Long-term low-level radiation exposure is associated with increased risk of developing which cancer?

• A. Leukemia
• B. Lymphoma
• C. Brain cancer
• D. Skin cancer

Answer: (A)

Ionizing radiation at low doses over long periods increases the risk of leukemia because bone marrow—the site where blood cells are produced—is particularly radiosensitive. Radiation can cause DNA damage in hematopoietic cells, and over time this can lead to malignant transformation and leukemia. The latency period is often several years, reflecting the time needed for malignant clones to develop. In dental radiography, individual exposures are small, so the absolute risk is tiny, but the underlying concept remains: leukemia is the cancer most consistently linked to long-term low-dose radiation exposure. Lymphoma, brain cancer, and skin cancer have associations in other contexts or at higher doses, but at low-dose, long-term exposure, leukemia is the strongest established risk.