A Gleason score of 7 predicts a worse outcome for prostate carcinoma patients treated with radiotherapy.

BACKGROUND

In most reported surgical series, prostate carcinoma patients with a Gleason score of 7 have had worse outcomes than those with other moderately differentiated cancers. Because of variations in reporting grade and grouping Gleason scores, radiation series have conflicting results.

METHODS

Five hundred sixty-three men with clinical Stage T1-T3, N0 or Nx, M0 adenocarcinoma of the prostate and known pretreatment prostate specific (PSA) levels received external beam radiation only. The median pretreatment PSA was 10.3 ng/mL (range, 0.2-191 ng/mL). The median duration of follow-up was 42 months (range, 2-114 months). Survival without biochemical failure (bNED) was defined as PSA < or = 1.5 ng/mL and not rising when measured on two consecutive occasions.

RESULTS

The 5-year rate of bNED control for all 563 patients was 62%. Increasing Gleason score predicted for decreased bNED control (78% for 2-4, 63% for 5-6, 37% for 7, and 33% for 8-10 at 5 years; P = 0.0001 for overall comparison). The bNED control rate for patients with a Gleason score of 7 was significantly less than the rate for those with Gleason 5-6 in both univariate (P = 0.0008) and multivariate (P = 0.0068) analysis. T classification by palpation, pretreatment PSA, and dose were also shown to be independent predictors of bNED control in multivariate analysis.

CONCLUSIONS

Even after adjustment for other known prognostic factors, a Gleason score of 7 was associated with worse bNED control than Gleason scores of 2-4 and 5-6 among patients treated with external beam radiotherapy only for clinically localized prostate carcinoma. Patients with a Gleason score of 7 should not be lumped together with those who have a Gleason score of 5-6; they may instead benefit from more aggressive treatment strategies.