DNA CONTENT AND S-PHASE FRACTION IN MALE BREAST CARCINOMAS

Eighty-five male breast carcinomas limited to the breast, diagnosed between 1958 and 1967 in Sweden, were investigated by flow cytometry using paraffin-embedded tissue. DNA ploidy and S-phase fraction (SPF) were studied in relation to lymph node status, tumour size and malignancy-grade, and with respect to clinical outcome. Median age at diagnosis was 65.5 years. Median survival time related to breast cancer was 78.7 months, and 37 patients died from the disease. Forty-nine (57.6%) carcinomas were aneuploid or had multiple stemlines. Median SPF was 8.9% for all tumours, for diploid and tetraploid (euploid) together 6.6%, and for aneuploid tumours 14.3% (p < 0.001). Ploidy was significantly related to the tumour size (p = 0.03), but no significant correlations with node status or malignancy grade were observed. In univariate survival analysis, node status, tumour size and malignancy grade predicted breast cancer mortality significantly. In a multivariate Cox's model, only node status and tumour size were independent prognostic factors. In contrast to females with breast cancer, ploidy and SPF had no significant relation to prognosis in males. This lack of predictive value of DNA analysis needs further evaluation. Studies based on extended materials are necessary to further investigate the role of DNA analysis as a predictor of outcome in male breast cancer patients.