DNA AND S-PHASE FRACTION ANALYSIS BY FLOW-CYTOMETRY IN PROSTATE-CANCER - CLINICOPATHOLOGICAL IMPLICATIONS

Background. Available prognostic factors for prostate cancer have not been proven consistently useful. The authors evaluated the prognostic value of DNA analysis by flow cytometry (FCM) in prostate cancer. Methods. Paraffin-embedded tumor specimens taken at tru-cut biopsy or transurethral resection (TURP) from 81 patients with prostate cancer were analyzed for DNA content and S-phase fraction (SPF) by FCM according to the method of Hedley et al (1983). Results. Thirty-five of the 63 (55.5%) evaluable DNA histograms had a diploid pattern, 18 (28.5%) a distinct aneuploid peak, and 10 (16%) a tetraploid pattern. An association was established between DNA ploidy abnormalities and Gleason score (P < 0.04) or presence of metastases at diagnosis (P < 0.0002). At Kaplan-Meier analysis, overall survival was significantly longer (P < 0.0002) in patients with diploid than in those with nondiploid tumors. Among patients with different risk categories, i.e. tumor size, Gleason score, and metastases at presentation, ploidy improved the detection of patients with poorer survival, with the exception of those with T1-T2 tumors. Cox regression analysis showed that ploidy was significantly related to survival. Bivariate models containing ploidy and SPF or Gleason score had a predictive value similar to that including all variables. Conclusion. The study data show that DNA ploidy provides additional prognostic information in patients with locally advanced or metastatic prostatic cancer. The role of SPF remains to be established.