Clinical characteristics and prognosis of familial nonmedullary thyroid carcinoma

Introduction: Familial non-medullary thyroid carcinoma (FNMTC) is defined by the presence of 2or more first-degree family members with differentiated thyroid carcinoma (DTC). The aim of this study is to compare clinicopathological features and prognosis of FNMTC and sporadic carcinoma (SC).

Materials and methods: Retrospective study of DTC included in the hospital database during the period 1990-2018.

Results: A total of 927 patients were analyzed, 61 of them were FNMTC, with a mean follow-up of 9.7±6.5 years. The prevalence of FNMTC was 6.6%, with a lower TNM staging presentation (P=.003) consequence of a higher proportion of tumors smaller than 2 centimeters (P=.003), combined with a greater multifocality (P=.034) and papillary histologic subtype (P=.022) compared to SC. No significant differences in age at diagnosis (P=.347), gender (P=.406), neither in other aggressiveness markers (bilaterality, extrathyroidal extension, lymph node involvement and metástasis) were detected. Rate of persistence/recurrence (P=.656), disease-free survival (P=.929) and mortality caused by the tumor itself (P=.666) were comparable. Families with ≥3 affected relatives, had smaller tumors (P=.005), more multifocality (P=.040) and bilaterality (P=.002), as well as a higher proportion of males (P=.020). Second generation patients present earlier FNMTC compared to those of the first generation (P=.001).

Conclusion: In our study FNMTC presents a lower TNM staging, higher multifocality and papillary variant, with similar aggressiveness and prognosis compared to SC.