All cases with cholangiocarcinoma were identified between September 1999 and November 2001 upon visitation to the Nakhon Phanom provincial hospital or one of the community hospitals in the province. All cases from the community hospitals had been referred to the Nakhon Phanom Provincial hospital for confirmation of the diagnosis. Diagnosis was based on abdominal ultrasonography by a single radiologist (P.K.) at the provincial hospital with serological supportive evidence including a raised CA 19-9 (≥40 μ/ml) and a normal level of alpha fetoprotein (AFP; <20 ng/ml), although the latter was not obligatory. Histological diagnosis was made for only 9 cases as the diagnosis without liver biopsy was usual in our study area. Because all clinically diagnosed cases both with and without ultrasound confirmation and serum tumour marker measurement were to be reported to the provincial cancer registry, the number of cases in our study should be smaller than that from the cancer registry for the corresponding time period. Local health personnel selected 1 candidate as a control, being matched by sex, age (within 5 years) and place of residence (amphur, district). Because the health personnel were familiar with the inhabitants in the local communities prior to our study, they easily found candidates for the matched controls. Although the health personnel did not intentionally choose such candidates among inhabitants who apparently were cooperative with the study, systematic random sampling was not employed and apparently ill persons were not contacted. Each control candidate was invited to the provincial hospital and underwent an abdominal ultrasonographic examination by the same radiologist used for the cases. Control candidates that had no ultrasonographic findings suggestive of cholangiocarcinoma or hepatocellular carcinoma were verified as controls. Only in 1 case did a candidate control have ultrasonographic findings suggestive for cholangiocarcinoma with subsequent serological findings of raised CA19-9 level and normal AFP. This candidate was diagnosed with cholangiocarcinoma and subsequently became a case. Another control was identified for this case, whereas a second control candidate was identified for the first proband case.
We found no material changes in the results if we excluded 3 cholangiocarcinoma cases with both abnormally increased serum AFP and CA19-9 levels via statistical analyses. Therefore, we treated these 3 subjects as cholangiocarcinoma in the subsequent analyses. All the cases and controls were inhabitants of the Nakhon Phanom province with a population of 340,539 males and 343,905 females as of July 1, 2000. None of the subjects we contacted declined to participate in our study, and a total of 85 male and 44 female case-control pairs were obtained. Although the study area is an economically deprived rural region, inhabitants were generally educated and literate (as shown in Table I).
Table I. Relations of Serum Anti-OV Antibody, Socio-Economic Status, Smoking, Alcohol Drinking and Past Dietary Habit to Risk of Cholangiocarcinoma, Nakhon Phanom, Thailand: Based on The Conditional Logistic Regression Model
การแปล กรุณารอสักครู่..
