Researchers in Sweden found that only a small minority of men diagnosed with low risk early stage prostate cancer die from the disease if not treated and suggest that surveillance as opposed to treatment may be a suitable option for such patients.

You can read a report on the study, by Dr Pär Stattin, of the Department of Surgical and Perioperative Science at Umea University, and colleagues, online in the 18 June advanced access issue of the Journal of the National Cancer Institute.

Treatment of localized, low risk prostate cancer is a controversial issue because while some experts advocate treatment such as surgery or radiotherapy, others say the risks of treatment outweigh the benefits and that surveillance or “watchful waiting” is a better option.

However, in their background information the authors write that they are not aware of any up to date population-based outcome studies on prostate cancer that include the three diagnostic criteria: stage (tumor size and spread), Gleason score (tissue pattern) and PSA (prostate-specific antigen level in the blood).

For their observational study, Stattin and colleagues used nationwide data from the National Prostate Cancer Register of Sweden on 6,849 men aged 70 and under who had been diagnosed with localized prostate cancer of low or intermediate risk of progression and treated with active surveillance (2,021), radical prostatectomy (3,399) or radiation therapy (1,429) from beginning of 1997 to end of 2002.

The authors defined intermediate prostate cancer as a diagnosis of local clinical stage T1-2, a Gleason score of 7 or less, and a serum PSA level of less than 20 ng/mL.

Nearly 40 per cent of the men included in the study had low risk prostate cancer which the researchers defined as clinical stage T1, Gleason score 2-6, and serum PSA level under 10 ng/mL. Of these, 1,085 patients were in the active surveillance group, while 1,601 were in the curative intent (prostatectomy, radiation therapy) group.

The researchers cross-referenced the records to another register, the Cause of Death Register, so they could calculate numbers of deaths from prostate cancer in the cohort and competing causes.

The results showed that:

  • For low and intermediate risk prostate cancers together, there was a 3.6 per cent risk of dying in 10 years in the surveillance only group (calculated cumulative 10-year prostate cancer-specific mortality 3.6 per cent, 95 per cent confidence interval, CI, 2.7 to 4.8 per cent).

  • This compared with 2.7 per cent in the curative intent group (95% CI 2.1 to 3.45%).

  • For low risk prostate cancer, this figure was 2.4 per cent in the surveillance group (95% CI 1.2 to 4.1%) and 0.7 per cent (95% CI 0.3 to 1.4%) in the curative intent group.

  • The 10-year risk of dying from competing causes was 19.2 per cent ( (95% CI 17.2 to 21.3%) in the surveillance group and 10.2 per cent (95% CI 9.0 to 11.4%) in the curative intent group.

Stattin and colleagues concluded that:

“A 10-year prostate cancer-specific mortality of 2.4% among patients with low-risk prostate cancer in the surveillance group indicates that surveillance may be a suitable treatment option for many patients with low-risk disease.”

In an accompanying editorial, Drs Siu-Long Yao and Grace Lu-Yao of The Cancer Institute of New Jersey, US, point out that this study, like other recent ones, suggest that the survival of patients with low risk cancers who opt for conservative management as opposed to radical treatment is similar to that of control subjects in their age group.

In fact, most men will die of something other than prostate cancer, so perhaps a diagnosis of prostate cancer should be regarded as a warning sign to start taking better care of one’s health, they suggested.

But, this could be easier said than done, because while research shows that many cancer patients are more likely to listen to health advice after diagnosis, “older men, like those with prostate cancer, appear to be less receptive to change”, they added.

“Outcomes in Localized Prostate Cancer: National Prostate Cancer Register of Sweden Follow-up Study.”
Pär Stattin , Erik Holmberg , Jan-Erik Johansson , Lars Holmberg , Jan Adolfsson , Jonas Hugosson , and on behalf of the National Prostate Cancer Register (NPCR) of Sweden.
Journal of the National Cancer Institute, Advance Access published on 18 June 18 2010.
DOI: 10.1093/jnci/djq154

Source: JNCI

Written by: Catharine Paddock, PhD