The Effect Of Selenium Yeast Supplement On Concurrent Chemoradiotherapy ForⅡB Cervical Cancer:A Randomized,Double-blind,Placebo-controlled PhaseⅡ Clinical Trial

Objective In this study,we compared the adverse reactions and short-term efficacy of the two groups in the process of treatment,to explore whether the efficacy of selenium yeast combined with concurrent chemoradiotherapy is superior to concurrent chemoradiotherapy alone.Methods Patients with stageⅡB cervical cancer who met the inclusion criteria were randomly divided into experimental group and control group.Experimental group received two selenium yeast tablets,twice a day and control group received two placebo twice a day.Both groups received external pelvic irradiation with 6MV X-ray at a prescribed doses of PGTV 54Gy/25f and PCTV 46Gy/25f,5 times a week.Five cycles of concurrent chemotherapy:intravenous injection of cisplatin with 30mg/m~2,once a week.At the later stage of radiotherapy,brachytherapy was given,using iridium 192 radioactive source.The dose at point A was 6Gy/time,4 times in total.After treatment,the incidence of myelosuppression,liver and kidney dysfunction,objective response rate of the two groups were compared.The whole blood selenium concentration had been measured before treatment,the third week of treatment and at the end of treatment.Results One hundred and four eligible patients enrolled and randomly assigned to experimental group（n=50）and control group（n=54）.The incidence of myelosuppression in the experimental group was 46（92%）compared to 50（92.59%）in the control group（P=0.85）.And there were 24（48%）and 17（31.48%）patients in the experimental group and control group with different degrees of liver damage（P=0.15）.No kidney damage observed in this study.ORR between experimental group and control group were 96%and 94.44%,respectively（P=0.47）.Before treatment,the baseline selenium level in the experimental group and control group were 58.34±17.63μg/L and 60.21±18.42μg/L（P=0.60）.And in the third week of treatment,the selenium level between two groups were 63.98±17.68μg/L and58.88±17.29μg/L（P=0.14）.There selenium level in the experimental group were76.16±24.47μg/L compared to the control group 57.48±14.92μg/L at the end of treatment（P<0.01）.The subgroup analysis:the incidence of thrombocytopenia in the moderately and well differentiated subgroup of the experimental group was 53.85%,which was significantly lower than that in the control group78.95%（P<0.01）.Conclusion Selenium yeast did not alleviate bone marrow suppression and liver and kidney damage associated with concurrent chemoradiotherapy.Selenium yeast did not improve the objective response rate in patients with locally advanced cervical cancer.Selenium yeast may have a protective effect on thrombocytopenia in patients with moderately highly differentiated cervical cancer undergoing simultaneous chemoradiotherapy.