Post-treatment lymphocytopaenia, integral body dose and overall survival in lung cancer patients treated with radical radiotherapy

FLASH radiotherapy spares lymphocytes in tumor-draining lymph nodes and increases infiltration of immune cells in tumors

Radiotherapy (RT) delivered at conventional dose rates (CONV) can both stimulate antitumor immune responses and inhibit these immune responses by depleting circulating lymphocytes. Given the observed normal tissue sparing associated with ultra-high dose rate (FLASH) RT, we hypothesized that FLASH RT may protect lymphocytes while increasing the immunogenicity of cancer cells. We irradiated cancer cell lines in vitro with FLASH RT or CONV RT and assessed immunogenic mRNA and protein expression. Both HPV-positive cell lines MEER and TC-1 showed upregulation of Calr, Hmgb1 , and cGAS-STING family members after FLASH RT but not after CONV RT in vitro . To assess changes in lymphocyte populations, we irradiated murine mEER tumors in syngeneic C57BL/6 mice with 27 Gy in 3 fractions of FLASH RT or CONV RT. In mice bearing FLASH irradiated tumors, tumor-draining lymph nodes contained greater numbers of CD8 + T cells (FLASH 1.7×10 4 vs 0.8×10 4 CONV; P <0.001) and CD4 + T cells (FLASH 2.3×10 4 vs CONV 1.2×10 4 ; P <0.001) after irradiation. FLASH RT was associated with increased numbers of activated CD44 + CD62L lo CD8 + and CD4 + lymphocytes. In irradiated tumors, FLASH RT was associated with increased CD8 + tumor-infiltrating lymphocytes, increased PD1 expression on these lymphocytes and increased PDL1 expression on macrophages. Compared with CONV RT, FLASH RT spared activated T cells in tumor-draining lymph nodes and in tumors but increased checkpoint inhibitor expression in tumors. These results suggest that FLASH RT may enhance antitumor immune responses by maintaining the immunogenic effects of RT while preserving lymphocyte numbers, which may be augmented with immune checkpoint blockade.

Significance

Radiation-induced lymphopenia is associated with poorer survival outcomes. New treatment approaches, like FLASH radiation therapy (FLASH RT), which reduce lymphopenia and enhance the antitumor response, could potentially lead to better outcomes for cancer patients.

Whole-body integral dose and post-radiotherapy lymphocytopaenia in solid tumours

Objective

Since modern radiotherapy techniques such as intensity-modulated radiotherapy (IMRT) pivot on a strategy of dose redistribution, it may increase integral dose and consequently worsening of lymphocytopaenia. In this study, our objective was twofold: first to validate the correlation between integral body dose and post-treatment lymphocytopaenia in a cohort of patients treated with curative-intent radiotherapy and second to validate its prognostic impact.

Methods and analysis

Patients treated with curative intent radiotherapy with complete blood counts were included in the study. Data on the following variables were collected: treatment site, prescribed dose, use of concurrent chemotherapy, mean body dose, mean body volume, treatment technique and disease-free survival.

Results

A total of 116 patients were included for analysis. There was a significant decline in lymphocyte counts after radiotherapy (2.2×109/L vs 0.8×109/L; p<0.001). Multivariate linear regression analysis of post-treatment lymphocytopaenia revealed a significant correlation with pretreatment lymphocyte counts, integral body dose, use of IMRT and use of concurrent radiosensitising chemotherapy. Univariate survival analysis was performed in 37 patients with squamous cell carcinoma of the head and neck. In the Cox proportional hazards model, post-treatment lymphocyte count was statistically significant as a continuous variable (Hazard Ratio=0.998, p=0.01) and as a dichotomous variable.

Conclusion

The negative correlation between integral body dose and post-treatment lymphocytopaenia was validated, and post-treatment lymphocytopaenia is an adverse prognostic factor in patients with head and neck cancer treated with curative-intent radiotherapy.

Lymphopenia associated with whole-brain radiotherapy and its effects on clinical outcomes of patients with brain metastases

There is increasing awareness of radiotherapy's potential side effects, such as lymphopenia. Therefore, this study aimed to establish the association between WBRT and the development of lymphopenia in patients with brain metastases undergoing brain radiotherapy (RT), along with evaluating the corresponding clinical outcomes. Including 116 patients with brain metastases undergoing brain radiotherapy, the study collected the absolute lymphocyte counts (ALC) within 2 weeks before brain radiotherapy (pre-radiotherapy, pre-RT), as well as ones at 1 and 2 months after completing RT (post-RT). Univariate and multivariate analyses were performed to identify associations between radiation modality and post-RT ALC. The relationships between post-RT ALC and overall survival were evaluated with Kaplan-Meier analysis and a multivariate Cox regression model. The median ALC definitely decreased at 1 month post-RT, but at 2 months post-RT, gradually rose but not to the pre-RT ALC. The multivariate analysis identified WBRT and lower pre-RT ALC as independent risk factors associated with the decrease in post-RT ALC at 1 month. It also revealed more than 4 brain metastases, G3-4 lymphopenia at 1 month and lower post-RT ALC at 2 months exhibited significantly worse prognosis regardless of the radiation modality. However, there was indeed an independent correlation between radiation modality and the outcome of intracranial progression-free survival (PFS). To approach the feasibility and reasonableness of treatment, clinicians should carefully consider various factors to achieve long-term survival of patients.

Normal Tissue Complication Probability Modeling of Severe Radiation-Induced Lymphopenia Using Blood Dose for Patients With Hepatocellular Carcinoma

PURPOSE

This study aimed to develop a normal tissue complication probability (NTCP) model to estimate the risk of severe radiation-induced lymphopenia (SRIL; absolute lymphocyte count [ALC] < 500/μL) by using the blood dose of patients with hepatocellular carcinoma (HCC).

METHODS AND MATERIALS

We retrospectively collected data from 75 patients with HCC who received radiation therapy (RT) between 2015 and 2018. The hematological dose framework calculated blood dose-volume histograms (DVHs) using a predefined blood flow model, organ DVHs, the number of treatment fractions, and beam delivery time. A Lyman-Kutcher-Burman model with a generalized equivalent dose was used to establish the NTCP model, reflecting the whole-blood DVHs. Optimization of the Lyman-Kutcher-Burman parameters was conducted by minimizing a negative log-likelihood function.

RESULTS

There were 6, 4, 18, 33, and 14 patients in the groups with radiation-induced lymphopenia grades 0, 1, 2, 3, and 4, respectively. The median pre- and post-RT ALC values were 1410/μL (range, 520-3710/μL) and 470/μL (range, 60-1760/μL), respectively. There was a correlation between mean blood dose and ALC depletion (Pearson r = -0.664; P < .001). The average mean blood doses in each radiation-induced lymphopenia group were 2.90 Gy (95% CI, 1.96-3.85 Gy) for grade 0 to 1, 5.29 Gy (95% CI, 4.12-6.45 Gy) for grade 2, 8.81 Gy (95% CI, 7.55-10.07 Gy) for grade 3, and 11.69 Gy (95% CI, 9.82-17.57 Gy) for grade 4. When applying the developed NTCP model to predict SRIL, the area under the receiver operating characteristic curve and Brier score values were 0.89 and 0.12, respectively.

CONCLUSIONS

We developed the first NTCP model based on whole-blood DVHs for estimating SRIL after abdominal RT in patients with HCC. Our results showed a strong correlation between blood dose and ALC depletion, suggesting the potential to predict the risk of SRIL occurrence using blood dose.

