Relationship Between Lymphocyte Nadir and Radiotherapy Efficacy or Prognosis of Patients with Esophageal Carcinoma

Objective To evaluate the predictive value of radiation-induced lymphopenia in short-term effect and prognosis of patients with esophageal carcinoma who received radiotherapy(RT). Methods We retrospectively analyzed clinicopathologic data of 112 patients undergoing radical intent RT in Xuzhou Gentral Hospital from Jan.2011 to Dec. 2012. Total lymphocyte counts were collected from the beginning to the end of RT for one year. The relationship between lymphocyte nadirs and clinicopathologic data, shortterm effect were assessed with Chi-squared test. Univariate and multivariate Cox analysis were used to assess the association between lymphocyte nadir and overall survival (OS). Results The total lymphocyte count for all patients before RT was (1.78±0.76) cells/mm3. The lymphocyte nadir during RT and the total lymphocyte count at one year after RT were (0.45±0.22) and (1.15±0.39) cells/mm3, respectively. Tumor length, maximum tumor width, and receipt of concurrent chemotherapy were influential factors for radiationinduced lymphopenia (all P<0.05). The response rate for patients with high and low lymphocyte nadir (≥and <0.5 cells/mm3) were 92% and 70%, respectively (χ²=7.66, P=0.007). The 1- and 2-year survival rates of patients with low lymphocyte nadir were significantly worse than that of high lymphocyte nadir groups (51.6%, 37.4% vs. 81.3%, 54.0%, χ²= 4.489, P=0.034). Both univariate and multivariate analysis revealed that TNM stage, tumor length and lymphocyte nadirs were independent factors for OS. Conclusion Lymphocyte nadir during RT, as an inexpensive and convenient marker, could predict short-term effect and provide prognostic values for esophageal carcinoma patients who received radical RT.