Although active surveillance is acceptable for low-risk prostate cancers, the strategy may be risky for patients with intermediate-risk disease, according to study results presented at the Genitourinary Cancers Symposium.
In a single-institution study, Andrew Loblaw, MD, radiation oncologist at Sunnybrook Health Sciences Centre in Toronto, and colleagues observed an association between active surveillance and shorter survival among some patients with intermediate-risk disease.
“Active surveillance is a conservative management approach in which patients are followed on a routine basis, usually using digital rectal examinations, physical examinations, PSA blood tests and biopsies from time-to-time,” Loblaw said during a press conference. “I want to emphasize that the goal of the treatment of these patients is still curative, as opposed to watchful waiting, which is a palliative approach.”
Loblaw and colleagues reviewed data on 945 patients who were on active surveillance at Sunnybrook Health Sciences Centre between 1995 and 2013. The cohort included 237 patients with intermediate-risk prostate cancer.
Patients who experienced disease progression at any point were offered treatment with radiation therapy or surgery. Of those with intermediate-risk disease, more than one-third (36.3%) opted for one of those treatment approaches.
Patients with low-risk disease experienced significantly higher rates of 10-year OS (83.6% vs. 68.4%) and 15-year OS (68.8% vs. 50.3%) than those with intermediate-risk disease.
Loblaw and colleagues also observed significantly longer 10-year cause-specific survival (98.2% vs. 95.5%) and 15-year cause-specific survival (96.3% vs. 88.5%) among patients with low-risk disease. Researchers determined patients with intermediate-risk disease were 3.75 (95% CI, 1.37-10.28) times more likely to die of prostate cancer than patients with low-risk disease.
“That really surprised us,” Loblaw said. “We found that this is a very safe and reasonable approach and appropriate for low-risk patients, which aligns with guideline recommendations. But, despite the selection factors that we used in our clinic for intermediate-risk patients, we’re still seeing a greater risk of dying from prostate cancer.
“We believe that more research is needed to better identify the groups of patients that may be watched conservatively,” Loblaw said. “We believe there is a group out there, but we want to be able to … identify this group so we can do so safely.” – by Anthony SanFilippo
Musunuru HB, et al. Abstract 163. Presented at: Genitourinary Cancers Symposium; Feb. 26-28, 2015; Orlando, Florida.
Disclosure: The researchers report travel expenses from, consultant/advisory roles with and honoraria from Amgen, Astellas, AstraZeneca, Bristol-Myers Squibb, Elekta, GlaxoSmithKline, Janssen, Merck, Novartis, Paladin, Roche and Sanofi.