Bone marrow micrometastasis might not be a short-term predictor of survival in early stages non-small cell lung carcinoma.

Objective: To determine the presence of occult micrometastasis (OM) in a selected population of surgically resectable patients presenting with non-small cell lung carcinoma (NSCLC) and to evaluate its prognostic value on relapses and survival.

Methods: From February 1996 to December 1999, 99 patients undergoing surgical treatment for NSCLC were prospectively investigated for the presence of occult bone marrow micrometastasis. Tumor cells were detected with monoclonal primary antibodies directed against low molecular weight cytokeratins.

Results: Median follow-up time was 14.3 months (range 0.2-45.6 months). Overall prevalence of OM was 22.2% (22 out of 99). The presence of OM was not correlated to pathology, T status, or N status. In survival analysis, the only independent predictors of overall survival were N0 status and Stage I (P=0.016 and 0.004, respectively), while T1 was a predictor of disease-free survival (P=0.044). Metastasis and loco-regional recurrence were observed at follow-up in 18.2 (four out of 22) and 9% (two out of 22) of patients OM(+) and in 14.3 (11 out of 77) and 7.8% (six out of 77) of patients OM(-), respectively (P=not significant). OM was a predictor neither of overall survival nor of disease-free survival (P=0.52 and 0.97, respectively). In Stage I patients, 1-year overall survival and 1-year disease-free survival were 89 and 98% for OM(-) patients and 88 and 90% for OM(+) patients, respectively (P=0.57 and P=0.75).

Conclusions: OM was present in >20% of surgically treated NSCLC patients and did not correlate to pathological variables. In contrast to previous published data, in this study the presence of OM had no influence on overall or disease-free survival.