The risk of malignancy (ROM) in thyroid nodules with BETHESDA III and IV results at cytology may widely vary, ranging between 10 and 30%; thus, the management (follow up versus surgery) remains controversial. This study was aimed to assess the ROM in a large cohort of patients undergoing surgery in a tertiary academic centre for these undetermined nodules
Thyroid surgery for BETHESDA III or IV nodules was performed in 534 patients. Anamnestic, surgical, pathological and biochemical data were evaluated.
Malignancy was found in 230 patients (43%). The ROM in BETHESDA III nodules was 33%; in BETHESDA IV nodules it was 56% (p<0.01). A younger age at the surgery (50.3 vs 53.5 years, OR 0.982; p=0.006) and a BETHESDA IV at cytology (OR 2.69; p<0,001) were predictive factors of malignancy. When focusing exclusively on BETHESDA III nodules, no significant predictive risk factors were found. In BETHESDA IV nodules, younger age (50 versus 55.4; OR 0.977; p=0.013) and size of the nodule larger than 3cm (OR 1.77; p=0.039) were significant predictive risk factors of malignancy
BETHESDA III and IV have a ROM surprisingly higher than expected. The prediction of malignancy remains challenging, especially for BETHESDA III nodules. Larger BETHESDA IV nodules in younger patients have a significantly higher ROM and should be surgically treated