Serial histologic evaluation of multiple primary squamous cell carcinomas of the esophagus.

A review of data on 205 patients with esophageal squamous cell carcinoma who underwent subtotal esophagectomy revealed 30 cases (14.6%) and 32 lesions with multiple primary squamous cell carcinomas. The incidence of this multiplicity was 11.7% and 25.6% in those with and without preoperative irradiation treatment, respectively. Among the 32 second lesions, there were 17 intraepithelial carcinomas, eight restricted to the mucosa, five invading the submucosa, one invading down to the proper muscular layer, and one involving the entire thickness of the esophageal wall. These second lesions were in the relatively early stage. Moreover, incidence of the coexistence of intraepithelial carcinoma contiguous to the main lesion was 42.1% and 100.0% in those with multiple cancers, with and without preoperative irradiation, respectively. The values were 7.6% and 53.1% in patients with a solitary carcinoma, respectively. These findings show the close relationship between multiplicity and intraepithelial carcinoma contiguous to the main lesion, and support the concept of multicentric or field carcinogenesis of esophageal squamous cell carcinoma.