Doxorubicin and concurrent radiotherapy for anaplastic thyroid cancer: We need to do better

Abstract

16506 Background: Anaplastic thyroid cancer (ATC) is a rare, aggressive malignancy. The potential for pathologic misclassification complicates the interpretation of published data. One treatment option for locoregionally (LR) advanced disease is weekly low-dose doxorubicin (D) with concurrent radiation therapy (RT), based on reported 2-year local control rates of 68% (ATC)/77% (other TC histologic subtypes) (Cancer 1987;60:2372). We looked to evaluate our experience with this general approach, but in a larger series which included pathologic confirmation of all ATC cases. Methods: Patients (pts) were identified through the Memorial Sloan-Kettering Cancer Center (MSKCC) Radiation Oncology and Pathology Databases. Inclusion criteria: diagnosis of ATC between 1984–2006, with pathology review at MSKCC; LR disease only, able to be encompassed within a RT portal; treatment at MSKCC with planned weekly D (10 mg/m2) and concurrent radiation. Prior surgery was allowed. Documentation of failure was based on clinical/radiographic assessment. Principal outcomes assessed: LR control (LRC: no failure at the primary site, in the neck, or the mediastinum), progression-free survival (PFS), and overall survival (OS). The Kaplan-Meier method was applied. Results: Thirty-seven patients were included in our analysis (median age 64; 54% female, 46% male). Median RT dose 5760 cGy, >4500 cGy in 32 (87%), administered through hyperfractionated or once-daily schedules. Median number of D treatments received 5.5, >4 in 24 (65%). 2-year outcomes: LRC 25%; PFS 8%; OS 18%. 6 patients remain alive at the time of last follow-up with survival durations of 4.1, 11.4, 11.7, 57.3, 58.5, and 140.7 months, respectively. A subset analysis was performed limited to the 24 patients (65%) who completed >4,500 cGy of radiation and >4 doses of D. 2-year outcomes were improved in this latter group, but remained disappointing, even among these more highly selected pts (LRC 30%; PFS 11%; OS 27%). Conclusions: Better therapy is needed for this poor prognostic disease. Future analyses will evaluate the impact of histologic subtype of ATC, radiation technique/dose, and surgical resection on outcome. No significant financial relationships to disclose.