Pretreatment lymphopenia is an easily detectable predictive and prognostic marker in patients with metastatic esophagus squamous cell carcinoma receiving first-line chemotherapy

To explore the influence of pretreatment lymphopenia on the toxicity and efficacy of first-line chemotherapy in patients with metastatic esophagus squamous cell carcinoma (ESCC). In total, 215 patients were included in this retrospective study. Correlations between pretreatment lymphopenia (lymphocyte count < 1 x 10(9)/L) and the occurrence of toxicity and the efficacy of first-line palliative chemotherapy were investigated. Pretreatment lymphopenia was found in 19.1% of the patients. The overall response rate (ORR) was 35.5% (65 of 183 patients). Patients with pretreatment lymphopenia had a lower ORR to chemotherapy compared with those without lymphopenia (22.2% vs. 38.8%, respectively; P = 0.045). Furthermore, the patients with pretreatment lymphopenia have higher grade 3-4 hematological toxicity than that of patients without pretreatment lymphopenia (19 of 41 patients, 46.3% vs. 54 of 174 patients, 31.0%; P = 0.048). Pretreatment lymphopenia was not correlated with grade 3-4 nonhematological toxicity. Multivariate analysis showed that pretreatment lymphopenia is an independent prognostic factor. Patients with pretreatment lymphopenia had a significantly shorter overall survival time than those without lymphopenia (8.2 months vs. 12.7 months; P = 0.020). This study shows that pretreatment lymphopenia is a good prognostic factor as well as a predictive factor for tumor response and chemotherapy-related hematological toxicity in metastatic ESCC.