[The clinical usefulness of flow cytometric DNA analysis in prostatic cancer]

Flow cytometry was used to measure the DNA content in archival paraffin-embedded prostatic cancer specimens from 54 patients with known outcomes. The specimens were obtained by transurethral resection of the prostate. DNA ploidy as a predictor of prognosis was compared with histological grade and clinical stage. Although no significant correlation between histological grade or clinical stage and ploidy pattern was demonstrated, an increased percentage of DNA aneuploid tumors was seen in higher histological grade and in advanced clinical stage. The survival rate calculated by Kaplan-Meier analysis showed that DNA ploidy pattern was a more reliable indicator to predict survival probability than histological grade or clinical stage. All patients with a near diploid pattern (11 patients) survived more than 5 years, whereas all those with an aneuploid pattern (21 patients) died within 3.5 years. Of 22 patients with a tetraploid pattern, 15 died of tumor progression within 5 years. The remaining 7 patients with favorable outcome had a relatively lower proliferation index (less than 65) in DNA histogram and none of them suffered from stage D disease. In conclusion, the results from this retrospective study suggest that flow cytometric DNA analysis in prostatic cancer would be useful as a means of providing prognostic information.