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Byline: Sarbani. Ghosh-Laskar, Sangeeta. Kakoti First postulated with radiobiological calculation by Withers et al ., in 1988 [sup][1] , accelerated repopulation of tumor clonogen is a valid contributor to our [...]

Introduction: Radiotherapy (RT)-based curative regimens for head and neck squamous cell carcinomas (HNSCC) deliver a dose of 66-70 Gray (Gy) over a period of 6-7 weeks, and incomplete treatments are unlikely to result in cure. Non-compliance to RT is major contributory factor to treatment failure. Aims: To assess the proportion of patients who do not complete planned treatment after initiation of curative RT. This study also aims to explore a possible relationship of non-compliance due to socio-economic, disease-related and treatment-related factors. Materials and Methods: The records of HNSCC patients treated from January 2012-December 2013 were audited. Data from the treatment records were to collect patient-related, disease-related, and social demographic parameters. Of the patients who had not completed treatment, the reasons behind the same were investigated. Results: Of the 324 patients of HNSCC who were initiated on radical RT, a total of 76 patients were found to have discontinued treatment without authorization of the treating clinician. There was no significant predilection for treatment non-compliance with regards to patient age, educational status, religion, site of the disease, use of neoadjuvant chemotherapy, or use of concurrent chemotherapy. There tended to be a higher association of treatment non-compliance among patients residing >100 km away from the treatment center, patients hailing from hilly regions, patients without the below poverty line (BPL) card, unemployed patients, and patients with stage IV-A/B disease. Of the 76 patients who did not complete treatment, telephonic questionnaire could be obtained from 54 patients. Causes for non-compliance included preference for traditional healers (22.2%), fear of toxicity (7.4%), logistic reasons (18.5%), financial reasons (24.1%), and lack of interest/faith in RT (5.6%). Conclusion: There is a high incidence of treatment default among patients of HNSCC during RT in this region. The revelation of the higher propensity for treatment default among patients from distant, hilly regions, unemployed, patients without BPL cards, and stages-IVA/IVB highlights the need for specific interventions for these special populations. [ABSTRACT FROM AUTHOR]

The growing importance of antitumour immunity by cancer immunotherapy has prompted studies on radiotherapy-induced immune response. Previous studies have indicated that programmed cell death-1 ligand (PD-L1) expression is regulated by DNA damage signalling. However, PD-L1 up-regulation after radiotherapy has not been fully investigated at the clinical level, particularly in the context of expression of DNA repair factors. The present study examined the correlation of mRNA expression between PD-L1 and non-homologous end joining (NHEJ) factors using The Cancer Genome Atlas database analysis. Among NHEJ factors, Ku80 mRNA expression was negatively correlated with PD-L1 mRNA expression levels in several types of cancer (colon adenocarcinoma, breast invasive carcinoma, skin cutaneous melanoma, lung adenocarcinoma, head and neck squamous cell carcinoma, uterine corpus endometrial carcinoma, cervical squamous cell carcinoma and endocervical adenocarcinoma). To verify the negative correlation in clinical samples, the present study analysed whether Ku80 expression levels affected PD-L1 up-regulation after radiotherapy using cervical squamous cell carcinoma samples. Quantitative evaluation using software analysis of immunohistochemically stained slides revealed that patients with low Ku80 positivity in biopsy specimens demonstrated increased PD-L1 expression levels after 10 Gy irradiation (Spearman's rank correlation coefficient=-0.274; P=0.017). Furthermore, PD-L1 induction levels in tumour cells after 10 Gy of irradiation were significantly inversely correlated with Ku80 expression levels (Spearman's rank correlation coefficient=-0.379; P<0.001). The present study also confirmed that short interfering RNA-mediated Ku80 depletion was associated with greater X-ray-induced PD-L1 up-regulation in HeLa cells. These results indicated that radiotherapy could enhance PD-L1 induction in tumour cells with low Ku80 expression in a clinical setting. Furthermore, these data highlighted Ku80 as a potential predictive biomarker for immune checkpoint therapy combined with radiotherapy., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Kumazawa et al.)

Radiotherapy induces an immune response in the cancer microenvironment that may influence clinical outcome. The present study aimed to analyse the alteration of CD8 + T-cell infiltration and programmed death-ligand 1 (PD-L1) expression following radiotherapy in clinical samples from patients with uterine cervical squamous cell carcinoma. Additionally, the current study sought to analyse the association between these immune responses and clinical outcomes. A total of 75 patients who received either definitive chemoradiotherapy or radiotherapy were retrospectively analyzed. CD8 + T-cell infiltration and PD-L1 expression were determined by immunohistochemistry using biopsy specimens before radiotherapy (pre-RT) and after 10 Gy radiotherapy (post-10 Gy). The PD-L1 + rate was significantly increased from 5% (4/75) pre-RT to 52% (39/75) post-10 Gy (P<0.01). Despite this increase in the PD-L1 + rate post-10 Gy, there was no significant association between both pre-RT and post-10 Gy and overall survival (OS), locoregional control (LC) and progression-free survival (PFS). On the other hand, the CD8 + T-cell infiltration density was significantly decreased for all patients (median, 23.1% pre-RT vs. 16.9% post-10 Gy; P=0.038); however, this tended to increase in patients treated with radiotherapy alone (median, 17.7% pre-RT vs. 24.0% post-10 Gy; P=0.400). Notably, patients with high CD8 + T-cell infiltration either pre-RT or post-10 Gy exhibited positive associations with OS, LC and PFS. Thus, the present analysis suggested that CD8 + T-cell infiltration may be a prognostic biomarker for patients with cervical cancer receiving radiotherapy. Furthermore, immune checkpoint inhibitors may be effective in patients who have received radiotherapy, since radiotherapy upregulated PD-L1 expression in cervical cancer specimens., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2021, Spandidos Publications.)