Pathological Gleason grade group 1 in Black men — implications for renaming it “not cancer” in high-risk populations
Evan Kovac1, Courtney Berg1, Matthew DeMasi2, Amjad Alwaal1, Robert Weiss1.
1Division of Urology, Rutgers New Jersey Medical School, Newark, NJ, United States; 2Division of Urology, Case Western Reserve University, Cleveland, OH, United States
Introduction: Many have suggested reclassifying Gleason grade group 1 (GG1) as “not cancer;”1-3 however, the metastatic potential of pathological (p) GG1 has not been widely studied in high-risk men. Thus, we sought to compare features of pGG1 prostate cancer (PCa) in Black and White men.
Methods: The National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) database was queried to identify all White and Black men who underwent primary radical prostatectomy (RP) with pelvic lymph node dissections (PLND) from 2006–2016. Patients were pathologically staged according to the American Joint Committee on Cancer’s 7th edition (2010) and assigned a Gleason score in accordance with the 2005 International Society of Urological Pathology (ISUP) grading system. Rates of pT3a, pT3b, pT4, pN1, and clinical M+ disease were calculated. Other variables analyzed included prostate-specific antigen (PSA) at diagnosis, age, and year of RP. Non-parametric testing was used to compare differences between White and Black men. Patients with incomplete grading or staging information were excluded.
Results: We identified 27 367 men (21 223 White and 6143 Black) who underwent RP and PLND from 2006–2016 with pGG1 PCa. The median age range was 60–64 years and 55–59 years for White and Black men, respectively. The median PSA at diagnosis was 5.1 (interquartile range [IQR] 4–6.8) and 5.2 (IQR 4.2–7.2) for White and Black men, respectively. Rates of pT3a, pT3b, and T4 in White men were 4.4%, 0.5%, and 0.07%, respectively, compared to 4.5%, 1.3%, and 0.5% for Black men, respectively. Rates of T3b and T4 were statistically higher in Black men (p<0.01 for both). Rates of pN1 and M+ were exceedingly low in both groups and were not statistically different (Table 1).
Conclusions: Black men with pGG1 PCa have low but statistically higher rates of locally advanced disease when compared to White men. Metastatic rates are exceedingly low and similar between the groups. Renaming GG1 to “not cancer” in high-risk populations is, therefore, controversial. This study is limited by the inability to conduct pathological and metastatic staging review, especially in cases where undergrading or overstaging are suspected.
[1] Anderson BB, Oberlin DT, Razmaria AA, et al. Extraprostatic Extension Is Extremely Rare for Contemporary Gleason Score 6 Prostate Cancer. Eur Urol. 2017 Sep;72(3):455-460.
[2] Hassan O, Han M, Zhou A, et al. Incidence of Extraprostatic Extension at Radical Prostatectomy with Pure Gleason Score 3 + 3 = 6 (Grade Group 1) Cancer: Implications for Whether Gleason Score 6 Prostate Cancer Should be Renamed "Not Cancer" and for Selection Criteria for Active Surveillance. J Urol. 2018 Jun;199(6):1482-1487.
[3] Ross HM, Kryvenko ON, Cowan JE, et al. Do adenocarcinomas of the prostate with Gleason score (GS) ≤6 have the potential to metastasize to lymph nodes? Am J Surg Pathol. 2012 Sep;36(9):1346-52.
