Late effects in ankylosing spondylitis patients treated with 224Ra

Area of Science:

• Radiological protection
• Oncology
• Rheumatology

Background:

• Ankylosing spondylitis (AS) patients treated with Radium-224 (224Ra) require long-term health effect monitoring.
• Previous studies on 224Ra cohorts indicated risks of bone tumors and other cancers.

Purpose of the Study:

• To evaluate long-term health effects, including cancer incidence, in AS patients treated with 224Ra.
• To compare outcomes between 224Ra-treated patients and a control group of AS patients.

Main Methods:

• A cohort of 1577 AS patients receiving 224Ra injections (1 MBq/week for 10 weeks) was established.
• A control group of 1462 AS patients with similar demographics was selected for comparison.
• Causes of death and cancer incidence were tracked until the end of 1998.

Main Results:

• A significant excess of leukemia (13 cases) was observed in the 224Ra-exposed group compared to the general population (P < 0.001).
• Myeloid leukemias showed a clear preponderance in the exposed group (8 cases vs. 1.7 expected, P < 0.001).
• Observed malignant bone tumors (4 cases) were fewer than predicted (8 cases), and no excess breast cancer was found.

Conclusions:

• Treatment with 224Ra for ankylosing spondylitis is associated with a significant excess risk of leukemia, especially myeloid leukemia.
• The risk of bone tumors appears lower than previously estimated, and breast cancer risk was not elevated in this cohort.
• Long-term follow-up is crucial for understanding the late effects of internal radionuclide therapy.