The neutrophil-to-lymphocyte ratio (NLR) is a strong predictor of poor prognosis in patients with various types of cancer. To date, the utility of NLR for prediction of prognosis in thyroid cancer patients has not been studied. Therefore, the aim of our study was to determine whether NLR is associated with other prognostic factors of papillary thyroid carcinoma and predictive of recurrence.

We conducted a retrospective review of 367 patients who underwent thyroidectomy for papillary thyroid carcinoma from January 2005 to December 2007. We measured the white blood cell count including neutrophil and lymphocyte within one month preoperatively. The NLR was defined as the absolute neutrophil count divided by absolute lymphocyte count. Logistic regression analysis was applied for comparison of NLR with other prognostic factors, including tumor size, lymph node metastasis, multiplicity, extrathyroidal invasion, and TNM stage. We also determined the cut-off value of NLR with a prediction for recurrence.

Median age of patients was 47 years (16~86 years) and the rate of papillary thyroid microcarcinoma was 65.7% (241/367 cases). Median follow-up period was 1,841 days (506~3,135 days). The median value of NLR was 1.68 (0.66~6.36). NLR was not related to any other prognostic factors of papillary thyroid carcinoma. The cut-off value of NLR for prediction of recurrence was 1.73, where the sensitivity was 66.7% and specificity was 69.8%.

Patients with NLR equal to or higher than 1.73 showed significantly higher recurrence of papillary thyroid carcinoma. Further validation study should be conducted for clinical use of NLR as a prognostic marker.