Active surveillance of prostate cancer

Active surveillance (AS) or watchful waiting is a management option for localized prostate cancer that can be offered to appropriate patients who would also be candidates for aggressive local therapies (surgery and radiotherapy), with the intent to intervene if the disease progresses. This distinguishes AS from watchful waiting, another observational strategy for men that would not be candidates for curative therapy (surgery, radiation) because of a limited life expectancy. AS offers men with a prostate cancer that is thought to have a low risk of causing harm in the absence of treatment, a chance to delay or avoid aggressive treatment and its associated side effects.

While prostate cancer (PCa) is the most common non cutaneous cancer and second leading cause of cancer-related death in American men, it is conservatively estimated that approximately 100,000 men per year in the United States who would be eligible for conservative treatment through active surveillance (AS), undergo unnecessary treatments. The management of localized prostate cancer is controversial and men with localized disease diagnosed today often undergo treatments with significant side effects that will not improve overall health outcomes. The 2011 NIH State-of-the-Science Conference Statement on the “Role of active surveillance in the management of men with localized prostate cancer” pointed out the many unanswered questions about observational strategies for prostate cancer that require further research and clarification. These included:

The consensus statement highlighted the need for well-designed studies to address these questions as an important health research priority. In the meantime, active surveillance for the treatment of low risk prostate cancer is now being offered to more and more patients where it is generally considered that prostate cancer will not cause the man harm during his lifetime if treatment is delayed or avoided. For these men, surveillance is thought to offer a more targeted approach to management; avoiding unnecessary treatment and its risk of associated side effects, while allowing for curative intervention for those that experience disease progression on observation.

Prostate specific antigen (PSA) based screening for prostate cancer led to earlier detection of prostate cancer (stage migration), and thus altered the course of the disease in the absence of treatment (natural history). The incidence and prevalence of prostate cancer increased with widespread PSA testing, as did the length of time that men live with their disease, as compared to the pre PSA era. The stage migration that occurred, with application of curative intervention at an earlier stage, undoubtedly led to a reduction inprostate cancer mortality. However, the extent to which this reduction was due to PSA based screening is debatable. Further, because prostate cancer progresses slowly and is found most often in older men with competing risks of mortality, the extent to which these changes in natural history have resulted in benefit and harm are also debatable.

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