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

CD8+ T cells in patients with hypopharyngeal squamous cell carcinoma are susceptible to radiation-induced damage

Radiotherapy (RT) is a commonly used clinical management for hypopharyngeal squamous cell carcinoma (HPSCC), which represents the most unfavorable prognosis among all subtypes of head and neck squamous cell carcinoma. However, radiation may cause lymphopenia, a significantly adverse event with detrimental prognostic implications for patients. While CD8+ T cells are vital in tumor immunity, the specific effects of RT on CD8+ T cells as well as the underlying mechanisms have not been clearly elucidated. Here we found that subpopulations of peripheral T lymphocytes exhibited differential profiles in patients with HPSCC compared to healthy individuals both pre- and post-irradiation. Importantly, CD8+ T cells from HPSCC patients showed greater reduction of cytokine production, more severe proliferation defect, and increased apoptosis compared to those from healthy individuals after in vitro irradiation. Mechanistically, the ATM-Chk2 pathway mediated the enhanced apoptosis of CD8+ T lymphocytes from HPSCC patients upon irradiation. Therefore, our study demonstrated that CD8+ T cells in patients with HPSCC exhibit a higher susceptibility to radiation-induced damage compared to those in healthy individuals. The ATM-Chk2 pathway represents a potential immunotherapeutic target for safeguarding CD8+ T cells in HPSCC patients against radiation-induced apoptosis.

Longitudinal Analyses and Predictive Factors of Radiation-Induced Lymphopenia After Postmastectomy Hypofractionated Radiation Therapy for Breast Cancer: A Pooled Cohort Study of 2 Prospective Trials

Purpose

Radiation-induced lymphopenia (RIL) correlates with poor prognoses in solid tumors. This study aimed to investigate the post-radiation therapy (RT) longitudinal lymphocyte changes and the impact of different RT techniques on RIL in breast cancer patients.

Methods and Materials

We prospectively assessed 607 breast cancer patients who received hypofractionated postmastectomy RT in 8 hospitals. Radiation therapy techniques included integrated photon-based intensity modulated technique (integrated RT) and a combination of photon irradiation of supraclavicular nodes and electron irradiation of the chest wall and/or the internal mammary node (hybrid RT). Peripheral lymphocyte counts (PLC) were determined before RT, weekly during RT, at 1 and 2 weeks, 3 and 6 months post-RT, and then every 6 months. The primary outcome was the nadir PLC during RT, for which associated factors were analyzed. Univariate, multivariable linear regression and propensity score matching analyses were performed to evaluate the effect of different RT techniques on nadir PLC.

Results

During RT, 121 (19.9%) patients had grade ≥3 RIL with a nadir PLC of 0.75 ± 0.33 × 109/L. The PLC started to recover at 1 week and reached pre-RT levels 1 year after RT and higher than pre-RT levels 2 years later. Multivariate analysis identified young age, low body mass index, radiation therapy targets involving multiple regions, integrated RT, and low pre-radiation therapy PLC as independent risk factors for nadir PLC (P < .005). The PLC at each time point during and after radiation therapy was lower in patients receiving integrated RT than in those receiving hybrid RT (P < .05). Before and after propensity score matching, integrated RT was significantly associated with lower nadir PLC after adjusting for radiation therapy targets and age (P < .001).

Conclusions

Breast cancer patients had prolonged lymphopenia post-RT. Integrated RT increased the risk of RIL and adversely affected recovery. Therefore, an appropriate RT technique should be considered to minimize RIL.

Defining the Optimal Radiation-induced Lymphopenia Metric to Discern Its Survival Impact in Esophageal Cancer

PURPOSE

A detrimental association between radiation-induced lymphopenia (RIL) and oncologic outcomes in patients with esophageal cancer has been established. However, an optimal metric for RIL remains undefined but is important for the application of this knowledge in clinical decision-making and trial designs. The aim of this study was to find the optimal RIL metric discerning survival.

