Impact of intraoperative frozen section pathology on the treatment outcome of unilateral papillary thyroid microcarcinoma and its influencing factors-a retrospective cohort study.

Background: Most patients with papillary thyroid carcinoma have a good prognosis. Excessive resection of thyroid and cervical lymph nodes is an important reason for affecting the quality of life of patients after surgery. Intraoperative rapid frozen pathological examination is an important step in the development of a surgical plan for thyroid cancer (especially micropapillary carcinoma); however, whether it affects the treatment outcome remains unclear.

Methods: The clinicopathological data of papillary thyroid microcarcinoma (PTMC) patients who underwent surgery in our center from 1 January 2021 to 31 December 2021 were retrospectively analyzed. Patients with unilateral low-risk PTMC who underwent radical surgery were selected as the main research subjects. The negative results of intraoperative frozen section of the central lymph node (CLN) of the affected side were the experimental group, and the positive results were the control group. Subjects with lesions larger than 10 mm and those who did not undergo intraoperative frozen section pathological examination were excluded. After excluding other risk factors for recurrence, we calculated the proportion of patients requiring radioactive iodine (RAI) treatment among those with metastases detected by intraoperative rapid frozen section pathology and its influencing factors. Patient data were analysed using SPSS version 20. Continuous variables were presented as means when symmetrical or as medians and ranges when asymmetrical. Categorical variables were presented as proportions. A P value <0.05 was considered significant.

Results: A total of 564 PTMC patients were included, among whom 122 patients (21.6%) underwent total thyroidectomy due to the presence of metastases in the ipsilateral CLNs. Compared with the experimental group, the patients with male, young age and tumor located in the middle and lower pole in the control group had higher lymph node metastasis (P<0.05).

Conclusions: The proportion of patients requiring postoperative RAI treatment for unilateral low-risk PTMC is relatively low, and the possibility that an intraoperative frozen pathological finding will change the treatment outcome is low. However, the need for postoperative RAI therapy notably increases when the intraoperative frozen pathological analysis reveals ipsilateral CLN metastases, especially in males, younger patients, and/or patients with lesions located in the middle and lower poles.