Pelvic bone marrow dose-volume predictors of late lymphopenia following pelvic lymph node radiation therapy for prostate cancer

BACKGROUND AND PURPOSE

Given the substantial lack of knowledge, we aimed to assess clinical/dosimetry predictors of late hematological toxicity on patients undergoing pelvic-nodes irradiation (PNI) for prostate cancer (PCa) within a prospective multi-institute study.

MATERIALS AND METHODS

Clinical/dosimetry/blood test data were prospectively collected including lymphocytes count (ALC) at baseline, mid/end-PNI, 3/6 months and every 6 months up to 5-year after PNI. DVHs of the Body, ileum (BMILEUM), lumbosacral spine (BMLS), lower pelvis (BMPELVIS), and whole pelvis (BMTOT) were extracted. Current analysis focused on 2-year CTCAEv4.03 Grade ≥ 2 (G2+) lymphopenia (ALC < 800/μL). DVH parameters that better discriminate patients with/without toxicity were first identified. After data pre-processing to limit overfitting, a multi-variable logistic regression model combining DVH and clinical information was identified and internally validated by bootstrap.

RESULTS

Complete data of 499 patients were available: 46 patients (9.2 %) experienced late G2+ lymphopenia. DVH parameters of BMLS/BMPELVIS/BMTOT and Body were associated to increased G2+ lymphopenia. The variables retained in the resulting model were ALC at baseline [HR = 0.997, 95 %CI 0.996-0.998, p < 0.0001], smoke (yes/no) [HR = 2.9, 95 %CI 1.25-6.76, p = 0.013] and BMLS-V ≥ 24 Gy (cc) [HR = 1.006, 95 %CI 1.002-1.011, p = 0.003]. When acute G3+ lymphopenia (yes/no) was considered, it was retained in the model [HR = 4.517, 95 %CI 1.954-10.441, p = 0.0004]. Performances of the models were relatively high (AUC = 0.87/0.88) and confirmed by validation.

CONCLUSIONS

Two-year lymphopenia after PNI for PCa is largely modulated by baseline ALC, with an independent role of acute G3+ lymphopenia. BMLS-V24 was the best dosimetry predictor: constraints for BMTOT (V10Gy < 1520 cc, V20Gy < 1250 cc, V30Gy < 850 cc), and BMLS (V24y < 307 cc) were suggested to potentially reduce the risk.

The Correlation Between Low-Dose Radiotherapy Area of the Mediastinum and CD8+T Cells and the Efficacy of Radiotherapy for Non-Small Cell Lung Cancer

Background

Radiation therapy (RT) can cause changes in peripheral blood immune cells. The relationship between the efficacy of radiation therapy for non-small cell lung cancer (NSCLC) and immune cell changes and the study of how mediastinal radiation dose parameters affect immune cell changes is still unclear. This study aims to analyze the relationship between immune cell changes induced by radiotherapy and the efficacy of NSCLC radiotherapy, as well as the relationship between radiotherapy dose parameters and immune cell changes.

Materials and Methods

We retrospectively analyzed the data of NSCLC patients receiving mediastinal radiation therapy from 2020 to 2022. Collect lymphocytes and circulating immune cells within one week before and after radiotherapy and collect the dose-volume parameters of the whole mediastinum in the patient's RT planning system. Analyze the changes in lymphocytes and radiotherapy effects after radiotherapy, and explore the relationship between radiotherapy dose parameters and immune cell changes.

Results

A total of 72 patients were enrolled. Compared with before radiotherapy, the proportion of CD3+T cells, CD8+T cells, and CD8/Treg in peripheral blood significantly increased after radiotherapy (P<0.05). The increase in CD8+T cells and CD8/Treg after radiotherapy was correlated with Objective response rate (ORR) (P<0.05). Based on binary logistic univariate and multivariate regression analysis, an increase in CD8+T cells after radiotherapy is an independent predictor of objective tumor response after radiotherapy (OR=12.71, 95% CI=3.64-44.64, P=0.01), and Volume of 200 cGy irradiation (V2) is an independent positive predictor of an increase in CD8+T lymphocyte ratio after radiotherapy (high group, OR=3.40, 95% CI=1.13-10.36, P=0.03).

Conclusion

The increase in CD8+T cells after radiotherapy can positively predict the short-term efficacy of radiotherapy. Mediastinal low-dose radiation therapy can increase CD8+T cells, thereby improving the short-term efficacy of radiotherapy. These potentially related mechanisms are worth further verification and exploration.

Blood Lymphocytes as a Prognostic Factor for Stage III Non-Small Cell Lung Cancer with Concurrent Chemoradiation

We aimed to identify blood lymphocytes as a prognostic factor for survival in patients with locally advanced stage III non-small cell lung cancer (NSCLC) treated with concurrent chemoradiotherapy (CCRT). This is a secondary study of 196 patients enrolled in the Korean Radiation Oncology Group 0903 phase III clinical trial to evaluate the prognostic significance of circulating blood lymphocyte levels. The median total lymphocyte count (TLC) reduction ratio during CCRT was 0.74 (range: 0.29-0.97). In multivariate analysis, patient age (p=0.014) and gross tumor volume (GTV, p=0.031) were significant factors associated with overall survival, while TLC reduction (p=0.018) and pretreatment neutrophil-to-lymphocyte ratio (NLR; p=0.010) were associated with progression-free survival (PFS). In multivariate logistic regression analysis, pretreatment NLR, GTV, and heart V20 were significantly associated with TLC reduction. Immunohistochemical analysis of programmed death ligand 1 and CD8 expression on T cells was performed on 84 patients. CD8 expression was not significantly associated with the pretreatment lymphocyte count (p=0.673), and PDL1 expression was not significantly associated with OS or PFS. Univariate analysis revealed that high CD8 expression in TILs was associated with favorable OS and was significantly associated with favorable PFS (p=0.032). TLC reduction during CCRT is a significant prognostic factor for PFS, and heart V20 is significantly associated with TLC reduction. Thus, in the era of immunotherapy, constraining the volume of the radiation dose to the whole heart must be prioritized for the better survival outcomes.

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.

Dosiomics and radiomics improve the prediction of post-radiotherapy neutrophil-lymphocyte ratio in locally advanced non-small cell lung cancer

PURPOSE

To develop and validate a dosiomics and radiomics model based on three-dimensional (3D) dose distribution map and computed tomography (CT) images for the prediction of the post-radiotherapy (post-RT) neutrophil-to-lymphocyte ratio (NLR).

METHODS

This work retrospectively collected 242 locally advanced non-small cell lung cancer (LA-NSCLC) patients who were treated with definitive radiotherapy from 2012 to 2016. The NLR collected one month after the completion of RT was defined as the primary outcome. Clinical characteristics and two-dimensional dosimetric factors calculated from the dose-volume histogram (DVH) were included. A total of 4165 dosiomics and radiomics features were extracted from the 3D dose maps and CT images within five different anatomical regions of interest (ROIs), respectively. Then, a three-step feature selection method was proposed to progressively filter features from coarse to fine: (i) model-based ranking according to individual feature's performance, (ii) maximum relevance and minimum redundancy (mRMR), (iii) select from model based on feature importance calculated with an ensemble of several decision trees. The selected feature subsets were utilized to develop the prediction model with GBDT. All patients were divided into a development set and an independent testing set (2:1). Five-fold cross-validation was applied to the development set for both feature selection and model training procedure. Finally, a fusion model combining dosiomics, radiomics and clinical features was constructed to further improve the prediction results. The area under receiver operating characteristic curve (ROC) were used to evaluate the model performance.

