A multi-institutional evaluation of active surveillance for low risk prostate cancer.

Purpose: For select men with low risk prostate cancer active surveillance is more often being considered a management strategy. In a multicenter retrospective study we evaluated the actuarial rates and predictors of remaining on active surveillance, the incidence of cancer progression and the pathological findings of delayed radical prostatectomy.
Materials and Methods: A cohort of 262 men from 4 institutions met the inclusion criteria of age 75 years or younger, prostate specific antigen 10 ng/ml or less, clinical stage T1-T2a, biopsy Gleason sum 6 or less, 3 or less positive cores at diagnostic biopsy, repeat biopsy before active surveillance and no treatment for 6 months following the repeat biopsy. Active surveillance started on the date of the second biopsy. Actuarial rates of remaining on active surveillance were calculated and univariate Cox regression was used to assess predictors of discontinuing active surveillance.
Results: With a median followup of 29 months 43 patients ultimately received active treatment. The 2 and 5-year probabilities of remaining on active surveillance were 91% and 75%, respectively. Patients with cancer on the second biopsy (HR 2.23, 95% CI 1.23-4.06, p = 0.007) and a higher number of cancerous cores from the 2 biopsies combined (p = 0.002) were more likely to undergo treatment. Age, prostate specific antigen, clinical stage, prostate volume and number of total biopsy cores sampled were not predictive of outcome. Skeletal metastases developed in 1 patient 38 months after starting active surveillance. Of the 43 patients undergoing delayed treatment 41 (95%) are without disease progression at a median of 23 months following treatment.
Conclusions: With a median followup of 29 months active surveillance for select patients appears to be safe and associated with a low risk of systemic progression. Cancer at restaging biopsy and a higher total number of cancerous cores are associated with a lower likelihood of remaining on active surveillance. A restaging biopsy should be strongly considered to finalize eligibility for active surveillance.