Is clinical stage T2c prostate cancer intermediate- or high-risk disease? Results from the SEARCH database.

Abstract

123 Background: Clinical stage T2c is a nebulous factor in the algorithm for prostate cancer risk stratification. According to D’Amico risk stratification cT2c is high-risk category where NCCN guidelines place this stage in intermediate-risk. As diagnostic work up with the use of MRI continues to escalate clinical staging may become more important. As cT2c represents a possible decision fork in treatment decisions we sought to investigate which risk group the clinical behavior of cT2c tumors more closely resembles. Methods: We retrospectively analyzed data from 1089 men who underwent radical prostatectomy (RP) from 1988 to 2009 who did not have low-risk CaP from the SEARCH database. We compared time to BCR between men with cT2c disease, those with intermediate-risk (PSA 10-20 ng/ml or Gleason sum (GS) =7), and those with high-risk (PSA>20 ng/ml, GS 8-10, cT3) using Cox regression models adjusting for age, race, year of RP, center, and percent cores positive. We also compared predictive accuracy of two Cox models wherein cT2c was considered either intermediate- or high-risk by calculating concordance index c. Results: A total of 68 men (3.4%) had cT2c tumors. After a median follow-up of 47.5 months, there was no difference in BCR risk between men with intermediate-risk CaP and those with cT2c tumors (HR=0.90; p=0.60). In contrast, there was a trend for men with high-risk CaP to have nearly 50% increased BCR risk compared to men with cT2c tumors (HR=1.50; 95% CI=0.97-2.30; p=0.07) which did not reach statistical significance. Concordance index c was higher in the Cox model wherein cT2c tumors were considered intermediate-risk (c=0.6147) as opposed to high-risk (c=0.6106). Conclusions: BCR risk for patients with clinical stage T2c was more comparable to men who had intermediate-risk CaP than men with high-risk. In addition, a model which incorporates cT2c disease as intermediate-risk has better predictive accuracy. These findings suggest men with cT2c disease should be offered treatment options for men with intermediate-risk CaP. As clinical staging more routinely incorporates MRI there is the potential to better identify bilateral organ-confined CaP and further establish risk classification.