Is DNA ploidy and proliferative activity of prognostic value in advanced gastric carcinoma?

We analyzed the DNA content of 116 gastric carcinomas and lymph node metastasis in 53 of these using flow cytometry on archival material. DNA index and proliferative activity (% S-phase) values were obtained in 111 and 76 tumors, respectively, and survival rates were obtained for 108. Tumor classification was based on histologic type, grade, and growth pattern and stage. All were advanced gastric carcinomas. Fifty four tumors (47%) were aneuploid. In single variable analysis, survival was related to stage (muscularis propria versus serosa P = .002) and lymph node metastasis (P = .04). Infiltrative tumor growth had a slightly worse prognosis (P = .06). In multifactorial analysis, tumor stage was the only independent prognostic factor. Neither DNA ploidy nor % S-phase values had any effect on survival, although, patients with tumors with higher DNA indexes (greater than 1.7) showed a tendency toward worse survival rates. We failed to prove the prognostic value of DNA ploidy in gastric carcinoma. Before its effect is ruled out, some factors have to be considered: (1) all tumors were in advanced stage and the true effect of ploidy on survival may have been diluted, (2) quality of fixation--near diploid aneuploid populations may have been overlooked, and (3) intratumoral DNA ploidy heterogeneity can cause sample discrepancy (20% in our series).