Purpose: To investigate the relationship between treatment-related lymphopenia and pathologic response to neoadjuvant chemoradiotherapy (CRT) in patients with esophageal squamous cell carcinoma (ESCC).
Methods: Between 2002 and 2016, 220 ESCC patients treated with neoadjuvant CRT followed by surgery were retrospectively analyzed. Absolute lymphocyte count was determined before, during, and 1 month after neoadjuvant CRT. Treatment-related lymphopenia was graded using Common Terminology Criteria for Adverse Events version 4.0. Relationship between lymphopenia with pathologic complete response (pCR) and recurrence were evaluated.
Results: Ninety-five patients (43.2%) achieved a pCR after neoadjuvant CRT and 71 patients (32.3%) developed recurrences. The incidence of grade 0, 1, 2, 3, and 4 lymphopenia during CRT were 1.8%, 6.8%, 31.4%, 38.2% and 21.8%, respectively. Patients with grade 4 lymphopenia had a significantly lower pCR rate than those with grade 0-3 lymphopenia (22.9% vs. 48.8%, P = 0.001). Moreover, grade 4 lymphopenia was significantly associated with a higher risk of recurrences (45.8% vs. 28.5%, P = 0.023). Multivariable analysis identified that primary tumor length, tumor location, and radiation dose were independent predictors for grade 4 lymphopenia.
Conclusions: ESCC patients with grade 4 lymphopenia during neoadjuvant CRT were associated with a significantly lower pCR rate and a higher recurrence risk.