METHODS AND MATERIALS

Patients with esophageal cancer treated with concurrent chemoradiation therapy (CRT; 2004-2022) were selected. Studied metrics included absolute lymphocyte counts (ALCs) and neutrophil counts-and calculated derivatives-at baseline and during CRT. Multivariable Cox regression models for progression-free survival (PFS) and overall survival (OS) were developed for each RIL metric. The optimal RIL metric was defined as the one in the model with the highest c-statistic.

RESULTS

Among 1339 included patients, 68% received photon-based and 32% proton-based CRT (median follow-up, 24.9 months). In multivariable analysis, the best-performing models included "ALC in week 3 of CRT" (corrected c-statistic 0.683 for PFS and 0.662 for OS). At an optimal threshold of <0.5 × 103/μL (ie, grade ≥3 RIL), ALC in week 3 was significantly associated with PFS (adjusted hazard ratio, 1.64; 95% CI, 1.27-2.13) and OS (adjusted hazard ratio, 1.56; 95% CI, 1.15-2.08), with 5-year PFS of 29% vs 40% and OS of 38% vs 51%, respectively.

CONCLUSIONS

Reaching grade ≥3 RIL in week 3 of CRT for esophageal cancer is the strongest RIL metric to distinguish survival outcomes. We suggest that this metric should be the target for lymphopenia-mitigating strategies and propose this metric to be included in future trials.

A PD-L1 siRNA-Loaded Boron Nanoparticle for Targeted Cancer Radiotherapy and Immunotherapy

Although the combination of radiotherapy and immunotherapy is regarded as a promising clinical treatment strategy, numerous clinical trials have failed to demonstrate synergistic effects. One of the key reasons is that conventional radiotherapies inevitably damage intratumoral effector immune cells. Boron Neutron Capture Therapy (BNCT) is a precise radiotherapy that selectively kills tumor cells while sparing adjacent normal cells, by utilizing 10B agents and neutron irradiation. Therefore, combinational BNCT-immunotherapy holds promise for achieving more effective synergistic effects. Here it develops a 10B-containing polymer that self-assembled with PD-L1 siRNA to form 10B/siPD-L1 nanoparticles for combinational BNCT-immunotherapy. Unlike antibodies, PD-L1 siRNA can inhibit intracellular PD-L1 upregulated by BNCT, activating T-cell immunity while also suppressing DNA repair. This can enhance BNCT-induced DNA damage, promoting immunogenic cell death (ICD) and further amplifying the antitumor immune effect. The results demonstrated that BNCT using 10B/siPD-L1 nanoparticles precisely killed tumor cells while sparing adjacent T cells and induced a potent antitumor immune response, inhibiting distal and metastatic tumors.

Lymphopenia is an adverse prognostic factor in rectal adenocarcinoma patients receiving long-course chemoradiotherapy

PURPOSE

Neoadjuvant radiotherapy (RT) or chemoradiotherapy (CRT) is the standard treatment for locally advanced rectal adenocarcinoma. The recent emerging data on preoperative immunotherapy as an effective therapeutic modality for mismatch repair deficient rectal carcinomas suggests that the immune system plays a significant role in tumor eradication. Although RT has been shown to stimulate anti-tumor immunity, it also leads to substantial lymphopenia, hindering the effect of immune response.

MATERIALS AND METHODS

We retrospectively analyzed 33 rectal adenocarcinoma patients who underwent CRT in our department, aiming to identify the effects of CRT on the peripheral blood lymphocyte counts (LC) and the potential impact of CRT-induced lymphopenia on tumor response and prognosis of patients.

RESULTS

A statistically significant decrease in the LC of patients was observed after CRT (median values of 2,184/μL and 517/μL before and after treatment, respectively; p < 0.001). While no correlation between ypT-stage, ypN status, and LC was found, poor tumor regression grade was significantly associated with lower LC (p = 0.036). Moreover, lymphopenia was associated with poorer distant metastasis-free survival (p = 0.003). Distant metastases were documented in 0% of patients with post-CRT LC above 518/μL vs. 44.5% of patients with lower LC values.

