Clinical outcome comparison of Grade Group 1 and Grade Group 2 prostate cancer with and without cribriform architecture at the time of radical prostatectomy.

Aims: Invasive cribriform and intraductal carcinoma are associated with aggressive disease in Grade Group 2 (GG2) prostate cancer patients. However, the characteristics and clinical outcome of patients with GG2 prostate cancer without cribriform architecture (GG2-) as compared with those with Grade Group 1 (GG1) prostate cancer are unknown. The aim of this study was to investigate the clinical and pathological characteristics of GG1 and GG2- prostate cancer in radical prostatectomy specimens.

Methods And Results: We reviewed 835 radical prostatectomy specimens for Grade Group, pT stage, surgical margin status, and the presence of cribriform architecture. Biochemical recurrence-free survival and metastasis were used as clinical outcomes. GG1 prostate cancer was seen in 207 patients, and GG2 prostate cancer was seen in 420 patients, of whom 228 (54%) showed cribriform architecture (GG2+) and 192 (46%) did not. GG2- patients had higher prostate-specific antigen levels (9.4 ng/ml versus 7.0 ng/ml; P < 0.001), more often had extraprostatic extension (36% versus 11%; P < 0.001) and had more positive surgical margins (27% versus 17%; P = 0.01) than GG1 patients. GG2- patients had shorter biochemical recurrence-free survival (hazard ratio 2.7, 95% confidence interval 1.4-4.9; P = 0.002) than GG1 patients. Lymph node and distant metastasis were observed neither in GG2- nor in GG1 patients, but occurred in 22 of 228 (10%) GG2+ patients.

Conclusion: In conclusion, patients with GG2- prostate cancer at radical prostatectomy have more advanced disease and shorter biochemical recurrence-free survival than those with GG1 prostate cancer, but both groups have a very low risk of developing metastasis.