Diagnostic x-ray procedures and risk of leukemia, lymphoma, and multiple myeloma.
Exposure to diagnostic x-rays and the risk of leukemia, non-Hodgkin's lymphoma (NHL), and multiple myeloma were studied within two prepaid health plans. Adult patients with leukemia (n = 565), NHL (n = 318), and multiple myeloma (n = 208) were matched to controls (n = 1390), and over 25,000 x-ray procedures were abstracted from medical records. Dose response was evaluated by assigning each x-ray procedure a score based on estimated bone marrow dose. X-ray exposure was not associated with chronic lymphocytic leukemia, one of the few malignant conditions never linked to radiation (relative risk [RR], 0.66). For all other forms of leukemia combined (n = 358), there was a slight elevation in risk (RR, 1.17) but no evidence of a dose-response relationship when x-ray procedures near the time of diagnosis were excluded. Similarly, patients with NHL were exposed to diagnostic x-ray procedures more often than controls (RR, 1.32), but the RR fell to 0.99 when the exposure to diagnostic x-ray procedures within 2 years of diagnosis was ignored. For multiple myeloma, overall risk was not significantly high (RR, 1.14), but there was consistent evidence of increasing risk with increasing numbers of diagnostic x-ray procedures. These data suggest that persons with leukemia and NHL undergo x-ray procedures frequently just prior to diagnosis for conditions related to the development or natural history of their disease. There was little evidence that diagnostic x-ray procedures were causally associated with leukemia or NHL. The risk for multiple myeloma, however, was increased among those patients who were frequently exposed to x-rays.
Boice
J D
JD
Epidemiology and Biostatistics Program, National Cancer Institute, Bethesda, MD 20852.
Morin
M M
MM
Glass
A G
AG
Friedman
G D
GD
Stovall
M
M
Hoover
R N
RN
Fraumeni
J F
JF
D000328:Adult; D002140:California; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000209:etiology; D007953:Leukemia, Radiation-Induced / Q000209:etiology*; D008228:Lymphoma, Non-Hodgkin / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000209:etiology*; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D009922:Oregon; D011829:Radiation Dosage; D011859:Radiography / Q000009:adverse effects*; D012044:Regression Analysis; D012307:Risk Factors