Are the differences between adenocarcinomas and epidermoid cancer of the esophagus merely histological?

Many therapeutic trials make no distinction between epidermoid carcinomas and esophagus adenocarcinomas because their natural history, treatment, and prognosis are considered identical. This study attempts to make a comparative analysis of these different parameters to find out whether or not this theory is legitimate. It would appear that the site of these two cancers is quite close, as is the occurrence of multicentric forms. The objective response rates and the complete histological response rates after radiotherapy, chemotherapy, or a combination of the two are very close. Some differences exist: minor differences, (without major therapeutic effect) which affect the intramural and metastatic extensions of these two types of carcinoma; and major differences, which focus on the lymphatic spreading (which is shifted upwards in cases of epidermoid carcinoma and shifted downwards in cases of adenocarcinomas) and the high incidence of secondary cancers in cases of epidermoid carcinomas. These two differences should recommend the application of different treatments and the taking into account of a different survival rate when prognostic comparisons are based on histology. It is possible that the higher incidence of advanced forms of epidermoid carcinomas at the time of the diagnostic (which reduces their rate of resection) is counterbalanced in the prognosis by the greater aggressiveness of adenocarcinomas, which for different reasons, result in a very similar rate of survival (although this is subject to confirmation). Thus the inclusion of these two histological types in the same therapy trial should not be accepted without reservation and should be the subject of more detailed studies.