Serosal imprint cytology in colonic cancer: a simple staging technique.

Accurate staging of colonic cancer is essential in defining the rational use of adjuvant treatments. Recent studies have shown that prognostic accuracy can be significantly improved by recognition of primary tumour extension to the free serosal surface. This study compares the technical results of serosal imprint cytology with the results of histology in assessing serosal involvement. When analysed in terms of the modified Dukes' staging the results of cytology imprints taken from the peritoneum overlying the colonic primary were positive for tumour cells in 4/13 Dukes' B, 7/14 Dukes' C, and 5/9 metastatic cancers. Imprint cytology was positive in 6/7 Dukes' B and C cases with histological serosal invasion and was suspicious in the remaining case. However, a further 5/20 cases without identified invasion on routine histology also had positive cytology. Imprint cytology is an adjunct to routine histology which is easily performed and allows more precise staging of serosal involvement in Dukes' B and C colonic cancers. Final evaluation of this technique requires long-term follow-up of patients.