The value of cytology in the diagnostics of lung cancer.

In order to elucidate the relative contributions made by cytology and histology in the diagnosis of lung cancer, we studied the cytology and histology reports of all patients who received a microscopic diagnosis of lung cancer in our hospital during the 7 years 1996-2002. This gave a total of 407 patients. The most frequent diagnoses were squamous cell carcinoma (34.9%), adenocarcinoma (24.8%), and small cell carcinoma (17.8%). One hundred and fifteen patients (28.3%) received their microscopic diagnosis based only on cytology, which therefore proved to be of great diagnostic value. The most useful type of cytology specimen was taken by bronchial lavage or bronchial brushing. These types of specimens provided the diagnosis in 71 patients (17.4%). Cytology was especially capable of finding squamous cell carcinomas. Small cell carcinomas were underrepresented (9.6% versus 17.8%) and unspecified carcinomas greatly overrepresented (9.6% versus 2.9%) among the diagnoses obtained by cytology alone. We conclude that cytology is of considerable diagnostic value, although not as specific as histology for the subtyping of carcinomas. Clinicians should be more aware of the usefulness of cytology, especially in cases where it is difficult to obtain bronchoscopic biopsy samples for histological examination.