Prostate cancer treatment outcomes data take center stage

August 15, 2006

New data on outcomes of surgery, radiotherapy, and watchful waiting, along with studies of minimally invasive surgical approaches provided the core for the AUA meeting take-home messages on management of localized prostate cancer. Findings of research on outcomes of different disease management options are important in providing longer-term follow-up that generally corroborates results of previous studies, said Richard D. Williams, MD, Rubin H. Flocks professor and chairman, department of urology, University of Iowa, Iowa City.

Information on the learning curve for robot-assisted prostatectomy also expands existing favorable data and is encouraging for urologists interested in transitioning into that minimally invasive technique.

Several studies provide strong evidence that retropubic radical prostatectomy (RRP) results in durable cancer control.

These studies are important for definitively establishing that RRP is associated with long-term, durable responses, Dr. Williams observed.

"It is only recently that the outcome data for men undergoing RRP are maturing to the point where we have 20 to 25 years of available follow-up," he noted. "In contrast, such extended follow-up is not available for men treated with radiation, either brachytherapy or external beam, as the protocols for those procedures have changed significantly in more recent years."

Dr. Williams acknowledged that RRP technique has also evolved, but he noted that the impact of modifications has primarily been on reducing complication rates, rather than affecting cancer control. In highlighting that recurrence may have a very late onset, the long-term studies of men who underwent RRP also reinforce the need for urologists to continue following their patients long-term.

"It would be erroneous for any urologist to think that a man who has remained cancer-free for 10 years might be safely discharged from ongoing monitoring," Dr. Williams said.

The good news, however, is that late recurrences do not appear to necessarily carry a poor prognosis.

"That finding is consistent with recent data on PSA doubling time as a prognostic indicator, since a patient with a very late recurrence would most likely have an extremely long PSA doubling time and favorable prognosis," he pointed out.

After an average of almost 12 years of follow-up, men treated with watchful waiting or radiation therapy have a significantly higher risk of cancer-specific death than do men who undergo RRP.

These data corroborate previous information based on shorter follow-up demonstrating a survival advantage for RRP compared with watchful waiting. As such, they should remind urologists to be very careful in selecting men for watchful waiting on the basis of such factors as advanced age, significant medical comorbidity, limited life expectancy, and/or low-grade tumor, said Dr. Williams.

However, he questioned the accuracy of the data for the comparison between RRP and radiotherapy, noting that it conflicts with other studies showing that cancer-specific survival for the two approaches is similar when men are matched stage for stage.

"It is very difficult to fairly compare outcomes in cohorts of men treated with external beam radiation versus RRP because pathological stage information is not available for the radiotherapy patients," Dr. Williams said. "Experience in RRP studies points to both the inaccuracy of clinical staging and the likelihood of understaging that would result in a poorer outcome in the radiation therapy patients due to selection bias."