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 Hürthle 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 Hürthle 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 Hürthle 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 Hürthle cell variant. Despite their unfavourable prognosis, a dramatic improvement in survival was observed in the most recent era (1991-2002).