CONCLUSION

Although further investigation is demanded, given the limited number of patients analyzed in the study, lymphopenia emerges as a significant adverse event that rectal adenocarcinoma patients face during treatment with neoadjuvant CRT, with subsequent implications on tumor response and prognosis. Protection of the immune system during CRT emerges as an important target for clinical research.

A comprehensive overview of radiation therapy impacts of various cancer treatments and pivotal role in the immune system

The cancer treatment landscape is significantly evolving, focusing on advanced radiation therapy methods to maximize effectiveness and minimize the adverse effects. Recognized as a pivotal component in cancer and disease treatment, radiation therapy (RT) has drawn attention in recent research that delves into its intricate interplay with inflammation and the immune response. This exploration unveils the underlying processes that significantly influence treatment outcomes. In this context, the potential advantages of combining bronchoscopy with RT across diverse clinical scenarios, alongside the targeted impact of brachytherapy, are explored. Concurrently, radiation treatments serve multifaceted roles such as DNA repair, cell elimination, and generating immune stress signaling molecules known as damage-associated molecular patterns, elucidating their effectiveness in treating various diseases. External beam RT introduces versatility by utilizing particles such as photons, electrons, protons, or carbon ions, each offering distinct advantages. Advanced RT techniques contribute to the evolving landscape, with emerging technologies like FLASH, spatially fractionated RT, and others poised to revolutionize the field. The comprehension of RT, striving for improved treatment outcomes, reduced side effects, and facilitating personalized and innovative treatments for cancer and noncancer patients. After navigating these advancements, the goal is fixed to usher in a new era in which RT is a cornerstone of precision and effectiveness in medical interventions. In summarizing the myriad findings, the review underscores the significance of understanding the differential impacts of radiation approaches on inflammation and immune modulation, offering valuable insights for developing innovative therapeutic interventions that harness the immune system in conjunction with RT.

Efficacy of Shenglin decoction in preventing acute severe lymphocytopenia in patients with non-small cell lung cancer undergoing concurrent chemoradiotherapy: a study protocol for a randomized controlled trial

Background

Definitive concurrent chemoradiotherapy (CCRT) followed by maintenance therapy with immune checkpoint inhibitors offers the best chance of cure for patients with stage III non-small cell lung cancer (NSCLC). A significant challenge in this regimen is the occurrence of acute severe lymphopenia (ASL), which can compromise treatment efficacy. Currently, there are no effective strategies for preventing and treating ASL. Shenglin decoction (SLD), a traditional Chinese herbal medicine formulation, has demonstrated preliminary efficacy in mitigating ASL. However, robust evidence from clinical trials and a clear understanding of its mechanism of action are still needed. This study aims to comprehensively assess the efficacy, safety, and underlying mechanisms of SLD in the prevention of ASL.

Methods

This prospective, dual-center, open-label, randomized controlled trial will enroll 140 stage III NSCLC patients. Participants will be randomly allocated in a 1:1 ratio to a control group or an experimental group. Both groups will undergo definitive CCRT. Alongside the commencement of CCRT, the experimental group will receive an additional oral SLD intervention for a duration of three months. The primary outcome is the incidence rate of ASL, defined as the proportion of patients who experience at least one instance of a total lymphocyte count falling below 0.5 × 10^9 cells/L within 3 months of initiating CCRT treatment. Additionally, 16S rRNA gene sequencing analysis of fecal samples to assess gut microbiota, as well as metabolomic analysis of fecal/blood samples, will be conducted to explore potential mechanisms.

Discussion

This study protocol aims to rigorously evaluate the efficacy and safety of SLD, as well as elucidate its mechanism of action in preventing ASL. Successful outcomes could establish SLD as an evidence-based intervention for ASL prevention in NSCLC patients undergoing CCRT.

Trial Registration

The trial was registered at the Chinese Clinical Trials Registry (ChiCTR2300071788, https://www.chictr.org.cn/).

