Men with favorable-risk prostate cancer have a very low risk of disease progression to a lethal phenotype, and they should be encouraged to consider surveillance rather than curative intervention, investigators said online in the Journal of Clinical Oncology.
Cancer-specific survival rates were 99.9% at 10 years and again at 15 years, in a single-arm prospective study of 1,298 men with favorable-risk disease offered active surveillance beginning in 1995, Dr. Jeffrey J. Tosoian and his colleagues from Johns Hopkins University School of Medicine and Hospitals in Baltimore reported. The study enrolled 926 men (71%) who met all criteria for very-low-risk cancer and 372 (29%) who met criteria for low-risk disease, they said (Journ Clin Onc 2015 Aug 31 [doi: 10.1200/JCO.2015.62.5764]).
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Curative intervention was recommended for disease reclassification when patients no longer met the inclusion criteria following biopsy results.
A total of 38 (3%) men died from other causes before any reclassification or treatment, while 9 succumbed to other causes after receiving prostate cancer treatment. The 47 men who died from causes other than prostate cancer had been receiving active surveillance for an average of 7 years (range, 1-18 years).
There were two deaths (0.15%) from prostate cancer, both in patients with very-low-risk disease. In addition, there were two cases of lymph node metastases and one distant metastasis.
The overall cancer-specific and metastasis-free survival rates were 93%, 99.9%, and 99.4%, respectively, at 10 years and 69%, 99.9%, and 99.4%, respectively, at 15 years.
Disease was reclassified during biopsy in 467 men at a median of 2 years (range, 0.3-16 years) after enrollment. Of this group, 233 involved reclassification of the tumor grade and 234 involved volume reclassification. At 5, 10, and 15 years after active surveillance was initiated, the cumulative incidence of any biopsy reclassification was 35%, 49%, and 56%, respectively, while the cumulative incidence of grade reclassification was 17%, 26%, and 31%, respectively.
This study was begun at a time when there was substantial resistance to monitoring men with prostate cancer, the authors noted, and therefore, “our intents were to demonstrate the safety of this approach for carefully selected men and to identify markers of a lethal phenotype that might lead to wider inclusion in active surveillance.”
“The expansion of active surveillance during the past decade and the sharing of institutional data sets will likely help delineate factors associated with varying outcomes and will allow patients to play a greater role in selecting the strategy that best suits their individual preferences,” wrote Dr. Tosoian and coauthors.
“Our data suggest that, for men with favorable-risk prostate cancer, the paradigm of immediate intervention must be replaced by one of immediate contemplation – a thoughtful assessment of prognostic risk, life expectancy, and the relative risks and benefits of available management options considered in the context of personal preferences,” the authors concluded.
There were no outside funding sources reported. Some coauthors reported consulting or advisory roles with Metamark Genetics, MDxHealth, Dianon Systems, DAKO, Trock, SonaCare Medical, Myriad Genetics, Rochon Genova, Rothwell Figg, and Roche.