Large study examines surveillance results in men with very low-, low-, intermediate-, and high-risk disease.
Active surveillance (AS) as a management paradigm is associated with low rates of mortality and metastases among patients with very low- or low-risk prostate cancer, and also among selected men with intermediate- and high-risk disease, according to a chart review of patients managed with AS at Cleveland Clinic.
The investigators also cited the high success of patients with deferred therapy, supporting the safety of AS in appropriate prostate cancer patients.
“What you can gather from our experience, with regards to the safety of AS, is that rarely do men chosen for surveillance have mortality as a result of their cancer,” said lead investigator Yaw Nyame, MD, who presented the findings at the AUA annual meeting. “It happens, but it’s just not common.”
Follow-up data from 635 men managed with AS for localized prostate cancer from 2002 to 2015 were reported. Patients selected for AS are managed with interval PSA measurement and prostate biopsy at the discretion of 11 different urologists. Curative treatment was recommended with an increase in disease grade or volume (>50% of total cores).
Of the 635 men, 514 were classified as very low risk/low risk (median age at diagnosis, 65.1 years) and 117 as intermediate risk/high risk (median age at diagnosis, 68.6 years). Data were insufficient to classify four of the men.
“When we first were offering active surveillance in our institution, we used criteria that had been established by clinicians at Johns Hopkins, and a lot of the patients that we were surveilling were not only low risk but they were very low risk because that’s where the data was most supportive of less intervention,” said Dy. Nyame, a urology resident at the Glickman Urological and Kidney Institute at Cleveland Clinic working with Eric A. Klein, MD, and colleagues.
“So if you look at our experience, we have a higher percentage of low-risk and very low-risk patients in our early experience that are being offered surveillance. At the same time, there were these rare patients that were a little older and a little sicker that were intermediate risk that we were offering surveillance to because we felt that the morbidity of surgery and risk of surgery outweighed the risk of prostate cancer mortality.”
About one-third of men in the intermediate-/high-risk category had a serum PSA of 10.1 to 20.0 ng/mL and an additional 6.8% had serum PSA >20.0 ng/mL. Some 57.3% of this group had Gleason 3+4 disease and 9.4% had a Gleason 4+3 pattern. More than 90% (92.3%) of the intermediate-/high-risk group group were considered intermediate risk by National Comprehensive Cancer Network (NCCN) criteria and 7.7% were NCCN high risk.
The median follow-up was 50.5 months (51.2 months in the very low-risk/low-risk cohort; 44.2 months in the intermediate-/high-risk cohort). The primary outcome was mortality and the development of metastasis.
All-cause mortality while on AS was 2.5% (16 deaths), with no prostate cancer-specific deaths, and 0.8% (4/533) developed metastatic disease. By risk category, the cumulative incidence of mortality at 5 years was 0.37% in the very low-risk/low-risk patients and 1.38% in the intermediate-/high-risk patients. The 5-year incidence of local or distant metastases was 0.15% and 0.24% in the two risk groups, respectively.
About one-third of men (35.2%) received treatment with curative intent, with a median time to treatment of 16 months. The most common primary therapy was radical prostatectomy (46.1%) followed by brachytherapy (37.1%), external beam radiation (7.8 %), and cryoablation (6.4%).
“Roughly sixty percent of the 635 men at 5 years didn’t require an operation or radiation, and that’s significant,” said Dr. Nyame. “Our data are very similar to what has been reported previously even though we had a more heterogeneous risk group, but longer follow-up is needed with our intermediate-/high-risk patients to ensure they have similar outcomes reported from the Toronto and Hopkins cohorts.”
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