Association between Repeated Praziquantel treatment and Papillary, and Intrahepatic Cholangiocarcinoma.

INTRODUCTION AND AIM: The carcinogenesis of tubular and papillary cholangiocarcinoma (CCA) differ. The available epidemiologic studies about risk factors for CCA do not differentiate between the tubular and papillary type. The current study investigated the relationship between the number of repeated use of Praziquantel (PZQ) treatments and each type of CCA. MATERIAL AND METHODS: This was a hospital-based, matched, case-control study of patients admitted to Srinagarind Hospital, Khon Kaen University. The patients were 210 pathologically-confirmed cases of CCA, while the controls were 840 subjects diagnosed with other diseases. The 4 controls were individually matched with each case by sex, age, and date of admission. The cases were classified according to location (intrahepatic vs. extrahepatic) and cell type (papillary vs. tubular). Multivariable conditional logistic regression was used for the analysis. RESULTS: After adjusting for confounders, there were statistically significant associations between intrahepatic and papillary CCA and repeated use of PZQ treatment. The respective odds of developing intrahepatic CCA for those who used PZQ once, twice, or more was 1.54 (95%CI:0.92-2.55 ), 2.28 (95%CI:0.91-5.73), and 4.21 (95%CI:1.61-11.05). The respective odds of developing papillary CCA for those who used PZQ once, twice, or more was 1.45 (95%CI:0.80-2.63), 2.96 (95%CI:1.06-8.24), and 3.24 (95%CI:1.09-9.66). There was no association between number of uses of PZQ treatment and developing extrahepatic or tubular CCA. CONCLUSION: The current study found an association between papillary and intrahepatic CCA and repeated use of PZQ treatment. We suggest further study on the risk factors for papillary and tubular CCA should be performed separately.

Thyroid cancer and thyroiditis in the goitrous region of Salta, Argentina, before and after iodine prophylaxis.

OBJECTIVE: The importance of iodine intake and thyroiditis in the pathogenesis of thyroid cancer remains controversial. We have investigated the natural history of thyroid cancer and thyroiditis in a goitrous region before and after iodine prophylaxis over a 31-year period. DESIGN: For the analysis of thyroid cancer the material was divided in two periods. The first 15 years (59 cases), including 5 years before prophylaxis, was compared with the second 16 years (85 cases), a period well after iodine supplementation of salt. Histological diagnosis of the tumours was based on the WHO system. Moderate to severe thyroiditis in the non-tumoral surrounding thyroid from female patients was recorded. For this, the material was analysed in the two periods in relation to the introduction of iodine prophylaxis in 1963, taking account of the age of the patients. RESULTS: Papillary carcinomas formed the largest group of tumours in both periods, with nearly twice as many in the second period as the first, while the numbers of follicular and medullary carcinomas remained about the same. The ratio of papillary to follicular carcinoma rose from 1.7:1 in the first period to 3.1:1 in the second. All three thyroid lymphomas were of the non-Hodgkin's type, and all occurred in the second period in females aged over 50. A severe lymphoid thyroiditis was present in the two cases with assessable background thyroid tissue. The frequency of lymphoid infiltrate in females rose from 8% (1/12) before 1963 to 25% (18/72) after prophylaxis in the whole series. After salt prophylaxis, thyroiditis was more frequent in patients with papillary carcinoma in general (31%), and clinically significant papillary carcinomas in particular (35%), than in those with non-papillary tumours (6%) (chi 2, P < 0.05 and P < 0.025, respectively). CONCLUSIONS: Our observations indicate that a high dietary intake of iodine may be associated with a high frequency of papillary carcinoma and thyroiditis, and that thyroiditis is more commonly associated with papillary carcinoma than with other thyroid tumours. The occurrence of non-Hodgkin's lymphomas only in the post-prophylaxis period may be linked to an increase in thyroiditis.