The need for paradigm shift: prognostic significance and implications of standard therapy-related systemic immunosuppression in glioblastoma for immunotherapy and oncolytic virotherapy

Despite significant advances in our knowledge regarding the genetics and molecular biology of gliomas over the past two decades and hundreds of clinical trials, no effective therapeutic approach has been identified for adult patients with newly diagnosed glioblastoma, and overall survival remains dismal. Great hopes are now placed on combination immunotherapy. In clinical trials, immunotherapeutics are generally tested after standard therapy (radiation, temozolomide, and steroid dexamethasone) or concurrently with temozolomide and/or steroids. Only a minor subset of patients with progressive/recurrent glioblastoma have benefited from immunotherapies. In this review, we comprehensively discuss standard therapy-related systemic immunosuppression and lymphopenia, their prognostic significance, and the implications for immunotherapy/oncolytic virotherapy. The effectiveness of immunotherapy and oncolytic virotherapy (viro-immunotherapy) critically depends on the activity of the host immune cells. The absolute counts, ratios, and functional states of different circulating and tumor-infiltrating immune cell subsets determine the net immune fitness of patients with cancer and may have various effects on tumor progression, therapeutic response, and survival outcomes. Although different immunosuppressive mechanisms operate in patients with glioblastoma/gliomas at presentation, the immunological competence of patients may be significantly compromised by standard therapy, exacerbating tumor-related systemic immunosuppression. Standard therapy affects diverse immune cell subsets, including dendritic, CD4+, CD8+, natural killer (NK), NKT, macrophage, neutrophil, and myeloid-derived suppressor cell (MDSC). Systemic immunosuppression and lymphopenia limit the immune system's ability to target glioblastoma. Changes in the standard therapy are required to increase the success of immunotherapies. Steroid use, high neutrophil-to-lymphocyte ratio (NLR), and low post-treatment total lymphocyte count (TLC) are significant prognostic factors for shorter survival in patients with glioblastoma in retrospective studies; however, these clinically relevant variables are rarely reported and correlated with response and survival in immunotherapy studies (e.g., immune checkpoint inhibitors, vaccines, and oncolytic viruses). Our analysis should help in the development of a more rational clinical trial design and decision-making regarding the treatment to potentially improve the efficacy of immunotherapy or oncolytic virotherapy.

Influence of treatment-related lymphopenia on the efficacy of immune checkpoint inhibitors in lung cancer: a meta-analysis

Background

Treatment-related lymphopenia (TRL) is common in patients with lung cancer, particularly in those with radiotherapy. However, the influence of TRL on the efficacy of immune checkpoint inhibitors (ICIs) for patients with lung cancer remains poorly understood. We performed a systematic review and meta-analysis to investigate the influence of TRL on survival of lung cancer patients on ICIs.

Methods

In order to accomplish the aim of the meta-analysis, a comprehensive search was conducted on databases including PubMed, Embase, Cochrane Library, and the Web of Science to identify observational studies with longitudinal follow-up. The Cochrane Q test was employed to evaluate heterogeneity among the included studies, while the I2 statistic was estimated. Random-effects models were utilized to merge the results, considering the potential impact of heterogeneity.

Results

Ten cohort studies with 1130 lung cancer patients who were treated with ICIs were included. Among them, 427 (37.8%) had TRL. Pooled results showed that compared to patients without TRL, patients with TRL were associated with poor progression-free survival (hazard ratio [HR]: 2.05, 95% confidence interval [CI]: 1.62 to 2.60, p < 0.001; I2 = 22%) and overall survival (HR: 2.69, 95% CI: 2.10 to 3.43, p < 0.001; I2 = 0%). Sensitivity analysis limited to patients with non-small cell lung cancer showed similar results (HR: 2.66 and 2.62, both p < 0.05). Moreover, subgroup analyses according to the diagnostic criteria of TRL, regression analysis model (univariate or multivariate), and indications of ICIs (for locally advanced or advanced lung cancer) showed consistent results (p for subgroup difference all > 0.05).

Conclusion

TRL was associated with poor survival of lung cancer patients who were treated with ICIs.

