Active surveillance a viable option for low-risk prostate cancer

May 15, 2008

Active surveillance remains a viable option for low-risk, localized prostate cancer, according to two studies presented today during the Annual Scientific Meeting of the American Urological Association (AUA), yet researchers point out a strong need for regular monitoring and development of stronger clinical predictors of progression.

Researchers from the University of Texas Health Science Center in San Antonio evaluated the efficacy of digital rectal exam (DRE), prostate-specific antigen (PSA) testing, repeat biopsy and endorectal magnetic resonance imaging (MRI) in accurately monitoring disease progression. Researchers conducted a retrospective review of 80 patients with low-risk prostate cancer (stage T1-T2, NX0, MO) who were managed with active surveillance from 2004 to 2007. Patients (mean age 65) underwent routine clinical checkups with DRE and PSA every four months and repeat biopsy at 18 months. Select patients (12) also underwent endorectal MRI.

The study shows that PSA and DRE were unreliable in predicting disease progression. Of the 41 percent of patients with an initial positive DRE, 42 percent with a previously abnormal DRE had a subsequent normal DRE. PSA at the time of repeat biopsy was insufficient in predicting subsequent positive biopsy, and a majority with a positive repeat biopsy also had a decreased PSA level. Endorectal MRI, not currently part of the routine surveillance protocol, was the most reliable predictor, and showed location and disease stage as expected in 50 percent of the patients being followed by MRI.

The second study, a multi-institutional retrospective review of data from four North American academic centers – Cleveland Clinic Foundation, Memorial Sloan-Kettering Cancer Center, University of British Columbia and University of Miami – indicated that active surveillance for appropriately selected patients with low-risk prostate cancer appears to be safe, durable and associated with low risk of systemic progression. Cancer detected on re-biopsy and the total number of involved cores are associated with a lower likelihood of remaining on active surveillance.

This study evaluated actuarial rates, incidence of metastatic disease, pathological findings subsequently undergoing radical prostatectomy and predictors of remaining on active surveillance in patients with low-risk, localized prostate cancer . The study cohort consisted of 262 patients (aged 75 and younger) with localized prostate cancer and low-risk clinicopathologic features who had at least two biopsies prior to going on active surveillance.

Median follow-up was 29.7 months. The presence of cancer in the second biopsy and the number of positive cores at first and second biopsy (combined) were strong indicators of progression requiring active treatment. Of the group, 43 patients subsequently underwent primary therapy (radical prostatectomy, radiation therapy or androgen deprivation). The one- two and five-year actuarial probabilities of remaining on active surveillance were 95 percent, 01 percent and 75 percent.

Source: American Urological Association