Surgery Found Best for Survival in Localized Prostate Cancer

GENEVA, Switzerland, Oct. 9 -- Surgery offered the best chance of 10-year survival in localized prostate cancer particularly for men younger than 70 and with poorly differentiated tumors, according to an observational study.

Compared with patients who had a prostatectomy, those given radiation therapy and those managed with watchful waiting had approximately twice the increased risk of dying of the disease multiadjusted hazard ratio, 2.3, (95% CI, 1.2-4.3) for radiation therapy and 2.0 (CI, 1.1-3.8) for watchful waiting, Christine Bouchardy, M.D., M.P.H., of Geneva University, and colleagues reported in the Oct. 8 issue of Archives of Internal Medicine.

For radiation therapy, the multiadjusted hazard ratio was 2.3, (95% CI, 1.2-4.3). It was 2.0 (CI, 1.1-3.8) for watchful waiting.

The mortality risk for hormone therapy alone was even higher at 3.5 times the risk with surgery (CI, 1.4-8.7) at five years, the researchers said.

Strategies for the management of localized prostate cancer are still being debated because randomized trials have not yet established which treatment provides the best long-term outcome. Therefore treatment choice is strongly influenced by patients' and physicians' personal preferences and experience, the researchers noted.

Even in this observational study, they said, basic limitations inherent in the design suggest that, until randomized clinical trials provide conclusive evidence, physicians and patients should be informed of these results but should take the study's limitations into consideration when making a treatment decision.

To compare the effect of all types of treatment on long-term survival, the researchers used data from the Geneva Cancer Registry to assess all 844 patients with a diagnosis of localized prostate cancer from January 1989 through December 1998.

Treatments included prostatectomy for 158 patients, radiation therapy for 205, watchful waiting for 378, hormone therapy for 72, and other types of therapy for 31.

Survival curves were compared using the log-rank test, and multivariate Cox proportional hazards analysis and propensity score methods were used to evaluate the independent effect of treatments on prostate cancer-specific mortality.

Treatment options only slightly influenced five-year mortality but had an important effect in the long-term, the researchers reported.

Specific 10-year survival was 83% for surgery (95% confidence interval 73%-93%), 75% for radiation therapy (CI, 67%-83%), and 72% (CI, 66%-80%) for watchful waiting, (P

Also, they added, the study was limited by the lack of information on comorbidites. Although differences in mortality from other causes were not statistically significant between treatment groups, the watchful waiting and hormone-therapy groups showed an almost 50% increase in mortality from other causes both at five years and at 10, suggesting the presence of baseline differences in prognostic factors.

Furthermore, they said, inasmuch as screening prevalence, diagnostic assessment, treatment, and surveillance had probably changed during the study period, these results may not be generalizable to the present situation.

Clinical trials to date have yielded only limited information on treatment efficacy, the researchers wrote, so that knowledge thus far is best provided by a few observational studies. To draw a conclusion on the different effects in patient subgroups, larger studies are needed, they said.

However, they added, there is growing evidence from this population-based study and other observational studies that prostatectomy offers the best chance of long-term specific survival.

Until clinical trials provide conclusive evidence, physicians and patients should be informed of these results and their limitations, Dr. Bouchardy and her colleagues said.