Purpose: To look for the possible efficacy of external beam irradiation (EBRT) for locally advanced papillary thyroid cancers.
Materials and methods: Between August 1981 and September 1997, 91 patients with locally advanced papillary thyroid cancers (pathologic Stage T4 or N1) were treated with surgical resection. After surgery, 23 patients received postoperative EBRT with or without ablative radioiodine therapy, and 68 patients were treated with ablative radioiodine therapy alone. The distribution of age, gender, and stage was comparable in both groups.
Results: The overall survival rates at 7 years were not significantly different statistically between the two groups at 98.1% for the no-EBRT group and 90% for the EBRT group (p = 0.506). The locoregional control rates at 5 years were significantly different (EBRT 95.2% and no EBRT 67.5%; p = 0.0408). Analysis of the prognostic factors, age, gender, stage, and use of radioiodine ablative therapy, indicated these were not significant variables, except for EBRT.
Conclusions: Adjuvant postoperative EBRT did not affect overall survival, but significantly improved locoregional control in patients with locally advanced papillary thyroid cancer (Stage pT4 or lymph node involvement).