RESULTS

The clinical-based and DVH-based models showed limited predictive power with AUCs of 0.632 (95% CI: 0.490-0.773) and 0.634 (95% CI: 0.497-0.771), respectively, in the independent testing set. The 9 feature-based dosiomics and 3 feature-based radiomics models showed improved AUCs of 0.738 (95% CI: 0.628-0.849) and 0.689 (95% CI: 0.566-0.813), respectively. The dosiomics & radiomics & clinical fusion model further improved the model's generalization ability with an AUC of 0.765 (95% CI: 0.656-0.874).

CONCLUSIONS

Dosiomics and radiomics can benefit the prediction of post-RT NLR of LA-NSCLC patients. This can provide a reference for evaluating radiotherapy-related inflammation.

The Correlation Between Lymphocyte Nadir and Radiation Therapy for Soft Tissue Sarcoma: Defining Key Dosimetric Parameters and Outlining Clinical Significance

Purpose

The objectives of this study were to identify key dosimetric parameters associated with postradiation therapy lymphopenia and uncover any effect on clinical outcomes.

Methods and Materials

This was a retrospective review of 69 patients (between April 2010 and January 2023) who underwent radiation therapy (RT) as a part of curative intent for soft tissue sarcoma (STS) at a single academic institution. All patients with treatment plans available to review and measurable absolute lymphocyte count (ALC) nadir within a year after completion of RT were included.

Results

Median follow-up was 22 months after the start of RT. A decrease in lymphocyte count was noted as early as during treatment and persisted at least 3 months after the completion of RT. On multivariable linear regression, the strongest correlations with ALC nadir were mean body dose, body V10 Gy, mean bone dose, bone V10 Gy, and bone V20 Gy. Five-year overall survival was 60% and 5-year disease-free survival was 44%. Advanced T-stage, chemotherapy use, use of intensity-modulated RT, lower ALC nadir, and the development of grade ≥2 lymphopenia at nadir were associated with worse overall survival and disease-free survival.

Conclusions

Post-RT lymphopenia was associated with worse outcomes in STS. There were associations between higher body V10 Gy and bone V10 Gy and lower post-RT ALC nadir, despite the varying sites of STS presentation, which aligns with the well-known radiosensitivity of lymphocyte cell lines. These findings support efforts to reduce treatment-related hematopoietic toxicity as a way to improve oncologic outcomes. Additionally, this study supports the idea that the effect of radiation on lymphocyte progenitors in the bone marrow is more significant than that on circulating lymphocytes in treatments with limited involvement of the heart and lung.

Proton and Carbon Ion Radiation Therapy Decreased Severe Lymphopenia by Reducing Thoracic Vertebra and Aortic Doses in Non-Small Cell Lung Cancer Versus Intensity Modulated Radiation Therapy

PURPOSE

Lymphopenia is a common adverse effect of radiation therapy (RT). Little is known about the difference in lymphopenia between intensity modulated (photon) radiation therapy (IMRT) and proton and carbon ion radiation therapy (PCIRT). This study aimed to investigate lymphopenia differences between IMRT and PCIRT in non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Clinical and dosimetric parameters were collected from 343 patients who received definitive IMRT or PCIRT for NSCLC. Severe lymphopenia (SRL) was defined as an absolute lymphocyte count (ALC) ≤0.5 × 103 cells/μL. Overall survival (OS) was analyzed using the Kaplan-Meier method. Propensity score matching was performed between the IMRT and PCIRT groups. Least absolute shrinkage and selection operator analysis was used to select appropriate dosimetric parameters. Univariate and multivariate logistic regression analyses were conducted to identify the predictors of SRL.

RESULTS

Compared with the IMRT group, the PCIRT group was less likely to develop SRL (P < .001). Compared with the non-SRL group, the SRL group showed significant association with poorer OS, with a median survival time of 29.2 versus 15.0 months (P = .046). IMRT was an independent risk factor of SRL (P = .004). A lower ALC before RT (P = .030) and larger planning target volume (PTV) (P = .002) were also significant independent risk factors for SRL. Moreover, the majority of dosimetric parameters of organs at risk in PCIRT were lower than those in IMRT (P < .001). Thoracic vertebra V5 (P = .002) and aorta V5 (P = .026) were identified as independent risk predictors of SRL after adding dosimetric parameters to the regression model.

CONCLUSIONS

Compared with IMRT, PCIRT could reduce SRL incidence, possibly by limiting thoracic vertebra and aortic doses, and SRL was associated with poor outcomes in patients with NSCLC.

Exploring causes and consequences of early discontinuation of durvalumab after chemoradiotherapy for non-small cell lung cancer

Introduction

For most locally advanced non-small cell lung cancer (LA-NSCLC) patients who complete definitive chemoradiotherapy (CRT) and do not experience disease progression, one year of adjuvant durvalumab is recommended. Here, we explore causes and consequences of early durvalumab discontinuation.

Materials and Methods

We reviewed patients treated for LA-NSCLC with definitive CRT who began adjuvant durvalumab between 2017 and 2021. Duration of durvalumab receipt and causes for early discontinuation were tabulated. Logistic regression models were utilized to evaluate predictors of early durvalumab discontinuation. Landmark analyses were performed to explore associations between early durvalumab discontinuation and clinical outcomes (progression-free survival (PFS), overall survival (OS)).

Results

Fifty-nine patients were included. Forty-one patients (69%) discontinued durvalumab early, most commonly for disease progression (n = 14) or lung toxicity (n = 10). Multivariable analysis revealed mean heart radiotherapy dose (MHD) was associated with risk of durvalumab discontinuation from progression (HR = 2.34 per 10 Gy, p = 0.052), and there was a trend suggesting an association between MHD and risk of durvalumab discontinuation from lung toxicity (HR = 2.16 per 10 Gy, p = 0.126). Median PFS duration following durvalumab initiation was 14 months, and median OS duration was 32 months. Landmark analyses that excluded patients with progression or death within one year of durvalumab initiation demonstrated improved outcomes for patients who completed one year of durvalumab (2-year PFS 100% v. 40%, p < 0.001; 2-year OS 100% v. 67%, p = 0.862). Improved outcomes were observed for patients who received MHD below the cohort median (9.3 Gy) compared to patients with higher MHD (median PFS 32 months v. 8 months, p < 0.001; 2-year OS 69% v. 44%, p = 0.088).

Conclusion

For LA-NSCLC patients treated with CRT followed by immunotherapy, extent of cardiac irradiation may be a risk factor for immunotherapy discontinuation, disease recurrence, and death.

Effect of Lymphopenia on Tumor Response and Clinical Outcomes Following Chemoradiotherapy in Stage III Non-Small Cell Lung Cancer

Background

Prior studies suggest lymphopenia, systemic immune-inflammatory index, and tumor response all impact clinical outcomes in Stage III NSCLC. We hypothesized that tumor response after CRT would be associated with hematologic metrics and might predict clinical outcomes.

