Cytokeratin Staining to Detect Residual Disease in Patients Undergoing Neoadjuvant Chemoradiation followed by Esophagectomy for Locally Advanced Esophageal Cancer

Thirty percent of patients undergoing neoadjuvant chemoradiation therapy (neo-CRT) for locally advanced esophageal cancer achieve a complete pathologic response (CPR) based on standard Hematoxylin and Eosin staining (CPR-HE). There is controversy regarding the prognostic value of CPR-HE. Immunohistochemical staining may be useful to detect subtle microscopic residual disease in such patients. We undertook this present study to test this hypothesis. Eighteen consecutive patients who achieved CPR-HE were identified. Seven patients had positive cytokeratin staining; three had microscopic residual disease that was not identified on original hematoxylin-eosin sections. Three of the seven patients (43%) with positive cytokeratin staining had systemic relapse (60 % of patients with systemic relapse).Cytokeratin staining could be a useful adjunct to routine hemaoxylin-eosin staining to identify residual tumor in such patients. The prognostic significance of CPR-CK, however, needs to be validated in a large cohort.