ORLANDO—New studies support the use of active surveillance (AS) for selected patients with localized, low-risk prostate tumors.
In a study of 262 men with low-risk prostate cancer, a team led by Scott E. Eggener, MD, assistant professor of surgery at the University of Chicago Medical Center, showed that active surveillance is a safe and durable op-tion that is associated with a low risk of systemic progression. All men had low-risk tumors, defined as clinical stage T1-T2a, a biopsy Gleason sum of 6 or less, a PSA level of 10 ng/mL or less, and three or fewer positive biopsy cores at initial diagnosis. To be included in the study, all men had to be age 75 years or younger, needed to have at least two biopsies prior to commencing AS, and not received active treatment for a minimum of six months after the second biopsy. The patients had a median age of 69 years.
After a median follow-up of 29 months, 43 patients eventually underwent primary therapy in the form of radical prostatectomy, radiation therapy, or androgen deprivation.
The one-, two-, and five-year actuarial probabilities of remaining on AS were 95%, 91%, and 75%, respectively, Dr. Eggener told colleagues here at the American Urological Association annual meeting. Patients with cancer detected on the second biopsy and a higher number of cancerous cores from the first and second biopsy combined were more likely to undergo primary therapy, he said. Age and PSA level at diagnosis, clinical stage, number of positive cores at initial diagnosis, and number of total biopsy core samples, and prostate volume did not predict outcome.
Of the 26 patients who underwent radical prostatectomy, 13 (50%) had a pathological Gleason sum of 7 or higher, 24 (92%) had organ-confined tumors, and one (4%) had lymph node involvement. One patient on AS had a PSA rise from 6 to 24 ng/mL over a six-month period and developed skeletal metastases.
Dr. Eggener noted that their findings are based on a relatively short follow-up period, but “active surveillance appears to be a safe and feasible management option for patients with very low risk prostate cancer. It certainly is not for every patient or every treating physician.”
AS is increasingly under-discussed with patients and underutilized, Dr. Eggener said, adding: “It should at least be on the table as one of the management options.”
Second biopsy is key
Dr. Eggener stressed the importance of the second biopsy, which gives additional information that could aid in patient risk stratification or exclude patients who may be inappropriate AS candidates. In a previous study, he said, up to 25% of patients who underwent a second biopsy had criteria that would exclude them from AS. “We feel
strongly that the second biopsy is essential for anyone considering active surveillance.”
With respect to age as a criterion for selecting patients for AS, Dr. Eggener observed that younger patients, such as those in their 50s, have a longer expected life span, so they might incur greater long-term risk of tumor progression if they opt for AS, he said. “But we don't have the data to advocate for or against active surveillance in that population,” he said.
Other studies presented at the conference showed that deferred treatment (DT) for prostate cancer—defined as no treatment for more than one year after diagnosis—and immediate treatment are associated with similar incidences of metastasis and prostate cancer death. In one study, William V. Shappley III, MD, of Brigham and Women's Hospital in Boston, and his colleagues identified 2,134 men in the Health Professionals Follow-up Study who were diagnosed with prostate cancer between 1986 and 2002. Of these men, 169 (7.9%) chose DT for their initial management. After a mean follow-up of seven years, 89 men (53%) remained untreated. The remaining 80 men received treatment an average of three years after diagnosis. Men aged 60-69 years were twice as likely as older men to abandon DT and receive active treatment. Those with Gleason scores higher than 6 were three times as likely as men with lower Gleason scores to receive active treatment.
When the investigators compared the DT patients with men who underwent immediate treatment, they found that both groups had similar rates of clinical metastases and prostate cancer death. The DT and immediate treatment groups had metastases rates of 6.5 and 6.7 events per 1,000 person-years, respectively, and 2.4 and 2.7 prostate cancer deaths per 1,000 person-years.
In another study, Dr. Shappley and collaborators looked at the 1,288 male physicians who participated in the Physicians' Health Study and who were diagnosed with prostate cancer. Nearly 10% of these men chose DT for their initial management.
Ninety-one percent of the DT group had low- or intermediate-risk disease. One third of the DT patients with low- and intermediate-risk disease have remained free of treatment for more than 10 years. The incidence of metastasis and prostate cancer death was similar for the DT and immediate treatment groups.