Clinical outcome of anaplastic thyroid carcinoma treated with radiotherapy of once- and twice-daily fractionation regimens

BACKGROUND. The purpose was to assess local control, survival, and toxicity after radiotherapy in patients with anaplastic thyroid carcinoma, and to compare clinical outcomes between once-daily and twice-daily fractionation regimens. METHODS. A retrospective review of patients with anaplastic thyroid carcinoma (n =47) who underwent external beam radiotherapy from 1983 to 2004 was conducted. Twenty-three patients underwent radical radiotherapy with a radiation dose > 40 Gy, and 24 patients underwent palliative radiotherapy with a dose <= 40 Gy. Of radical radiotherapy, radiation was given with once-daily (14 patients) or twice-daily fractionation (9 patients; 1.5 Gy per fraction) to a total dose of 45-66 Gy. Most patients (37 patients; 78.7%) were followed to death. RESULTS. The 6-month local progression-free rate in patients who underwent radical radiotherapy was 94.1%, significantly higher compared with palliative radiotherapy (64.6%; P =.02). The median actuarial overall survival was greater in patients with radical radiotherapy (11.1 months) compared with palliative radiotherapy (3.2 months; P <.0001). The median overall survival in patients with twice-daily fractionation (13.6 months) was 3.3 months longer than patients treated with once-daily fractionation (10.3 months), but the difference was not statistically significant (P =.3). For patients treated with twice-daily fractionation, 3 patients had Grade 3 acute skin toxicity, and no patient had Grade 3 or higher esophageal toxicity. CONCLUSIONS. Radiotherapy can result in local control of anaplastic thyroid carcinoma. A twice-daily fractionation regimen is well tolerated and has a trend to longer survival, which deserves a larger study. (c) 2006 American Cancer Society.