High lymphocyte count during neoadjuvant chemoradiotherapy is associated with improved pathologic complete response in esophageal cancer.

BACKGROUND AND PURPOSE

Neoadjuvant chemoradiation (nCRT) can reduce tumor infiltrating lymphocytes. We examined absolute lymphocyte count (ALC) nadir during nCRT for esophageal cancer (EC) and pathologic complete response (pCR).

MATERIALS AND METHODS

Patients with stage I-IVA EC (n = 313) treated 2007-2013 with nCRT followed by surgery were analyzed. ALC was obtained before, during/weekly, and one month after CRT. pCR was defined as no viable tumor cells at surgery. High ALC was defined as nadir of ≥0.35 × 10/μL (highest tertile). Comparison of continuous and categorical variables by pCR was assessed by ANOVA and Pearson's chi-square. Univariate/multivariate logistic regression was used to assess predictors of pCR and high ALC nadir.

RESULTS

Eighty-nine patients (27.8%) achieved a complete pathological response (pCR). For patients with pCR, median ALC nadir was significantly higher than those without (0.35 × 10/μL vs 0.29 × 10/μL, p = 0.007). Patients maintaining high ALC nadir had a higher pCR rate (OR1.82, 95%CI 1.08-3.05, p = 0.024). Predictors of high ALC included treatment with proton therapy vs. IMRT (OR4.18, 95%CI 2.34-7.47, p < 0.001), smoking at diagnosis (OR2.80, 95%CI 1.49-5.25, p = 0.001), early stage I-II disease (OR2.33, 95%CI 1.32-4.17, p = 0.005), and SCC histology (OR3.70, 95%CI 1.01-14.29, p = 0.048). Mean body dose (MBD) was inversely related to high ALC nadir (OR0.77 per Gy, 95%CI 0.70-0.84, p < 0.001).

CONCLUSION

A higher ALC level during nCRT is associated with a higher rate of pCR for esophageal cancer patients undergoing trimodality therapy.