The Prognostic Value of Tumor Multifocality in Clinical Outcomes of Papillary Thyroid Cancer
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Context Multifocality is often treated as a risk factor for papillary thyroid cancer (PTC), prompting aggressive treatments, but its prognostic value remains unestablished. Objective To investigate the role of tumor multifocality in clinical outcomes of PTC. Methods Multicenter study of the relationship between multifocality and clinical outcomes of PTC in 2638 patients (623 men and 2015 women) with median [interquartile range (IQR)] age of 46 (35 to 58) years and median (IQR) follow-up time of 58 (26 to 107) months at 11 medical centers in six countries. Surveillance, Epidemiology and End Results (SEER) data were used for validation. Results Disease recurrence in multifocal and unifocal PTC was 198 of 1000 (19.8%) and 221 of 1624 (13.6%) (P < 0.001), with a hazard ratio of 1.55 [95% confidence interval (CI), 1.28 to 1.88], which became insignificant at 1.13 (95% CI, 0.93 to 1.37) on multivariate adjustment. Similar results were obtained in PTC variants: conventional PTC, follicular-variant PTC, tall-cell PTC, and papillary thyroid microcarcinoma. There was no association between multifocality and mortality in any of these PTC settings, whereas there was a strong association between classic risk factors and cancer recurrence or mortality, which remained significant after multivariate adjustment. In 1423 patients with intrathyroidal PTC, disease recurrence was 20 of 455 (4.4%) and 41 of 967 (4.2%) (P = 0.892) and mortality was 0 of 455 (0.0%) and 3 of 967 (0.3%) (P = 0.556) in multifocal and unifocal PTC, respectively. The results were reproduced in 89,680 patients with PTC in the SEER database. Conclusions Tumor multifocality has no independent risk prognostic value in clinical outcomes of PTC; its indiscriminate use as an independent risk factor, prompting overtreatments of patients, should be avoided.
Journal of Clinical Endocrinology and Metabolism
© 2017 Oxford University Press. This is a pre-copy-editing, author-produced PDF of an article accepted for publication in the Journal of Clinical Endocrinology and Metabolism following peer review. The definitive publisher-authenticated version The Prognostic Value of Tumor Multifocality in Clinical Outcomes of Papillary Thyroid Cancer, Journal of Clinical Endocrinology and Metabolism, Volume 102, Issue 9, 1 September 2017, Pages 3241–3250 is available online at: https://doi.org/10.1210/jc.2017-00277
Clinical Sciences not elsewhere classified