Men who undergo MRI of the prostate around the time of a low-risk prostate cancer diagnosis are nearly twice as likely to be managed with active surveillance as are men who do not get MRI, investigators found.
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The findings suggest that MRI at the time of diagnosis can enhance patient and physician confidence in the decision to choose active surveillance (AS) over immediate surgery or radiation therapy in men with low-risk disease, according to Michael S. Leapman, MD, and his colleagues from Yale University, New Haven, Conn.
“Despite initial high costs associated with obtaining and interpreting MRI studies of the prostate, economic modeling studies imply that MRI would be cost effective if it resulted in increased utilization of AS for low- and very-low-risk PCa [prostate cancer]. The association identified in our study between MRI use and initial observation may serve as an informative basis for examining strategies to improve the quality of PCa care with the anticipated growing use of this technology,” they wrote in Urology.
Although active surveillance is increasingly accepted as an initial management strategy for patients with low-risk (Gleason score 6 or less) localized prostate cancer, the majority of patients with low-risk disease still receive definitive treatment.
“Although longitudinal studies support the safety of AS, uncertainty about the possibility of underestimating an indvidual’s risk of harboring aggressive disease remains a strong motivator to treat,” Dr. Leapman and his associates noted.
To see whether MRI of the prostate may have an effect on the use of active surveillance in men with low-risk disease, the investigators reviewed records from the Surveillance, Epidemiology and End Results (SEER) Medicare database to identify men diagnosed with low-risk prostate cancer during 2010-2013.
They looked at the association between MRI and patient management (ascertained by claims) and evaluated clinical and demographic factors associated with the receipt of MRI.
They identified 8,144 patients with low-risk prostate cancer during the study period, of whom 495 (6.1%) had undergone MRI scans. They found that the use of MRI in patients with low-risk cancer increased from 3.4% in 2010 to 10.5% in 2013.
MRI was performed significantly more frequently among 3,060 patients who were managed with observation, with 265 (8.7%) receiving scans, compared with 230 (4.5%) of the 5,084 patients who underwent treatment within a year of diagnosis.
In multivariable analysis that controlled for demographics, factors significantly associated with increased likelihood of undergoing observation versus definitive therapy included MRI, white vs. nonwhite race, later years of diagnosis, higher income status (by ZIP code), unmarried vs. married, treatment region (more common in the West and Midwest versus Northeast or South), and in referral regions with higher population density of urologists.
In a propensity score–matched analysis designed to smooth out potential confounders, the investigators found that receipt of MRI around the time of diagnosis was associated with a significantly higher likelihood of active surveillance, with an odds ratio of 1.90 (95% confidence interval, 1.56-2.32).
“Efforts to facilitate observational approaches for low-risk PCa are highly valuable to improving the quality of cancer care. Because the use of prostate MRI has grown, and is likely to continue expanding, the cost-effectiveness of MRI-driven pathways are increasingly relevant to the sustainability of the practice,” the authors wrote.
SOURCE: Leapman MS et al. Urology. 2018 Aug 11. doi: 10.1016/j.urology.2018.07.041.