Investigators at the University of California, Los Angeles, report that surgical overtreatment of prostate cancer (PCa) at their institution is in decline.
Decreased rates of overdiagnosis, better patient selection for surgery, or change in referral pattern may be among the reasons for the trend, according to Amirali Salmasi, MD, MS, of the David Geffin School of Medicine at UCLA and colleagues.
In a review of 1283 men who underwent radical prostatectomy (RP), Dr Salmasi’s team found that the frequency of overtreatment—defined as the presence of insignificant PCa in RP specimens—decreased significantly from 15% in 2009 to 3% in 2016, according to a paper published online ahead of print in Urologic Oncology.
The investigators defined insignificant PCa as a tumor with a Gleason score no higher than 6 and a tumor diameter of 10 mm or less as a surrogate for tumor volume less than 0.5 cc. The odds of overtreatment decreased by a significant 12% annually during the study period.
On multivariable analysis, patients with a PSA density of 0.15 or greater had significant 70% decreased odds of insignificant PCa than those with a PSA density below 0.15. A biopsy Gleason score of 3+4 was associated with significant 85% decreased odds of insignificant PCa compared with a score of 3+3.
In addition, the study showed that black patients had significant 87% decreased odds of insignificant PCa compared with white men. The authors commented that “it is difficult to parse out the exact reasons for this finding, but it may be due to inherent biology, access to care or other unknown reasons.”
Results also showed that pathologic evidence of advanced disease at the time of surgery (T3a or higher with or without lymph node involvement) remained unchanged, according to the investigators. The incidence of advanced disease was 33% in 2009 and 37% in 2016.
The authors concluded that surgical overtreatment of insignificant PCa “has declined in a long-term trend that appears to be maintained.” Dr Salmasi’s team said the decline probably has a multifactorial explanation. The decrease in overtreatment may reflect lower rates of overdiagnosis of early-stage PCa.
Another possibility is improved risk stratification and patient selection for surgery. The investigators pointed out that the proportion of patients with biopsy-proven Gleason score 3+3 cancer who underwent RP decreased from 52% in 2009 to 13% in 2016. The decreased rate of surgical overtreatment also could be due to improved risk stratification using multi-parametric magnetic resonance imaging and genomic testing. “It also is likely that changes in the referral pattern to our tertiary centers may have influenced our surgical cohort in that more advanced patients are likely to be referred to our center.”
Salmasi A, Faiena I, Wu J, et al. Radical prostatectomy then and now: Surgical overtreatment of prostate cancer is declining from 2009 to 2016 at a tertiary referral center. Urol Oncol. 2018; published online ahead of print.