Exfoliative cytology of normal buccal mucosa to predict the relative risk of cancer in the upper aerodigestive tract using the MN-assay

The high frequency of second or third primary tumors was first explained by Slaughter et al. with the concept of field cancerisation. Another theory p ostulates micrometastatic lesions as a reason for this phenomenon. The micr onuelei (MN)-assay was evaluated to provide evidence for the concept of fie ld cancerisation and to quantify the premalignant field change of normal mu cosa in order to predict the individual cancer risk. MN-assay was tarried o ut in 55 patients with squamous cell carcinoma of the head and neck, in 16 patients with a leucoplakia and in 99 healthy controls. A detailed question naire for population monitoring was completed. Buccal cytosmears of healthy mucosa of the study participants were examined for the MN count per 1000 c ells. There was a direct correlation between tobacco abuse and increasing M N count as a sign of a cytogenetic damage of buccal mucosa cells. Alcohol d id not influence the formation of MN. Both buccal sites were damaged in the same degree as proof of field cancerisation. The relative cancer risk (odd s ratio) for smoking healthy controls with a definite MN frequency was esti mated. Our study underscores the importance of the MN-assay as a biomarker to predict the relative cancer risk in the upper aerodigestive tract under suspicion of the individual susceptibility and the exposition to known carc inogenic agents such as tobacco and alcohol. The concept of field cancerisa tion was confirmed. (C) 2000 Elsevier Science Ltd. All rights reserved.