Endocrine Abstracts

Background: Familial non medullary thyroid carcinoma (FNMTC) is a not very well known histopatologic entity. Nowadays there are controversial publications about his aggresiveness and prognosis

Objective: To know the clinical outcomes and histopathological characteristics of our patients with FNMTC and to compare them with a cohort of patients with sporadic non medullary thyroid carcinoma (CDT).

Methods: We conducted a retrospective descriptive study including 55 familial non medullary carcinoma patients belonging 27 families diagnosed beetwen 1983 and 2017. Every family had two or more first degree relatives with FNMTC. They were compared with an aleatory sample of our cohort of patients with sporadic differentiated thyroid carcinoma (DCT) (750 cases).

Results: 25 (92.6%) families had 2 members affected. 7 (21.21%) families had one member diagnosed with papillary microcarcinoma. 70.9% were women. Median age at diagnosis was 45.9 (37.8–56.5) years. 15 (55.56%) families were siblings and 13 (48.15%) parent-child. The age of presentation between parents-child show a significative difference of 20 (15–27) years (P<0.05). Histologically, 85% were papillary, and 15% were follicular. Multifocality was observed in 38%,19.6% showed extrathyroid extension and 6% surgical margins affected. Staging at diagnosis revealed 67.3% of patients were at stage I, 7.7% stage II, 19.2% stage III, and 1.9% at stage VIb, the 3.8% of patients presented metastasis at diagnosis. Total thyroidectomy was carried in 93.3% patients, central neck cervical dissection was added in 51.1% and the 10.6% recieved also a lateral neck linphadenectomy. 55 (98.21%) recieved radioactive iodine remmant ablation. More than 1 RAI were applied in 9 (21.2%) patientes. Median radiactive activity recieved was 105 (100–118) mCi. After a median follow-up of 4 (1–8) years, excellent response was observed in 86.4%, indeterminated response (biochemical or estructural) in 4.5% and incomplete response in 4.5%. 2 cancer related deaths were observed in our cohort. We haven’t found any mayor prognosis difference between our FNMTC and our sporadic DTC cohort. A higher presence of aggresive histology tumors was observed in the FNMTC cohort (10.7% Vs 4%, P<0.05).

Conclusions: We haven’t found significative histopathological, survival or prognosis differences between our FNMTC and sporadic DCT cohorts. Although we have a wide series, families with three affected members are under represented. We have to consider the probability of sporadic disease in the pedigrees with only two members affected. Earlier age presentation in second generation patients was observed in our cohort.