Differentiated thyroid carcinoma with distant metastases at presentation: prognostic factors and outcome

Background Differentiated thyroid cancer (DTC) presenting with distant metastases is uncommon. Prognostic factors that affect survival remain unclear. Aim To evaluate factors influencing the survival of patients with DTC presenting with distant metastases. Method A retrospective study of 111 patients (62 F, 49 M) with DTC who presented with distant metastases (M1) treated at the Royal Marsden Hospital from 1940 to 2002. Results The median follow-up of living patients was 3.9 years (0.3-48) with a 10-year cause-specific survival rate of 31%. Histology identified 46 papillary, 60 follicular and five Hurthle cell cancers. Sites of metastases comprised 54 lung (49%), 27 bone (24%), 21 multiple sites (19%) and nine with other single sites affected (8%). Near-total, total or completion thyroidectomy was performed in 56% of patients, radioiodine ablation in 76% and radioiodine therapy in 67%. External beam radiotherapy was given to 12 patients and the same number received chemotherapy. Univariate analysis was performed with cause-specific survival as the main outcome measure. Age over 70, poorly differentiated tumours and Hurthle cell cancers were associated with worse outcomes (P < 0.01). Patients with multiple organ metastases had a worse survival (P = 0.02). Radical surgery did not significantly improve outcome compared to more conservative forms of surgery (subtotal thyroidectomy, hemi-thyroidectomy or lobectomy) but patients receiving radioiodine ablation and therapy had improved survival (P < 0.01). Multivariate analysis identified age over 70, poorly differentiated tumours and Hurthle cell variant to be the only independent factors associated with worse outcome (P < 0.01). Treatment in the 1991-2002 era was associated with an improved survival compared to all previous decades (P = 0.009). conclusions Patients with DTC presenting with distant metastases have a worse outcome if aged over 70, have poorly differentiated tumours or have Hurthle cell variant. Despite their unfavourable prognosis, a dramatic improvement in survival was observed in the most recent era (1991-2002).