Small medullary thyroid carcinoma: post-operative calcitonin rather than tumour size predicts disease persistence and progression

Abstract

Objective: Recently, small medullary thyroid carcinomas (smallMTCs; %1.5 cm) are frequently diagnosed, occasionally as incidental findings in surgical specimens. Their clinical course varies. We examined tumour size as a predictor of clinical behaviour. Design: A retrospective study. Methods: A total of 128 smallMTC patients (35.2% males and 45% familial) were followed up for 0.9-30.9 years. According to tumour size (cm), patients were classified into four groups: group 1, 0.1-0.5 (nZ33); group 2, 0.6-0.8 (nZ33); group 3, 0.8-1.0 (nZ29) and group 4, 1.1-1.5 (nZ33). Results: Pre-and post-operative calcitonin levels were positively associated with the tumour size (P!0.001). Capsular and lymph node invasion were more frequent in groups 3 and 4 (P!0.03); the stage was more advanced and the outcome was less favourable with an increasing tumour size (P!0.001). Groups 1 and 2 patients were more frequently cured (group 1, 87.8%; group 2, 72.7%; group 3, 68.9%; and group 4, 48.5%; PZ0.002). The 10-year probability of lack of disease progression according to the tumour size differed between patients with tumour sizes of 0.1-1.0 and 1.1-1.5 cm (96.6%, 81.3%, x 2 Z4.03, PZ0.045 for log-rank test). Post-operative calcitonin was the only predictor significantly associated with the 10-year progression of disease. Post-operative calcitonin levels R4.65 pg/ml predicted disease persistence (sensitivity 93.8% and specificity 90%) and R14.5 pg/ml predicted disease progression (sensitivity 100%, specificity 82%, receiver operating characteristic curve analysis). Conclusions: Tumour size may be of clinical importance only in patients with MTCs O1 cm in size. Post-operative calcitonin is a more important predictor than size for disease progression.

Postoperative biochemical remission of serum calcitonin is the best predictive factor for recurrence‐free survival of medullary thyroid cancer: a large‐scale retrospective analysis over 30 years

“…MTC survival could have been affected by several prognostic factors such as age, 21 male gender, invasive histological characteristics, 22 the adequacy of primary surgery 2,23 and the calcitonin doubling time. 2,24,25 In agreement with other studies, we found that male gender, tumour size >2 cm and distant metastasis were significant prognostic factors for survival. In the present study, although there was a decrease in tumour size, the percentage of male and distant metastasis remained similar over time, and the proportion of tumour >2 cm remained about 25% even in 2011-2012.…”

“…Although pathologic characteristics and recurrence‐free survival improved during recent periods, mortality was unchanged over time. MTC survival could have been affected by several prognostic factors such as age, male gender, invasive histological characteristics, the adequacy of primary surgery and the calcitonin doubling time . In agreement with other studies, we found that male gender, tumour size >2 cm and distant metastasis were significant prognostic factors for survival.…”

“…Saltiki et al . suggested that postoperative calcitonin level ≥14·5 pg/ml might predict disease progression and was the only predictor associated with the 10‐year progression of the disease …”

“…There exist a few reports supporting our results. Two recent studies suggested postoperative calcitonin level was an important predictive factor for disease progression and persistence, 24,27 so postoperative calcitonin levels could be a reliable index of disease status and complete resection of tumours. 28 Saltiki et al suggested that postoperative calcitonin level ≥14Á5 pg/ml might predict disease progression and was the only predictor associated with the 10-year progression of the disease.…”

Bilateral Medullary Thyroid Carcinoma in a 3-Year-Old Female Patient with Multiple Endocrine Neoplasia 2A Syndrome Undergoing Prophylactic Thyroidectomy: Should Current Guidelines Be Revised?

“…In addition, patients’ probability for cure from MTC has been found to be associated with lymph node status, ranging from 95% when no lymph nodes are involved, 31–57% when 1–10 lymph nodes are involved, and 0–4% when more than 10 lymph nodes are involved with MTC [12-14]. Previous publications have demonstrated the possibility of lymph node involvement regardless of the size of the tumor and even in micro-medullary carcinomas of less than 0.5 cm in diameter [15]. The performance of thyroidectomy prior to the development of MTC and definitely prior to the development of lymph node involvement in nearly all cases is a crucial aspect of the prophylactic nature of the procedure.…”