Endocrine Abstracts

Aim: Postoperative calcitonin (postCT) is a prognostic factor for disease progression in MTC patients. We evaluated the disease course in patients with persistently elevated post-CT.

Methods: Of all MTC patients (n=273) followed-up in our Unit (for 1–37, median 7 years), 140 (39.3% men, 67.1% sporadicMTCs) had persistently elevated postCT (≥2.0 pg/ml). Clinical and biochemical data were recorded. Patients were classified in four groups according to postCT: group1: (2–12 pg/ml, n=34, 24.3%), group 2: (13–50 pg/ml, n=26, 18.6%), group 3: (51–200 pg/ml, n=30, 21.4%), group 4: (>200 pg/ml, n=50, 35.7%).

Results: Men had post-CT>50 (P=0.005) more frequently. SporadicMTCs had post-CT>200 more frequently than familialMTC (43.6% vs 19.6%,P=0.019). With increasing postCT, unfavorable histopathological features and multiple surgeries (n≥2) were more frequent (P<0.001), tumor size was larger (median (IQR) 1.0(1.8), 1.25(1.23), 1.5(0.9), 2.5(1.8) cm, P<0.001) and preoperative-CT was higher (200(334), 17.9(732), 455(1011), 2500 (>10.000), P=0.002) in the four groups respectively. Distant metastases at diagnosis were present only in group4 patients (31.3%, all with post-CT>400). Metastatic disease appeared in 8% of group 1, 8% of group 2, 29.6% of group 3 and 68.9% of group four during follow up; progression was recorded in 5.9%, 19.2%, 26.7% and 78.0% while disease remission at last follow-up (after multiple interventions) was recorded in 71.0%, 27.3%, 14.3% και 0.0%, in the four groups respectively (P<0.001). The 10-year probability of absence of disease progression differed significantly between the four groups (group1: 94.1%, group 2: 80.8%, group 3: 73.3%, group 4: 22%, χ²=30.3, P<0.001 Log Rank). In Cox-proportional hazard analysis when age, sex, histological features, disease stage at diagnosis and postCT group were taken into account, the only predictor for disease progression were postCT (P=0.037), familial disease (P=0.016) and stage (P=0.05).

Conclusions: This study confirms that postCT are significant predictors of the clinical course in MTC patients. Approximately 20% of patients with postCT>200 showed slow disease progression. Increased awareness is required for patients with low-CT-secreting MTC as their levels may not reflect the disease extent.