Major Finding: Gleason scores of 7 or higher were twice as common, 44% vs. 22%, in low-risk men who delayed radical prostatectomy compared with men who passed up active surveillance for immediate surgery, but many of the delayed surgeries were ordered after Gleason score reached 7 or higher on surveillance biopsies.
Data Source: 1,120 men who were eligible for active surveillance: 772 who chose the monitoring strategy and 348 who opted for immediate radical prostatectomy.
Disclosures: The investigators and discussant disclosed no conflicts of interest.
CHICAGO — A prospective cohort study comparing immediate radical prostatectomy with delayed surgery in 1,120 men who qualified for active surveillance suggests waiting is a viable option for most patients deemed to be at low risk of developing prostate cancer.
Men in the delayed-surgery group were twice as likely to have a Gleason score of 7 or higher, reported Bruce J. Trock, Ph.D., and his coinvestigators from Johns Hopkins University, Baltimore. The delayed-surgery group also had more tumors that were not organ confined.
This appeared to be the result of selection bias, however. Many of the delayed surgeries were ordered after a surveillance biopsy showed the patient had a Gleason score of 7 or higher, explained Dr. Trock, director of the division of epidemiology at the university's Brady Urological Institute. When these men were excluded, surgical pathology was similar in the remaining men who delayed radical prostatectomy and those who opted for immediate surgery.
“So it appears that a missed high-grade tumor at [the initial] biopsy is the predominant risk in the active-surveillance cohort,” Dr. Trock said, suggesting that higher risk was confined to men who had been undergraded in their initial biopsies. The median time to delayed surgery was 23 months, he noted.
The study began in 1995 and compared 772 men in an active-surveillance cohort with 348 men who were eligible for active surveillance but instead elected to have immediate radical prostatectomy.
Eligibility for active surveillance included a prostate-specific antigen density less than 0.15 ng/mL per cc, biopsy Gleason score of 6 or less, two or fewer positive cores, and 50 % or less of any biopsy core involved with tumor.
Progression was considered to occur if the pathology of a follow-up biopsy exceeded these eligibility criteria and triggered a recommendation for treatment. Of the 772 men enrolled in the active-surveillance program, 116 (15%) have since undergone radical prostatectomy: 25 had “no trigger” indicating higher-risk disease but chose surgery anyway, 43 had a biopsy upgrade (Gleason score 7 or higher), and 48 had more than two positive cores or more than 50% of a core involved with tumor.
These 116 patients were frequency matched 1:3 with 348 men who met eligibility for active surveillance but decided on immediate radical prostatectomy.
Looking just at the men who underwent surgery, the study found that 44% of the delayed-surgery group had Gleason 7 or greater at surgery vs. 22 % of the immediate-surgery group. Non–organ confined tumors occurred in 27% of the delayed surgeries vs. 16% of the immediate surgeries.
These differences were even more pronounced when the men upgraded at a surveillance biopsy were compared with the immediate-surgery group: 76% vs. 22%, respectively, for Gleason score of 7 or higher and 34% vs. 16% for non–organ confined disease. Among 67 men who were not upgraded before delayed surgery, 25% had Gleason scores of 7 or higher and 23% had non–organ confined disease. Neither measure was significantly different from the pathology in the immediate-prostatectomy group.
The clinical translation of these findings is that about 15% of men under active surveillance undergo radical prostatectomy within 2-3 years, according to Dr. Trock. Overall, the risk of adverse pathology at radical prostatectomy is low: The chance of a high-grade Gleason score greater than or equal to 7 is 4.5 per 100 person-years, while the risk of non–organ confined pathology is 1.2 per 100 person-years.