Endocrine Abstracts

Introduction and objectives

Thyroid cancer treatment tends to be individualized based on risk stratification and increasingly less aggressive for low-risk tumors, as recent studies have shown that low doses of I-131 are just as effective than higher doses with excellent remission rates. The objective of our study was to evaluate the response after 1 year of treatment with 30 mCi of I-131 in patients with differentiated thyroid cancer.

Material and methods

Retrospective observational study. 13 patients were included with a mean age of 49.8 ± 10.4 years (61%women). All of them underwent total thyroidectomy followed by a 30 mCi dose of I-131. To evaluate the response at one year, TSH and thyroglobulin levels, cervical ultrasound and total body scan were performed. At each visit, dynamic risk staging was performed, classifying them into: excellent response, incomplete biochemical and/or structural response, and indeterminate response. Statistical analysis was performed using the SPSS program (SPSS, inc, v 15.0)

Results

The pathological study showed 76.9%papillary thyroid carcinoma, 58.3%high risk variants (38%classic variant, 15.4%follicular pattern, 15.4%minimally invasive encapsulation, 7.7%tall cells, 7.7%columnar cells, 7.7%oncocytic features). 92%of the patients were classified as low risk or stage I, according to the TNM system. The mean MACIS value was 4.79 ± 0.87. Mean TSH at follow-up 0.84 ± 1.59 μIU/ml. 69.2%presented an excellent response, 23.1%an indeterminate response, and 7.7%an incomplete structural response.

Conclusions

In our experience, patients appropriately selected to receive low doses of iodine have a good response and tolerance to treatment. Dynamic risk staging is an effective follow-up tool, allowing individualization of the therapeutic strategy to reduce the risk of recurrence.