Risk of Hodgkin's disease subsequent to tonsillectomy: a population-based cohort study in Sweden.

Although some studies have linked excess of Hodgkin's disease (HD) to tonsillectomy, the findings have not been consistent. In particular, risk of HD by age at tonsillectomy has not been fully evaluated, despite the notable change in immunologic function of the tonsils between childhood and adulthood. To evaluate the risk of HD and other lymphomas, associated with tonsillectomy according to age at surgery, a population-based cohort study was conducted. Using nationwide Swedish hospitalization records, 55,169 patients undergoing tonsillectomy with/without adenoidectomy (T/A) were identified during the period 1964-1983. By linkage with the nationwide Total Population, Migration, Cancer and Causes-of-Death registries, these patients were followed up for as long as 25 years. After exclusion of the first post-operative year, a total of 533 first primary-cancer cases was identified between 1965 and 1989. Small excess risk was observed for HD (20 cases, SIR = 1.4, 95% CI 0.9-2.2). HD risk was more pronounced among patients tonsillectomized before age 12 (7 observed vs. 1.7 expected, SIR = 4.1, 95% CI 1.6-8.4), but declined significantly with older ages at T/A. While our data suggest a small increase in HD among all patients undergoing T/A and a significant excess for those under age 12 at surgery, we cannot exclude the possibility that the excess may be due to factors underlying the disorders that led to surgery.