Long-term results of reoperation and localizing studies in patients with persistent or recurrent medullary thyroid cancer

HYPOTHESIS: Reoperation benefits patients with locoregional, persistent, or recurrent medullary thyroid cancer (MTC). Currently available localizing studies have limited utility for detecting all foci of residual MTC. DESIGN: A retrospective study with a mean follow-up time of 7.5 years (median, 13 years; range, 2.2-29 years). SETTING: A tertiary referral medical center. PATIENTS: Thirty-three patients who underwent 46 reoperations for locoregional residual MTC. RESULTS: Sixty-four percent of residual MTC was located in the lateral cervical nodes, 22% in the central cervical nodes or thyroid bed, and 14% in the anterior mediastinum (197 of 1128 nodes resected were positive for MTC). After reoperation, basal calcitonin levels were undetectable in 2 patients, reduced by greater than 50% in 10 patients, and either increased or were not reduced by greater than 50% in the remaining patients. On reoperation, one patient had a thoracic duct injury that required reexploration and ligation. Patients who had a greater than 50% decrease in calcitonin levels after reoperation were less likely to develop distant metastases compared with patients who did not have a greater than 50% decrease (P<.05). The sensitivities of magnetic resonance imaging (n = 31), computed tomographic scan (n = 16), ultrasound (n = 9), and dimercaptosuccinic acid scan (n = 3) were 91%, 86%, 88%, and 100%, respectively. CONCLUSIONS: Although reoperation in patients with residual MTC rarely results in biochemical cure, cervical reexploration is safe and in selected patients may limit MTC progression. Lateral cervical node dissection could be beneficial at the time of initial surgical treatment because of the high frequency of residual MTC in the lateral cervical nodes. Noninvasive imaging studies were helpful but far from perfect for guiding the reexploration for locoregional residual MTC.