Rapid thyroid nodule growth is not a marker for well-differentiated thyroid cancer

BACKGROUND: Rapid growth of thyroid nodules is described as being associated with thyroid cancer. The objective of the study was to determine how the growth rate of thyroid nodules during follow-up is associated with the risk of thyroid cancer. METHODS: Retrospective analysis of patients undergoing thyroid surgery for nodular disease and a repetitive preoperative ultrasound work-up of at least 6 months was done. Nodule growth was considered relevant when a volume increase >49 % was detected. Growth patterns were described as rapid for a volume increase present over 6 to 24 months. RESULTS: Of the 297 analysed patients, 226 (76 %) displayed relevant nodule growth and 71 (24 %) no relevant growth. A rapid growth pattern was seen in 73 patients (32 %). Well-differentiated thyroid cancer was diagnosed in 33 patients (11 %; 27 papillary, 6 follicular) with a relevant nodule growth in 2 and no relevant growth in 31 patients. No rapid growth pattern was observed in any case of well-differentiated thyroid cancer. A rapid growth pattern occurred only in benign nodules (70 patients) and in 1 patient each with a lymphoma, a metastasis of a renal cell cancer and a metastasis of a gastric adenocarcinoma. Therapy with levothyroxine and/or iodine was administered to 129 patients (43 %) and was significantly inversely correlated with nodule growth (odds ratio 0.27; CI 95 % 0.14–0.53, p < 0.001). CONCLUSIONS: Thyroid nodule growth alone and especially a rapid growth pattern during follow-up for thyroid nodular disease is not a marker for well-differentiated thyroid cancer and should not be used as a stand-alone argument for thyroid surgery.