For the evaluation of
cancer risks associated with immunodeficiencies experienced by patients with
Hansen's disease (
leprosy) and for the assessment of possible adverse effects of
dapsone therapy, a follow-up study was conducted of 1,678 patients admitted to the National
Hansen's Disease Center in Carville, La., between 1939 and 1977. Overall, no substantial
cancer mortality was observed (standardized mortality ratio = 1.3), nor was there any excess among patients exhibiting defects in cellular immunity by virtue of lepromatous forms of the disease. Notable was the absence of any significant excess of
lymphoma (5 observed vs. 2.3 expected), despite the predominance of this
tumor in certain other immunodeficiency states. Several
cancer sites (oral, bladder, and kidney) occurred excessively, but reasons for the elevations were obscure. Although
dapsone has been implicated as a
carcinogen in laboratory animals, the use of
sulfones, including
dapsone, did not appear to affect significantly the risk of any
cancers in this population.