Lymphopenia during radiotherapy in patients with oropharyngeal cancer

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.

Higher radiation dose on immune cells is associated with radiation-induced lymphopenia and worse prognosis in patients with locally advanced esophageal squamous cell carcinoma

Background

To explore the effective dose to immune cells (EDIC) for better prognosis while avoiding radiation-induced lymphopenia (RIL) in patients with locally advanced esophageal squamous cell carcinoma (ESCC).

Materials and methods

Overall, 381 patients with locally advanced ESCC receiving definitive radiotherapy with or without chemotherapy (dRT ± CT) between 2014 and 2020 were included in this study. The EDIC model was calculated by radiation fraction number and mean doses to the heart, lung, and integral body. The correlation between EDIC and clinical outcomes was analyzed using Cox proportional hazards regression, and risk factors for RIL were determined by logistic regression analysis.

Results

The median EDIC was 4.38 Gy. Multivariate analysis revealed that low-EDIC significantly improved the OS of patients when compared with high-EDIC (HR = 1.614, P = 0.003) and PFS (HR = 1.401, P = 0.022). Moreover, high-EDIC was associated with a higher incidence of grade 4 RIL (OR = 2.053, P = 0.007) than low-EDIC. In addition, we identified body mass index (BMI), tumor thickness, and nodal stage as independent prognostic factors of OS and PFS, while BMI (OR = 0.576, P = 0.046) and weight loss (OR = 2.214, P = 0.005) as independent risk factors of grade 4 RIL. In subgroup analyses, the good group had better clinical outcomes than the remaining two groups (P< 0.001).

Conclusion

This study demonstrated that EDIC significantly correlates with poor clinical outcomes and severe RIL. Optimizing treatment plans to decrease the radiation doses to immune cells is critical for improving the outcomes.

Haematological and renal toxicity of radiation therapy in neuroblastoma paediatric patients

PURPOSE

The objective of this study was to evaluate the renal and hematologic toxicity in paediatric patients with adrenal high-risk neuroblastoma who have received radiation therapy (RT) as part of radical treatment.

MATERIAL AND METHODS

Pediatric patients diagnosed with high-risk adrenal neuroblastoma who received RT as part of the definitive treatment between January 2004 and May 2020 in a single institution were selected. Complete blood counts (CBC) and creatinine clearance (CrCl) pre-RT and post-RT were compared through the Wilcoxon signed-rank test and correlated with survival analysis by Cox regression.

RESULTS

Forty-two children with a median age of 3 years at diagnosis and 2.8 years of follow-up were selected. A significant and acute decrease in lymphocytes was found (p = 0.002) 1 month from RT. Patients with a drop higher than 50% of the previous value experimented a significant reduction in overall survival (55 vs 10%; p = 0.031). At the end of the follow-up, a significant increase in all blood counts was observed. With respect to renal function, an acute and significant decrease in CrCl was observed tin patients younger than 4 years who received RT (p = 0.013). However, it was not clinically relevant.

CONCLUSION

Our data suggest that acute lymphopenia occurs after RT and could be associated with a poorer prognosis. Other blood counts are reduced after RT and all of them are in physiological range at the end of follow-up. Our cohort presented excellent renal outcomes without any case of chronic renal dysfunction.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

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

Background

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

Methods

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

Results

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

Conclusion

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

Head and neck cancers volume reduction: should we reduce our prophylactic node radiation to spare the antitumor immune response?

Radiotherapy for locally advanced head and neck cancer classically include large prophylactic node volume. However, the use of these large volumes can be responsible for significant toxicity. Furthermore, the disappointing results of radioimmunotherapy combinations in head and neck tumors raise concerns about radiotherapy's potential negative impact on the immune response when large lymph node volumes are treated. Besides, in other tumor locations, such as lung cancers, the volumes of elective irradiation have been considerably reduced, with the same local control as before. This opinion piece reviews the current state of radiation volumes in head and neck cancers, the rationale for these volumes, the potential impact of radiotherapy on immune response, and the volume changes that would improve the efficacy of radioimmunotherapy combinations.

The impact of radiation induced lymphopenia in the prognosis of head and neck cancer: A systematic review and meta-analysis

OBJECTIVES

Radiotherapy is a key part of head and neck cancer (HNC) treatment. Radiation induced lymphopenia (RIL) is a severe complication of radiotherapy. The aim of this study was to evaluate the prognostic role of RIL in HNC patients.

