Influence of tumor burden on red blood cell deformability in small cell lung cancer patients.

Red blood cell deformability was measured in 54 newly diagnosed patients with small cell bronchogenic carcinoma and in 22 normal hospital employees. Twenty-one small cell cancer patients had disease confined to one hemithorax plus draining lymph nodes (one organ system), 15 had involvement of one additional metastatic site (two organ systems), 12 had two metastatic sites (three organ systems) and 6 patients had 4 organ systems involved. Patients with one or two organ system involvement had red cell deformability results comparable to the normal control group. Patients with tumor extension to 3 or 4 organ systems had significantly decreased deformability relative to patients with lesser tumor burdens. Based on the lowest deformability results in the control population small cell cancer patients were divided into those with normal or impaired red blood cell deformability. The latter patients were significantly more anemic and had higher red cell mean corpuscular volumes than their normal counterparts. Patients with impaired deformability also had significantly elevated blood glucose levels and significantly lower serum inorganic phosphorus and iron binding capacity. Since red cell deformability is the principal determinant of capillary blood flow abnormal deformability may result in decreased tumor oxygenation and decreased, and non-uniform, delivery of chemotherapeutic agents to tumor tissue.