New Swedish Data on Active Monitoring vs. Immediate Treatment

www.ProstateCancerInfoLink.net | 06.21.2010

New data from the Swedish national prostate cancer registry suggest that the 10-year prostate cancer-specific mortality rate is less than 2.5 percent for men who opt for careful disease monitoring as opposed to immediate invasive treatment.

According to a new study by Stattin et al. in the Journal of the National Cancer Institute, the use of active monitoring, along with deferred treatment when necessary, was associated with only a 2.4 percent mortality rate after 10 years of follow-up compared to an 0.7 percent 10-year mortality rate among men who selected immediate radical prostatectomy or radiation. The full text of this article is available online, together with an editorial from Yao and Lu-Yao that provides additional comment.

Stattin and his colleagues identified 6,849 patients of 70 years of age or younger who were diagnosed between January 1, 1997 and December 31,. 2002. To be included in this retrospective analysis, the patients had to have been diagnosed with clinical stage T1–2 prostate cancer, a Gleason score of 7 or less, a serum PSA level of less than 20 ng/mL, and managed with some form of active monitoring (including active surveillance and watchful waiting) or immediate curative intent.

Data from their analysis demonstrated the following:

•2,201/6,849 patients werre managed with an active monitoring process.
•3,399/6,849 patients had a radical prostatectomy.
•1,429/6,849 patients received radiation therapy.
•2,686/6,849 patients had low-risk prostate cancer (defined as clinical stage T1, Gleason score 2-6, and a serum PSA level of less than 10 ng/ml).
•For all men with low- and intermediate-risk prostate cancers,the 10-year prostate cancer–specific mortality was 3.6 percent in the active monitoring group and 2.7 percent in the curative intent group.
•For men with low-risk disease only, the 10-year prostate cancer–specific mortality was 2.4 percent among the 1,085 patients in the active monitoring group and 0.7 percent among the 1,601 patients in the curative intent group.
•The 10-year risk of dying from competing causes was 19.2 percent in the active monitoring group and 10.2 percent in the curative intent group.
•The actual median follow-up time was 8.2 years.

Now there are a lot of cautions that need to be noted in interpreting these data. For starters, this is a retrospective analysis of data that reflect the biases of the patients and their physicians. It is not a randomized, controlled clinical trial. So, for example, there was no set protocol followed by all of the patients who received active monitoring.

In addition, the design of the study inevitably had a strong “selection bias,” meaning that a higher proportion of healthy patients with prostate cancer with adverse factors were inevitably assigned to receive a radical prostatectomy as opposed to active monitoring. And there is no information on tumor extent in biopsy specimens, serum PSA levels after the date of diagnosis, or progression to metastatic disease.

Just to demonstrate the strength of the selection bias, patients with greater degrees of comorbidity (a Charlson index of 2 or higher) had a 43.8 percent probability of being managed with active monitoring, whereas patients with a Charlson index of 0 or 1 only had a 28.4 percent probability of being managed with active surveillance. So the results outlined above were observed despite the fact that generally less healthy patients were more likely to receive active monitoring than generally healthier patients.

Having said that, Yao and Lu-Yao, in their editorial, comment that this study shows that, in a relatively recently diagnosed series of patients, “survival in most (Gleason ≤7 disease), but not all (Gleason 8 to 10), patients with localized disease managed conservatively is now similar to that of age-matched control subjects.”

According to Stattin and his colleagues, after the median of 8.2 years of follow-up, deaths from all causes in the active monitoring group group of patients was “similar to that of the background population, whereas all-cause mortality was lower than expected in the radiation therapy group and especially in the prostatectomy group.”

Stattin’s group also stated, however, that longer follow-up is needed because most patients currently diagnosed with localized prostate cancer are in their 60s and have a life expectancy of more than 15 years.

The bottom line to all of this is that there are increasing amounts of data to suggest the value of active monitoring for patients with low-risk disease who are 70 years of age and younger. The problem is still that of how we can best distinguish between the patients who can be effectively and safely managed with active surveillance and other forms of monitoring and those who need early invasive treatment to prevent progression to advanced disease if at all possible.

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