Although this story relates to thyroid cancer, I think there is a telling "subplot" to it as it relates to RAI treatment and radiation exposure. RAI treatment is used as a treatment option for Graves' disease as are anti-thyroid drugs, thyroidectomy, and other alternative treatments like herbs.

Thyroid Cancer Outcomes Worse with Previous Radiation Exposure, including RAI

Thyroid cancer patients with a history of radiation exposure have more aggressive disease and worse clinical outcomes than patients without previous radiation exposure, according to findings published in April's issue of the Archives of Otolaryngology, Head and Neck Surgery.

Dr. Jeremy L. Freeman and colleagues from Mount Sinai Hospital, Toronto, reviewed 125 patients diagnosed with thyroid cancer who had a history of radiation exposure prior to surgical treatment. The criteria included a history of radiation exposure at least 3 years before diagnosis of thyroid cancer. Type of exposure included radiotherapy, radioactive iodine treatment (RAI), and occupational, diagnostic or environmental exposure.

The mean age of patients was 48 years and the of first exposure to radiation 19 years. Eight-nine per cent (89%) of patients had papillary thyroid carcinoma.

The patients were followed up for 10 years. Of those, 16% had local recurrence of disease, and 9% had distant metastases. The investigators compared this with a group of 574 general thyroid carcinoma patients and found that the radiation-exposed patients were more likely to undergo total or near-total thyroidectomy (83% versus 38%), to require multiple operative procedures (23% versus 2%), and to require adjuvant external radiotherapy (6% versus 1%) compared to the general thyroid cancer patients.

Patients who had previous radiation exposure were more likely than the general thyroid cancer group to have:

• multifocal tumors (63% versus 36%)
• extrathyroid extension (26% versus 8%)
• stage IV disease (16% versus 5%)
• distant metastases (9% versus 2%).

Eight percent (80%) of radiation-exposed patients had disease at follow-up, compared with three percent (3%) of the general thyroid cancer group. Radiation-exposed patients were more likely to have died of thyroid disease at follow-up (4% versus 1.5%).

The investigating team concluded that, while most patients with well-differentiated thyroid cancer can expect good outcomes, patients who have been exposed to radiation are more likely to require aggressive treatment.

Source: Reuters Health, 2009-04-29
Arch Otolaryngol Head Neck Surg 2009;135:355-359.