Investigating the Influence of Body Mass Index on Organs at Risk Doses for Adjuvant High-Dose-Rate Vaginal Cuff Brachytherapy in Patients with Early-Stage Endometrial Carcinoma: A Single-Center Experience

Background: Endometrial cancer is the most common gynecologic malignancy in developed countries, with obesity recognized as a major risk factor contributing to its incidence. The rising prevalence of obesity has significant implications for treatment planning, particularly in radiation therapy approaches such as high-dose-rate (HDR) vaginal cuff brachytherapy, which is commonly used as adjuvant therapy in early-stage endometrial carcinoma. Body Mass Index (BMI) is a key factor in brachytherapy, as increased adiposity may alter dosimetric parameters, affecting radiation distribution and doses received by organs at risk (OARs). Understanding the correlation between BMI and radiation dose to OARs is essential for optimizing treatment planning and minimizing adverse effects. Identifying dose variations across different BMI categories may help refine patient-specific brachytherapy approaches to ensure both efficacy and safety. Objectives: This study aims to investigate the influence of Body Mass Index (BMI) on the doses received by organs at risk (OAR) during high-dose-rate (HDR) vaginal cuff brachytherapy in patients diagnosed with early-stage endometrial carcinoma. Understanding the relationship between BMI and OAR doses could enhance treatment planning and minimize complications. Methods: We collected brachytherapy data for 242 endometrial cancer patients treated with adjuvant HDR vaginal cuff brachytherapy. The patients were categorized based on their BMI into normal weight, overweight, and obese groups. Dosimetric data were collected for OARs, including the bladder, rectum, and sigmoid colon, and also for dose fractionation, D90%, and the active length of the brachytherapy cylinder. The analysis included comparing the doses received by each organ across different BMI categories using appropriate statistical methods. Results: Preliminary findings indicated a significant variation in the doses to OARs correlating with BMI classifications. Obese patients exhibited slightly higher mean doses to the rectum and sigmoid compared to those with a normal BMI. The statistical analysis demonstrated that as BMI increased, the dose to these organs at risk also tended to increase, suggesting a need for adjusted treatment planning strategies in this population. Conclusions: Obesity is a key concern in endometrial cancer patients, with higher BMI linked to slightly increased doses to the rectum and sigmoid, though treatment remained homogeneously delivered. Future prospective clinical studies are essential to explore the relationship between these dosimetric findings, specifically the correlation between higher BMI, increased doses to organs at risk (OARs), and late treatment-related toxicities. This research is needed to better understand the long-term implications and to optimize therapeutic outcomes.