Diagnosis of colon cancer by lavage cytology with an orally administered balanced electrolyte solution

We wished to evaluate the feasibility of colon lavage cytology using an orally administered balanced electrolyte solution.

Thirty-three patients undergoing colonoscopy for suspected colorectal cancer were entered into the study. Fifteen of these patients eventually had pathological confirmation of colorectal cancer, and one patient had prostatic adenocarcinoma with invasion of the rectum. The other 17 patients had no colonoscopic evidence of neoplasm and therefore served as controls. Prior to colonoscopy, patients received 10 mg of bisacodyl by mouth and enough Colyte to produce a clear anal effluent for cytological examination. The colon lavage cytology was interpreted by a cytopathologist blinded to the clinical features of each case.

In 14 of 15 (93%) cases of biopsy proven colorectal cancer, the lavage cytology was positive: 10 cases demonstrated adenocarcinoma cells and four cases showed dysplastic cells. In contrast, the cytology was negative for dysplastic or malignant cells in the control patients.

Colon lavage cytology using an orally administered balanced electrolyte solution provides acceptable specimens for cytological evaluation and had a 93% sensitivity and 100% specificity in our population.