Update in utility of secondary node dissection for papillary thyroid cancer.

BACKGROUND: Detection of recurrent/persistent thyroid cancer has improved significantly in the past decade. Disease is detected earlier in recently treated patients and localized in patients long out from initial treatment. This update reviews recent literature regarding the utility of secondary node dissection for papillary thyroid carcinoma. Outcomes include disease-free status measured biochemically and clinically.
RESULTS: The utility of secondary node dissection as measured by clinically detectable disease exceeds 70% for all series and 90% for most. The utility as measured biochemically is more modest, with rates of biochemical cure ranging from 27-81% depending upon strictness of definition and patient selection. In predominately radioiodine scan-negative patients, using the strictest definition of biochemical cure, undetectable stimulated thyroglobulin (Tg) of less than 0.5 ng/ml, a rate of 27% is reported. Biochemical cure rates are reportedly 30-51% for stimulated Tg of less than 2 ng/ml and 56-71% for basal Tg of less than 2 ng/ml, with higher preoperative Tg levels less likely to achieve biochemical cure. Radioiodine-avid disease appears more amenable to cure, with 81% of patients achieving negative stimulated Tg after repeat I131 treatment and radio-assisted surgery. Complication rates of secondary nodal surgery appear similar to initial surgery in experienced hands; however, bilateral reoperative central neck dissection is associated with significantly higher complication rates than unilateral.
SUMMARY: Surgical resolution of clinically detectable disease is likely. Biochemical cure rates are more modest, with the greatest likelihood of biochemical cure occurring in patients with radioiodine-avid disease. In radioiodine-negative patients, there may be a higher likelihood of biochemical cure for those with lower preoperative detectable Tg levels.