Endocrine Abstracts

Medullary Thyroid Cancer (MTC) is sporadic in approximately 75% whilst 25% of MTC occurs as hereditary forms due to RET mutations. Prognosis is relatively good with 10-year survival rates of 65%. However, many patients develop recurrent disease and imaging is critical to localise the site of recurrence. Eighty-eight MTC patients, attending the Royal Marsden Hospital NHS Trust were included in an analysis of overall survival. Median Follow-up duration was 7.5 years (IQR: 4.5–13.5). Twenty cases were hereditary and had a median survival 12 year (7.7–22.5 95%CL). Sixty-eight patients with Sporadic MTC had a shorter survival outcome, median survival 5. 7 year (5.0–7.7 95%CL). Overall median survival rate was 7.3 years (5.3–9.3 95%CL). Hazard Ratio for Sporadic Hereditary is 2.1 (1.2–3.5, P=0.005). According to Kaplan-Meier estimate, 65%(n=13) of these Hereditary MTC survive 10 years. In contrast, 10 year survival rate of sporadic cases was 28% (n=19). We also evaluated the sensitivity of different imaging modalities within three bands of calcitonin levels (0–100, 100–400, and > 400 ng/l). The findings demonstrated that USS neck had a superior sensitivity for localising diseases in those with calcitonin with less than 400: 0.25 (.0.073–.0.524 95%CL, calcitonin 0–100), 0.857 (0.421–0.996 95%CL calcitonin 100–400,) and .0 556 (.0.308–785 95%CL calcitonin > 400). In contrast, in patients with calcitonin > 400, CT neck and body has a higher sensitivity 0.667 (.0.49–0.814 95%CL) and .0745 (.0.604–0.857 95%CL) respectively. Thus, USS neck should be considered as first line imaging modality in follow-up in MTC in those with calcitonin < 400 and CT should be considered at higher calcitonin levels in order to identify site of disease relapse. In addition, Hereditary MCT has better prognosis than sporadic cases.