Neoadjuvant Chemoradiotherapy Upregulates the Immunogenicity of Cold to Hot Tumors in Esophageal Cancer Patients

To test the hypothesis that neoadjuvant chemoradiotherapy (NACRT) is more effective against hot esophageal squamous cell carcinoma (ESCC) and that it may upregulate tumor immunogenicity. There have been several recent reports showing the efficacy of immune check-point inhibitors (ICIs) against esophageal cancer, especially immunologically hot tumors. In addition, several studies have suggested that chemotherapy and radiotherapy may convert cold tumors to hot tumors. Of 105 ESCC patients who underwent surgery after NACRT between 2010 and 2018 at our hospital, 99 whose biopsy tissue samples were obtained were enrolled. Based on immunohistochemical analysis, tumors that were FOXA1 (+) and/or EYA2 (+) were defined as hot tumors, others were cold tumors. We then investigated the association between tumor immunogenicity and clinicopathological features. The 29 patients with hot tumors before NACRT had a significantly better 5-year disease-specific survival (DSS) rate than the remaining 70 patients with cold tumors (85% vs 64%; P = 0.036). In a multivariate analysis, tumor immunogenicity was a significant independent predictor of DSS. Of 68 patients without a pathological complete response (non-pCR) in their primary tumor, 51 (75%) had hot tumors after NACRT. Moreover, 75% (36/48) of tumors that were cold before NACRT were converted to hot tumors after NACRT. Patients with hot ESCC tumors treated with NACRT plus esophagectomy had a better prognosis than those with cold tumors. NACRT upregulated cold tumor immunogenicity to hot tumors, suggesting NACRT may increase the sensitivity of ESCC to adjuvant ICIs.