Feasibility study: watchful waiting for localized low to intermediate grade prostate carcinoma with selective delayed intervention based on prostate specific antigen, histological and/or clinical progression.

Purpose: We assessed the feasibility of a watchful waiting protocol with selective delayed intervention using clinical, prostate specific antigen (PSA) or histological progression as treatment indications for clinically localized prostate cancer.
Materials and Methods: In this prospective, single arm cohort study patients with favorable clinical parameters (stage T1b to T2b N0M0, Gleason score 7 or less and PSA 15 ng./ml. or less) are conservatively treated with watchful waiting. When a patient meets disease progression criteria, arbitrarily defined by the 3 parameters of the rate of PSA increase, clinical progression or histological upgrade on repeat prostate biopsy, appropriate treatment is implemented. Patients are followed every 3 months for the first 2 years and every 6 months thereafter. Serum PSA measurement and digital rectal examination are done at each visit and repeat prostate biopsy is performed 18 months after study enrollment.
Results: Since November 1995, the study has accrued 206 patients with a median followup of 29 months (range 2 to 66). Of these men 137 remain on the surveillance protocol with no disease progression, while 69 were withdrawn from study for various reasons. There was clinical, PSA and histological progression in 16, 15 and 5 cases, respectively. The estimated actuarial probability of remaining on the surveillance protocol was 67% at 2 years and 48% at 4. The probability of remaining progression-free was 81% and 67% at 2 and 4 years, respectively.
Conclusions: A policy of watchful waiting with selectively delayed intervention based on predefined criteria of disease progression is feasible. This strategy offers the benefit of an individualized approach based on the demonstrated risk of clinical or biochemical progression with time and, thus, it may decrease the burden of therapy in patients with indolent disease, while providing definitive therapy for those with biologically active disease.