Cancer risk after splenectomy.

Splenectomy may have an impact on immunologic function. To the authors' knowledge, the only previous epidemiologic study investigating cancer risk among patients splenectomized because of trauma reported no increased cancer risk. In contrast, several investigations have suggested that splenectomy in patients with Hodgkin's disease increases the risk for secondary leukemia independent of treatment. To evaluate the cancer risk of patients who underwent splenectomy after traumatic rupture of the spleen, 1103 patients were identified between 1977 and 1989 through Danish hospital discharge records. Another 5212 splenectomized patients also were identified to perform additional analyses for assessing cancer risk subsequent to splenectomy for nontraumatic indications including benign and malignant conditions. Cancer occurrence was determined by performing a linkage to the Danish Cancer Registry. For comparison, expected numbers of cases of cancer were calculated from national cancer incidence rates. The number of cancer cases observed among posttraumatic splenectomized patients matched the expected number (relative risk = 1.0; n = 20; 95% confidence interval = 0.6-1.6) in an average follow-up of 6.8 years. Additional analyses identified possible excesses of a number of site-specific neoplasms among certain subgroups of patients undergoing splenectomy for nontraumatic reasons, but the numbers in the subgroup analyses were small. No increased risk for cancer was observed among patients who underwent splenectomy because of trauma. However, an increased risk for some specific cancer sites was found in patients who underwent splenectomy for nontraumatic reasons, although the effect of treatments for underlying disease and lifestyle habits such as cigarette smoking could not be ruled out in explaining these excess risks.