Integrated transcriptomic and metabolomic profiles reveal the protective mechanism of modified Danggui Buxue decoction on radiation-induced leukopenia in mice

Leukopenia caused by radiation hinders the continuous treatment of cancers. Danggui Buxue Decoction (DBD) has been widely used in clinical owing to low toxicity and definite therapeutic effects to increase leukocytes. Meanwhile, icaritin (ICT) has also been proved to have the effect of boosting peripheral blood cells proliferation. However, there is no study to prove the efficacy of MDBD (Modified Danggui Buxue Decoction), a derivative herbal formula composed of DBD and ICT, in the treatment of radiation-induced leukopenia. In this study, we performed a model of 3.5 Gy whole-body radiation to induce leukopenia in mice. The results of pharmacodynamic studies demonstrated that MDBD could significantly increase the white blood cells in peripheral blood by improving the activity of bone marrow nuclear cells, reducing bone marrow damage, modulating spleen index, and regulating hematopoietic factors to alleviate leukopenia. We also analyzed the integrated results of metabolomics and transcriptomics and found that MDBD could relieve leukopenia and alleviate bone marrow damage by targeting steroid biosynthesis and IL-17 signaling pathway, in which the key genes are Jun, Cxcl2 and Egr1. Therefore, our study provides a basis for the effectiveness and compatibility in the combination of traditional Chinese medicine formula and small molecule drugs.

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.

Prophylactic cranial irradiation-related lymphopenia affects survival in patients with limited-stage small cell lung cancer

Background

The study aimed to identify the relations of the absolute lymphocyte count (ALC) nadir during prophylactic cranial irradiation (PCI) and patient outcomes in limited-stage small cell lung cancer (LS-SCLC).

Methods

We analyzed 268 L S-SCLC patients who underwent PCI from 2012 to 2019. ALC values were collected prior, during, and 3 months post PCI. Kaplan-Meier and Cox regression analyses were performed to assess the relation of ALC to patient prognosis. Two nomograms were developed on the basis of clinical variables for survival prediction.

Results

Compared with the ALC before PCI (1.13 × 10⁹ cells/L), the ALC nadir during PCI was significantly reduced by 0.68 × 10⁹ cells/L (P < 0.001) and raised to 1.02 × 10⁹ cells/L 3 months post PCI. Patients with a low ALC nadir during PCI (<0.68 × 10⁹ cells/L) had inferior progression free survival (PFS) (median PFS: 17.2 m vs. 43.7 m, P = 0.019) and overall survival (OS) (median OS: 29.0 m vs 39.1 m, P = 0.012). Multivariate Cox analysis revealed that age, smoking history, clinical stage, and ALC nadir were independent OS (P = 0.006, P = 0.005, P < 0.001 and P = 0.027, respectively), as well as independent PFS predictors (P = 0.032, P = 0.012, P = 0.012 and P = 0.018, respectively). After internal cross-validation, the corrected concordance indices of the predictive nomograms for PFS and OS were 0.637 and 0.663, respectively.

Conclusion

LS-SCLC patients with a low ALC nadir during PCI likely have worse survival outcomes. Dynamic evaluation of the ALC during PCI is recommended for LS-SCLC patients.

Immune Response and Immune Checkpoint Molecules in Patients with Rectal Cancer Undergoing Neoadjuvant Chemoradiotherapy: A Review

It is well-established that tumor antigens and molecules expressed and secreted by cancer cells trigger innate and adaptive immune responses. These two types of anti-tumor immunity lead to the infiltration of the tumor's microenvironment by immune cells with either regulatory or cytotoxic properties. Whether this response is associated with tumor eradication after radiotherapy and chemotherapy or regrowth has been a matter of extensive research through the years, mainly focusing on tumor-infiltrating lymphocytes and monocytes and their subtypes, and the expression of immune checkpoint and other immune-related molecules by both immune and cancer cells in the tumor microenvironment. A literature search has been conducted on studies dealing with the immune response in patients with rectal cancer treated with neoadjuvant radiotherapy or chemoradiotherapy, assessing its impact on locoregional control and survival and underlying the potential role of immunotherapy in the treatment of this cancer subtype. Here, we provide an overview of the interactions between local/systemic anti-tumor immunity, cancer-related immune checkpoint, and other immunological pathways and radiotherapy, and how these affect the prognosis of rectal cancer patients. Chemoradiotherapy induces critical immunological changes in the tumor microenvironment and cancer cells that can be exploited for therapeutic interventions in rectal cancer.

