Endocrine Abstracts

Objectives: Medullary thyroid carcinoma (MTC) has varying clinical course with familial cases (fMTC) diagnosed earlier than sporadic ones (sMTC). We examined the presentation of these entities in our centre.

Methods: 223 MTC patients (familial: 42.6%, males: 36.8%) were followed for 0.9–30 years (mean 6.23±5.9, median 4.0 years). 44 (19.7%) fMTC patients were operated after genetic screening.

Results: Median age at diagnosis was for fMTC: 32.4±16.3 years (range 4–73) and for sMTC: 52.4±13.6 years (range 16–81, P<0.001). This difference remained when cases diagnosed after genetic screening were excluded (P=0.001). fMTC was more frequent in women than men (48.2% vs 32.9%, P=0.018). Capsular invasion, lymph node invasion, distant metastasis at diagnosis was similar. The size of sMTCs was more frequently ≥1.5 cm (P=0.012). Stage at diagnosis was more favorable in fMTCs (stages I and II: 60.4% vs 51.2%, stage III: 8.8% vs 23.2%, and stage IV: 42.1% vs 57.9%, P=0.021). Preoperative and postoperative calcitonin levels were significantly lower in fMTCs. fMTC had more frequently remission (62.9% vs 49.2%) and less frequently progressive disease (9% vs 36.3%, P<0.001).

After excluding patients diagnosed through genetic screening, no difference in stage at diagnosis was observed. Tumour size and postoperative calcitonin levels did not differ. Outcome was more favorable in fMTC compared to sporadic (remission: 56.3% vs 48.8%, stable: 29.2% vs 14.6%, and disease progression: 14.6% vs 36.6%, P=0.008). The 10-year probability of lack of progression of disease differed significantly between familial and sporadic MTCs (85.4% vs 63.4%, Kaplan–Meier analysis, χ²=19.01, P<0.001).

Conclusions: After excluding those diagnosed through genetic screening, although stage at diagnosis is currently similar and does not differ between familial and sporadic cases, disease outcome remains worse in sporadic MTCs. Women may have increased awareness for genetic screening in familial cases.