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

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.