[Neoadjuvant chemotherapy with tegafur suppository for rectal cancer--effects of tegafur on nuclear DNA content of cancer cells--Tochigi Colorectal Cancer Study Group].

To assess the significance of neoadjuvant chemotherapy for large bowel cancer, we investigated an effect of tegafur on cancer cell kinetics by DNA content flow cytometric analysis. The pathologic specimens analyzed in this study were obtained from 28 patients with rectal cancer who had received tegafur suppositories prior to surgery. Mean cumulative doses administered were 13.4 g, and mean duration was 12.7 days. In 24 of the 28 specimens, the DNA ploidy and DNA index of the cancer cells were essentially unchanged after the chemotherapy, and DNA aneuploidy was present in 67%. The proportion of cells in S-phase in DNA aneuploid tumors was significantly higher than in DNA diploid tumors. The proportion of cells in G0G1-phase was inversely correlated to that in S-phase. After the chemotherapy, the proportions of cells in S-phase increased both in DNA diploid and aneuploid tumors, although a significantly higher mean value was found only for the latter (p < 0.05). In the DNA aneuploid tumors, there was a higher frequency of responders confirmed by histological evaluation (44%) as compared to the DNA diploid tumors (25%), and a tendency for increases in S-phase fraction of the responders to be greater than in non-responders. These results suggest that DNA flow cytometry-derived parameters may conceivably be useful in predicting the antitumor effect of 5-FU and its derivatives against large bowel cancer.