Are unsatisfactory outcomes after concurrent chemoradiotherapy for locally advanced non-small cell lung cancer due to treatment-related immunosuppression?

Association of effective dose to immune cells and vertebral marrow dose with hematologic toxicity during neoadjuvant chemoradiotherapy in esophageal squamous cell carcinoma

BACKGROUND

To explore the correlation between effective dose to immune cells (EDIC) and vertebral bone marrow dose and hematologic toxicity (HT) for esophageal squamous cell carcinoma (ESCC) during neoadjuvant chemoradiotherapy (nCRT).

METHODS

The study included 106 ESCC patients treated with nCRT. We collected dosimetric parameters, including vertebral body volumes receiving 10-40 Gy (V10, V20, V30, V40) and EDIC and complete blood counts. Associations of the cell nadir and dosimetric parameters were examined by linear and logistic regression analysis. The receiver operating characteristic (ROC) curves were used to determine the cutoff values for the dosimetric parameters.

RESULTS

During nCRT, the incidence of grade 3-4 lymphopenia, leukopenia, and neutropenia was 76.4%, 37.3%, and 37.3%, respectively. Patients with EDIC ≤ 4.63 Gy plus V10 ≤ 140.3 ml were strongly associated with lower risk of grade 3-4 lymphopenia (OR, 0.050; P < 0.001), and patients with EDIC ≤ 4.53 Gy plus V10 ≤ 100.9 ml were strongly associated with lower risk of grade 3-4 leukopenia (OR, 0.177; P = 0.011), and patients with EDIC ≤ 5.79 Gy were strongly associated with lower risk of grade 3-4 neutropenia (OR, 0.401; P = 0.031). Kaplan-Meier analysis showed that there was a significant difference among all groups for grade 3-4 lymphopenia, leukopenia, and neutropenia (P < 0.05).

CONCLUSION

The dose of vertebral bone marrow irradiation and EDIC were significantly correlated with grade 3-4 leukopenia and lymphopenia, and EDIC was significantly correlated with grade 3-4 neutropenia. Reducing vertebral bone marrow irradiation and EDIC effectively reduce the incidence of HT.

Prognostic value of neutrophil-to-lymphocyte ratio change in patients with locally advanced non-small cell lung cancer treated with thoracic radiotherapy

In prior investigations, a correlation was established between patient outcomes in locally advanced non-small cell lung cancer (LA-NSCLC) following thoracic irradiation and parameters, such as pre/post-treatment neutrophil-to-lymphocyte ratio (NLR) and NLR change (ΔNLR). However, these parameters could potentially be influenced by radiation-related variables, such as gross tumor volume (GTV). The primary aim of this study was to elucidate the factors impacting post-treatment NLR and ΔNLR and to further assess their prognostic relevance. In this retrospective study, a cohort of 188 LA-NSCLC patients who underwent thoracic radiation between 2012 and 2017 was assessed. The calculation of pre/post-treatment NLR involved the use of absolute neutrophil and lymphocyte counts. ΔNLR was defined as the difference between post- and pre-treatment NLR values. To assess the relationships between various variables and overall survival (OS), local progression-free survival (LPFS), and distant metastasis-free survival (DMFS), the Kaplan-Meier technique and Cox proportional hazards regression were employed. Additionally, Spearman's rank correlation analysis was carried out to investigate correlations between the variables. The analysis revealed that both post-treatment NLR (r = 0.315, P < 0.001) and ΔNLR (r = 0.156, P = 0.032) were associated with GTV. However, OS, LPFS, and DMFS were not independently correlated with pre/post-treatment NLR. ΔNLR, on the other hand, exhibited independent associations with OS and DMFS (HR = 1.054, P = 0.020, and P = 0.046, respectively). Elevated ΔNLR values were linked to poorer OS (P = 0.023) and DMFS (P = 0.018) in the Kaplan-Meier analysis. Furthermore, when stratifying by GTV, a higher ΔNLR remained to be associated with worse OS and DMFS (P = 0.047 and P = 0.035, respectively) in the GTV ≤ 67.41 cm3 group, and in the GTV > 67.41 cm3 group (P = 0.028 and P = 0.042, respectively), highlighting ΔNLR as the sole independent predictive factor for survival and metastasis, irrespective of GTV.

