Prostatectomy Beats Active Surveillance Long Term -- or Does It?
The 29-year follow-up makes data hard to interpret
by Mike Bassett, Contributing Writer, MedPage Today
December 12, 2018
Long-term follow-up of prostate cancer patients randomized to radical prostatectomy or active surveillance (a.k.a. "watchful waiting") showed a substantial and statistically significant survival advantage for the surgical procedure, according to the “Scandinavian Prostate Cancer Group Study Number 4” (SPCG-4)
Supposedly radical prostatectomy added a mean of 2.9 years to their life expectancy after 23 years, according to the researchers.
But how meaningful is that? The BIG problem is that the data collection of the study extends over 3 decades (29 years). The rules of diagnosis and management have changed so much over those years that it’s almost meaningless to make this claim!
Someone diagnosed with prostate cancer today would find it hard to see how the outcome of this study would apply to him, according to James Mohler, MD, of Roswell Park Comprehensive Cancer Center in Buffalo, New York.
As of December 2017, 80% of the men enrolled in the study had died. The cumulative incidence of death from all causes at 23 years was 72% in the radical prostatectomy group and 84% in the watchful waiting group.
Seventy-one deaths in the radical prostatectomy group and 110 in the watchful waiting group were due to prostate cancer, for an absolute difference in risk of 11.7 percentage points (95% CI 5.2-18.2).
Distant metastases were diagnosed in 92 men in the radical prostatectomy group and 150 men in the watchful waiting group. At 23 years the cumulative incidence of metastases was 26.6% in the radical prostatectomy group and 43.3% in the watchful waiting group (difference 16.7 percentage points; 95% CI 9.6-23.7).
But the researchers did not report mortality for the two treatment groups stratified by baseline Gleason score. That severely weakens the value of the study.
Moreover, adverse events such as incontinence and sexual dysfunction were also not addressed in the current report (a 2011 publication indicated similar rates of erectile dysfunction in the two groups but a nearly fourfold higher prevalence of urinary leakage in the prostatectomy patients).
And the study authors themselves admitted, "The mean number of years gained is a crude measure, since any given man who is randomly assigned to undergo the procedure either might not benefit at all or might have a much greater benefit than the mean number for the whole group indicates. However, the measure puts in perspective what is risked by delaying intervention."
But Mohler, who was not involved in the study, said that because of the way that prostate cancer diagnosis and management has changed since 1989, it's unclear what the findings mean for current patients. The concern is that diagnosing cancer earlier – like it is done today – might fail to show this gain in life benefit because of contamination of modern-day patients with lots of patients that don't really need to be treated.
In other words, don’t rush out to get your prostatectomy. Or more exactly, don’t let urologists use this study to railroad you into immediate action. According to Mohler, it would be wrong for patients and urologists to say that this study proves that more men should have radical prostatectomy... That's why this study, starting in 1989, is so hard to interpret in 2018.
It remains that if the prostate cancer is aggressive, removal is the safest course of action.
Primary Source
New England Journal of Medicine
Source Reference: Bill-Axelson A, et al "Radical Prostatectomy or Watchful Waiting in Prostate Cancer -- 29-Year Follow-up" N Engl J Med 2018; DOI: 10.1056/NEJMoa1807801.