognostic factors, we evaluated the independent prognostic relevance of these hematological parameters by Cox regression models in disease-free survival (DFS) and cancer-specific survival (CSS). We found patients in the highest tertile of NLR (>2.40), PLR (>111.00) were at significantly higher risk of DFS and CSS (P<0.05) compared with those in the lowest tertile after multivariate analysis, whereas presenting significantly higher risk in the lowest tertile of lymphocytes (<1.60×109/L) and LMR (<3.50). Additionally, the tertile category of NLR as well as PLR increased and lymphocytes as well as LMR decreased in shorter DFS and CSS by the Kaplan-Meier method and the log-rank test. In conclusion, this study indicated that preoperative lymphocytes, NLR, PLR and LMR were significantly associated with LSCC progression, DFS and CSS, and these hematological parameters could be considered independent prognostic values for patients with LSCC.

Pretreatment hematologic markers as prognostic factors in patients with nasopharyngeal carcinoma: A systematic review and meta-analysis

BACKGROUND

Pretreatment hematologic parameters of the inflammatory response, including lymphocyte, neutrophil, and platelet counts, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio, have emerged as prognostic factors for patients with cancer. This systematic review and meta-analysis aimed to summarize the association between the hematologic markers and prognosis of nasopharyngeal carcinoma (NPC).

METHODS

A systematic search of PubMed, Google Scholar, MEDLINE, EMBASE, Web of Science, and the Cochrane Library was conducted up to April 2016. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were extracted and synthesized to examine prognostic outcomes including cancer-specific survival (CSS), overall survival (OS), progression-free survival (PFS), distant metastasis-free survival, and local relapse-free survival (LRFS).

RESULTS

Fourteen studies comprising 11,651 NPC patients were ultimately included, and all eligible studies were conducted in East Asia. The OS, CSS, PFS, distant metastasis-free survival, and LRFS risks differed among patients according to hematologic marker levels. All of the parameters were associated with prognostic outcomes in patients with NPC. NLR and lymphocyte counts were most commonly reported. A high NLR was significantly associated with poor NPC prognosis (pooled HR 1.42, 95% CI 1.21-1.67 for CSS; pooled HR 1.77, 95% CI 1.41-2.23 for OS; pooled HR 1.67, 95% CI 1.36-2.06 for PFS; pooled HR 1.64, 95% CI 1.15-2.34 for LRFS). High lymphocyte count indicated favorable NPC prognosis (pooled HR 0.72, 95% CI 0.64-0.81 for OS; pooled HR 0.71, 95% CI 0.56-0.91 for PFS).

CONCLUSIONS

Meta-analysis indicated that NLR and lymphocyte counts could be prognostic predictors in NPC for East Asian population. Patients with a high NLR or low lymphocyte count had poor prognosis. However, due to the limitation of included population, the conclusion was limited to East Asian patients only.

Minimum absolute lymphocyte counts during radiation are associated with a worse prognosis in patients with unresectable hepatocellular carcinoma

BACKGROUND

Peripheral blood lymphocytes play an important role in antitumour immunity. We examined the relationship between the minimum absolute lymphocyte counts (Min ALCs) during radiotherapy (RT) and clinical outcomes in patients with hepatocellular carcinoma (HCC).

METHODS

Data from a total of 69 HCC patients who had received RT were retrospectively analysed. Peripheral blood lymphocytes were measured before RT, weekly during RT and after RT. Regression and mixed-effect models were used to assess the relationships with and potential predictors of overall survival (OS). Receiver-operating characteristic (ROC) curve analysis was used to define optimal cut-off points of continuous variables for outcomes.

RESULTS

The median follow up was 30 months (range, 4-68 months). The median survival time (MST), 1-year OS rate and 2-year OS rate of the whole group were 25 months, 51% and 39%, respectively. The average circulating lymphocyte counts declined during RT (1493.19 versus 503.48 cells/µl, p < 0.001). A lower Min ALC was associated with worse OS (p = 0.001), with a cut-off value of 450 cells/µl (sensitivity and specificity, 50% and 70.6%, respectively). The MSTs, 1-year OS rates and 2-year OS rates were 15 months versus 47 months, 27% versus 78% and 4% versus 71% for patients with relatively lower (⩽450 cells/µl) and higher Min ALCs (>450 cells/µl), respectively (p < 0.001). After adjusting for potential confounders, multivariate Cox regression analysis demonstrated that Min ALC independently predicted patients' OS (HR, 0.32; 95% CI, 0.15-0.69).

CONCLUSIONS

Lower Min ALCs during RT may act as a worse prognostic factor for HCC after RT.

Dosimetric Predictors of Treatment-related Lymphopenia induced by Palliative Radiotherapy: Predictive Ability of Dose-volume Parameters based on Body Surface Contour

Background

Radiation-related lymphopenia has been associated with poor patient outcome. Our aim was to identify predictors of lymphopenia after palliative radiotherapy, with a focus on dose-volume parameters.

Patients and methods

To retrospectively assess patients with various cancers who had undergone palliative radiotherapy, we delineated three organs at risk: the volume enclosed by the body surface contour (body A), the volume left after excluding air, pleural effusion, ascites, bile, urine, and intestinal content (body B), and the volume of the bone marrow (BM). We then noted the absolute volume of the three organs at risk that had received 5-30 Gy, and assessed the predictive value for post-treatment lymphopenia of grade 3 or higher (LP3+).

Results

Of 54 patients, 23 (43%) developed LP3+. Univariate logistic regression analysis showed that body A V5, body A V10, body B V5, body B V10, the number of fractions, and splenic irradiation were significant predictors of LP3+ (p < 0.05). By multivariate analysis, body A V5, body A V10, body B V5, body B V10, and the number of fractions retained significance (p < 0.05). BM dose-volume parameters did not predict lymphopenia.

Conclusions

Higher body A and body B dose-volume parameters and a larger number of fractions may be predictors of severe lymphopenia after palliative radiotherapy.