Radiation worsens thyroid cancer patient outcomes

Patients who have been exposed to radiation prior to developing thyroid cancer have more aggressive disease and worse clinical outcomes, according to new research from Mount Sinai Hospital in Toronto.
The findings are particularly worrisome for individuals who were treated with radiation of the head and neck for acne, extensive diagnostic imaging of the head and neck; received radiation therapy for another body site or who have had occupational exposure to radiation without adequate protection.
The comparison of outcomes of thyroid cancer patients who had not been exposed to radiation versus patients who were exposed at least three years prior to diagnosis was published in the April 2009 issue of the Archives of Otolaryngology – Head & Neck Surgery (Volume 135:4, pp 355-359).
Lead author Dr Raewyn Seaberg and colleagues in the Department of Otolaryngology identified 125 patients treated at Mount Sinai Hospital between 1963 and 2007 who had been exposed to radiation three years or more prior to surgical treatment. They compared the medical treatment required and outcomes of these individuals to those of 574 patients who had never been exposed to radiation.
Around 56 per cent of radiation-exposed patients had been treated for acne or another benign childhood condition, a practice that was common in 1930-1960. Occupational exposure was the next most common reason for radiation exposure, at 26 per cent, followed by environmental exposure at 11 per cent, radiation to other body sites at 6 per cent, and radioactive iodine treatment at 4 per cent.
The subgroup of patients exposed to direct external radiation therapy to the head and neck accounted for most patients with stage IV disease (56 per cent), MACIS (metastases, age, completeness of surgical excision, local invasion, and tumour size) scores higher than 8 (60 per cent), local recurrence (63 per cent), distant metastases (55 per cent), and death from thyroid cancer (80 per cent). The aggressiveness of the cancer and the long-term outcomes at a median of 10.6 years were worse for patients who had prior exposure to radiation.
(thyroid