Purpose: Recent studies have shown increased prostate cancer control rates with radiation dose escalation. Herein the experience of dose escalation by high dose rate brachytherapy (HDR-BT) adjunct to the three-dimensional conformal radiation therapy (3D-CRT) for prostate cancer is presented.
Patients and methods: During the period between August 2005 and July 2007, patients with intermediate and high risk prostate cancer were treated with 3D-CRT of dose 46Gy ÷ 23 fractions to whole pelvis followed by: Arm A (102 patients): prostate boost with HDR-BT 14 Gy × 2 sessions and Arm B (103 patients): prostate boost via 3D-CRT of dose 26 Gy ÷ 13 fractions. Primary objectives were overall survival (OS), distant metastases free survival (DMFS) and PSA progression free survival (PPFS) rates. Secondary objectives were the toxicity profile and post-radiation histopathological response.
Results: At median follow up of 3.5 years, PPFS, DMFS and OS rates were; 97.8% versus 89.0% (p = 0.009), 98.1% versus 93.6% (p = 0.13) and 98.8% versus 91.6% (p = 0.24) in Arm A and Arm B. respectively. Grade 3 or 4 delayed genitourinary toxicities occurred in 2% and 4.8% of patients in Arm A and Arm B, respectively. Delayed grade 3 and 4 gastrointestinal toxicities were seen in 2% and 3.9% of patients in Arm A and Arm B, respectively. The post-radiation prostate biopsies were negative in 14/17(82.3%) and 9/15 (60%) in Arm A and Arm B, respectively.
Conclusion: 3D-CRT combined with HDR-BT resulted in better PPFS and lower morbidity than 3DCRT alone for intermediate and high risk prostate cancer.