Is the Histopathological Subtype Important for Tumor Response to Irradiation in non-metastatic Esophageal Cancers

Esophageal cancer is still a health problem in middle income countries. The up-front treatment in localized disease is crucial for a better survival. Data from literature are in favor of a better response to radiotherapy of squamous histology. We have run a retrospective study to compare the response of histological subtypes of esophageal cancer to radiotherapy according to irradiation. Of 44 cases (53.7%) of squamous cell localized esophageal carcinoma and 38 (46.3%) of adenocarcinoma, the response after radiotherapy containing multimodal neoadjuvant treatment was 29.5% (13pts) versus 39.5% (15pts) (p=0.475). No correlation was found between histology and tumor shrinkage. Survival was found similar between the two subgroups. Indeed, median relapse free survival was 11 months for both groups with 95% CI [8.86-13.13] or 95% CI [4.526-17.47], log rank 0.394 and median overall survival was 12 months, 95% CI [9.44-14.55] in squamous versus 15 months, 95% [8.30-21.69] in adenocarcinoma cases, log rank 0.195. In univariate regression, the median relapse free survival was significantly associated with irradiation dose and the concomitance of chemotherapy to radiotherapy, while in multivariate analysis only the last variable remained significant: HR 0.425, 95% CI [0.225-0.806], p=0.009. Our analysis showed a tendency to a better response in adenocarcinoma esophageal cancer after multimodal radiotherapy containing treatment.