Salvage radical prostatectomy (SRP) may benefit carefully selected patients with recurrent prostate cancer (PCa) following radiotherapy, researchers concluded.
The findings from their multi-institutional prospective study of 41 men who underwent open SRP for radiorecurrent PCa compare favorably with previous research suggesting that patients who respond best to SRP are those with lower PSA values and lower-grade disease prior to radiation treatment, and a prolonged post-radiotherapy PSA nadir, James L. Mohler, MD, of Roswell Park Comprehensive Cancer Center in Buffalo, New York, and colleagues reported in Prostate Cancer and Prostatic Diseases.
The 41 men were enrolled from 1997 to 2006 as part of the Cancer and Leukemia Group B (CALGB) 9687 trial. The group, which had a median age of 64 years at SRP, included 24 men who underwent external beam radiation therapy, 11 who had brachytherapy, and 6 who received both. The median time from radiation therapy to SRP was 64 months. With respect to pathologic staging, 44%, 54% and 3% had pT2, pT3, and pT4 disease, respectively. Of the 41 men, 17% and 12% had positive surgical margins and positive pelvic lymph nodes, respectively.
In other findings, 17 (45%) of 38 evaluable patients had urinary incontinence (defined as use of 3 or more pads per day) prior to SRP, with 88% reporting urinary incontinence at 6 months, 85% at 12 months, and 63% at 24 months following SRP. At a median follow-up of 91 months, the 2-, 5-, and 10-year rates of biochemical progression-free survival were 51%, 39%, and 33% respectively, according to Dr Mohler’s team. The overall survival rates at those time points were 100%, 89%, and 52%, respectively.
The men had a median pre-radiation therapy PSA level of 5.5 ng/mL and most had a pre-treatment Gleason score of 7 or less. The median duration of post-radiotherapy PSA nadir was 30 months and the median time between radiation and SRP was more than 5 years.
Dr Mohler and his colleagues noted that 25% to 35% of men with clinically localized PCa receive radiation therapy as definitive treatment, and the cancer recurs despite improvements in patient selection, delivery techniques, and use of concomitant systemic therapy. They pointed out that radiation therapy for PCa has changed since the study started enrolling patients. Most of the cohort did not have intensity-modulated radiation therapy or high-dose radiation therapy, which today are considered standard of care. In addition, 75% of patients with known pre-radiation clinical staging had palpable disease. “As a result, the enrolled patients do not represent a current population of radiation patients and therefore the enrolled patients should be expected to have worse outcomes after both radiation and SRP,” they wrote.
The study had other limitations, as well. Their cohort was younger than the average age of failure after initiation treatment of PCa, and it was too small for post-hoc multivariable analysis to determine who was at greater risk of treatment failure.
Despite the limitations, the authors wrote, strengths of the study include its prospective and multi-institutional design with long-term oncologic outcomes. Most recent published series, they pointed out, have been retrospective, single-institution studies with shorter follow-up.
Mohler JL, Halabi S, Ryan ST, et al. Management of recurrent prostate cancer after radiotherapy: long-term results from CALGB 9687 (Alliance), a prospective, multi-institutional salvage prostatectomy series. Prostate Cancer Prostatic Dis. 2018; published online ahead of print.