Bone marrow involvement in small cell lung cancer: Prognostic significance and correlation with hematological and biochemical parameters

The more metastatic sites and bone marrow metastasis in small cell lung cancer (SCLC), the worse the prognosis. Diagnosing the bone marrow invasion at the beginning of the therapy is important for determining of the prognosis and planning the treatment. Abnormalities of some blood parameters may help to estimate the extent of bone marrow invasion by cancer cells. In this retrospective review, the changes in routine laboratory tests that may indicate bone marrow invasion, the predictive values of these tests, and the prognostic importance of bone marrow invasion were evaluated in SCLC patients who were being followed up according to a protocol. One hundred and forty‐four patients with SCLC were enrolled in this study. Retrospectively, it was evaluated that 25 (17.4%) of the patients had bone marrow metastasis. According to univariate analysis, there was a significant difference between hemoglobin, white blood cell count, platelet count, lactate dehydrogenase, alkaline phosphatase and uric acid of the patients with and without bone marrow involvement. Among the biochemical parameters, the elevated LDH and AP had the highest sensitivity and specificity as indicators of bone marrow invasion (0.80–0.82 and 0.84–0.78, respectively). The median overall survival of extensive‐stage disease with and without bone marrow metastasis were 4.0 ± 1.0 months (95% CI 2.2–5.7) and 7.0 ± 1.2 months (95% CI 4.7–9.3), respectively (P = 0.03). Bone marrow metastasis was found to be an indicator of a bad prognosis. Bone marrow biopsy, that is an invasive procedure, can be performed on selected patients who have changes of routine laboratory tests suggesting bone marrow invasion.