Prognosis and prognostic factors of patients with papillary carcinoma showing distant metastasis at surgery (M1 patients) in Japan

Distant metastasis (DM) at surgery is a prominent prognostic factor in patients with papillary carcinoma of the thyroid. However, the clinical outcomes of these patients (M1 patients) remain unclear. In this study, we investigated the prognosis and prognostic factors of M1 patients. Seventy-one of 5969 patients who underwent initial surgery in Kuma Hospital between 1987 and 2004 were classified as M1 and enrolled in this study. Five-year and 10-year cause specific survival (CSS) rates were 78.8 +/- 5.2% and 76.3 +/- 5.7%, respectively. Patients aged 55 years or older, having tumor larger than 4 cm, massive extrathyroid extension to adjacent organs other than the recurrent laryngeal nerve and cricothyroid or inferior constrictor muscle, and DM to organs other than the lung showed a significantly worse CSS on univariate analysis. On multivariate analysis, the first three parameters were recognized as independent prognostic factors for M1 patients. Patients who underwent locally curative surgery, having DM showing radioactive iodine (RAI) uptake, and who underwent thyroid stimulation hormone (TSH) suppression therapy showed a better CSS rates than those who underwent only palliative surgery, having DM without RAI uptake, and who did not undergo TSH suppression therapy, although there was no significant difference in CSS between these groups. These findings suggest that evaluation of preoperative and intra-operative findings is important to predict the prognosis of M1 patients, the same as that in patients without DM. Locally curative surgery, RAI therapy, and TSH suppression therapy are actively recommended for M1 patients when conditions permit.