Ann Thorac Surg 1997;64:944
© 1997 The Society of Thoracic Surgeons
Invited Commentary
Invited Commentary
Haruhiko Kondo, MD
Division of Thoracic Surgery, National Cancer Center Hospital, 1-1, Tsukiji 5-chome, Chuo-ku, Tokyo 104, Japan
See also page 941.
The amount of malignant pleural effusion in lung cancer patients is usually moderate to extreme. It is sometimes bloody, and its cytology is positive for cancer cells. However, sometimes there is a discrepancy between the cytologic positivity and the amount of pleural effusion. For example, there may be massive pleural effusion with negative cytology in patients with obstructive pneumonia caused by lung cancer. And there may be cytologically malignant pleural effusion but in only a very small amount.
This study by Kjellberg and associates reports the incidence of malignant pleural lavage cytology in 78 patients without pleural effusion who underwent curative resection for lung cancer and the risk factors for its positivity. My colleagues and I have reported the results of our similar study on 467 patients who underwent pulmonary resection for lung cancer. As Kjellberg and associates pointed out, the rate of positivity of pleural lavage cytology is significantly higher in patients with adenocarcinomas than in those with other cell types. In our series, 13% of the patients (33/252) with adenocarcinomas had positive lavage cytologies. These results may reflect the tendency to a peripheral location of adenocarcinoma. However in our series, we also found strong correlations of the positivity of pleural lavage cytology with the visceral pleural involvement, microscopic vascular invasion, lymphatic permeation, and microscopic visceral pleural dissemination of the tumor, which Kjellberg and associates did not demonstrate. These correlations suggest that the pleural cavity is, in a sense, a lymphatic space and that the exfoliation of cancer cells into the pleural cavity may occur not only when the tumor is exposed on the pleural surface but also when subpleural lymphatics are invaded by the tumor, even if there is not yet the blockage of the lymphatic drainage to the mediastinal lymph nodes that causes the accumulation of pleural effusion. Positive pleural lavage cytologies indicate the above conditions.
As we reported in 1993, the prognosis for the group with positive results was as poor as that for patients with stage III B or stage IV disease. Therefore positive pleural lavage cytology should be regarded as the existence of malignant pleural effusion, that is, T4 disease, although the accuracy of cytologic examination remains one of the problems to be solved.
Related Article
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Pleural Cytologies in Lung Cancer Without Pleural Effusions
- Sten I. Kjellberg, Carolyn M. Dresler, and Melvyn Goldberg
Ann. Thorac. Surg. 1997 64: 941-944.
[Abstract]
[Full Text]
