A phase I pilot study of preoperative radiotherapy for prostate cancer: Long-term toxicity and oncologic outcomes.

Abstract

60 Background: Pre-operative radiotherapy (PreORT) improves local control in various cancer types, and has become an established oncologic treatment strategy. During 2001-2004, we conducted a phase I pilot study assessing the role of short-course PreORT for men with unfavourable intermediate- and high-risk localized prostate cancer (PCa). We present long-term follow-up toxicity and oncologic outcomes. Methods: Eligible patients had histologically proven PCa, cT1-T2N0M0, PSA > 15-35 ng/ml with any Gleason score, or PSA 10-15 ng/ml with Gleason score ≥7. Patients received 25 Gy in five consecutive daily fractions to the prostate, followed by radical prostatectomy (RadP) within 14 days after RT completion. Primary outcomes were intra-operative morbidity, and late genitourinary (GU) and gastrointestinal (GI) toxicities. Acute toxicity was assessed during radiotherapy treatment on daily basis using RTOG grade scoring scale. Patients were assessed post-RadP clinically and with PSA at 1 and 6 months, and every 6 months. Intra- and Post-RadP toxicity was documented prospectively and scored as per Common Terminology Criteria for Adverse Events v4.0. Biochemical failure (BF) was determined based on two consecutive post-RadP PSA > 0.2 ng/ml. Results: Fifteen patients were enrolled; 14 patients completed PreORT followed by RadP, which also included bilateral lymph node dissections in 13 cases. Median follow-up was 12.2 years (range 6.7-16.3 years). Late GU toxicity was common, with 2 patients (14.3%) experiencing G2 toxicity, and 6 patients (42.8%) G3 toxicity. There were no G4-5 late GU toxicity. Late GI toxicity was infrequent, with only 1 patient (7.1%) experiencing transient G2 proctitis. At last follow-up, 8 (57.1%) and 6 (42.8%) patients experienced BF and metastatic disease recurrence, respectively. Conclusions: The use of PreORT in men with high-risk PCa is associated with unexpected high-rates of late GU toxicity. Future studies examining the role of RT pre-RadP must cautiously select RT technique and dose schedule. Importantly, long-term follow-up data is essential to fully determine the therapeutic index of PreORT in the management of localized PCa. Clinical trial information: NCT00252447.