Comparing Watchful Waiting and Prostatectomy
PIVOT, the Prostate Intervention Versus Observation Trial, started in 1994 and included 731 men randomly assigned to either watchful waiting or radical prostatectomy groups. Previous reports from the study found no significant differences in mortality between men in the two groups. Recently, investigators reported on follow-up data approximately 19.5 years into the study.
Key findings in the new results include a 5.5% improvement in overall survival for men in the prostatectomy group, compared to a 3% improvement reported for the study in 2012. Men with low-risk and high-risk disease in the prostatectomy group only had a 0.7% and 2.3% improvement in overall survival, respectively. However, men with intermediate-risk disease saw the greatest benefit in the prostatectomy group, with a 14.5% improvement in overall survival.
While more men in the surgery group had problems with urinary incontinence and erectile dysfunction, fewer men in the surgery group were treated for disease progression than in the watchful waiting group. However, the authors noted that treatment was primarily for asymptomatic, local or biochemical PSA progression.
As Dr. Catalona has previously reported in QUEST, PIVOT has many flaws. First, the study was conducted largely at Veterans Administration Hospitals and included a large proportion of men with other serious medical problems who died of other causes before their prostate cancer treatment could be adequately evaluated. Also, the study is statistically underpowered, which means the study size is too small to definitively compare surgery and watchful waiting for prostate cancer. A commentary by Gerald Chodak, M.D., in Medscape also reported that PIVOT could have a selection bias and contamination, with 15% of men assigned to the radical prostatectomy group not having surgery and 20% of men assigned to the watchful waiting group having surgery, radiation or some other form of therapy. These factors could bias the study results in favor of watchful waiting.
N Engl J Med. 2017 Jul 13;377(2):132-142. doi: 10.1056/NEJMoa1615869.
PIVOT: Latest Data on Surveillance Versus Surgery for Prostate Cancer – Medscape – Aug 30, 2017.