The effect of implementing pre-surgical ultrasound-guided fine-needle aspiration biopsy on thyroid surgery, a 6-year interrupted time series analysis in Qilu Hospital of Shandong University

Zhiyan Liu; Shaofeng Sui; Peng Su; Xiaofang Zhang; Jing Hu; Feifei Sun; Bo Han

doi:10.21037/gs-20-348

The effect of implementing pre-surgical ultrasound-guided fine-needle aspiration biopsy on thyroid surgery, a 6-year interrupted time series analysis in Qilu Hospital of Shandong University

Gland Surg. 2020 Oct;9(5):1716-1723. doi: 10.21037/gs-20-348.

Authors

Zhiyan Liu^{1

2}, Shaofeng Sui³, Peng Su², Xiaofang Zhang², Jing Hu², Feifei Sun², Bo Han²

Affiliations

¹ Department of Pathology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
² Department of Pathology, Qilu Hospital of Shandong University, Shandong University, Jinan, China.
³ Department of Occupational and Environmental Health Monitoring and Assessment, Shandong Center for Disease Control and Prevention, Jinan, China.

Abstract

Background: Thyroid fine-needle aspiration biopsy (FNAB) is not well developed in most of the large academic hospitals in China, including Qilu Hospital of Shandong University. Ultrasound-guided FNAB (UG-FNAB) was initiated as a pre-surgical diagnostic method in 2015 in Qilu Hospital, and the current study evaluates its impact on the number of thyroid surgeries and the ratio of malignancy (ROM) in surgically resected cases, comparing the post and pre-UG-FNAB periods.

Methods: Thyroid surgery and UG-FNAB data for the study period (Jan 2013 to Dec 2018) were collected from the hospital information system (HIS). A natural experimental approach using segmented linear regression was performed on the interrupted time-series (ITS) data to estimate the level-change of the number and the trend-change of ROM of surgically resected cases following the implementation of UG-FNAB diagnosis.

Results: The number of UG-FNAB cases in Qilu Hospital increased rapidly from 1,367 in 2015 to 3,402 in 2018, with an average annual increase of 678 cases. Comparing the pre-UG-FNAB and post-UG-FNAB periods, the overall ROM of thyroid resections increased from 58.7% to 73.2% (P<0.01). Due to the implementation of UG-FNAB, the regression line of surgical cases showed an inflection point in March 2015, and the slope of the regression line of post-intervention was lower than that of pre-intervention. For each additional month, the ROM in thyroid surgical cases increased by 0.389% (P<0.01). After excluding the influence of time, the ROM in surgically resected thyroid cases increased by 4.781% due to the application of the UG-FNAB examination (P<0.01).

Conclusions: This successful implementation of UG-FNAB further improved overall ROMs in surgically resected cases particularly as we acquired further experience with the procedure and reduced unnecessary diagnostic surgeries for patients with benign and borderline lesions.

Keywords: FNA cytology; Thyroid; diagnostic surgery; interrupted time series analysis; risk of malignancy.