Presentation Authors: Young Dong Yu*, Tae Heon Kim, Seung Ryeol Lee, Young Kwon Hong, Dong Soo Park, Gyeonggi-Do, Korea, Republic of
Introduction: To evaluate the effect of obesity regarding rectal complications (RC) within the patients who underwent low does rate (LDR)-brachytherapy for the treatment of early localized prostate cancer (PCa).
Methods: From January 2014 to May 2017, total 126 patients with early localized PCa were treated with 125-I LDR-brachytherapy. The patients were classified into three body mass index (BMI) categories; normal ( < 25 kg/m2), overweight (25-29 kg/m2), obese (â‰¥30 kg/m2). Pre-implantation magnetic resonance imaging was performed in all study cohorts and the median-sagittal image was used to measure the thickness of anterior perirectal fat (APF). Post-implantation RC was graded using the radiation therapy oncology group (RTOG) scoring criteria. Multivariate logistic regression analyses were used to evaluate the factors influencing the rate of RC â‰¥RTOG 2.
Results: 41, 36 and 49 patients were categorized as the normal, overweight and obese groups, respectively. The BMI groups did not show significant differences regarding Gleason score, prostate specific antigen (PSA), and clinical stage between one another. However, the obese group had a significantly greater prevalence rate of diabetes mellitus (DM) and profoundly lower rate of RC â‰¥RTOG 2 than the normal and overweight groups (p=0.040, p < 0.001). BMI showed significant correlations with APF thickness. Multivariate analysis showed that DM, BMI and maximal rectal dose (Dmaxr) were independent predictors of RC â‰¥RTOG 2 (p=0.027, p < 0.001, p < 0.001). However, BMI failed to achieve independent predictor status when APF was included in the analysis. APF thickness >5mm was a strong independent predictor of RC â‰¥RTOG 2 (p < 0.001).
Conclusions: APF thickness was an independent predictor of post-implantation RC whereas the patients with greater APF showed a lower rate of RC â‰¥RTOG 2. BMI was a useful factor for predicting RC â‰¥RTOG 2 after prostate LDR-brachytherapy. DM patients were significantly more likely to have RC after prostate brachytherapy.