Patterns, Predictive Factors, and Prognostic Impact of Contralateral Lateral Lymph Node Metastasis in N1b Papillary Thyroid Carcinoma.
BACKGROUND
Although the incidence among patients with bilateral lateral lymph node metastasis (LLNM) in N1b papillary thyroid carcinoma (PTC) is reported to be as high as 40%, only a few reports have addressed the characteristics of contralateral LLNM. Therefore, this study aimed to investigate the characteristics of patients with contralateral LLNM in N1b PTC.


METHODS
This study retrospectively reviewed 834 patients with N1b PTC who underwent modified radical neck dissection between January 1997 and June 2015.


RESULTS
Of the 834 N1b PTC patients, unilateral LLNM was found in 728 patients (87.3%) and bilateral LLNM in 106 patients (12.7%). The independent predictors of contralateral LLNM in N1b PTC patients were male sex (adjusted odds ratio [OR], 1.647; p = 0.039), tumor larger than 4 cm (adjusted OR, 6.700; p < 0.001), multiplicity (adjusted OR, 1.754; p = 0.040), bilobar involvement (adjusted OR, 1.971; p = 0.010), and bilateral central LN metastasis (CLNM) (adjusted OR, 2.829; p = 0.025). Moreover, contralateral LLNM significantly increased the risk of overall (adjusted hazard ratio [HR], 1.943; p = 0.016) and lateral neck (adjusted HR, 2.246; p = 0.015) locoregional recurrence.


CONCLUSIONS
In the preoperative period, the meticulous evaluation of contralateral lateral neck may be required for male N1b PTC patients with tumor larger than 4 cm, multiplicity, bilobar involvement, and/or bilateral CLNM. In the postoperative period, N1b PTC patients may be re-stratified according to the contralateral LLNM, and meticulous follow-up assessment is required for N1b PTC patients with contralateral LLNM.
Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Seo Ki
SK
Kim
Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Inhye
I
Park
Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Nayoon
N
Hur
Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Musaed
M
Rayzah
Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, South Korea.
Jun Ho
JH
Lee
Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Jun-Ho
JH
Choe
Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Jung-Han
JH
Kim
Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. jskim0126@skku.edu.
Jee Soo
JS
Kim
D000328:Adult; D002291:Carcinoma, Papillary / Q000556:secondary* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy