title: Does preoperative neutrophil lymphocyte ratio predict risk of recurrence and occult central nodal metastasis in papillary thyroid carcinoma?
abstract: BACKGROUND
  Preoperative neutrophil to lymphocyte ratio (NLR) might be prognostic in papillary thyroid carcinoma (PTC). Given the controversy of prophylactic central neck dissection (pCND) in clinically nodal-negative (cN0) PTC, our study evaluated whether preoperative NLR predicted disease-free survival (DFS) and occult central nodal metastasis (CNM) in cN0 PTC.
  
  
  METHODS
  A total of 191 patients who underwent pCND were analyzed. Complete blood counts with differential counts were taken before operation. NLR was calculated by dividing preoperative neutrophil count with lymphocyte count. Patients were categorized into NLR tertiles: first (NLR < 1.93; n = 63), second (NLR = 1.93-2.79; n = 64), and third tertile (NLR > 2.79; n = 64). Four other patient types, namely, benign nodular goiter, clinically nodal-positive (cN1) PTC, poorly differentiated thyroid carcinoma, and anaplastic thyroid carcinoma (ATC), were used as references.
  
  
  RESULTS
  Age at operation (p < 0.001) and tumor size (p = 0.037) significantly increased with higher NLR. First tertile had significantly more TNM stage I tumors (p = 0.01) and lowest MACIS score (p = 0.002). Tumor size [hazard ratio (HR) 1.422, 95% confidence interval (CI) 1.119-1.809, p = 0.004] and multicentricity (HR = 2.545, 95% CI 1.073-6.024, p = 0.034) independently predicted DFS, whereas old age [odds ratio (OR) 1.026, 95% CI 1.006-1.046, p = 0.009), male (OR 2.882, 95% CI 1.348-6.172, p = 0.006), and large tumor (OR 1.567, 95% CI 1.209-2.032, p = 0.001) independently predicted occult CNM. NLR was not significantly associated with DFS or occult CNM. ATC had significantly higher NLR than cN1 PTC (7.28 vs. 2.74, p < 0.001).
  
  
  CONCLUSIONS
  Although a higher NLR may imply a poorer tumor profile, it was not significantly associated with a worse DFS or higher risk of occult CNM in cN0 PTC. Perhaps, future research should focus on the prognostic value in other thyroid cancer types with a poorer prognosis.
authors.affiliation: Department of Surgery, The University of Hong Kong, Hong Kong SAR, China, blang@hkucc.hku.hk.
authors.forename: Brian Hung-Hin
authors.initials: BH
authors.lastname: Lang
authors.forename: Cathy Po-Ching
authors.initials: CP
authors.lastname: Ng
authors.forename: Kin Bun
authors.initials: KB
authors.lastname: Au
authors.forename: Kai Pun
authors.initials: KP
authors.lastname: Wong
authors.forename: Kandy K C
authors.initials: KK
authors.lastname: Wong
authors.forename: Koon Yat
authors.initials: KY
authors.lastname: Wan
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002277:Carcinoma / Q000097:blood* / Q000473:pathology / Q000556:secondary*; D002291:Carcinoma, Papillary; D018572:Disease-Free Survival; D005260:Female; D006044:Goiter, Nodular / Q000097:blood; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery; D008207:Lymphatic Metastasis; D018655:Lymphocyte Count; D008214:Lymphocytes; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D009364:Neoplasm Recurrence, Local / Q000097:blood*; D009367:Neoplasm Staging; D009504:Neutrophils; D018570:Risk Assessment; D012737:Sex Factors; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000097:blood* / Q000473:pathology*; D047368:Tumor Burden