The following article features coverage from the American Urological Association (AUA) 2019 meeting. Click here to read more of Renal & Urology News’ conference coverage.

CHICAGO—Almost half of patients with clinical Gleason Score 8/Grade Group 4 (cGG4) prostate cancer (PCa) diagnosed on transrectal prostate biopsy experience pathologic Gleason Score downgrading at radical prostatectomy (RP), according to a study presented at the 2019 American Urological Association annual meeting. In addition, researchers identified biopsy-based risk factors that can predict the likelihood of downgrading.

“If these risk factors for downgrading are validated, they can be used to tailor patient counseling regarding risk of truly having Gleason 8 disease versus less significant PCa,” lead investigator Vignesh T. Packiam, MD, a urologic oncology fellow at Mayo Clinic in Rochester, Minnesota, told Renal & Urology News.

Dr. Packiam and his collaborators identified 244 men with cGG4 PCa who underwent RP from 2006 to 2017. Pathologic examination of RP specimens resulted in the downgrading of 118 (48%) patients. Of these, 73 were pathologically downgraded to GG3, 42 to GG2, and 3 to GG1.

Downgraded patients were significantly more likely to have a lower percent GG4 cores in the total (23% vs 37%) and positive (58% vs 80%) cores than patients not downgraded, Dr. Packiam’s team reported in a poster presentation. Increasing number of cores of GG4 was associated with decreased odds of downgrading. On multivariable analysis, each additional GG4 core was significantly associated with 15% decreased odds of downgrading, whereas each additional GG1-GG3 core was significantly associated with 17% increased odds of downgrading.

The median follow-up duration among survivors was 5.8 years. Downgraded patients had significantly improved oncologic outcomes, including 10-year biochemical recurrence-free (66% vs. 29%), systemic progression-free (75% vs 51%), and PCa-specific (97% vs. 84%), and overall survival (86% vs 74%).

Dr. Packiam noted that characterization of risk factors for pathologic downgrading of cGG4 disease potentially can allow patients to be managed with intermediate-risk radiation therapy/androgen deprivation therapy (ADT) protocols. For example, Dr. Packiam said a patient with risk factors for downgrading may benefit from 4–6 months of ADT (intermediate-risk protocol) rather than 18–36 months of ADT (high-risk protocol). However, this approach would require prospective validation,

Read more of Renal & Urology News’ coverage of the AUA 2019 meeting by visiting the conference page.

Reference

Packiam VT, Boorjian SA, Tsivian M, et al. Contemporary incidence and predictors of downgrading for Gleason 8 prostate cancer: Implications for risk classification and treatment. Presented at the 2019 American Urological Association annual meeting held May 3-6 in Chicago. Abstract MP09-11.