Follow-up of localized prostate cancer, with emphasis on previous undiagnosed incidental cancer

To determine the natural course of incidental untreated transition zone prostate cancer and thus help to identify criteria to predict the prognosis and to determine treatment for individual patients.

A total of 1135 unselected surgical specimens of the prostate, examined during 1974 and 1975, were reviewed while unaware of case by two experienced pathologists. The patients from which the samples were obtained were followed for up to 20 years or death by The Cancer Registry of Norway and the outcome compared with the histological review.

The histology review revealed a total of 311 cancers, of which 73 had not been initially recorded; these patients had received no treatment. The kappa coefficient for interobserver reproducibility was 0.86 for carcinoma. The follow-up showed that patient age was the strongest predictor of survival, followed by histological grade and percentage of tumour involvement. Only two of the 73 patients with untreated transition zone cancer died from prostate cancer during the follow-up, compared with 78 of 144 patients with standard management of transition zone tumours. The 5- and 10-year relative survival rates for the 144 patients with standard management of transitional zone tumours and for the 53 patients with peripheral zone tumours were 56% and 26%, and 45% and 33%, respectively. Metastasis (+ or -) was the only individual prognostic factor in the multivariate analysis.

This study shows that patients with incidental low-grade tumours have a low probability of dying from prostate cancer and may thus be followed expectantly. The biological distinction between atypical hyperplasia and stage T1a cancer is unclear. The survival of men with prostate cancer is significantly reduced with loss of differentiation and with increasing tumour volvement.