Combine radiotherapy and immunotherapy in esophageal squamous cell carcinoma

Immune checkpoint inhibitors(ICIs) have improved the survival of advanced esophageal squamous cell carcinoma (ESCC) patients. Radiotherapy is one of the common therapies to treat esophageal cancer. However, whether combination radiation therapy can increase the efficacy of immunotherapy is still up for debate. Radiotherapy combined with immunotherapy has proven to be a reliable and effective treatment for tumors, and it can work in combination with immunotherapy to achieve better anti-tumor effects. This review aims to discuss the efficacy and safety of combining radiotherapy and immunotherapy to treat ESCC by stages as well as the optimum radiotherapy dose and target volume, with a summary of clinical trials in ESCC.

Prediction of Radiation-induced Lymphopenia following Exposure of the Thoracic Region and Associated Risk of Infections and Mortality

AIMS

Large blood volumes are irradiated when the heart is exposed to radiation. The mean heart dose (MHD) may be a good surrogate for circulating lymphocytes exposure. We investigated the association between MHD and radiation-induced lymphopenia and explored the impact of the end-of-radiation-therapy (EoRT) lymphocyte count on clinical outcomes.

MATERIALS AND METHODS

In total, 915 patients were analysed: 303 patients with breast cancer and 612 with intrathoracic tumours: oesophageal cancer (291), non-small cell lung cancer (265) and small cell lung cancer (56). Heart contours were generated using an interactive deep learning delineation process and an individual dose volume histogram for each heart was obtained. A dose volume histogram for the body was extracted from the clinical systems. We compared different models analysing the effect of heart dosimetry on the EoRT lymphocyte count using multivariable linear regression and assessed goodness of fit. We published interactive nomograms for the best models. The association of the degree of EoRT lymphopenia with clinical outcomes (overall survival, cancer treatment failure and infection) was investigated.

RESULTS

An increasing low dose bath to the body and MHD were associated with a low EoRT lymphocyte count. The best models for intrathoracic tumours included dosimetric parameters, age, gender, number of fractions, concomitant chemotherapy and pre-treatment lymphocyte count. Models for patients with breast cancer showed no improvement when adding dosimetric variables to the clinical predictors. EoRT lymphopenia grade ≥3 was associated with decreased survival and increased risk of infections among patients with intrathoracic tumours.

CONCLUSION

Among patients with intrathoracic tumours, radiation exposure to the heart contributes to lymphopenia and low levels of peripheral lymphocytes after radiotherapy are associated with worse clinical outcomes.

Evolution of systemic therapy for stages I-III non-metastatic non-small-cell lung cancer

The treatment goal for patients with early-stage lung cancer is cure. Multidisciplinary discussions of surgical resectability and medical operability determine the modality of definitive local treatment (surgery or radiotherapy) and the associated systemic therapies to further improve the likelihood of cure. Trial evidence supports cisplatin-based adjuvant therapy either after surgical resection or concurrently with radiotherapy. Consensus guidelines support neoadjuvant chemotherapy in lieu of adjuvant chemotherapy and carboplatin-based regimens for patients who are ineligible for cisplatin. The incorporation of newer agents, now standard for patients with stage IV lung cancer, into the curative therapy paradigm has lagged owing to inefficient trial designs, the lengthy follow-up needed to assess survival end points and a developmental focus on the advanced-stage disease setting. Surrogate end points, such as pathological response, are being studied and might shorten trial durations. In 2018, the anti-PD-L1 antibody durvalumab was approved for patients with stage III lung cancer after concurrent chemoradiotherapy. Since then, the study of targeted therapies and immunotherapies in patients with early-stage lung cancer has rapidly expanded. In this Review, we present the current considerations in the treatment of patients with early-stage lung cancer and explore the current and future state of clinical research to develop systemic therapies for non-metastatic lung cancer.

