If you are diagnosed with low-risk prostate cancer and your doctor says you are a candidate for active surveillance (AS), how can you be sure? This is a crucial question, and a new study from a German-Canadian team adds important information for patients to consider before choosing AS.[i]
The authors began by identifying a cohort of 1,331 men classified as low-risk patients based on the D’Amico classification (PSA ? 10, Gleason score ? 6, and clinical stage T1-2a). Out of this population, 825 men (62%) were further determined to be candidates for AS based on the following criteria:
- PSA ? 10ng/mL
- Gleason score ? 3+3
- ? 2 positive biopsy cores
- ? 50% tumor content per core
- ? clinical stage T1-2a
All had radical prostatectomy (RP) between 2008-13. There were two study end points: a) the presence of intermediate- or high-risk characteristics (Gleason ?3+4 or ? stage T3), or b) the exclusive presence of high-risk characteristics (Gleason ?4+4 or ?pT3 or N1) based on RP specimens (histopathology). In other words, once they knew the final pathology results, the researchers could compare the initial classification of all 1,331 men—especially the AS candidates—with the PCa that was actually found after RP. Many of the patients were upgraded or upstaged, based on their RP results.
|Upgraded||Upstaged||Had intermediate or high risk PCa||Had exclusive high risk PCa|
The team analyzed the men’s pre-RP clinical factors to calculate the greatest predictors for upgrading or upstaging. They found that in all cases the most powerful predictor was the percent of biopsy core positive for PCa (greater than 50%). For patients found to have either intermediate or high risk PCa, the additional independent predictors were number of positive cores, PSA, and age. For those found to have exclusively high-risk PCa, involvement per core and PSA values were independent predictors.
The authors concluded that while non-AS candidates were at higher risk for either upgrading or upstaging at final pathology (post-RP), tumor involvement greater than 50% per core was the strongest predictor of adverse pathology. “Therefore,” they wrote, “D’Amico low-risk criteria are not safe enough to identify AS candidates.” For me, this study makes a compelling case for the importance of having a 3T multiparametric MRI before opting for AS. The visual detection of PCa can help determine the size, location and extent of a tumor. In addition, an MRI-targeted biopsy offers the greatest likelihood of accurate Gleason diagnosis. Why take chances with going on AS when there could be undetected aggressive disease? 3T mpMRI can make the difference between a gamble and peace of mind.
[i] Schiffmann J, Wenzel P, Salomon G et al. Heterogeneity in D?Amico classification-based low-risk prostate cancer: Differences in upgrading and upstaging according to active surveillance eligibility. Urol Oncol. 2015 Jul;33(7):329.13-19.