Materials and Methods

Patients with stage III NSCLC treated at a single institution between 2011 and 2018 were retrospectively reviewed. Pre-treatment gross tumor volume (GTV) was recorded then reassessed at 1-4 months post-CRT. Complete blood counts before, during and after treatment were recorded. Systemic immune-inflammation index (SII) was defined as neutrophil × platelet/lymphocyte. Overall survival (OS) and progression free survival (PFS) were calculated using Kaplan-Meier estimates, and compared with Wilcoxon tests. A multivariate analysis of hematologic factors impacting restricted mean survival was then performed using pseudovalue regression, accounting for other baseline factors.

Results

106 patients were included. After median follow-up of 24 months, median PFS and OS were 16 and 40 months, respectively. Within the multivariate model, baseline SII was associated with OS (p = 0.046) but not PFS (p = 0.09), and baseline ALC correlated with both PFS and OS (p = 0.03 and p = 0.02, respectively). Nadir ALC, nadir SII, and recovery SII were not associated with PFS or OS.

Conclusion

In this cohort of patients with stage III NSCLC, baseline hematologic factors were associated with clinical outcomes including baseline ALC, baseline SII and recovery ALC. Disease response was not well correlated with hematologic factors or clinical outcomes.

Non-Small Cell Lung Cancer Treatment with Molecularly Targeted Therapy and Concurrent Radiotherapy—A Review

Lung cancer is the leading cause of death worldwide for both men and women. Surgery can be offered as a radical treatment at stages I and II and selected cases of stage III (III A). Whereas at more advanced stages, combined modalities of treatment are applied: radiochemotherapy (IIIB) and molecularly targeted treatment (small molecule tyrosine kinase inhibitors, VEGF receptor inhibitors, monoclonal antibodies, and immunological treatment with monoclonal antibodies). Combination treatment, composed of radiotherapy and molecular therapy, is increasingly employed in locally advanced and metastatic lung cancer management. Recent studies have indicated a synergistic effect of such treatment and modification of immune response. The combination of immunotherapy and radiotherapy may result in the enhancement of the abscopal effect. Anti-angiogenic therapy, in combination with RT, is associated with high toxicity and should be not recommended. In this paper, the authors discuss the role of molecular treatment and the possibility of its concurrent use with radiotherapy in non-small cell lung cancer (NSCLC).

Higher aorta dose increased neutrophil-to-lymphocyte ratio resulting in poorer outcomes in stage II-III non-small cell lung cancer

BACKGROUND

This study focused on the relationship between the neutrophil-to-lymphocyte ratio (NLR) and the dose of organs at risk in patients with stage II-III non-small cell lung cancer (NSCLC) receiving intensity-modulated radiotherapy.

METHODS

The clinical characteristics and dosimetric parameters of 372 patients were collected retrospectively. A high NLR was defined as that ≥1.525. Survival analysis was conducted using the Kaplan-Meier and Cox regression analysis. Least absolute shrinkage and selection operator (LASSO) analysis was conducted to select appropriate dosimetric parameters. The risk factors of NLR were evaluated using univariate and multivariate logistic regression analyses.

RESULTS

Patients with a high NLR had poorer progression-free survival (PFS) (p = 0.011) and overall survival (OS) (p = 0.061). A low NLR (<1.525) predicted better PFS (hazard ratio [HR] 0.676, 95% confidence interval [CI]: 0.508-0.900, p = 0.007) and OS (HR 0.664, 95% CI: 0.490-0.901, p = 0.009). The aorta dose differed between the low and high NLR groups (all <0.1) in the univariate analysis. An aorta V10 was confirmed as a significant risk factor for a high NLR (odds ratio [OR] 1.029, 95% CI: 1.011-1.048, p = 0.002). Receiving chemotherapy before (OR 0.428, 95% CI: 0.225-0.813, p = 0.010) and during (OR 0.491, 95% CI: 0.296-0.815, p = 0.006) radiotherapy were predictive factors of a low NLR.

CONCLUSION

The aorta dose was significantly associated with a high NLR. Patients with stage II-III NSCLC with a high NLR had poorer prognosis. Receiving chemotherapy before and/or during radiotherapy predicted a low NLR.

High proportion of circulating CD8 + CD28- senescent T cells is an independent predictor of distant metastasis in nasopharyngeal canrcinoma after radiotherapy

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a kind of epithelial carcinoma that is common in East and Southeast Asia. Distant metastasis after radiotherapy remains the main cause of treatment failure and preradiotherapy immune system function can influence prognosis. Our study aimed to identify immune-related prognostic factors for NPC after radiotherapy and establish a prognostic model to predict progression-free survival (PFS) and distant metastasis-free survival (DMFS).

METHODS

We enrolled NPC patients and divided them into training and validation cohorts with follow-up. We collected clinical information and investigated immune cells, EBV DNA and cytokines in the peripheral blood of NPC patients before radiotherapy and EBV DNA after radiotherapy. Among these immune cells, we included CD8⁺CD28^- T cells, which are a unique T-cell immunosenescent subset that increases in human peripheral blood with increasing age and declining immune function. Based on the detection results and clinical information, we utilized Cox regression and least absolute shrinkage and selection operator (LASSO) regression to screen the PFS and DMFS prognostic factors and build nomograms to predict the PFS and DMFS of NPC. We also verified the results in the validation set.

RESULTS

Three factors associated with PFS were selected: proportion of CD8⁺CD28^- T cells posttreatment EBV and N stage. Three factors associated with DMFS were screened: proportion of CD8⁺CD28^- T cells, posttreatment EBV and N stage. CD8⁺CD28^- T cells are correlated with systemic inflammation and posttreatment immunosuppression. The C-indexes were 0.735 and 0.745 in the training and validation cohorts for predicting PFS. For DMFS, the C-indexes were 0.793 and 0.774 in the training and validation cohorts.

CONCLUSIONS

The pretreatment proportion of CD8⁺CD28^- T cells is a candidate prognostic biomarker for NPC after radiotherapy. The constructed nomogram models based on CD8⁺CD28^- T cells have good predictive value.

Reduced radiation exposure to circulating blood cells in proton therapy compared with X-ray therapy in locally advanced lung cancer: Computational simulation based on circulating blood cells

Background

We estimated the dose of circulating blood cells (CBCs) in patients with locally advanced non-small cell lung cancer for predicting severe radiation-induced lymphopenia (SRIL) and compared pencil-beam scanning proton therapy (PBSPT) and intensity-modulated (photon) radiotherapy (IMRT).

Materials and methods

After reviewing 325 patients who received definitive chemoradiotherapy with PBSPT (n = 37) or IMRT (n = 164). SRIL was diagnosed when two or more events of an absolute lymphocyte count < 200 µL occurred during the treatment course. Dose information for the heart and lungs was utilized for the time-dependent computational dose calculation of CBCs.

Results

The dose distribution of CBCs was significantly lesser in the PBSPT group than that in the IMRT group. Overall, 75 (37.3%) patients experienced SRIL during the treatment course; 72 and 3 patients were treated with IMRT and PBSPT, respectively. SRIL was associated with poor progression-free and overall survival outcomes. Upon incorporating the dose information of CBCs for predicting SRIL, CBC D90% > 2.6 GyE was associated with the development of SRIL with the baseline lymphocyte count and target volume. Furthermore, PBSPT significantly reduced the dose of CBC D90% (odds ratio = 0.11; p = 0.004) compared with IMRT.

