Calcitonin and carcinoembryonic antigen doubling times as prognostic factors in medullary thyroid carcinoma: a structured meta-analysis

Summary Context In the management of patients with medullary thyroid carcinoma (MTC), calcitonin doubling time (dt) has gained interest as an independent predictor of recurrence and survival. Objective To perform a structured meta‐analysis of the diagnostic value of calcitonin dt, carcinoembryonic antigen (CEA) dt and the combination and to define dt strata with the highest predictive power. Design The study was a meta‐analysis using individual data. Methods Ten studies containing data on the post‐operative kinetics of tumour marker(s) and (recurrence free) survival were included. Results Calcitonin‐ and CEA‐dt are significant indicators for survival (hazard ratios (HR) 21·52 respectively infinite for dt 0–1 year compared to dt >1 year) and recurrence (HR 5·33 respectively 6·80 for dt 0–1 year compared to dt >1 year). The highest predictive power was found for the dt classification 0–1 year vs. >1 year. CEA dt has a higher predictive value than calcitonin dt in the subgroup of patients for which both parameters were available. Conclusion The dts of both calcitonin and CEA are strong prognostic indicators for MTC recurrence and death. CEA dt has a higher predictive value than calcitonin dt and therefore measuring both tumour markers is essential for proper risk stratification.