The failure of surgical resection to cure all patients with early-stage (ie, stage I and II) non-small cell lung cancers (NSCLCs) suggests that some of these patients may have early micrometastases (MMs). In contrast, some earlier stage small cell lung cancers (SCLCs) have been associated with marrow MMs. In studies of lymph node-negative breast cancer, patients with marrow positive for MMs have significantly poorer outcomes.
To evaluate whether early MMs predicted outcomes in patients with lung cancer, 24 patients undergoing surgical resection of suspected stage I or II lung cancer consented to donate blood and bone marrow samples. For the 24 subjects, the final pathologic diagnoses were as follows: benign disease, 5 patients; leiomyosarcoma, 1 patient; SCLC, 7 patients; and NSCLC, 11 patients. Mononuclear cells were separated from blood and marrow samples using lymphocyte separation medium, and cytospins of 50 to 100,000 cells were prepared. These were stained immunocytochemically using the CAM 5.2 and MAK-6 cocktails of antibodies, which were validated against a spectrum of American Type Culture Collection (Manassas, VA) lung cancer cell lines.