Conclusion

The results of this study demonstrate the significance of the dose distribution of CBCs in predicting SRIL. Furthermore, reducing the dose of CBCs after PBSPT minimized the risk of SRIL. Lymphocyte-sparing radiotherapy in PBSPT could improve outcomes, particularly in the setting of maintenance immunotherapy.

Meta-analysis and Critical Review: Association Between Radio-induced Lymphopenia and Overall Survival in Solid Cancers

Purpose

Immune system modulation, with the use of immune checkpoint inhibitors, has drastically changed the field of oncology. Strong preclinical data indicate that radiation therapy (RT) may enhance the response rate to such drugs via in situ vaccination, although these data do not consider immune radiotoxicity. This meta-analysis investigates whether radio-induced lymphopenia (RIL) is associated with overall survival (OS).

Methods and Materials

A systematic literature search and quantitative analysis were planned, conducted, and reported per the Preferred Reporting Items for Systematic Reviews and Meta-analyses and Quality of Reporting of Meta-analyses checklists. The literature from January 1990 to March 2021 was searched to identify clinical studies with OS data in patients treated with RT and presenting with lymphopenia. A random-effect model was employed for the meta-analysis. Heterogeneity was assessed using the I² statistic. Publication bias was estimated using a P-curve analysis.

Results

A total of 56 studies with 13 223 patients and 11 types of cancers were selected. The mean follow-up time was 35.9 months. Over a third of patients had RIL (37.25%). After removing outlying studies (n = 14), the between-study heterogeneity variance was estimated at t² = 0.018 (P = .01) with an I² value of 36.0% (95% confidence interval, 6%-56%). The results showed that RIL was significantly associated with worse OS (hazard ratio: 1.70; 95% confidence interval, 1.55-1.86; P < .01; 95% prediction interval, 1.27-2.26). A subgroup analysis was performed based on the type of primary tumor, and a difference between the subgroups was found (P < .01). Based on the P-curve analysis, a significant evidential value was found, and no significant publication bias was identified among the studies.

Conclusions

RIL is a significant prognostic factor for mortality in virtually all solid cancers. Pooled-effect estimates indicate a significantly reduced risk of death in patients without RIL. Tailoring RT regimens to spare the immune system and updating dosimetric constraints for new organs at risk, such as major blood vessels, organs with rich blood supplies, bones, and all lymph node areas, may improve prognoses.

Hypofractionated concurrent chemoradiotherapy related lymphopenia and its association with survival in locally advanced non-small cell lung cancer patients

BACKGROUND

To evaluate longitudinal changes of concurrent chemoradiotherapy (CCRT) related lymphopenia and its association with survival in locally advanced non-small cell lung cancer (LA-NSCLC) patients.

METHODS

Total lymphocyte count (TLC) at baseline, weekly intervals during CCRT and monthly intervals up to 12 months after CCRT were documented. The Common Terminology Criteria for Adverse Events version 5.0 was used to grade the severity of lymphopenia. Cox regression analysis was performed to evaluate the association between overall survival (OS) and CCRT related lymphopenia at different timepoints. Logistic regression model was used to determine the clinical factors associated with TLC level.

RESULTS

381 LA-NSCLC patients treated with definitive CCRT without consolidation therapy (NCT02573506/NCT02577341) between 2011 to 2020 were analyzed. With a median follow-up of 45.8 months, the median OS was 41.0 months for all patients. Univariable analysis demonstrated that the 3 weeks during CCRT Grade (G) 4 lymphopenia (P=0.018), 2 months after CCRT G1-4 lymphopenia (P=0.004), 6 months after CCRT (6m-post-CCRT) G1-4 lymphopenia (P=0.001), and TLC nadir (P=0.020) were significantly associated with poorer OS. Multivariable analysis suggested that 6m-post-CCRT G1-4 lymphopenia (HR 2.614; P=0.041) were one of the independent predictors of OS. Further analysis inferred that radiation dose (OR: 1.328; P=0.005), GTV volume (OR: 1.004; P=0.036), and baseline TLC (OR: 0.288; P=0.001) were associated with 6m-post-CCRT lymphopenia.

CONCLUSION

The persistent lymphopenia at 6 months after CCRT was an independent prognostic factor of OS in LA-NSCLC patients. Higher radiation dose, larger gross tumor volume and lower baseline TLC were significantly related to 6m-post-CCRT lymphopenia.

Radiation-induced eosinophil increase ratio predicts patient outcomes in non-small celllung cancer

Background and purpose

Radiotherapy (RT) is a double-edged sword in regulating immune responses. This study aimed to investigate the impact of thoracic RT on circulating eosinophils and its association with patient outcomes in non-small cell lung cancer (NSCLC).

Materials and methods

This retrospective study included 240 patients with advanced NSCLC treated with definitive thoracic RT from January 2012 to January 2020. Statistics included Kaplan-Meier analysis of overall survival (OS) and progression-free survival (PFS), multivariate Cox analyses to identify significant variables, and Spearman’s correlation to qualify the relationship between dose-volume histogram (DVH) parameters and EIR.

Results

Absolute eosinophil counts (AECs) showed an increasing trend during RT and an obvious peak in the 1^st month after RT. Thresholds of eosinophil increase ratio (EIR) at the 1^st month after RT for both OS and PFS were 1.43. Patients with high EIR above 1.43 experienced particularly favorable clinical outcomes (five-year OS: 21% versus 10%, P<0.0001; five-year PFS: 10% versus 8%, P=0.014), but may not derive PFS benefit from the addition of chemotherapy to RT. The higher a patient’s EIR, the larger the potential benefit in the absence of chemotherapy. DVH parameters including heart mean dose and heart V10 were negatively associated with EIR. None of these DVH parameters was correlated with the clinical outcomes.

Conclusion

EIR may serve as a potential biomarker to predict OS and PFS in NSCLC patients treated with RT. These findings require prospective studies to evaluate the role of such prognostic marker to identify patients at risk to tailor interventions.

Redefine the Role of Proton Beam Therapy for the Locally-Advanced Non-Small Cell Lung Cancer Assisting the Reduction of Acute Hematologic Toxicity

Purpose

To investigate the potential clinical benefit of utilizing intensity-modulated proton therapy (IMPT) to reduce acute hematologic toxicity for locally advanced non-small cell lung cancer (LA-NSCLC) patients and explore the feasibility of a model-based patient selection approach via the normal tissue complication probability (NTCP).

Methods

Twenty patients with LA-NSCLC were retrospectively selected. Volumetric modulated arc photon therapy (VMAT) and IMPT plans were generated with a prescription dose of 60 Gy in 30 fractions. A wide range of cases with varied tumor size, location, stations of metastatic lymph nodes were selected to represent the general cancer group. Contouring and treatment planning followed RTOG-1308 protocol. Doses to thoracic vertebral bodies (TVB) and other organ at risks were compared. Risk of grade ≥ 3 acute hematologic toxicity (HT3+) were calculated based on the NTCP model, and patients with a reduction on NTCP of HT3+ from VMAT to IMPT (△NTCP_HT3+) ≥ 10% were considered to ‘significantly benefit from proton therapy.’

Results

Compared to VMAT, IMPT significantly reduced the dose to the TVB, the lung, the heart, the esophagus and the spinal cord. Tumor distance to TVB was significantly associated with △NTCP _HT3+ ≥ 10%. For the patients with tumor distance ≤ 0.7 cm to TVB, the absolute reduction of dose (mean, V30 and V40) to TVB was significantly lower than that in patients with tumor distance &gt; 0.7 cm.