METHOD

We conducted a PRISMA guideline based systemic review and meta-analysis. The studies were identified on the PubMed, Embase and Cochrane Library from 2007 to October 2021. The quality of each study was assessed by Newcastle-Ottawa Quality Assessment Form for Cohort Studies (NOS).

RESULTS

There were 8 studies with 2,733 samples finally included in current study. The meta-analysis showed that the odds ratio of developing grade 3-4 RIL was 13.49 (95%CI = 7.03-25.89, I² = 94%). The incidence rate of grade 3-4 RIL ranged from 73%-88%. Multivariate meta-analysis found that the RIL significantly decreased the overall survival (HR = 2.94, 95%CI = 1.83-4.74, I² = 0%) and distant metastasis free survival of HNC (HR = 3.79, 95%CI = 2.06-6.97, I² = 0%). After sensitivity analysis and excluding a potential study that caused heterogeneity, the new pooled multivariate meta-analysis showed RIL was a risk factor to the progression free survival of HNC patients (HR = 3.16, 95%CI = 1.77-5.63, I² = 0%).

CONCLUSION

This is the first meta-analysis which showed severe RIL decreased the overall survival and promoted the progression of HNC patients. Future large-scale prospective studies are required to evaluate the association between severe RIL and the prognosis of HNC.

Prognostic impact of lymphopenia and neutrophil-lymphocyte ratio for patients with anal squamous cell carcinoma

Background

Outcomes after definitive chemoradiation for squamous cell carcinoma are generally favorable. However, biomarkers to further yield prognostic information are desired. Treatment-related lymphopenia as well as an elevated baseline neutrophil-lymphocyte ratio have been associated with worse survival in several cancer types. We evaluated absolute lymphocyte count and neutrophil-lymphocyte ratio at baseline and at treatment-related nadir in patients with anal cancer for associations with oncologic endpoints.

Methods

We conducted a retrospective analysis of 428 consecutive patients with non-metastatic anal cancer treated with definitive, intensity-modulated radiation therapy-based chemoradiation. We analyzed absolute neutrophil and lymphocyte counts at several timepoints: pretreatment, weekly during treatment, and in the six weeks following treatment completion. Neutrophil-lymphocyte ratio was calculated at baseline and treatment-related nadir. We estimated oncologic endpoints using life tables and compared them using the log-rank test. We conducted univariate and multivariable time-to-event analyses using Cox proportional hazards.

Results

Median absolute lymphocyte count at baseline and nadir were 1.80 [interquartile range (IQR), 1.45-2.32] k/µL and 0.26 (IQR, 0.18-0.36) k/µL, respectively, and 31% developed treatment-related grade 4 lymphopenia. Median neutrophil-lymphocyte ratio at baseline and nadir were 2.34 (IQR, 1.68-3.30) and 8.80 (IQR, 5.86-12.68), respectively. Estimates of overall survival, local failure-free survival, distant metastasis-free survival (DMFS), and freedom from colostomy at 5 years were 87%, 86%, 82%, and 88%, respectively. Baseline and nadir absolute lymphocyte count were not associated with selected outcomes on univariate analysis. On multivariable analysis, factors independently associated with death included T3-T4 disease, HIV-positive status, treatment break, and baseline neutrophil-lymphocyte ratio >3. Baseline neutrophil-lymphocyte ratio showed a trend toward association with distant progression or death (P=0.07). The 5-year overall survival estimates for patients with baseline neutrophil-lymphocyte ratios ≤3 and >3 were 92.3% and 80.6%, respectively.

Conclusions

Lymphopenia during and after chemoradiation for anal cancer is common but does not appear to be associated with worse survival, recurrence, or metastases. However, elevated baseline neutrophil-lymphocyte ratio was independently associated with overall survival, local recurrence-free survival, and DMFS. Further studies are needed to determine the clinical utility of baseline neutrophil-lymphocyte ratio to guide treatment and follow-up.

Chronological Analysis of Acute Hematological Outcomes after Proton and Photon Beam Craniospinal Irradiation in Pediatric Brain Tumors

Purpose

This study aimed to compare the early hematological dynamics and acute toxicities between proton beam craniospinal irradiation (PrCSI) and photon beam craniospinal irradiation (PhCSI) for pediatric brain tumors.

