ECE2024 Rapid Communications Rapid Communications 8: Thyroid | Part II (5 abstracts)
1Ferrara, Dept of medical Sciences, Ferrara, Italy; 2Ferrara, UOC of Endocrinology, AOU Ferrara, Ferrara, Italy
Introduction: Thyroid nodules (TN) may display somatic RAS mutations, that, however, lack of diagnostic value. In our experience, somatic RAS mutation evaluation could be useful since it has a very high negative predictive value. In the past, somatic RAS mutation had been associated with a good prognosis in thyroid cancer.
Objective: This study aims to evaluate whether somatic RAS mutation may associate with TN differential growth pattern.
Methods: Our study included 2174 patients referring our center for TN assessment by ultrasound (US), fine needle aspiration biopsy and subsequent cytological and molecular evaluation, represented by somatic BRAFV600E mutation by a CE-IVD Real-time PCR kit (DIATECH, Italy). In BRAF V600E negative TN displaying a non-malignant cytology, somatic RAS mutations were investigated by by a CE-IVD Real-time PCR kit (DIATECH, Italy). We selected 1092 TN undergoing somatic RAS mutations evaluation with a basal and at least one follow-up US evaluation (median follow-up 2 years) and calculated TN volume with the ellipsoid formula.
Results: Among the 1092 TN with US follow-up somatic RAS mutations were identified in 49 TN (RAS+), while 1043 TN where wild type for somatic RAS mutations (RAS-). Each group was divided in 3 categories: 1) TN displaying a volume increase, 2) TN displaying a volume reduction, 3) TN displaying stable volume during follow-up. We found that somatic RAS mutations were equally distributed among the 3 categories. On the contrary, initial volume was significantly higher in RAS- vs RAS+ TN in both category 1 (3.65 vs 1.08 ml) and 2 (4.71 vs 2.18 ml) (P<0.01). In addition, volume variations RAS+ TN were not significant, while category 1 RAS- TN showed a ~twofold increase in volume (P<0.01) and category 2 RAS- TN showed a ~1.5-fold reduction in volume (P<0.01).
Conclusions: Our data smggest that somatic RAS mutations do not associate with TN volume variations. On the contrary, in our study they associate with a smaller and stable volume, supporting the hypothesis of a protective effect of these mutations.