Survival and prognostic factors of radioiodine refractory pulmonary metastatic differentiated thyroid carcinoma (DTC).

Abstract

6093 Background: The challenging key point of management of radioiodine refractory DTC patients is to define those who could benefit from experimental drugs in clinical trials. Methods: We reviewed clinical and pathological data of patients with refractory pulmonary metastatic DTC treated in our center from 1990 to 2011. Survival was estimated with the method of Kaplan-Meier. Associated prognostic factors were studied in Cox model based analyses. Results: Among 167 pulmonary metastatic DTC, 46% (n=76) met a criterion of radioiodine refractory disease: at least one metastases without I131 uptake: 61% (n=46); progressive disease despite I131: 22% (n=17) and absence of complete response despite a cumulated dose >600mCi: 17% (n=13). There were 63% of female (n=48) and the median age was 64 years (range 18-87). The initial treatment was total thyroidectomy in 92% (n=70), lymph node dissection in 71%, (n=54) and radioiodine therapy in 100% of patients. Pathological features were papillary histology in 61% (n=46), follicular histology in 29% (n=22) and poor differentiated histology in 10% (n=8). pT stage was 1ab, 2, 3, and 4 in 11%, 13%, 63% and 13% respectively, pN stage after lymph node dissection was 0, 1a and 1b in 33%, 7% and 60% respectively. Metastasis were present at diagnosis in 45% (n=34) of cases. The refractory feature was established at the time of diagnosis and in the follow-up in 18% and 82% of cases respectively. When the disease was considered as refractory, the median overall survival was 5.5 years. The refractory feature at the initial diagnosis was the only independent prognostic factor correlated with poor survival (p<0.001). Conclusions: Patients who are considered as radioiodine refractory at the initial diagnosis of DTC have poor prognosis and should be considered for clinical trials in case of progression.