Risk of Cancer-related Death for Men with Biopsy Grade Group 1 Prostate Cancer and High-risk Features: A European Multi-institutional Study

International Society of Urological Pathology grade group 1 (GG 1) prostate cancer (PCa) is generally considered insignificant, with recent suggestions that it should even be considered as "noncancerous". We evaluated outcomes for patients with GG 1 PCa on biopsy (bGG 1) and high-risk features (prostate-specific antigen [PSA] >20 ng/ml and/or cT3-4 stage) to challenge the hypothesis that every case of bGG 1 PCa has a benign disease course. We used the multi-institutional EMPaCT database, which includes data for 9508 patients with high-risk PCa undergoing surgery. We included patients with bGG 1 PCa (n = 848) in our analysis and divided them into three groups according to PSA >20 ng/ml, cT3-4 stage, or both. The estimated 10-yr cancer-specific survival (CSS) rate was 96% in the overall population, 88% in the group with both PSA >20 ng/ml and cT3-4 stage, 97% in the group with PSA >20 ng/ml alone, and 98% in the group with cT3-4 stage alone. Similar CSS outcomes were found in subgroups with GG 1 PCa on pathology (n = 502) and with GG 1 on biopsy diagnosed after 2005 (n = 253). Study limitations include the lack of magnetic resonance imaging (MRI) staging and MRI-targeted biopsies. In conclusion, patients with GG 1 and either PSA >20 ng/ml or cT3-4 stage have a low risk of dying from their cancer after surgery. However, patients with GG 1 PCa and both PSA >20 ng/ml and cT3-4 stage are at higher risk of cancer-specific mortality and active treatment should be discussed for this subgroup.

Patient summary: We assessed outcomes for patients diagnosed with low-grade prostate cancer on biopsy who also had one or two factors associated with high risk disease. Men with both of those risk factors had a higher risk of dying from their prostate cancer. Active treatment should be discussed for this subgroup of patients.