Optimizing the treatment of AMES high-risk papillary thyroid carcinoma

A minority of patients with papillary thyroid carcinoma (PTC) is at high-risk of developing recurrent disease and death. Risk group stratification as defined by age, metastases to distant site, extrathyroidal invasion, and tumor size (AMES) criteria is frequently employed to identify high-risk patients for aggressive surgical and adjuvant treatments. The present study aimed at evaluating risk factors and the impact of treatment on cause-specific mortality (CSM) in this group of high-risk patients. From 1961 to 2000,150 of 499 patients surgically treated for PTC were considered as high-risk by AMES criteria. At 10-years CSM was significantly higher in high-risk patients (28%) than in low-risk patients (2%) (p < 0.0001). The clinicopathologic features, treatment, and outcome of AMES high-risk patients were retrospectively studied and risk factors for CSM were analyzed. There were 58 men and 92 women with a median age of 62 years (range: 18-87 years). Bilateral thyroidectomy was performed for 143 (95%) patients and concomitant neck dissection was performed for 82 patients (55%). Thirty-six patients (24%) underwent incomplete tumor excision with residual disease. Radioactive iodine (I131) ablation and external-beam irradiation were administered to 102 (68%) and 46 patients (31%), respectively. Over a median follow-up of 7.6 years, the overall mortality was 23% and 44%, whereas the CSM was 14% and 28% at 5 and 10 years, respectively. Using the Cox proportional hazard model, distant metastasis at presentation, incomplete tumor excision, and no postoperative I131 treatment were independent prognostic factors of poor survival. Patients who underwent an incomplete excision showed improved survival after I131 ablation (p = 0.0008), external-beam irradiation (p = 0.02), or both forms of treatment (p = 0.04). Within this high-risk AMES group, International Union Against Cancer (UICC) pTNM staging and MACIS (Metastasis, Age, Completeness, Invasion, Size) scoring correlated significantly with CSM. AMES high-risk PTC patients should undergo total thyroidectomy aiming at complete tumor resection followed by I131 ablation. External-beam irradiation should be added for patients with residual disease after an incomplete excision.