Role of Surveillance Biopsy with No Cancer as a Prognostic Marker for Reclassification: Results from the Canary Prostate Active Surveillance Study.

BACKGROUND

Many patients who are on active surveillance (AS) for prostate cancer will have surveillance prostate needle biopsies (PNBs) without any cancer evident.

OBJECTIVE

To define the association between negative surveillance PNBs and risk of reclassification on AS.

DESIGN, SETTING, AND PARTICIPANTS: All men were enrolled in the Canary Prostate Active Surveillance Study (PASS) between 2008 and 2016. Men were included if they had Gleason ≤3+4 prostate cancer and <34% core involvement ratio at diagnosis. Men were prescribed surveillance PNBs at 12 and 24 mo after diagnosis and then every 24 mo.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Reclassification was defined as an increase in Gleason grade and/or an increase in the ratio of biopsy cores to cancer to ≥34%. PNB outcomes were defined as follows: (1) no cancer on biopsy, (2) cancer without reclassification, or (3) reclassification. Kaplan-Meier and Cox proportional hazard models were performed to assess the risk of reclassification.

RESULTS AND LIMITATIONS

A total of 657 men met inclusion criteria. On first surveillance PNB, 214 (32%) had no cancer, 282 (43%) had cancer but no reclassification, and 161 (25%) reclassified. Among those who did not reclassify, 313 had a second PNB. On second PNB, 120 (38%) had no cancer, 139 (44%) had cancer but no reclassification, and 54 (17%) reclassified. In a multivariable analysis, significant predictors of decreased future reclassification after the first PNB were no cancer on PNB (hazard ratio [HR]=0.50, p=0.008), lower serum prostate-specific antigen, larger prostate size, and lower body mass index. A finding of no cancer on the second PNB was also associated with significantly decreased future reclassification in a multivariable analysis (HR=0.15, p=0.003), regardless of the first PNB result. The major limitation of this study is a relatively small number of patients with long-term follow-up.

CONCLUSIONS

Men who have a surveillance PNB with no evidence of cancer are significantly less likely to reclassify on AS in the PASS cohort. These findings have implications for tailoring AS protocols.

PATIENT SUMMARY

Men on active surveillance for prostate cancer who have a biopsy showing no cancer are at a decreased risk of having worse disease in the future. This may have an impact on how frequently biopsies are required to be performed in the future.