Evolution of systemic therapy for stages I-III non-metastatic non-small-cell lung cancer

The treatment goal for patients with early-stage lung cancer is cure. Multidisciplinary discussions of surgical resectability and medical operability determine the modality of definitive local treatment (surgery or radiotherapy) and the associated systemic therapies to further improve the likelihood of cure. Trial evidence supports cisplatin-based adjuvant therapy either after surgical resection or concurrently with radiotherapy. Consensus guidelines support neoadjuvant chemotherapy in lieu of adjuvant chemotherapy and carboplatin-based regimens for patients who are ineligible for cisplatin. The incorporation of newer agents, now standard for patients with stage IV lung cancer, into the curative therapy paradigm has lagged owing to inefficient trial designs, the lengthy follow-up needed to assess survival end points and a developmental focus on the advanced-stage disease setting. Surrogate end points, such as pathological response, are being studied and might shorten trial durations. In 2018, the anti-PD-L1 antibody durvalumab was approved for patients with stage III lung cancer after concurrent chemoradiotherapy. Since then, the study of targeted therapies and immunotherapies in patients with early-stage lung cancer has rapidly expanded. In this Review, we present the current considerations in the treatment of patients with early-stage lung cancer and explore the current and future state of clinical research to develop systemic therapies for non-metastatic lung cancer.

Sarcopenia and dosimetric parameters in relation to treatment-related leukopenia and survival in anal cancer

Background

Treatment-related white blood cell (WBC) toxicity has been associated with an inferior prognosis in different malignancies, including anal cancer. The aim of the present study was to investigate predictors of WBC grade ≥ 3 (G3+) toxicity during chemoradiotherapy (CRT) of anal cancer.

Methods

Consecutive patients with locally advanced (T2 ≥ 4 cm—T4 or N+) anal cancer scheduled for two cycles of concomitant 5-fluorouracil and mitomycin C chemotherapy were selected from an institutional database (n = 106). All received intensity modulated radiotherapy (IMRT; mean dose primary tumor 59.5 Gy; mean dose elective lymph nodes 45.1 Gy). Clinical data were extracted from medical records. The highest-grade WBC toxicity was recorded according to CTCAE version 5.0. Pelvic bone marrow (PBM) was retrospectively contoured and dose-volume histograms were generated. The planning CT was used to measure sarcopenia. Dosimetric, anthropometric, and clinical variables were tested for associations with WBC G3+ toxicity using the Mann–Whitney test and logistic regression. Cox proportional hazard regression was used to assess predictors for overall survival (OS) and anal cancer specific survival (ACSS).

Results

WBC G3+ was seen in 50.9% of the patients, and 38.7% were sarcopenic. None of the dosimetric parameters showed an association with WBC G3+ toxicity. The most significant predictor of WBC G3+ toxicity was sarcopenia (adjusted OR 4.0; P = 0.002). Sarcopenia was also associated with an inferior OS (adjusted HR 3.9; P = 0.01), but not ACSS (P = 0.07). Sensitivity analysis did not suggest that the inferior prognosis for sarcopenic patients was a consequence of reduced doses of chemotherapy or a prolonged radiation treatment time. Patients who experienced WBC G3+ toxicity had an inferior OS and ACSS, even after adjustment for sarcopenia.

Conclusions

Sarcopenia was associated with increased risks of both WBC G3+ toxicity and death following CRT for locally advanced anal cancer. In this study, radiation dose to PBM was not associated with WBC G3+ toxicity. However, PBM was not used as an organ at risk for radiotherapy planning purposes and doses to PBM were high, which may have obscured any dose–response relationships.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01876-5.

