Deoxyribonucleic acid ploidy of core biopsies and metastatic lymph nodes of prostate cancer patients: impact on time to progression. The European Organization for Research and Treatment of Cancer Genitourinary Group

We studied 98 patients with locally confined but lymph node positive prostatic cancer (1 stage T1, 29 stage T2, 55 stage T3 and 2 stage T4) who were not treated by radical prostatectomy. A retrospective analysis was done of deoxyribonucleic acid (DNA) ploidy of pretreatment core biopsies of the primary tumor and lymph node metastases. While DNA ploidy has been shown to be an important prognostic factor if applied to radical prostatectomy specimens, core biopsy specimens and nodal metastases have rarely been studied. Of the 98 patients 87 were evaluable for DNA ploidy: 45 (52%) had diploid, 13 (15%) had tetraploid and 29 (33%) had aneuploid tumors. The ploidy of the primary tumor and of the lymph node metastases correlated significantly with the rate of progression and interval to progression. Also, significant correlations were noted between the percentages of cells in the S phase or S plus G2 phases of the cell cycle and interval to progression. Most patients in this study are part of the European Organization for Research and Treatment of Cancer protocol 30846, a prospective randomized study of early versus delayed treatment in lymph node positive, otherwise locally confined prostate cancer. This study is ongoing. Early endocrine treatment was associated with a significantly longer interval to progression. In a Cox regression analysis of the prognostic factors involved in this study, early endocrine treatment was more important than ploidy or proliferation patterns. Stage (T category) and histopathological grade did not show a correlation with progression. Followup is still too short and the numbers of patients are too small for relevant subgroup analysis. DNA ploidy measurement by flow cytometry on archival (paraffin embedded) core biopsy and lymph node material is possible, and produces meaningful results in predicting the prognosis of prostatic cancer. Since this information can be made available before treatment decisions, its exact value in the management of locally confined prostate cancer can be determined.