DNA Ploidy and S-Phase Fraction as Prognostic Factors in Surgically Resected Gastric Carcinoma: A 7-Year Prospective Study

Abstract

Background: DNA ploidy and S-phase fraction (SPF) measured by DNA flow cytometry (FC) have been previously shown to correlate with several clinicopathological variables in several types of tumours. Patients and Methods: DNA FC was performed on multiple frozen tumour samples obtained from 115 patients undergoing curative surgery for gastric cancer (GC). The findings were prospectively tested for correlation with traditional clinicopathological indicators of prognosis. Results: Overall, 20 tumours (17.4%) were diploid, 46 (40.0%) monoclonal and 49 (42.6%) multiclonal. Excluding 4 patients who died within 1 month of surgery, high SPF (>9.6%) was detected in 55 patients (49.6%) and was found to be significantly associated with vascular invasion and multiclonality (p=0.02). An association of borderline statistical significance emerged with macroscopic type (p=0.06) and pN and pM status (p=0.07). Multivariate regression analysis did not show a significant effect of SPF (p=0.11) or DNA ploidy (p=0.28) on 7-year survival. Conclusion: Aneuploidy appears to be a prognostic factor of low penetrance, whereas SPF is a more promising parameter of tumour aggressiveness in patients with GC.