Abstract: Objective To investigate the relationship between the DNA repair rate（DRR） of peripheral blood lymphocytes（PBLC） and platinumcontaining chemotherapy efficacy in advanced gastrointestinal malignancies.
Methods The DRR of PBLC from 112 patients with advanced gastrointestinal cancer patients（cancer group） were detected by single cell gel electrophoresis（SCGE）， and other 60 patients with healthy subjects were selected as controls（control group）. Cancer patients were treated in parallel platinumcontaining chemotherapy regimens to evaluate the shortterm effect. In cancer group， the DRR of the two platinum groups before and after exposure to platinum were analyzed. Then， the correlation between the DRR of cancer group and clinical pathological features and efficacy of chemotherapy regimens containing platinum was also investigated.
ResultsTail length（TL） and tail moment（TM） were utilized to detect the DRR of esophageal cancer（Z=-4.687， P=0.000； Z=-4.939， P=0.000）， gastric cancer（Z=-5.473， P=0.000； Z=-3.789， P=0.000） and colorectal cancer（Z=-5.796， P=0.000； Z=-5.206， P=0.000）. The PBLC DRRs of cancer group were lower than that of control group counterpart. The PBLC DRR of cancer group exhibit no correlation to sex， age， ECOG score， alcohol habits and tissue differentiation of the tumor（P＞0.05）. Among 112 patients， 110 cases were evaluable for efficacy. For esophageal cancer， there were 3 cases of PR， 6 cases of SD and 12 cases of PD with response rate（RR） of 14.3％ and disease control rate（DCR） of 42.9％. For gastric cancer， there were 1 case of CR， 5 cases of PR， 10 cases of SD and 20 cases of PD with RR of 16.7％ and DCR of 44.4％. For colorectal cancer， there were 2 cases of CR， 8 cases of PR， 13 cases of SD and 30 cases of PD with RR of 18.9％ and DCR of 43.4％.When TL was utilized as an evaluation index of DRR， the DRR of esophageal cancer（r=-0.500， P=0021）， gastric cancer（r=-0546， P=0001） and colorectal cancer（r=-0.362， P=0.008） were negatively correlated with chemotherapy. Using TM as an evaluation index for DRR， the DRR of esophageal cancer（r=-0.481， P=0.027） and gastric cancer（r=-0.361， P=0.030） were negatively correlated with chemotherapy， but no correlation with chemotherapy was shown in colorectal cancer（r=-0.256， P=0.064）. Conclusion In comparison to healthy individuals， gastrointestinal cancer patients possess low DNA repair capacity. DRR is negatively correlated with shortterm efficacy of advanced esophageal and gastric cancer patients treated with platinumcontaining chemotherapy regimens.