The molecular basis of immuno-radiotherapy

PURPOSE

Radiotherapy (RT) and immunotherapy are powerful anti-tumor treatment modalities. Experimental research has demonstrated an important interplay between the cytotoxic effects of RT and the immune system. This systematic review provides an overview of the basics of anti-tumor immunity and focuses on the mechanisms underlying the interplay between RT and immune anti-tumor response that set the molecular basis of immuno-RT.

CONCLUSIONS

An 'immunity acquired equilibrium' mimicking tumor dormancy can be achieved post-irradiation treatment, with the balance shifted toward tumor eradication or regrowth when immune cells' cytotoxic effects or cancer proliferation rate prevail, respectively. RT has both immunosuppressive and immune-enhancing properties. The latter effect is also known as radio-vaccination. Its mechanisms involve up- or down-regulation of membrane molecules, such as PD-L1, HLA-class-I, CD80/86, CD47, and Fas/CD95, that play a vital role in immune checkpoint pathways and increased cytokine expression (e.g. INFα,β,γ, IL1,2, and TNFα) by cancer or immune cells. Moreover, the interactions of radiation with the tumor microenvironment (fibroblasts, tumor-infiltrating lymphocytes, monocytes, and dendritic cells are also an important component of radio-vaccination. Thus, RT may have anti-tumor vaccine properties, whose sequels can be exploited by immunotherapy agents to treat different cancer subtypes effectively.

Strong Humoral but Not Cellular Immune Responses against SARS-CoV-2 in Individuals with Oncohematological Disease Who Were Treated with Rituximab before Receiving a Vaccine Booster

The humoral immune response developed after receiving the full vaccination schedule against COVID-19 is impaired in individuals who received anti-CD20 therapy 6-9 months before vaccination. However, there is little information about the cellular immune responses elicited in these individuals. In this study, we analyzed the humoral and cellular immune responses in 18 individuals with hematological disease who received the last dose of rituximab 13.8 months (IQR 9.4-19) before the booster dose. One month after receiving the booster dose, the seroconversion rate in the rituximab-treated cohort increased from 83.3% to 88.9% and titers of specific IgGs against SARS-CoV-2 increased 1.53-fold (p = 0.0098), while the levels of neutralizing antibodies increased 3.03-fold (p = 0.0381). However, the cytotoxic activity of peripheral blood mononuclear cells (PBMCs) from rituximab-treated individuals remained unchanged, and both antibody-dependent cellular cytotoxicity (ADCC) and direct cellular cytotoxicity (CDD) were reduced 1.7-fold (p = 0.0047) and 2.0-fold (p = 0.0086), respectively, in comparison with healthy donors. Breakthrough infections rate was higher in our cohort of rituximab-treated individuals (33.33%), although most of the infected patients (83.4%) developed a mild form of COVID-19. In conclusion, our findings confirm a benefit in the humoral, but not in the cellular, immune response in rituximab-treated individuals after receiving a booster dose of an mRNA-based vaccine against COVID-19.

Risk of Bacterial, Viral, and Fungal Infections in Patients With Solid Malignant Tumors Treated With Curative Intent Radiation Therapy

Purpose

The incidence, etiology, and association of infections with radiation therapy (RT)-induced lymphopenia in patients with solid tumors is not well elucidated.

Methods and Materials

We identified possible, probable, and definite infections caused by bacteria, fungi, and viruses, combining data on medication, microbiology, and diagnoses. Definite infections had either a diagnosis or a positive microbiological isolation. We analyzed the incidence and adjusted incidence-rate ratio of infections in the year after the start of RT among patients who received RT plus chemotherapy and RT monotherapy, by type of infection and according to the degree of RT-induced lymphopenia.

