A role for radiotherapy in the management of advanced medullary thyroid carcinoma: the Mayo Clinic experience

Outcomes of external beam radiotherapy (EBRT) in advanced medullary thyroid carcinoma (MTC) are largely unknown. Retrospective review of data from patients with MTC, diagnosed from June 1, 1970, through December 31, 2007. Overall survival and locoregional tumor control rates were calculated. Seventeen patients had adjuvant or palliative EBRT delivered to 41 sites. Six patients initially had adjuvant EBRT (median, 60.80 Gy); none had relapse in the treated area. Five patients with locoregional recurrence after surgery were treated (median, 59.40 Gy), and durable disease control was achieved in 3. Twelve patients received palliative EBRT to 29 sites of metastatic disease (median, 30.00 Gy), which provided sustained symptom relief at 45% of sites. Five- and ten-year overall survival rates were 44% and 19%, respectively. Adjuvant EBRT may be most effective for prevention of locoregional recurrence. EBRT may provide sustained control of advanced, metastatic disease in select patients.