N. Zern1, A. Glover3, A. Aniss2, M. Sywak2, L. Delbridge2, S. Sidhu2 1University Of Washington,Department Of General Surgery,Seattle, WA, USA 2University Of Sydney,Endocrine Surgical Unit,Sydney, NSW, Australia 3Memorial Sloan-Kettering Cancer Center,New York, NY, USA
Introduction: Incidental malignancy after thyroidectomy for multinodular goiter is not rare. This study examines clinical outcomes of patients with incidental carcinoma after thyroidectomy for benign disease.
Methods: A retrospective review of our thyroid cancer database was performed for years 2000-2015. Patients were analyzed who underwent total thyroidectomy for benign multinodular goiter. Patients were included for analysis as cases without suspected malignancy if preoperative fine needle aspiration was benign, non-diagnostic or not performed, and if final pathology showed an incidental differentiated thyroid carcinoma > 1 cm. Micro-carcinomas were excluded from this study. These cases were matched to thyroidectomy patients with suspected malignancy based on gender, age and size of tumor. Primary outcome measure was recurrence defined by need for further surgery.
Results: 71 patients underwent thyroidectomy for benign goiter with incidental carcinoma >1 cm. 72% were female with average age of 54 years at operation. The predominant histology was papillary carcinoma (77%). 27/71 patients (38%) underwent nodal resection. 10/27 (37%) had positive nodal metastases. Matched controls with preoperatively suspected malignancy (n=137) showed similar histology, however 53/96 (55%) patients who underwent nodal resection had nodal metastases. Follow up was similar between groups (25 vs. 31 months, p=0.1) as was total dose of radioactive iodine therapy (5.6 vs. 5.4 GBq, p=0.8). Significantly more patients required an operation for recurrence in the control group, 11.7% vs. 2.8% (p=.04).
Conclusion: Incidental thyroid carcinoma in benign multinodular goiter has low rates of recurrence. Standard investigations in these patients failed to yield a diagnosis of cancer preoperatively, likely due to the favorable features of these tumors. The absence of aggressive pathology leads to a better outcome following surgical resection.