Can preoperative modified systemic inflammation score (mSIS) be used to predict malignancy in persistent nondiagnostic thyroid nodules?

BACKGROUND/AIM: Despite the use of ultrasound guidance, a significant part of thyroid biopsies are nondiagnostic (ND). We aimed to investigate the utility of the preoperative modified systemic inflammation score (mSIS) to predict malignancies in patients with persistent ND thyroid nodules (TNs). MATERIALS AND METHODS: Records of 924 patients underwent thyroidectomy between September 2016 and May 2019 were retrospectively reviewed. The calculation of mSIS was as follows: mSIS 0 [patients with albumin (ALB) ≥ 4.0 g/dL and lymphocyte to monocyte ratio (LMR) ≥ 3.4], mSIS 1 [ALB < 4.0 g/dL or LMR < 3.4], and mSIS 2 [ALB < 4.0 g/dL and LMR < 3.4]. RESULTS: One hundred and thirty-six patients were included in the study. Of the patients with a median age of 49 (21–81) years, 26 (19.1%) were male, and 110 (80.9%) were female. Besides low lymphocyte count (P = 0.03), and ALB levels (P < 0.01), higher BMI (P = 0.02) were also associated with malignancy. In patients classified as mSIS 2, 1 and 0; malignancy rates were 100%, 25.8%, and 16.1%, respectively. The association between preoperative mSIS and thyroid malignancies was statistically significant (P < 0.01). CONCLUSION: We recommend that when patients with persistent ND TNs are assigned to mSIS 2 or 1, surgery should not be delayed due to the risk of malignancy.