Comparable recurrence risk for MRI-detected Gleason Grade Group (GG) 2 and systematic biopsy-detected GG1 prostate cancer.

Abstract

To determine the likelihood of definitive treatment and risk of post-treatment recurrence for patients with Gleason Grade Group (GG) 2 cancer diagnosed using targeted biopsies relative to men with GG1 cancer diagnosed using systematic biopsies. We performed a retrospective study using a large tertiary centre registry (the HUS Acamedic data lake) to retrieve data on prostate cancer (PCa) diagnosis, treatment, and cancer recurrence. We included patients with either GG1 PCa detected by systematic biopsies (n = 3317) or GG2 PCa detected with targeted biopsies (n = 554) between 1993 and 2019. We assessed the risk of curative treatment and recurrence after treatment. Kaplan-Meier curves were used to estimate treatment- and recurrence-free survival, and Cox proportional hazards regression was used to evaluate the risk of post-treatment recurrence. Patients with systematic biopsy-detected GG1 cancer had a significantly longer median time to treatment (31 months) than those with targeted biopsy-detected GG2 cancer (4 months; P < 0.0001). Risk of recurrence after curative treatment was similar in the two groups, with the upper bound of the 95% confidence interval (CI) excluding any significant difference (hazard ratio 1.04, 95% CI 0.75-1.43; P = 0.83). Men diagnosed with GG2 PCa based on MRI-targeted biopsy had a similar risk of recurrence after treatment compared to men with GG1 disease diagnosed using systematic biopsy, although they were more likely to undergo curative treatment. These findings suggest that at least a portion of the apparent increase in GG2 diagnoses in the MRI era may reflect reclassification rather than more aggressive disease. Improved risk stratification is needed to identify which men with MRI-era GG2 cancer may be suitable for active surveillance.