CYTOFLUOROMETRIC EVALUATION OF NUCLEAR-DNA CONTENT DISTRIBUTION IN RENAL NEOPLASMS TREATED BY CONSERVATIVE SURGERY

The prognostic value of nuclear DNA content in 21 patients who underwe nt conservative surgery for renal tumors was the object of a retrospec tive study. Cytofluorometric evaluation of nuclear DNA content distrib ution was performed on smears obtained from 50-mu m thick histologic s ections prepared with the Hedley technique, using a Leitz MPVII micros pectrophotometer. The DNA indexes were plotted in the form of frequenc y histograms. DNA measurements were repeated by a cell image analysis system (CAS 200; Becton Dickinson) in 16/21 cases. Nuclear DNA content was diploid in 12 cases, triploid in 4, tetraploid in 2 and multiclon al in 3. No statistically significant correlation was found between pl oidy and tumor stage and size, using Kendall's tau test, while there w as a significant correlation between tumor ploidy and nuclear grade (p < 0.01). Excluding 2 postoperative deaths, with an average follow-up of 54 months, tumor diffusion was observed in 2 patients (1 with multi clonal and 1 with triploid DNA content) and a local recurrence in a pa tient with a triploid tumor. Of the remaining 16 no evidence of diseas e (NED) cases, 10 have a diploid DNA tumor content, 2 diploid, 2 tetra ploid and 2 multiclonal. It is concluded that even after conservative surgery for renal neoplasms a diploid DNA content is a favorable progn ostic factor. A completely negative prognostic impact of nondiploid tu mors is not confirmed, since although all three negative events occurr ed in this group, there are also 4 NED patients with respectively 70, 46, 43 and 40 months' follow-up.