Long-term follow-up of conservatively managed incidental carcinoma of the prostate: a multivariate analysis of prognostic factors

Abstract

Objective: To evaluate the disease-specific mortality of conservatively managed incidental carcinoma of the prostate (T1a and T1b) in relation to prognostic factors.

Material and methods: Since 1987 all patients with prostate cancer have been recorded and followed in the population-based Prostate Cancer Register of the South-East Healthcare Region in Sweden, which is covered by four departments of pathology. At two of these departments, tissue was obtained from 197 consecutive, previously untreated patients (aged <80 years) with incidental carcinoma who underwent transurethral resection of the prostate between 1987 and 1991. The amount of tumour, Gleason score and levels of Ki-67, p53, chromogranin A and serotonin were determined. Univariate analysis and multiple Cox regression hazard analysis were used for analysis.

Results: During follow-up (mean 7.8 years; maximum 17.5 years), 158 patients (80%) had died, 33 of them of prostate cancer, corresponding to 17% of the entire cohort. Of 86 patients with Gleason score < or =5, three died of prostate cancer. Independent predictors of disease-specific mortality in multivariate analysis were category T1b prostate cancer, Gleason score >5 and high immunoreactivity of Ki-67.

Conclusions: Elderly men with category T1a and/or Gleason score 4-5 prostate cancer have a favourable prognosis with conservative management. Immunohistochemical staining with Ki-67 may be of help in situations where further prognostic information is required.