DNA ploidy and S-phase fraction analysis in peritoneal carcinomatosis from ovarian cancer: correlation with clinical pathological factors and response to chemotherapy

OBJECTIVE: We investigated the correlation between ploidy or S-phase fraction (SPF) and the clinical pathological characteristics of patients with peritoneal carcinomatosis from ovarian cancer. We also assessed their relation with the in vivo and in vitro response to several chemotherapeutic agents. PATIENTS AND METHODS: Fifty-three patients with peritoneal carcinomatosis from ovarian cancer were enrolled. Frozen tumor tissue was dissociated by a detergent–trypsin method, and the resulting cell suspension was stained with RNase A and propidium iodide. Samples were then analyzed for ploidy and SPF by flow cytometry. Fresh tumor tissue was dissociated by enzymatic digestion, and cells were exposed to different concentrations of cisplatin, adriamycin, carboplatin, gemcitabine and taxol for 72 hours. In vitro drug sensitivity was then measured using the sulforhodamine B assay. RESULTS: No significant correlation was found between ploidy or SPF and patient characteristics, even though primary carcinomas were mainly hyperdiploid and more proliferative than recurrent tumors. SPF differed significantly among ploidy categories (P=0.01), and high SPF was associated with short-term survival (P=0.48). Patients with multiploid tumors were the most resistant to platinum-based chemotherapy, whereas those with hyperdiploid tumors were the most responsive. In vitro multiploid tumors were the least sensitive, while hypodiploid samples showed the highest sensitivity to the tested drugs. Sensitivity to adriamycin was significantly correlated with ploidy (P=0.03), whereas sensitivity to taxol was correlated with SPF (P=0.04). CONCLUSION: Our results indicate that ploidy and SPF could facilitate the choice of therapy for patients with peritoneal carcinomatosis.