Abstract： Objective To determine the peripheral serum expressions and clinical value of carcinoembryonic antigen (CEA) and carbohydrate antigen CA19-9,CA242,CA72-4 and a single sialic acid ganglioside (CA50) antigen in advanced pancreatic cancer patients treated by three-dimensional conformal radiotherapy (3D-CRT) combined with endogenous field hyperthermia.Methods 60 patients inoperable,advanced pancreatic cancer were treated by 3D-CRT combined with endogenous field hyperthermia.Radiation dose (DT) was 46 ～ 66 GY/23 ～ 33 F.Hyperthermia temperature was 41 ～ 43 ℃ 2 times/week,lasted 60 min each time.The expressions of CEA,CA19-9,CA242,CA72-4 and CA50 in peripheral serum were detected by Electrochemiluminescence immunoassay (ECLIA) every 2 weeks during treatment,and correlation were analyzed with tumor diameter,clinical stage,lymph node metastasis.Results From the 8th week,with 3D-CRT combined with endogenous field hyperthermia ongoing,CEA,CA19-9,CA50 andCA242 expression levels showed a gradual decline.CEA,CA19-9,CA50 and CA242 expression levels were (6.22 ± 2.71 ) μg/L,(43.44 ± 12.93 ) μg/L,(23.21 ± 7.71 )g/L and (24.26 ± 8.92) μg/L in 6 weeks,respectively.The difference was statistically significant among week 6 and week 0,week2,week 4 ( P ＜0.05),however there was no significant difference between week 6 and week 8 ( P ＞ 0.05 ).The CA724 expression did not change significantly ( P ＞ 0.05 ).There were positively correlation between CEA,CA199,CA50 and CA242 with pancreatic cancer tumor size,clinical stage and lymph node metastasis( respectively r =0.877,0.725,0.826,all P ＜ 0.01 ),however CA72-4 had no correlations ( P ＞ 0.05).Conclusions CEA,CA19-9,CA50 and CA242 expressions in peripheral serum of pancreatic cancer patients were closely related to the treatment.Their joint detection can be served as independent objective evaluation reference information for the treatment efficacy and prognosis.