Radiation therapy and low dose doxorubicin in thyroid cancer: A phase II study.

Abstract

6100 Background: The role of external beam radiation therapy has remained controversial in the management of differentiated thyroid cancer (DTC). There is an absence of prospective studies in this area despite the importance of locoregional control (LRC) in the neck. We performed a prospective phase II study to better evaluated both LRC and toxicity with intensity modulated radiation therapy (IMRT). Methods: We enrolled 26 patients in a prospective single institution phase II study. The first 7 did not receive chemotherapy; the next 19 received weekly doxorubicin (10 mg/m2) concurrently with IMRT (70Gy). Inclusion criteria included non-anaplastic, non-medullary DTC that is either grossly recurrent after surgery or unresectable with a Karnofsky Performance status > 60%. The primary objective was 2-year LRC rate of 90% in the group receiving concurrent chemotherapy compared to a historical LRC rate of 40%. Swallow evaluation was collected every 6 months for 2 years (not reported). Results: The median age was 63 years (29-83); 65% were male and 50% had distant metastatic disease at time of study entry; histology was papillary (65%), poorly differentiated (27%) and Hurthle Cell (8%). The BRAF V600E mutation status was known in 9 patients, 6 of which were positive. All patients completed IMRT without delay. Patients received a median of 7 (5-9) doses of doxorubicin. Of the 26 patients, 5 have died (none related to treatment) of which 4 had metastases at time of IMRT initiation. Median followup is 420 days (59-864 days). Only one patient has had proven failure in the neck (RT alone group). No proven LR failure has been noted in the chemotherapy group. No patients required permanent PEG use. Conclusions: Concurrent doxorubicin and IMRT appears to be effective in controlling LR disease in patients with recurrent or resectable DTC. Longer term follow up and toxicity data (swallowing evaluations) does need to be collected and analyzed. Clinical trial information: NCT01882816.