Overall Survival and Radiation Treatment Modality for Low-risk and Intermediate-risk Prostate Cancer: Analysis of a Hospital-based Big Database

Abstract

Both external beam radiation therapy (EBRT), including proton beam therapy, and brachytherapy are used for treating low-risk and intermediate-risk prostate cancer (CaP) patients. While they are usually considered to be equally effective, there may be differential utilization based on availability of treatment modality or physician and/or patient’s preference. In this study, the practice pattern of modality used and the efficacy of radiation therapy (RT) modality in the survival of CaP patients has been evaluated. We have analyzed the National Cancer Database (NCDB) for stage T1-2B prostate cancer patients treated from 2004 to 2015. Patients were stratified according to the National Comprehensive Cancer Network (NCCN) guidelines: low-risk (clinical stage T1–T2a, GS of 6, and PSA < 10), intermediate-risk (clinical stageT2b or T2c, GS of 7, or PSA of 10–20). Considered non-surgical patients who were treated either with EBRT (3DCRT, IMRT, SBRT, or Proton) or brachytherapy (LDR or HDR). Included patients (n=194,214) received primary/initial treatment as well as boost with the same EBRT modality, i.e. IMRT or 3DCRT or Proton; no boost was considered for SBRT, LDR and HDR. Considered total dose was 70-81Gy for IMRT, 3DCRT and Proton; 30-40Gy for SBRT; monotherapy was considered for LDR and HDR. Kaplan-Meier analysis was used for determining the survival probability. Software was used for statistical analysis; p-value < 0.05 was considered statistically significant. The median age of the selected patients was 68 years (range: 29-90). The median follow-up was 72.6 months (range: 0-157.4months). Mean overall survival (OS) are provided in the table below (table 1). Observed marginal differences in OS of patients treated with IMRT and 3DCRT; brachytherapy performed better than photons (3DCRT, IMRT and SBRT). No difference in OS was noticed between LDR or HDR brachytherapy. Patient treated with Proton had highest OS for both low- and intermediate-risk CaP. All these differences in OS were statistically significant (p<0.05). This study indicates that IMRT is most commonly used modality followed by brachytherapy for treating low- and intermediate-risk CaP patients. Photon beam therapy appears to be superior to other modalities of RT for far the overall survival is concerned. Brachytherapy performed better than 3DCRT and IMRT. Multivariable risk model analysis is underway.Abstract 2694; Table 1Overall survival (OS) of Low-risk and Intermediate-risk prostate cancer patients.Treatment modality3DCRTIMRTSBRTProtonLDRHDRp-valueNumber of patients (n=194,214)3,683 (1.9%)99,231 (51.1%)7,750 (4.0%)5,386 (2.8%)51,508 (26.5%)26,656 (13.7%)Mean OS for Low-risk pts (mo)123.5127.5129.5139.6136.0135.8< 0.001Mean OS for Interm-risk pts (mo)115.0117.6122.1132.8127.0128.4< 0.00110-yr OS for combined Low-risk and Intermediate-risk pts71.2%80.6%91.3%93.8%86.1%86.3%<0.05 Open table in a new tab