Stereotactic body radiotherapy for refractory cervical lymph node recurrence of nonanaplastic thyroid cancer

Abstract

Objective: To investigate the feasibility and efficacy of stereotactic body radiotherapy as salvage treatment for cervical node recurrence from nonanaplastic thyroid cancer refractory to other modalities. Study Design: Pilot study. Setting: A single institution-based practice. Subjects and Methods: Between August 2002 and November 2007, nine patients with recurrent nonanaplastic thyroid cancer were treated with stereotactic body radiotherapy for nodal metastases. Radiotherapy was delivered in one to three fractions, and the median dose was 36 Gy (range 30-39 Gy). Results: Twenty-nine nodes in nine patients were treated. Seven patients had papillary carcinoma, and two had medullary carcinoma. These patients developed nodal recurrence after they received salvage surgery and/or radioisotope (RI) treatment for recurrent thyroid cancer. All nodes were in the cervical or supraclavicular areas, excepting one hilar node. Retropharyngeal node metastases were present in five patients. The median follow-up period was 23 months (range 4-63 mo). No local progression was observed in nodes treated by stereotactic body radiotherapy. Four patients developed new metastases in nontarget regional nodes after radiotherapy, and in two of these, regional failure was salvaged by additional stereotactic body radiotherapy. No serious adverse events were observed in any patient. Conclusion: In select patients, stereotactic body radiotherapy may be a feasible option for treating refractory nodal recurrence from nonanaplastic thyroid cancer. Further studies are necessary to define the role of stereotactic body radiotherapy in the management of thyroid cancer.