title: Long-Term Recurrence of Small Papillary Thyroid Cancer and Its Risk Factors in a Korean Multicenter Study.
abstract: Small papillary thyroid cancer (PTC) generally has an excellent prognosis. However, long-term recurrence is not uncommon and sometimes leads to morbidity or mortality.
  
  
  
  To identify high-risk factors for long-term recurrence in patients with small PTC by stratifying their pathologic characteristics.
  
  
  
  We conducted a nationwide, retrospective, multicenter study of 3282 patients with PTC sized ≤2 cm from 9 high-volume hospitals in Korea.
  
  
  
  The maximally selected χ2 method was used to find the best cutoff points of tumor size, the number of metastatic lymph nodes (LNs), and the ratio of metastatic/examined LNs (LNR) to predict recurrence. Kaplan-Meier analysis and the Cox proportional hazards regression model were used to analyze recurrence and risk factors.
  
  
  
  The optimal tumor size cutoff was 1.8 cm (10-year recurrence rates for tumors sized 0.1 to 1.7 cm and 1.8 to 2.0 cm: 7.7% vs 17.2%, respectively). Metastatic LNs ≤1 and ≥2 provided optimal estimates of recurrence (10-year recurrence rates: 4.0% vs 16.8%, respectively). The LNR of 0.19 was the optimal cutoff point for predicting the risk of recurrence (10-year recurrence rates for LNRs of 0 to 0.18 and 0.19 to 1: 2.7% vs 16.2%, respectively). LN metastasis, lobectomy, tumor size ≥1.8 cm, and bilateral tumors were independent risk factors for recurrence.
  
  
  
  Long-term recurrence was increased in patients who underwent lobectomy or with tumor sized ≥1.8 cm, 2 or more metastatic LNs, or bilateral tumors. For patients with these high-risk features, total thyroidectomy could be considered to avoid reoperation.
authors.affiliation: Center for Thyroid Cancer, National Cancer Center, Goyang 10408, Republic of Korea.|Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
authors.forename: Yul
authors.initials: Y
authors.lastname: Hwangbo
authors.affiliation: Department of Internal Medicine, Korea Cancer Center Hospital, Seoul 01812, Republic of Korea; Departments of.
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Center for Thyroid Cancer, National Cancer Center, Goyang 10408, Republic of Korea.
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Lee
authors.affiliation: Center for Thyroid Cancer, National Cancer Center, Goyang 10408, Republic of Korea.
authors.forename: You Jin
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
authors.forename: Do Joon
authors.initials: DJ
authors.lastname: Park
authors.affiliation: Internal Medicine and.
authors.forename: Young Sik
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Otolaryngology-Head and Neck Surgery, Kosin University College of Medicine, Busan 49267, Republic of Korea.
authors.forename: Kang Dae
authors.initials: KD
authors.lastname: Lee
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea.
authors.forename: Seo Young
authors.initials: SY
authors.lastname: Sohn
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea.
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea.
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Chung
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul 06591, Republic of Korea.
authors.forename: Dong Jun
authors.initials: DJ
authors.lastname: Lim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul 06591, Republic of Korea.
authors.forename: Min Hee
authors.initials: MH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Korea Cancer Center Hospital, Seoul 01812, Republic of Korea; Departments of.
authors.forename: Min Joo
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Chungnam National University Hospital, Daejeon 35015, Republic of Korea.
authors.forename: Young Suk
authors.initials: YS
authors.lastname: Jo
authors.affiliation: Department of Internal Medicine, Chungnam National University Hospital, Daejeon 35015, Republic of Korea.
authors.forename: Min Ho
authors.initials: MH
authors.lastname: Shong
authors.affiliation: Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea.
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Koong
authors.affiliation: Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju 52727, Republic of Korea; and.
authors.forename: Jong Ryeal
authors.initials: JR
authors.lastname: Hahm
authors.affiliation: Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju 52727, Republic of Korea; and.
authors.forename: Jung Hwa
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.|Department of Internal Medicine, Seoul Natinal University Boramae Medical Center, Seoul 07061, Republic of Korea.
authors.forename: Ka Hee
authors.initials: KH
authors.lastname: Yi
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology / Q000601:surgery; D002291:Carcinoma, Papillary; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D011379:Prognosis; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods* / Q000706:statistics & numerical data; D012307:Risk Factors; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology / Q000601:surgery; D013965:Thyroidectomy / Q000379:methods* / Q000706:statistics & numerical data