Conclusion

IMPT decreased the probability of HT3+ compared to VMAT by reducing the dose to the TVB in LA-NSCLC patients. Patients with tumor distance to TVB less than 0.7 cm are likely to benefit most from proton over photon therapy.

Prognostic role of controlling nutritional status score in hematological malignancies

BACKGROUND

Controlling nutritional status (CONUT) score, based on three indexes including serum albumin (ALB), total cholesterol (CHO), and absolute lymphocyte count (ALC), has been closely associated with the prognosis of cancer patients. Multiple studies revealed the significance of CONUT score in hematological malignancies, including diffuse large B-cell lymphoma (DLBCL), peripheral T-cell lymphoma (PTCL), multiple myeloma (MM), and leukemia.

OBJECTIVE

This review aimed to explore the prognostic role of CONUT score in hematological malignancies.

METHODS

We conducted this review through Pubmed to summarize the published studies on the CONUT score in hematological malignancies, using the terms: Controlling nutritional status, CONUT score, hematological malignancy, lymphoma, multiple myeloma, and leukemia.

RESULT

CONUT score can reflect not only the nutritional status but also the inflammatory status of patients with hematological malignancies. It can assist in predicting the survival of patients with DLBCL, PTCL, MM, adult T-cell leukemia (ATL), myelodysplastic syndrome (MDS), and acute myeloid leukemia with myelodysplasia related changes (AML-MRC).

CONCLUSION

CONUT score plays an important role in predicting the prognosis of patients with hematological malignancies.

Biomarkers in muscle invasive bladder cancer

Muscle invasive bladder cancer (MIBC) carries a poor prognosis with a 5-year overall survival rate of 40-50%. For localized disease, radical treatment options are cystectomy or radiotherapy with or without a radiosensitiser. Neoadjuvant or adjuvant chemotherapy is often delivered in addition to either. Metastatic disease can be treated with palliative systemic chemotherapy or immunotherapy. Standard clinicopathological information is insufficient to guide treatment decisions in several clinical scenarios in MIBC and there has been substantial effort to identify predictive and prognostic biomarkers. Despite this, no biomarker has been sufficiently qualified in prospective clinical trials to justify routine use. In this chapter we discuss these biomarkers and provide insight into the significant unmet need for robust biomarkers to inform treatment decisions and ultimately improve outcomes for bladder cancer patients.

Dosimetric Modeling of Lymphopenia in Patients With Metastatic Cancer Receiving Palliative Radiation and PD-1 Immune Checkpoint Inhibitors

Purpose

Methods and Materials

Results

Conclusions

Early onset of severe lymphopenia during definitive radiotherapy correlates with mean body dose and predicts poor survival in cervical cancer

BACKGROUND:

Lymphopenia during definitive radiotherapy (RT) has been shown to reduce survival in patients with cervical cancer. However, there are few studies on the significance of onset time of lymphopenia during RT in patients with cervical cancer.

OBJECTIVE:

This study aimed to exam the prognostic significance of early onset of severe lymphopenia (EOSL) during definitive RT in patients with cervical cancer.

METHODS:

Newly diagnosed cervical cancer patients treated with definitive RT from January 2015 to December 2019 were eligible for this retrospective study. EOSL was defined as first onset of grade 3–4 lymphopenia ⩽ 3 weeks from the start of RT. Mean body dose (MBD) was the mean radiation dose absorbed by the body during the whole course of external beam RT (EBRT) and was directly obtained from the dose volume histogram (DVH) of the EBRT planning. Logistic regression analysis and restricted cubic spline (RCS) models were applied to assess relationships between clinicopathological factors and EOSL. Survival analysis was performed using Kaplan-Meier curves and log-rank test. A COX regression model was developed to predict overall survival (OS).

RESULTS:

A total of 104 patients were included and 59.6% had EOSL. MBD (P= 0.04), concurrent cisplatin (P= 0.011), and pre-RT absolute lymphocyte count (ALC) (P= 0.001) were associated with EOSL. A linear relationship (P for non-linearity = 0.803) between MBD and risk of EOSL was found. Patients with EOSL had decreased OS (2-yr 75.1% vs 91.1%, P= 0.021) and progression-free survival (PFS) (2-yr 71.2% vs 83.7%, P= 0.071). An OS prediction COX model was developed with C-index of 0.835 and AUC of 0.872.

CONCLUSIONS:

EOSL during definitive RT correlates with MBD and predicts poor survival in patients with cervical cancer.

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.

The effects of stereotactic body radiotherapy on peripheral natural killer and CD3+CD56+ NKT-like cells in patients with hepatocellular carcinoma

BACKGROUND

Both natural killer (NK) and CD3⁺CD56⁺natural killer T (NKT)-like cells play critical roles in the antitumor response. This study aimed to explore the effects of stereotactic body radiotherapy (SBRT) on peripheral NK and NKT-like cells in patients with hepatocellular carcinoma (HCC), and to identify possible surface markers on these cells that correlate with the prognosis.

METHODS

Twenty-five HCC patients were prospectively enrolled in our study, and 10 healthy individuals were served as healthy controls. Flow cytometry was used to determine the counts and the percentages of peripheral NK and NKT-like cells, cells with certain receptors, and cells with intracellular interferon-γ and TNF-α secretion at different time points, including time points of prior to SBRT, at post-SBRT, and 3-month and 6-month after treatment. The Kaplan-Meier method with the log-rank test was applied for survival analysis.

RESULTS

The peripheral NKT-like cells was increased at post-SBRT. Meanwhile, elevated levels of inhibitory receptors and reduced levels of activating receptors of NK cells were also observed in NK cells at post-SBRT, but the levels was not significantly different at 3-month and 6-month as compared with the baseline levels. Lower percentage of NKp30⁺NK cells before SBRT and higher percentage of CD158b⁺NK cells after SBRT were associated with poor progression-free survival. In addition, higher percentage of CD3⁺CD56⁺ NKT-like cells was associated with a higher overall survival rate in HCC patients.

CONCLUSIONS

SBRT has an apparent effect on both peripheral NK and CD3⁺CD56⁺NKT-like cells. Lower percentage of NKp30⁺NK cells before SBRT and higher percentage of CD158b⁺NK cells after SBRT are correlated with poor patients' PFS. Higher percentage of CD3⁺CD56⁺ NKT-like cells is associated with higher OS in HCC patients.

Radiotherapy in the Era of Immunotherapy With a Focus on Non-Small-Cell Lung Cancer: Time to Revisit Ancient Dogmas?

Radiation-induced immune effects have been extensively deciphered over the last few years, leading to the concept of the dual immune effect of radiotherapy with both immunostimulatory and immunosuppressive effects. This explains why radiotherapy alone is not able to drive a strong anti-tumor immune response in most cases, hence underlining the rationale for combining both radiotherapy and immunotherapy. This association has generated considerable interest and hundreds of trials are currently ongoing to assess such an association in oncology. However, while some trials have provided unprecedented results or shown much promise, many hopes have been dashed. Questions remain, therefore, as to how to optimize the combination of these treatment modalities. This narrative review aims at revisiting the old, well-established concepts of radiotherapy relating to dose, fractionation, target volumes and organs at risk in the era of immunotherapy. We then propose potential innovative approaches to be further assessed when considering a radio-immunotherapy association, especially in the field of non-small-cell lung cancer (NSCLC). We finally propose a framework to optimize the association, with pragmatic approaches depending on the stage of the disease.

