Men younger than 60 years with high-risk prostate cancer (PCa) have better overall survival when their initial treatment is radical prostatectomy (RP) rather than radiation (RT), according to researchers at the 2017 American Society of Clinical Oncology (ASCO) annual meeting.
Adeel Kaiser, MD, and colleagues of the University of Maryland in Baltimore, found a significant 48% improvement in overall survival with RP at a median follow-up of 50 months. Estimated survival at 8 years also favored surgery: 85.1% vs 74.9% for RT.
The team adjusted for other factors expected to affect prognosis, including year of treatment, comorbidity score, Gleason score, T stage, use of hormone therapy and chemotherapy, type of radiation therapy, PSA, age, race, and insurance status.
They based their analysis on 16,944 younger patients from the National Cancer Data Base who had Gleason score 8 to 10 PCa with no metastasis or nodal involvement. During 2004 to 2013, 12,155 of the men underwent RP and 4789 received RT as initial therapy. RT was external beam radiation (EBRT) alone or EBRT with brachytherapy at a median dose of 77.4 Gy. A majority of RT patients (82.5%) also received hormone therapy. In the surgery group, 17.2% of patients received radiation; most at a dose above 64.8 Gy.
“The results should be viewed as hypothesis-generating rather than definitive,” Dr Kaiser told Renal & Urology News. “Patients undergoing surgery are afforded postsurgical pathological analysis and therefore may be offered additional or multimodal therapy, including adjuvant or salvage radiation, when adverse risk factors are noted. Or patients in the radiation group may have been understaged and failed to receive more aggressive therapy with regard to radiation field design or hormonal therapy. Brachytherapy boost was not widespread in the time period we examined, for example. It is unusual for radiation patients to undergo surgery after radiation.”
Overall survival was the only endpoint the investigators could analyze with this database, so they couldn’t attribute the findings to fewer deaths from prostate cancer. Since selection bias is possible with any retrospective review, future prospective research is warranted. The team is planning a trial investigating whether surgery patients reap benefit from the addition of radiation and systemic therapy.
Kaiser A, Bentzen S, Siddiqui M, et al. Survival impact of initial local therapy selection for men under 60 with high risk prostate cancer. J Clin Oncol 2017;35 (suppl; abstr 5082). Poster presented at the 2017 American Society of Clinical Oncology annual meeting in Chicago on June 5. Poster 156.