[Long-term investigation of the risk of malignant diseases following intravenous radium-224 treatment for ankylosing spondylitis]. / Langzeituntersuchung zum Risiko maligner Erkrankungen nach intravenöser Behandlung des Morbus Bechterew mit Radium-224.

ABSTRACT

BACKGROUND AND PURPOSE: In German-speaking countries, the intravenous treatment of ankylosing spondylitis (AS) with radium-224 ((224)Ra) was common between the late 1940s and 2005. In this long-term investigation, the risk of malignant diseases following intravenous (224)Ra treatment for AS was assessed. PATIENTS AND METHODS: In a prospective long-term study, 1,471 patients with AS who were treated with (224)Ra between 1948 and 1975 have been followed together with a control group of 1,324 AS patients treated neither with radioactive drugs nor with X-rays. Standardized questionnaires to evaluate the patients' health status were used. Observed numbers of malignant diseases were compared with those of the control group as well as with expected numbers for a normal population. RESULTS: After 26 years of follow-up, causes of death have been certified for 1,006 patients of the exposure group (control group 1,072 patients). Significantly increased rates of myeloid leukemia (12 cases observed vs. 2.9 expected; p < 0.001), kidney cancer (18 vs. 9.1; p < 0.01), thyroid cancer (4 vs. 1.2; p = 0.03) and borderline significantly increased rates of cancer of female genital organs (10 vs. 5.6; p = 0.06) were found in the exposure group in contrast to no significant increases of these diseases in the control group. Rates of pulmonary and gastrointestinal malignancies were not increased. Lymphatic leukemia (exposure group 8 vs. 2.7; p < 0.01; control group 7 vs. 3; p = 0.03) was significantly elevated due to a high rate of chronic lymphatic leukemia in both, the exposure as well as the control group. CONCLUSION: Treatment of AS with (224)Ra led to increased incidences of myeloid leukemia and malignancies of kidneys, thyroid and female genital organs. Although this kind of therapy is now abandoned, there is a need for close follow-up of patients who received it.