The Impact of Lymphopenia and Dosimetric Parameters on Overall Survival of Esophageal Cancer Patients Treated with Definitive Radiotherapy

Purpose

The objectives of the present study are to perform a survival analysis of patients with thoracic esophageal squamous cell carcinoma (ESCC) receiving definitive radiotherapy and to identify prognostic factors from among the hematological and dosimetric factors.

Methods

Cases of thoracic ESCC treated with radical RT between 2014 and 2017 were identified. The impact of clinicopathological factors on overall survival (OS) were analyzed using the Cox proportional hazards model. Absolute lymphocyte counts (ALC) and the neutrophil-to-lymphocyte ratio (NLR = ANC/ALC) were assessed before, during, and after radiotherapy (RT). Cox regression was used to correlate clinical factors with hematologic toxicities, dosimetric parameters and overall survival. Multiple logistic regression analysis was used to identify associations between lymphopenia and dosimetric parameters. With the overall survival status and real time events, the X-tile program was utilized to determine the optimal cut-off value of pretreatment NLR, and ALC nadir.

Results

Ninety-nine ESCC patients were enrolled in the present study. They had a median OS of 23 months. The median RT dose was 55.75Gy (46–66Gy), and the mean dose (D_mean) of the thoracic vertebrae (TVB) was 27.04±9.65Gy. Based on the multivariate analysis, the V20 of TVB, the pretreatment NLR, and the ALC nadir were associated with significantly worse OS. Concurrent CRT, which entailed increasing the mean TVB dose and V20 of TVB, was linked to a higher probability of lymphopenia risk (P<0.05). This was ascertained through the multiple logistic regression analysis.

Conclusion

In ESCC patients who received definitive RT, V₂₀ of TVB, pretreatment NLR, and ALC nadir during RT were independent prognostic factors and chemotherapy regimen, mean TVB dose, and V₂₀ of TVB were associated with lymphopenia.

Hematological toxicity in patients with solid malignant tumors treated with radiation - Temporal analysis, dose response and impact on survival

PURPOSE

To describe the kinetics of the peripheral blood components after radiotherapy, to examine radiation exposure vs. End-of-Radiation-Therapy (EoRT) counts and to associate the EoRT lymphocyte count with death and cancer treatment failure.

MATERIALS AND METHODS

Cohort study of patients who received curative intent radiotherapy for solid tumor diagnoses from 2009-2016 at Rigshospitalet, Copenhagen and had available 3D radiation exposure data. We illustrated peripheral blood count kinetics within 12 months before and after radiotherapy start and analyzed the impact of the irradiated body volume. We investigated overall survival and cancer treatment failure according to EoRT lymphopenia using Cox regression analyses.

RESULTS

We analyzed 4055 patients with both pre-treatment and EoRT platelet counts and 2318 patients who also had neutrophil and lymphocyte counts. Only the lymphocyte decline after radiotherapy start was clinically relevant and remained low one year after radiotherapy. The higher the volume of the body exposed to radiation, the lower the EoRT blood counts. Female gender (p < 0.001), number of fractions (p = 0.010), dose-volume (p < 0.001) and concomitant use of chemotherapy, particularly the platinum compounds (p < 0.001) were independently associated with a lower EoRT lymphocyte count. Patients with head and neck cancer had the lowest EoRT lymphocyte count. Patients with lymphopenia had a higher risk of death in the year after radiotherapy, compared with patients with no lymphopenia.

CONCLUSION

Radiation schemes with fewer fractions and radiation techniques allowing reduction of the volume of the body exposed to radiation could be expected to better preserve patients' immune function.

Association of severe lymphopenia and disease progression in unresectable locally advanced non-small cell lung cancer treated with definitive chemoradiation and immunotherapy

BACKGROUND

Definitive chemoradiation with consolidative immunotherapy offers the best chance for cure in patients with unresectable, locally advanced non-small cell lung cancer (NSCLC). However, treatment-related lymphopenia (TRL) may negatively impact outcomes.

METHODS

Patients definitively treated with chemoradiation and immunotherapy from 2015 to 2019 at a single tertiary academic center were identified. Severe lymphopenia was defined as <0.5 × 10⁹ cells/L. Progression-free survival (PFS) was calculated by Kaplan Meier methodology. Univariate and multivariate Cox Proportional Hazard modeling was used to correlate clinical variables with disease outcome. Immune-related adverse events (irAEs) were assessed according to CTCAE version 5.0 criteria.

RESULTS

Seventy-eight patients were included in the final cohort. The median age was 66 years (IQR: 58-73), 55 % were males, and 88 % had a KPS of >70. At baseline, 90 % (n = 70/78) of patients had a normal ALC and one patient had severe lymphopenia. After chemoradiation, the median ALC decreased from 1.52 × 10⁹cells/L (IQR: 1.23-1.98) to 0.72 × 10⁹cells/L (IQR: 0.52-0.94) (p < 0.001), 22 % (n = 17/78) of patients had a normal ALC, and 23 % (n = 18/78) of patients developed severe lymphopenia. Patients who initiated consolidative immunotherapy with severe lymphopenia had worse PFS than those who did not (median 217 days [IQR: 120-434] vs. 570 days [IQR: 401-NR], p < 0.001). On multivariate modeling, severe lymphopenia at the time of immunotherapy initiation remained an independent predictor of worse PFS (HR 4.90, p < 0.001).

CONCLUSIONS

This is the first report to associate severe TRL with disease progression in patients with locally advanced NSCLC receiving consolidative immunotherapy. Factors associated with development of lymphopenia and strategies to mitigate lymphopenic effects should be considered.

Proton beam therapy reduces the risk of severe radiation-induced lymphopenia during chemoradiotherapy for locally advanced non-small cell lung cancer: A comparative analysis of proton versus photon therapy

HYPOTHESIS

We investigated differences in severe radiation-induced lymphopenia (SRL) after pencil beam scanning proton therapy (PBSPT) or intensity-modulated (photon) radiotherapy (IMRT) for patients with locally advanced non-small cell lung cancer.

METHODS

We retrospectively reviewed 223 patients who received definitive concurrent chemoradiotherapy with PBSPT (n = 29) or IMRT (n = 194). SRL was defined when ≥2 events of absolute lymphocyte counts (ALCs) of <200 cells/μL were observed in weekly laboratory tests conducted during treatment. Stepwise multivariate logistic regression with 10-fold cross-validation was performed to identify predictive values of SRL. Furthermore, 1:2 propensity score matching (PSM) analysis was performed between the PBSPT and IMRT groups.

RESULTS

Baseline ALC was comparable between the PBSPT and IMRT groups (median, 2130 vs. 2040 cells/μL; p = 0.983). Lung volumes receiving ≥ 5-20 GyE and the mean dose were significantly lower in patients receiving PBSPT than those receiving IMRT (p < 0.001). Among 72 (32.3%) patients with SRL; 69 (95.8%) and 3 (4.2%) patients were treated with IMRT and PBSPT, respectively. After multivariable analysis, PBSPT reduced SRL compared to IMRT (odds ratio [OR] 0.13, p = 0.003). Specifically, lung V5Gy were identified as the strongest predictor of SRL before (OR 1.11) and after PSM (OR, 1.07) (p < 0.05). With a median follow-up of 23.0 months, the 2-year overall survival in patients with SRL was worse than that those without SRL (63.4% vs. 79.9%; p = 0.003).