The Influence of Severe Radiation-Induced Lymphopenia on Overall Survival in Solid Tumors: A Systematic Review and Meta-Analysis

PURPOSE

Emerging evidence suggests a detrimental prognostic association between radiation-induced lymphopenia (RIL) and pathologic response, progression-free survival, and overall survival (OS) in patients who undergo radiation therapy for cancer. The aim of this study was to systematically review and meta-analyze the prognostic impact of RIL on OS in patients with solid tumors.

METHODS AND MATERIALS

PubMed/MEDLINE and Embase were systematically searched. The analysis included intervention and prognostic studies that reported on the prognostic relationship between RIL and survival in patients with solid tumors. An overall pooled adjusted hazard ratio (aHR) was calculated using a random-effects model. Subgroup analyses for different patient-, tumor-, treatment-, and study-related characteristics were performed using meta-regression.

RESULTS

Pooling of 21 cohorts within 20 eligible studies demonstrated a statistically significant association between OS and grade ≥3 versus grade 0-2 RIL (n = 16; pooled aHR, 1.65; 95% confidence interval [CI], 1.43-1.90) and grade 4 RIL versus grade 0-3 (n = 5; aHR, 1.53; 95% CI, 1.24-1.90). Moderate heterogeneity among aHRs was observed, mostly attributable to overestimated aHRs in 7 studies likely subject to model-overfitting. Subgroup analysis showed significant prognostic impact of grade ≥3 RIL in 4 brain tumor (aHR, 1.63; 95% CI, 1.06-2.51), 4 lung cancer (aHR, 1.52; 95% CI, 1.01-2.29), and 3 pancreatic cancer (aHR, 1.92; 95% CI, 1.10-3.36) cohorts.

CONCLUSIONS

This meta-analysis demonstrates a significant detrimental prognostic association between grade ≥3 lymphopenia and OS in patients receiving radiation therapy for solid tumors. This finding appears consistent for tumors of the brain, thorax, and upper abdomen and provides an imperative to further elucidate the potential survival benefit of lymphopenia-mitigating strategies.

Impact of neutrophil-to-lymphocyte ratio throughout the course of chemoradiotherapy on overall survival and distant failure in unresectable stage III non-small cell lung cancer

Purpose

Neutrophil-to-lymphocyte ratio (NLR) has been reported to be associated with treatment outcomes in various cancers; however, the optimal timing to measure NLR is unclear. In this study, “average-NLR” was newly devised, which reflects the NLR throughout the course of radiotherapy, and its usefulness was assessed for stage III non-small cell lung cancer (NSCLC) patients treated with chemoradiotherapy.

Materials and methods

A total of 111 patients who received definitive chemoradiotherapy for unresectable stage III NSCLC were reviewed. Patient/tumor-related factors, treatment-related, and NLR-related factors (average-NLR, pre- and post-radiotherapy NLR, NLR-nadir, NLR-maximum) were assessed using univariate and multivariate analyses.

Results

The median follow-up period was 43.8 months among the survivors. In the multivariate analysis, average-NLR and post-radiotherapy NLR were significant factors for the overall survival (OS) (p = 0.016 and 0.028) and distant failure (DF) (p = 0.008 and 0.040). For the patients with low, intermediate, and high average-NLR, the median OS was 41.2, 37.7, and 14.8 months, respectively, and the median DF free time was 52.5, 13.5, and 8.9 months, respectively.

Conclusion

Average-NLR and post-radiotherapy NLR were significant factors for the OS and DF. Average-NLR, which was available immediately after the completion of chemoradiotherapy, seemed to be helpful for treatment decisions.

Is a higher estimated dose of radiation to immune cells predictive of survival in patients with locally advanced non-small cell lung cancer treated with thoracic radiotherapy?

