Seoul St. Mary's Hospital study: Breast cancer radiation does not raise skin cancer risk

A research team at Seoul St. Mary's Hospital has found that radiation therapy following breast cancer surgery does not significantly increase the risk of skin cancer in Korean patients. The study, published in the ‘British Journal of Cancer’, analyzed data from 19,856 patients over an average follow-up period of 11.5 years.

Comparing a radiation group to a non-radiation group, the skin cancer incidence rates were 0.97% and 1.02%, respectively, showing no meaningful difference. This contradicts previous Western studies that reported a 12% to 57% higher risk in radiation patients. Researchers attributed this discrepancy to racial differences in melanin levels and advancements in medical technology, specifically the use of 3D conformal radiation therapy (3D-CRT) which minimizes damage to healthy skin.

The study identified other significant risk factors for skin cancer, including older age, the presence of moles, pre-cancerous skin lesions (such as actinic keratosis or Bowen's disease), and lymphedema. Patients with pre-cancerous lesions faced a 12.9 times higher risk, while those with moles faced a 5.3 times higher risk. While the results are encouraging for mid-term safety, researchers noted that longer-term follow-up exceeding 20 years is necessary to confirm absolute long-term safety.