Prognostic factors for survival of patients with pathological Gleason score 7 prostate cancer: differences in outcome between primary Gleason grades 3 and 4

Abstract

Purpose: We evaluated differences in clinical and pathological outcomes between Gleason 3 + 4 and 4 + 3 prostate cancer.

Materials and methods: The radical prostatectomy whole mounted specimens from 263 men with pathological Gleason 7 tumors were identified. Gleason 3 + 4 and 4 + 3 tumors were compared in regard to pathological variables and outcome. Significance of clinical and pathological data on progression-free survival was analyzed.

Results: Of the tumors 34% had a primary Gleason grade of 4, and were more likely than those with primary grade 3 to have seminal vesicle involvement (34% versus 18%, p = 0.006), a higher pathological stage (pT3 55% versus 42%, N+ 13% versus 3%, 0.001), extraprostatic extension (58% versus 38%, 0.001) and higher median preoperative prostate specific antigen (PSA) (13.5 versus 9.0 ng./ml., respectively <0.001). Mean followup plus or minus standard deviation was 6.8 +/- 1.9 years. The overall 10-year crude, cancer specific and progression-free survival rates were 83%, 99% and 58%, respectively. Primary Gleason grade was significantly associated with progression-free (risk ratio 1.6, 95% confidence interval 1.08 to 2.5, p = 0.02) but not crude and cancer-specific survival. Univariately, primary Gleason grade 4 was associated with progression-free survival, as were percent Gleason 4, seminal vesicle invasion, lymph node involvement, pT stage, margin status, DNA ploidy, preoperative PSA, cancer volume and extent of extraprostatic extension. Multivariately, only preoperative PSA (p <0.001), seminal vesicle invasion (<0.001) and DNA ploidy (0.002) were associated with progression-free survival. Primary Gleason grade and percent Gleason 4 were not identified as independently associated with progression-free survival.

Conclusions: In patients with Gleason 7 score prostate cancer primary Gleason grade 3 and 4 cancers are different in pathological parameters and prognosis. However, primary Gleason grade does not provide any additional information than other known prognostic factors, such as preoperative PSA, seminal vesicle invasion and DNA ploidy.