Materials and Methods

We retrospectively reviewed patients with pediatric brain tumors who received craniospinal irradiation (CSI). The average change in hemoglobin levels (ΔHb_avg), absolute lymphocyte counts (ΔALC_avg), and platelet counts (ΔPLT_avg) from baseline values was evaluated and compared between the PrCSI and PhCSI groups at 1 and 2 weeks after the initiation of CSI, 1 week before and at the end of radiotherapy, and 3–4 weeks after the completion of radiotherapy using t-test and mixed-model analysis.

Results

The PrCSI and PhCSI groups consisted of 36 and 30 patients, respectively. There were no significant differences in ΔHb_avg between the two groups at any timepoint. However, ΔALC_avg and ΔPLT_avg were significantly lower in the PhCSI group than in PrCSI group at every timepoint, demonstrating that PrCSI resulted in a significantly lower rate of decline and better recovery of absolute lymphocyte and platelet counts. The rate of grade 3 acute anemia was significantly lower in the PrCSI group than in in the PhCSI group.

Conclusion

PrCSI showed a lower rate of decline and better recovery of absolute lymphocyte and platelet counts than PhCSI in the CSI for pediatric brain tumors. Grade 3 acute anemia was significantly less frequent in the PrCSI group than in the PhCSI group. Further large-scale studies are warranted to confirm these results.

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.

Lymphopenia and intratumoral lymphocytic balance in the era of cancer immuno-radiotherapy

INTRODUCTION

The immune response has been recognized as a major tumor-eradication component of radiotherapy.

OBJECTIVE

This review studies, under a clinical perspective, two contrasting effects of radiotherapy, namely immunosuppression and radiovaccination.

MATERIALS AND METHODS

We critically reviewed the available clinical and experimental experience on radiotherapy-induced lymphopenia.

RESULTS

Radiation-induced tumor damage promotes radio-vaccination, enhances cytotoxic immune responses, and potentiates immunotherapy. Nevertheless, radiotherapy induces systemic and intratumoral lymphopenia. The above effects are directly related to radiotherapy fractionation and field size/location, and tumor characteristics.

DISCUSSION

Hypofractionated stereotactic and accelerated irradiation better promotes radio-vaccination and produces less severe lymphopenia. Adopting cytoprotective policies and combining lympho-stimulatory agents or agents blocking regulatory lymphocyte activity are awaited to unmask the radio-vaccination effect, enhancing the efficacy immuno-radiotherapy.

CONCLUSION

Radiation-induced lymphopenia and immunosuppression are important issues that should be considered in the design of immuno-radiotherapy clinical trials.

Radiation-induced lymphopenia: the main aspects to consider in immunotherapy trials for endometrial and cervical cancer patients

BACKGROUND

Although the chemotherapy-induced depletion of circulating white blood cells (WBC) is well recognized, the impact of exclusive radiotherapy (RT) on the different subpopulations of WBC remains unexplored. This may be important for immunotherapy administrated in combination with radiation, especially in malignant tumors usually treated with RT or chemoradiotherapy (CRT), and characterized by a high mutational burden, such as endometrial (EC) or cervical cancer (CC). We aimed to evaluate the impact of RT and CRT on circulating WBC in uterine cancers and its correlation with survival.

MATERIAL AND METHODS

A total of 202 consecutive patients with uterine cancers treated with RT or CRT between 2009 and 2016 in a large European center and with available basal and post-treatment blood tests were retrospectively evaluated. EC and CC patients were analyzed separately. The differences between pre- and post- treatment WBC mean values were evaluated independently in patients treated with CRT and exclusive RT. Two-sided T test for paired samples and Kaplan-Meier curves were applied for analysis (p value < 0.05, SPSS v.23).

RESULTS

Among EC patients, 29 received CRT and 34 exclusive postoperative RT, while in CC cohort, 105 were treated with CRT and 34 with RT. In both cohorts, CRT affected significantly all WBC subtypes, whereas exclusive RT decreased only lymphocytes population (p = 0.000). Radiation-induced lymphopenia (RIL) had no impact on survival outcomes.

CONCLUSIONS

The selective depletion of lymphocytes after RT was significant in both EC and CC. Our results are of interest for further research on RIL and for design of immunotherapy-based clinical trials.