BACKGROUND AND PURPOSE

In previous studies, the estimated dose of radiation to immune cells (EDRIC) showed a correlation with overall survival (OS) of patients with locally advanced non-small cell lung cancer (LA-NSCLC) who received thoracic radiotherapy. However, several factors such as gross tumor volume (GTV) and lymph node (N) stage may impact EDRIC. The purpose of this study was to identify the factors influencing EDRIC and to further assess the prognostic relevance of EDRIC.

MATERIALS AND METHODS

We retrospectively analyzed 201 patients with LA-NSCLC who received radiotherapy between 2012 and 2017. EDRIC was calculated based on the model developed by Jin et al. Kaplan-Meier method and Cox proportional hazards regression were used to analyze the correlation of potential factors with OS, local progression-free survival (LPFS), and distant metastasis-free survival (DMFS). Spearman's rank correlation was used to assess the correlation between variables.

RESULTS

Both GTV and N stage showed a positive correlation with EDRIC (r = 0.347, P < 0.001 and r = 0.249, P < 0.001, respectively). EDRIC was independently associated with DMFS (HR 1.185, P < 0.001). GTV was associated with OS (HR 1.006, P < 0.001), LPFS (HR 1.003, P = 0.017), and DMFS (HR 1.003, P = 0.032). While using GTV as a stratification factor in Kaplan-Meier analysis, EDRIC showed a trend of negative correlation with OS in GTV ≤ 66.6 cm³ group (P = 0.061).

CONCLUSION

EDRIC was an independent prognostic factor for metastasis and it was affected by GTV and N stage. However, the effect of EDRIC on OS was influenced by GTV.

Using Auto-Segmentation to Reduce Contouring and Dose Inconsistency in Clinical Trials: The Simulated Impact on RTOG 0617

PURPOSE

Contouring inconsistencies are known but understudied in clinical radiation therapy trials. We applied auto-contouring to the Radiation Therapy Oncology Group (RTOG) 0617 dose escalation trial data. We hypothesized that the trial heart doses were higher than reported due to inconsistent and insufficient heart segmentation. We tested our hypothesis by comparing doses between deep-learning (DL) segmented hearts and trial hearts.

METHODS AND MATERIALS

The RTOG 0617 data were downloaded from The Cancer Imaging Archive; the 442 patients with trial hearts and dose distributions were included. All hearts were resegmented using our DL pipeline and quality assured to meet the requirements for clinical implementation. Dose (V5%, V30%, and mean heart dose) was compared between the 2 sets of hearts (Wilcoxon signed-rank test). Each dose metric was associated with overall survival (Cox proportional hazards). Lastly, 18 volume similarity metrics were assessed for the hearts and correlated with |Dose_DL - Dose_RTOG0617| (linear regression; significance: P ≤ .0028; corrected for 18 tests).

RESULTS

Dose metrics were significantly higher for DL hearts compared with trial hearts (eg, mean heart dose: 15 Gy vs 12 Gy; P = 5.8E-16). All 3 DL heart dose metrics were stronger overall survival predictors than those of the trial hearts (median, P = 2.8E-5 vs 2.0E-4). Thirteen similarity metrics explained |Dose_DL - Dose_RTOG0617|; the axial distance between the 2 centers of mass was the strongest predictor (CENT_Axial; median, R² = 0.47; P = 6.1E-62). CENT_Axial agreed with the qualitatively identified inconsistencies in the superior direction. The trial's qualitative heart contouring score was not correlated with |Dose_DL - Dose_RTOG0617| (median, R² = 0.01; P = .02) or with any of the similarity metrics (median, Rs = 0.13 [range, -0.22 to 0.31]).

CONCLUSIONS

Using a coherent heart definition, as enabled through our open-source DL algorithm, the trial heart doses in RTOG 0617 were found to be significantly higher than previously reported, which may have led to an even more rapid mortality accumulation. Auto-segmentation is likely to reduce contouring and dose inconsistencies and increase the quality of clinical RT trials.