CONCLUSIONS

Reduced irradiated lung volumes of PBSPT consequently reduced SRL. In addition, lung V5Gy contributed to the SRL. Reduction of SRL through the optimized RT might be essential to improve the outcomes.

Radiotherapy-Related Lymphopenia Affects Overall Survival in Patients With Lung Cancer

INTRODUCTION

Lymphopenia after radiotherapy has an adverse effect on the patient's outcome. However, the relationship between radiotherapy dose delivery and lymphopenia is not fully understood. This work used image-based data mining to identify anatomical regions where the received dose is correlated with severe lymphopenia.

METHODS

A total of 901 patients with lung cancer were analyzed. A Cox model was used to assess prognostic factors of overall survival (OS). Two matched groups were defined-patients with lymphopenia of grade 3 or higher and patients without lymphopenia of grade 3-based on tumor volume, baseline lymphocytes, and prescribed dose. Then, data mining was used to identify regions where dose correlates significantly with lymphopenia of grade 3 or higher. For this, dose matrices were aligned using registration of the computed tomography images to one reference patient. Mean dose distributions were obtained for the two groups, and organs of significance were detected. Dosimetric parameters from the identified organs that had the highest correlation with lymphocytes at nadir were selected. Multivariable analysis was conducted for lymphopenia of grade 3 or higher on the full lung cohort, and the model was tested on 305 patients with esophageal cancer.

RESULTS

Adjusted Cox regression revealed that lymphopenia of grade 3 or higher is an independent factor of OS. The anatomical regions identified were the heart, lung, and thoracic vertebrae. Dosimetric parameters for lymphopenia included thoracic vertebrae V20, mean lung dose, and mean heart dose, which were further validated in the esophageal cancer cohort.

CONCLUSIONS

We report that severe lymphopenia during radiotherapy is a poor prognostic factor for OS in patients with lung cancer and could be mitigated by minimizing thoracic vertebrae V20, mean lung dose, and mean heart dose to limit the irradiation of stem cells and blood pool.

Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio associations with heart and body dose and their effects on patient outcomes in locally advanced non-small cell lung cancer treated with definitive radiotherapy

Background

Inflammation plays a vital role in tumor growth and progression and can be affected by radiotherapy (RT) and chemotherapy. We sought to investigate the prognostic significance of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), and their associations with dosimetric factors in locally advanced non-small cell lung cancer (LA-NSCLC).

Methods

In this retrospective study, subjects consisted of 244 patients who had received definitive RT ± chemotherapy for LA-NSCLC between 2012 and 2016. Absolute lymphocyte count (ALC), NLR and PLR recorded at pretreatment, during RT and post-RT were analyzed. Multivariable analysis (MVA) was performed to correlate clinical factors and inflammatory biomarkers with progression-free survival (PFS) and overall survival (OS) using a Cox regression model. Relationships between NLR or PLR with OS and PFS were evaluated with Kaplan-Meier analysis and compared with log-rank test results. Multiple stepwise linear regression was used to assess the associations between dosimetric factors and NLR or PLR.

Results

The median PFS and OS for all patients were 8.6 and 15.8 months, respectively. On MVA for PFS and OS, higher 1-month post-RT start NLR [hazard ratio (HR) 1.049; 95% CI: 1.018–1.080; P=0.001] or higher 1-month post-RT start PLR (HR 1.001; 95% CI: 1.000–1.002; P<0.001) was associated with inferior PFS. Higher 1-month post-RT start NLR (HR 1.040; 95% CI: 1.013–1.069; P=0.004) or PLR (HR 1.001; 95% CI: 1.001–1.002; P<0.001) was also an independent predictor of OS. ALCmin, baseline NLR and PLR were not associated with treatment outcomes. Multiple stepwise linear regression analysis confirmed that baseline NLR (P<0.001), heart V20 (P<0.001), heart V40 (P<0.001), and mean body dose (MBD) were significantly associated with 1-month post-RT start NLR. Also, baseline PLR (P<0.001) and MBD (P<0.001) were significantly associated with 1-month post-RT start PLR.

Conclusions

Higher NLR and PLR during treatment were associated with worse patient outcomes, and heart dose or body dose was correlated with NLR or PLR in advanced NSCLC patients treated with definitive RT.

Splenic Hematopoietic and Stromal Cells in Cancer Progression

Tumor-derived secretory factors orchestrate splenic hematopoietic and stromal cells to fuel metastasis. The spleen acts as a reservoir site for hematopoietic stem and progenitor cells, which are rapidly exploited as myeloid-derived suppressor cells at the cost of tumor-reactive lymphoid cells. Splenic erythroid progenitor cells and mesenchymal stromal cells contribute directly and indirectly to both tumor immune escape and the metastatic cascade. Animal models provide valuable mechanistic insights, but their translation to a clinical setting highlights specific challenges and open issues. In this review, we envision the exploitation of the spleen as a source for novel biomarkers and therapeutic approaches.

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."

Comparison of the dose on specific 3DCT images and the accumulated dose for cardiac structures in esophageal tumors radiotherapy: whether specific 3DCT images can be used for dose assessment?

BACKGROUND

Cardiac activity could impact the accuracy of dose assessment for the heart, pericardium and left ventricular myocardium (LVM). The purpose of this study was to explore whether it is possible to perform dose assessment by contouring the cardiac structures on specific three-dimensional computed tomography (3DCT) images to reduce the impact of cardiac activity.

METHODS

Electrocardiograph-gated 4DCT (ECG-gated 4DCT) images of 22 patients in breath-hold were collected. MIM Maestro 6.8.2 (MIM) was used to reconstruct specific 3DCT images to obtain the Maximal intensity projection (MIP) image, Average intensity projection (AIP) image and Minimum intensity projection (Min-IP) image. The heart, pericardium and LVM were contoured in 20 phases of 4DCT images (0, 5%... 95%) and the MIP, AIP and Min-IP images. Then, a radiotherapy plan was designed at the 0% phase of the 4DCT images, and the dose was transplanted to all phases of 4DCT to acquire the dose on all phases, the accumulated dose of all phases was calculated using MIM. The dose on MIP, AIP and Min-IP images were also obtained by deformable registration of the dose. The mean dose (D_mean), V₅, V₁₀, V₂₀, V₃₀ and V₄₀ for the heart, pericardium and LVM in MIP, AIP and Min-IP images were compared with the corresponding parameters after dose accumulation.

RESULTS

The mean values of the difference between the D_mean in the MIP image and the D_mean after accumulation for the heart, pericardium and LVM were all less than 1.50 Gy, and the dose difference for the pericardium and LVM was not statistically significant (p > 0.05). For dose-volume parameters, there was no statistically significant difference between V₅, V₁₀, and V₂₀ of the heart and pericardium in MIP, AIP, and Min-IP images and those after accumulation (p > 0.05). For the LVM, only in the MIP image, the differences of V₅, V₁₀, V₂₀, V₃₀ and V₄₀ were not significant compared to those after dose accumulation (p > 0.05).

CONCLUSIONS

There was a smallest difference for the dosimetry parameters of cardiac structures on MIP image compared to corresponding parameters after dose accumulation. Therefore, it is recommended to use the MIP image for the delineation and dose assessment of cardiac structures in clinical practice.