Eighty men with early prostate cancer began AS at the authors' institution between 1993 and 2002. Eligibility included histologically confirmed prostatic adenocarcinoma, fitness for radical treatment, clinical stage T1/T2, N0/X, M0/X, a prostate specific antigen (PSA) level of <= 20 ng/mL, and a Gleason score of <= 7. PSA was measured and a digital rectal examination conducted at 3-6 month intervals. The decision between continued monitoring or radical treatment was informed by the rate of rise of PSA, and was made according to the judgement of each patient and clinician. During the same period, 32 men with localized prostate cancer (any T stage, N0/X, M0/X, any PSA, Gleason score <= 7) were managed by WW; hormonal treatment was indicated for symptomatic prostate cancer progression. The PSA doubling time (DT) was calculated using linear regression of ln(PSA) against time, using all pretreatment PSA values.

At a median follow-up of 42 months, 64 (80%) of the 80 patients on AS remained under observation, 11 (14%) received radical treatment and five (6%) died from other causes. No patient developed evidence of metastatic disease, none started palliative hormone therapy, and there were no deaths from prostate cancer. Of the 11 patients who received radical treatment all remained biochemically controlled with no clinical evidence of recurrent disease. The median PSA DT while on AS was 12 years. Twenty (62%) of the 32 patients on WW remained on observation, eight (25%) received palliative hormonal therapy and four (12%) died, including one from prostate cancer.

AS is feasible in selected men with early prostate cancer. The natural history of this disease often appears extremely indolent, and most men on AS will avoid radical treatment. There is a marked contrast between AS (with radical treatment for biochemical progression) and WW (with palliative treatment for symptomatic progression). Ongoing studies are seeking to optimize the AS protocol, and to compare the long-term outcomes with those of immediate radical treatment.