Prostate cancer outcomes related to risk category

Key Points

Umeå, Sweden-Outcomes for men with prostate cancer are strongly related to risk category according to clinical stage, Gleason score, and serum PSA, and there is a continuous risk of death from the disease up to 15 years after diagnosis, say Swedish researchers.

There are limited results from national-level data on long-term outcomes in contemporary prostate cancer according to risk categories, prompting the current study.

The risk categories included low-risk prostate cancer (clinical local stage T1-2, PSA <10.0 ng/mL and Gleason score 6 on biopsy), intermediate risk (T1-2 or Gleason score 7 or PSA 10.0 to 20.0 ng/mL), high risk (T3-4 or Gleason score 8-10 or PSA 20.0 to 50.0 ng/mL), regionally metastatic (N1 or PSA 50.0 to 100.0 ng/mL and M0 or MX), and distant metastatic (M1 or PSA >100.0 ng/mL).

There were strong increases in calculated cumulative 15-year prostate cancer-specific mortality with increasing risk category, and there was a continuous risk of prostate cancer-specific mortality throughout the follow-up period.

Mortality risk seen at 15-year follow-up

In patients with low-risk prostate cancer, risk of prostate cancer-specific mortality at 15 years of follow-up was 9%, cardiovascular mortality risk was 18%, and risk of death from other competing causes was 25%. For men in the same age group with intermediate-risk prostate cancer, risk of prostate cancer-specific mortality was 19%, cardiovascular mortality risk was 21%, and mortality risk from other competing causes was 25%.

"This is the very first time that data for Gleason scores and PSA values are used in such a study," said Dr. Stattin, professor of urology at Umeå University Hospital, Umeå, Sweden. He noted that the SEER (Surveillance, Epidemiology, and End Results) database did not register specific Gleason scores or PSA levels before 2004.

The difference between the risk of prostate cancer-specific mortality for men with low- and intermediate-risk disease was 10%.

"Men with prostate cancer that is detected with PSA screening often have a low-risk tumor. These men are more aware of their health and have a lower risk of dying from other causes than an age-matched background population," said Dr. Stattin.

This supports the notion that one could actively monitor men with low risk of prostate cancer in lieu of surgery. Two prospective studies on active surveillance are ongoing in Europe in the form of Prostate Cancer Research International: Active Surveillance and the Study of Active Monitoring of Low Risk Prostate Cancer in Sweden.

"PSA screening of men over 70 years of age will influence mortality in prostate cancer very little. PSA testing is used suboptimally both in Sweden and the U.S., and far too many PSA tests are performed in elderly men. But mortality in prostate cancer continues even 15 years after diagnosis," noted Dr. Stattin, who presented the results at the 2011 European Association of Urology annual congress in Vienna, Austria.

Session co-moderator J. Morote Robles, MD, of Universidad Autónoma de Barcelona, Barcelona, Spain asked how Dr. Stattin and colleagues were able to determine the cause of death in the very large patient cohort.

"We retrieved data from the Cause of Death Register, which has been shown to contain accurate data on death causes for men diagnosed with localized prostate cancer in two studies by Fall et al and Godtman et al," Dr. Stattin answered.

"Are these data representative for all cases of prostate cancer in Sweden?" asked co-moderator J. Walz, MD, of Hôpital Sainte-Marguerite, Marseille, France.

"Yes, we had more than 97% capture of cases that were recorded in the Swedish Cancer Register to which report is compulsory and regulated by law. Thus, data in NPCR are truly population-based," Dr. Stattin said.