Prostatic carcinoma cell DNA content measured by flow cytometry and its relation to clinical outcome.

DNA content of prostate tumour cells has been measured by flow cytometry of cell suspensions prepared from fixed tissue by an enzyme disaggregation technique. Two classes of tumours have been identified: diploid tumours, with a DNA content similar to benign cells and aneuploid tumours with grossly abnormal DNA values. The prognosis for the aneuploid tumours was significantly worse than diploid tumours (P less than 0.001). When ploidy is combined with histological grading, here using the Gleason numerical system, it is possible to predict which patients, whatever their age at diagnosis, will die from their tumour and which patients will probably die before their tumour kills them. With these facts it is possible to select patients for active or expectant treatment.