Results

A total of 4450 of 6334 (70.3%) patients experienced 11264 infections overall; 1424 (22.5%) patients developed 2104 definite infections in the first year after RT. Infections were more frequent among patients who received RT plus chemotherapy (2590 of 3469; incidence: 16.5 [95% confidence interval {CI}, 16.1-17.0], per 100 patient-years) compared with patients who received RT monotherapy (1860 of 2865; incidence: 12.7 [95% CI, 12.3-13.2]). The incidence of infection was highest in the first 3 months overall (28.2 vs 18.0 in patients who received RT plus chemotherapy compared with those who received RT monotherapy) and for definite infections (4.7 vs 3.8). The proportion of specific bacterial infections were similar among patients who received RT plus chemotherapy versus those who received RT monotherapy. Urinary tract infections were the most frequent (51.2% vs 56.2%), followed by pneumonias (24.1% vs 22.4%). Viral and fungal infections were more frequent among patients who received RT plus chemotherapy, but they were uncommon. In multivariable analyses, patients who received RT plus chemotherapy with a lymphopenia grade of 1-2 or ≥3 versus no lymphopenia at end of RT had an increased risk of bacterial infections 0 to 3 months after RT (incidence rate ratio, 1.45 [95% CI, 1.06-1.97] and 1.71 [95% CI, 1.26-2.34], respectively). Limiting to definite bacterial infections, the incidence rate ratio for lymphopenia grade ≥3 versus no lymphopenia was 2.66 (95% CI, 1.40-5.03).

Conclusions

The incidence of bacterial infections 0 to 3 months after RT plus chemotherapy for solid tumors was high, especially among patients with RT-induced lymphopenia grade 1-2 and ≥3.

Construction of prognostic signature of breast cancer based on N7-Methylguanosine-Related LncRNAs and prediction of immune response

Background: Long non-coding RNA (LncRNA) is a prognostic factor for malignancies, and N7-Methylguanosine (m7G) is crucial in the occurrence and progression of tumors. However, it has not been documented how well m7G-related LncRNAs predict the development of breast cancer (BC). This study aims to develop a predictive signature based on long non-coding RNAs (LncRNAs) associated with m7G to predict the prognosis of breast cancer patients.

Methods: The Cancer Genome Atlas (TCGA) database provided us with the RNA-seq data and matching clinical information of individuals with breast cancer. To identify the signature of N7-Methylguanosine-Related LncRNAs and create a prognostic model, we employed co-expression network analysis, least absolute shrinkage selection operator (LASSO) regression analysis, univariate Cox regression analysis, and multivariate Cox regression analysis. The signature was assessed using the Kaplan-Meier analysis and Receiver Operating Characteristic (ROC) curve. A nomogram and principal component analysis (PCA) were employed to confirm the predictive signature’s usefulness. Then, we examined the drug sensitivity between the two risk groups and utilized single-sample gene set enrichment analysis (ssGSEA) to investigate the association between predictive factors and the tumor immune microenvironment in high-risk and low-risk groups.

Results: Nine m7G-related LncRNAs (LINC01871, AP003469.4, Z68871.1, AC245297.3, EGOT, TFAP2A-AS1, AL136531.1, SEMA3B-AS1, AL606834.2) that are independently associated with the overall survival time (OS) of BC patients make up the signature we developed. For predicting 1-, 3-, and 5-year survival rates, the areas under the ROC curve (AUC) were 0.715, 0.724, and 0.726, respectively. The Kaplan-Meier analysis revealed that the prognosis of BC patients in the high-risk group was worse than that of those in the low-risk group. When compared to clinicopathological variables, multiple regression analysis demonstrated that risk score was a significant independent predictive factor for BC patients. The results of the ssGSEA study revealed a substantial correlation between the predictive traits and the BC patients’ immunological status, low-risk BC patients had more active immune systems, and they responded better to PD1/L1 immunotherapy.

