**5. Conclusions**

Thyroid lobectomy was not associated with the risk of recurrence in patients with multifocal PTCs. Multifocality in PTC may not always require aggressive surgery.

**Supplementary Materials:** The following is available online at https://www.mdpi.com/article/ 10.3390/cancers14020432/s1: Figure S1. Comparison of survival analysis by the operative extent: log(-log(survival)) plot.

**Author Contributions:** Conceptualization, J.W. and H.K.; methodology, J.W.; validation, H.K.; formal analysis, J.W. and H.K.; resources, H.K.; data curation, H.K.; writing—original draft preparation, J.W.; writing—review and editing, J.W. and H.K.; project administration, H.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Institutional Review Board of Ewha University Medical Center Mokdong Hospital (approval number: 2021-07-015 and date of approval: 30 July 2021).

**Informed Consent Statement:** Patient consent was waived by the institutional review board, because (1) this research involved no more than minimal risk to subjects and (2) this research could be carried out practicably without the waiver.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to institutional policy.

**Conflicts of Interest:** The authors declare no conflict of interest.
