Vitamin D Status and Clinical Outcomes in Locally Advanced Cervical Cancer

Overview

Background. Definitive chemoradiotherapy represents the standard therapeutic approach for the management of locally advanced cervical cancer. Vitamin D plays an important role in the regulation of cellular growth and differentiation, immune system function, and the modulation of inflammatory processes. Hypovitaminosis D may be associated with the development of cervical cancer, whereas its impact on the effects of oncological treatment remains insufficiently elucidated. The aim of this study is to investigate the predictive significance of vitamin D in patients with locally advanced cervical cancer treated with definitive chemoradiotherapy. Methods. This study is designed as a clinical, observational, prospective cohort study. Patients with locally advanced cervical cancer undergoing definitive chemoradiotherapy at the Clinic for Radiation Oncology, University Clinical Center Kragujevac, will be enrolled. Vitamin D concentrations will be measured before the initiation of treatment in both serum and cervical lavage samples. Baseline vitamin D levels will be analyzed in relation to treatment outcome and the occurrence of acute radiation toxicity. In addition, vitamin D concentrations will be evaluated in the context of clinical and morphological parameters, therapeutic response, and treatment-related toxicity. Expected Results. This study will enable an assessment of the actual significance of pretreatment vitamin D concentrations in serum and cervical lavage as a potential novel biomarker in relation to chemoradiosensitivity and/or chemoradioresistance of cervical cancer, as well as the response of organs at risk, in patients with locally advanced disease.

Definitive concurrent chemoradiotherapy is the standard treatment for locally advanced cervical cancer. Although it achieves high response rates, some patients do not attain a complete therapeutic response, potentially because of chemoradioresistance. Radiotherapy also exerts immunomodulatory effects within the tumor microenvironment, which may be particularly relevant in cervical cancer because of its association with persistent human papillomavirus infection. Identifying biomarkers associated with treatment response and toxicity could therefore support more individualized treatment strategies. Vitamin D regulates cellular proliferation and differentiation, immune responses, and inflammatory processes. Hypovitaminosis D and reduced vitamin D receptor expression have been associated with cervical cancer and other malignancies. However, the predictive value of pretreatment vitamin D status in patients undergoing modern definitive chemoradiotherapy remains insufficiently established. Pretreatment vitamin D concentrations will be measured in serum and cervical lavage fluid. All participants will receive standard definitive treatment comprising external beam radiotherapy, brachytherapy, and concurrent weekly cisplatin-based chemotherapy. Acute treatment-related toxicity will be assessed throughout chemoradiotherapy, and the definitive therapeutic response will be evaluated by pelvic magnetic resonance imaging five months after treatment completion. Pretreatment serum and cervical lavage vitamin D concentrations will be analyzed in relation to therapeutic response, acute treatment-related toxicity, and relevant clinical, morphological, treatment-related, and sociodemographic parameters. The study will also evaluate the correlation between systemic and local vitamin D concentrations and explore potential cut-off values for predicting complete therapeutic response and clinically significant acute toxicity. Participants with low pretreatment vitamin D concentrations will not receive supplementation as part of the study protocol.