Utilization of IMRT and Brachytherapy for Low-Risk and Intermediate-Risk Prostate Cancer Patients: Analysis of the RealWorld Scenario

Abstract

Purpose: Two main techniques in radiation therapy (RT) for the treatment of low-risk and intermediate-risk prostate cancer (PCa) are intensity-modulated radiation therapy (IMRT) and brachytherapy (BT). In this study, the pattern of utilization of IMRT, low dose-rate (LDR) BT, and high dose-rate (HDR) BT has been evaluated using a large hospital based registry database. Methods: We analyzed a very large data set of N0, M0, non-surgical, stage T1-T2c prostate cancer patients diagnosed between 2004 and 2015 from the National Cancer Database (NCDB). Based on the RT techniques used, we considered three groups of patients: (1) IMRT (n=61,159; 48.4%) who received an initial as well as a boost treatment with the IMRT, (2) BT LDR (n=43,293; 34.3%), and (3) BT HDR (n=21,938; 17.3%). A total dose of 70-81Gy for IMRT was considered. For brachytherapy, LDR and HDR or unspecified brachytherapy was considered as monotherapy. Patients were stratified according to the National Comprehensive Cancer Network (NCCN) guidelines into: low-risk [clinical stage T1-T2a, Gleason Score (GS) of ≤ 6 (Grade Group 1), and Prostate-specific antigen (PSA) of < 10 ng/mL] and intermediate-risk [clinical stage T2b-T2c, GS of 7 (Grade Groups 2 and 3), and PSA of 10-20 ng/mL]. OS probability was determined using the Kaplan-Meier estimator. Propensityscore matched (PSM) analysis was performed for each risk group (low and intermediate) for the three research treatment modalities (IMRT, BT LDR, and BT HDR). IBM SPSS software was used for statistical analysis; p-value <0.05 was considered statistically significant. Results: There has been a relative increase in IMRT usage for the treatment of both low-risk (29% to 53%) and intermediaterisk (53% to 77%) PCa patients from 2004 to 2015. Observed comparable median OS in low-risk and intermediate-risk patients in these three modalities IMRT (74.8/63.4 mo.), LDR (77.7/65.7 mo.) and HDR (83.5/72.1 mo.). Conclusion: The pattern of utilization of RT modality seems inclined toward increased use of IMRT over brachytherapy (59% vs. 41%) for both the low-risk and intermediate-risk PCa patients. Over the years, use of IMRT increased more in low-risk patient group than in intermediate-risk group.