Conclusion: The prognostic signature, which is based on m7G-related LncRNAs, can be utilized to inform patients’ customized treatment plans by independently predicting their prognosis and how well they would respond to immunotherapy.

Association of neutrophil-to-lymphocyte ratio, radiotherapy fractionation/technique, and risk of development of distant metastasis among patients with locally advanced rectal cancer

BACKGROUND

We investigated the prognostic impact of the neutrophil-to-lymphocyte ratio (NLR) in patients with locally advanced rectal cancer (LARC) and whether modifiable factors in radiotherapy (RT) influenced the NLR.

METHODS

Data of 1386 patients who were treated with neoadjuvant RT and concurrent or sequential chemotherapy for LARC between 2006 and 2019 were evaluated. Most patients (97.8%) were treated with long-course RT (LCRT; 50-50.4 Gy in 25-28 fractions) using three-dimensional conformal radiotherapy (3D-CRT) (n = 851) or helical tomotherapy (n = 504), and 30 patients underwent short-course RT (SCRT; 25 Gy in 5 fractions, followed by XELOX administration for 6 weeks). Absolute neutrophil and lymphocyte counts were obtained at initial diagnosis, before and during the preoperative RT course, and after preoperative concurrent chemoradiotherapy. The primary endpoint was distant metastasis-free survival (DMFS).

RESULTS

The median follow-up time was 61.3 (4.1-173.7) months; the 5-year DMFS was 80.1% and was significantly associated with the NLR after RT but not before. A post-RT NLR ≥ 4 independently correlated with worse DMFS (hazard ratio, 1.42; 95% confidence interval, 1.12-1.80), along with higher ypT and ypN stages. Post-RT NLR (≥ 4) more frequently increased following LCRT (vs. SCRT, odds ratio [OR] 2.77, p = 0.012) or helical tomotherapy (vs. 3D-CRT, OR 1.29, p < 0.001).

CONCLUSIONS

Increased NLR after neoadjuvant RT is associated with increased distant metastasis risk and poor survival outcome in patients with LARC. Moreover, high NLR following RT is directly related to RT fractionation, delivery modality, and tumor characteristics. These results are hypothesis-generating only, and confirmatory studies are required.

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.

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

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

A Rational Approach to Unilateral Neck RT for Head and Neck Cancers in the Era of Immunotherapy

Radiotherapy plays an important role in the definitive and adjuvant treatment of head and neck squamous cell carcinoma (HNSCC). However, standard courses of radiation therapy may contribute to the depletion of circulating lymphocytes and potentially attenuate optimal tumor antigen presentation that may be detrimental to the efficacy of novel immunotherapeutic agents. This review explores the advantages of restricting radiation to the primary tumor/tumor bed and ipsilateral elective neck as it pertains to the evolving field of immunotherapy.

Combining the past and present to advance immuno-radiotherapy of cancer

Since its first clinical application, 120 years ago, radiotherapy evolved into a major anti-cancer treatment modality, offering high cure rates in many human malignancies. During the past ten years, the establishment of immune checkpoint inhibitors (ICIs) in cancer therapeutics has vigorously reintroduced the immune system's role in the outcome of radiotherapy and, conversely, the role of radio-vaccination in the efficacy of immunotherapy. The knowledge and clinical experience that founded the current era of immuno-radiotherapy started alongside with the birth of radiotherapy, and evolved through exhaustive experimental work, clinical trials on active specific immunotherapy, frustrating attempts to validate the importance of cytokine administration with radiotherapy, and, finally, the encouraging ICI-based clinical trials that opened the door to a far more encouraging perspective; radio-vaccination, through its old and new methods, is rising as a research field that promises to cure, previously incurable, disease. In this critical review, we focus on the scientific knowledge gathered through more than a century of research on radiotherapy interactions with the immune system. Understanding the origins of this promising therapeutic approach will substantially contribute to developing new immuno-radiotherapy policies in the fight against cancer.