Factors associated with downgrading in patients with high grade prostate cancer

To determine the factors associated with downgrading between biopsy and prostatectomy in the contemporary era using extended-template biopsy techniques.

The UCSF Urologic Oncology Database was used to identify subjects diagnosed with high grade prostate cancer (primary pattern 4 or 5) in at least one core on extended-pattern biopsy. Multivariable logistic regression analysis was performed to identify independent factors associated with downgrading at radical prostatectomy, defined as a change from primary pattern 4 or 5 to primary pattern 3.

Downgrading occurred in 68 (34%) of 202 subjects who met the study criteria. Fourteen (47%) of 30 subjects with ≤25% of cores that were high grade and 9 (43%) of 21 subjects with <10% of total tissue containing cancer were downgraded. In a multivariable model, patients with mixed grade cores had much higher odds of downgrading than those with all high grade cores (OR 3.0 95% 1.3-7.1), P < 0.01). The proportion (per 10% increment) of positive cores containing high grade cancer (OR 0.8 95% CI 0.7-0.9 P < 0.01) and the percent (per 10% increment) of total tissue containing cancer (OR 0.7 95% CI 0.6-0.9 P = 0.01) were significantly associated with lower odds of downgrading.

Downgrading following radical prostatectomy is a common event. Biopsy over-grading may preclude men from active surveillance or lead to unnecessary lymphadenectomy, excess radiation, or prolonged hormone therapy. The proportion of positive biopsy cores that are high grade and the percent of total tissue containing cancer should be incorporated into decision making.