Premalignant and malignant cells in sputum from lung cancer patients.

BACKGROUND

The objective of this study was to assess the frequency of premalignant and malignant cells in sputum from patients with lung cancer and to measure the dependence of these cells on cancer stage, histologic type, tumor size, and tumor location.

METHODS

This analysis included 444 patients with lung cancer. First, all patients were asked to produce sputum spontaneously; then, they underwent sputum induction. Slide preparations of the sputa were screened for the presence of abnormal cells.

RESULTS

Of all patients with lung cancer who had produced adequate specimens, 74.6% had sputum that was positive for premalignant or worse cells, whereas 48.7% had sputum that was positive for malignant cells alone. Surprisingly, the presence of premalignant or worse cells in sputum depended only moderately on disease stage (82.9% of stage IV cancers vs 65.9% of stage I cancers), tumor size (78.6% of tumors >2 cm vs 64.7% of tumors <or=2 cm), and location (83.3% of central lesions vs 68% of peripheral lesions) and was found to be independent of histologic tumor type (78.4% of squamous cell carcinomas vs 71.5% of adenocarcinomas, 74.5% of small cell carcinomas, and 75% of large cell carcinomas).

CONCLUSIONS

The findings of the current study suggested the important potential of sputum cytology for lung cancer detection and risk assessment across all stages, histologic types, tumor sizes, and locations. However, the high sensitivities in this study were achieved with a level of scrutiny not feasible in the laboratory routine. The diagnostic potential of sputum cytology may be exploited better through the standardization and automation of sputum preparation and analysis.