Registering Study Analysis Plans (SAPs) Before Dissecting Your Data—Updating and Standardizing Outcome Modeling

Public preregistration of study analysis plans (SAPs) is widely recognized for clinical trials, but adopted to a much lesser extent in observational studies. Registration of SAPs prior to analysis is encouraged to not only increase transparency and exactness but also to avoid positive finding bias and better standardize outcome modeling. Efforts to generally standardize outcome modeling, which can be based on clinical trial and/or observational data, have recently spurred. We suggest a three-step SAP concept in which investigators are encouraged to (1) Design the SAP and circulate it among the co-investigators, (2) Log the SAP with a public repository, which recognizes the SAP with a digital object identifier (DOI), and (3) Cite (using the DOI), briefly summarize and motivate any deviations from the SAP in the associated manuscript. More specifically, the SAP should include the scope (brief data and study description, co-investigators, hypotheses, primary outcome measure, study title), in addition to step-by-step details of the analysis (handling of missing data, resampling, defined significance level, statistical function, validation, and variables and parameterization).

Modeling the Impact of Cardiopulmonary Irradiation on Overall Survival in NRG Oncology Trial RTOG 0617

PURPOSE

To quantitatively predict the impact of cardiopulmonary dose on overall survival (OS) after radiotherapy for locally advanced non-small cell lung cancer.

EXPERIMENTAL DESIGN

We used the NRG Oncology/RTOG 0617 dataset. The model building procedure was preregistered on a public website. Patients were split between a training and a set-aside validation subset (N = 306/131). The 191 candidate variables covered disease, patient, treatment, and dose-volume characteristics from multiple cardiopulmonary substructures (atria, lung, pericardium, and ventricles), including the minimum dose to the hottest x% volume (Dx%[Gy]), mean dose of the hottest x% (MOHx%[Gy]), and minimum, mean (Mean[Gy]), and maximum dose. The model building was based on Cox regression and given 191 candidate variables; a Bonferroni-corrected P value threshold of 0.0003 was used to identify predictors. To reduce overreliance on the most highly correlated variables, stepwise multivariable analysis (MVA) was repeated on 1000 bootstrapped replicates. Multivariate sets selected in ≥10% of replicates were fit to the training subset and then averaged to generate a final model. In the validation subset, discrimination was assessed using Harrell c-index, and calibration was tested using risk group stratification.

RESULTS

Four MVA models were identified on bootstrap. The averaged model included atria D45%[Gy], lung Mean[Gy], pericardium MOH55%[Gy], and ventricles MOH5%[Gy]. This model had excellent performance predicting OS in the validation subset (c = 0.89).

CONCLUSIONS

The risk of death due to cardiopulmonary irradiation was accurately modeled, as demonstrated by predictions on the validation subset, and provides guidance on the delivery of safe thoracic radiotherapy.

Lymphocyte-Sparing Radiotherapy: The Rationale for Protecting Lymphocyte-rich Organs When Combining Radiotherapy With Immunotherapy

There is now strong clinical and preclinical evidence that lymphocytes, for example, CD8+ T cells, are key effectors of immunotherapy and that irradiation of large blood vessels, the heart, and lymphoid organs (including nodes, spleen, bones containing bone marrow, and thymus in children) causes transient or persistent lymphopenia. Furthermore, there is extensive clinical evidence, across multiple cancer sites and treatment modalities, that lymphopenia correlates strongly with decreased overall survival. At the moment, we lack quantitative evidence to establish the relationship between dose-volume and dose-rate to critical normal structures and lymphopenia. Therefore, we propose that data should be systematically recorded to characterise a possible quantitative relationship. This might enable us to improve the efficacy of radiotherapy and develop strategies to predict and prevent treatment-related lymphopenia. In anticipation of more quantitative data, we recommend the application of the principle of As Low As Reasonably Achievable to lymphocyte-rich regions for radiotherapy treatment planning to reduce the radiation doses to these structures, thus moving toward "Lymphocyte-Sparing Radiotherapy."