THE IMPORTANCE OF HETEROGENEITY AND OF MULTIPLE SITE SAMPLING IN THE PROSPECTIVE DETERMINATION OF DEOXYRIBONUCLEIC-ACID FLOW-CYTOMETRY

Multiple fresh specimens from 59 nonsmall cell carcinomas of the lung, 38 carcinomas of the gastric tract and 55 carcinomas of the colon and rectum were analyzed by deoxyribonucleic acid (DNA) flow cytometry (F C) after radical resection to evaluate tumor ploidy as an independent prognostic factor. The minimum follow-up period was five years (range of five to ten years). Aneuploidy was observed in 98.0 percent of carc inomas of the lung, in 70.9 percent of carcinomas of the colon and rec tum and in 63.1 percent of carcinomas of the gastric tract. FC DNA het erogeneity, in terms of different number of DNA stem lines or differen t DNA indices between core and periphery, or both, was found in 50.0 p ercent of carcinomas of the lung, 47.0 percent of carcinomas of the co lon and rectum and in 34.5 percent of carcinomas of the gastric tract. A diploid pattern was more frequently observed in less advanced stage s of the gastrointestinal tract. By univariate analysis (Kaplan-Meier) , patients with carcinoma of the lung with hypodiploid or hypertetrapl oid peaks, or both, and aneuploid gastric tumors had poorer prognosis. These differences were only marginally significant. Cox analysis demo nstrated that the single most important prognostic variable for predic ting die overall survival rate was the stage of disease. Tumor DNA con tent can be considered a marker of advanced stages, particularly in tu mors of the gastrointestinal tract, but there is no evidence that it i s an independent prognostic variable able to predict long term surviva l in patients who have been radically resected.