Morphologic alterations in esophageal squamous cell carcinoma after preoperative high dose rate intraluminal brachytherapy

BACKGROUND: Total esophagectomy specimens from 4 patients given preoperative high dose rate intraluminal brachytherapy (HDRILBT) of 20 Gray (GY) in 2 fractions of 10 Gy each week were reviewed for radiation changes. METHODS: In all patients, preoperative biopsy specimens showed moderate to poorly differentiated squamous cell carcinoma with minimal to negligible keratin production. The esophagectomy specimens were sampled at the resection margins, the edge of irradiated length, 1 cm from the proximal and distal edge of visible tumor, the center of the tumor, and the lymph nodes. RESULTS: Radiation change in the form of fibrosis was limited to the submucosa at the resection margins, the circular muscle layer at the edge of irradiated length, and full thickness at 1 cm from the edge of the visible tumor and the center of the tumor. Surface epithelium did not show any changes at the resection margins but did show basal cell hyperplasia at the edge of the irradiated length and ulceration at 1 cm from the edge of the visible tumor and the center of the tumor. Endarteritis obliterans was seen only 1 cm from the edge of the visible tumor and the center of the tumor. Necrosis, intense keratin formation, and giant cell reaction were observed at the center of the tumor. When compared with the preradiotherapy biopsies, the amount of keratin in the postradiotherapy specimens was extensive. HDRILBT may cause induction of the keratin gene in the irradiated cells to stimulate differentiation toward better differentiated cells. CONCLUSIONS: HDRILBT may cause the keratin gene in the irradiated cells to induce differentiation toward better differentiated cells. Preoperative high dose rate intraluminal brachytherapy may have a role in improving the prognosis of patients with early esophageal cancer treated with a combination of radiotherapy and surgery.