OBJECTIVES: The occurrence of a second primary cancer in the esophagus in patients with head and neck squamous cell carcinoma is frequent and is associated with a poor prognosis. The aim of this study was to evaluate the yield of abrasive esophageal cytology as a means of screening for metachronous cancer of the upper aerodigestive tract. STUDY DESIGN: We retrospectively reviewed the results of abrasive esophageal cytology performed twice yearly for the screening of patients with prior head and neck cancer. METHODS: From 1987 to 1996, 320 patients treated for head and neck cancer underwent 1,673 abrasive cytology examinations of the esophagus during a mean follow-up period of 4 years. Cytological results were classified as negative, suspect, or positive for malignancy. RESULTS: Twenty-five patients without symptoms had one or more suspect or positive cytologic findings, leading to 29 endoscopic examinations. These revealed 20 premalignant or early malignant lesions of the esophagus (2 dysplasias, 18 squamous cell carcinomas), 2 glandular carcinomas, and 10 clinically unsuspected oral or pharyngeal carcinomas. In seven patients, positive cytological results were associated with clinically visible head and neck cancer. Of the 34 patients with suspect cytological results for malignancy, 10 had no evidence of tumor at endoscopy and 24 had no endoscopic examination because of refusal or because suspected cells were not found in additional examinations. Negative results on cytological examination were found for 254 patients throughout their follow-up, and none of them developed esophageal cancer during a mean follow-up period of 3 years. CONCLUSIONS: For patients with head and neck cancer, abrasive sponge cytology is useful for detecting esophageal cancer at an early stage. In addition, it may reveal unsuspected second primaries or recurrences in the head and neck region.