Background:The impact of red cell distribution width (RDW) on outcomes in elderly patients after surgery for non-small cell lung cancer (NSCLC) is not fully understood. Methods: We retrospectively analyzed 992 NSCLC patients who underwent curative resection between 1998 and 2012. The following variables were included in the analyses to evaluate the role of RDW: age, gender, smoking index, leukocyte count, neutrophil to lymphocyte ratio (NLR), hemoglobin, platelet count, albumin, C-reactive protein, carcinoembryonic antigen, respiratory function, histology, T factor, N factor, surgical approach, surgical procedures, complications and prognosis. Results: High RDW (>13.8) was an independent risk factor for morbidity [hazard ratio (HR) 2.1; P<0.01], recurrence (HR 2.0; P=0.01), overall survival (OS) (HR 2.1; P<0.01) and disease-free survival (DFS) (HR 2.0; P<0.01) in elderly patients (age ≥75 years, n=275), whereas it was not in younger patients (age <75 years, n=717). The surgical outcome was extremely poor in those older than 80 years with a RDW greater than 15% (morbidity, 56%; postoperative stay, 23 days; OS, 24%; DFS, 0%). RDW was unaffected by age (R =0.01; P=0.86) and elevated RDW without anemia was more prognostic than high RDW due to anemia in elderly patients. Conclusions: High RDW was significantly associated with high morbidity and reduced survival in elderly patients who underwent resection for NSCLC. Therefore, this parameter should be taken into account when surgery is considered in the elderly. investigation of the etiology of anemia (1). The volume of erythrocytes is consistent, and RDW is normal in the case of anemia caused by rapid bleeding, whereas the increase of relatively large reticulocytes during the recovery process of anemia raises RDW in the case of slowly progressing anemia. RDW has recently been reported to also be an inflammatory indicator. There is mounting evidence linking elevated RDW and adverse outcomes in cardiac disease (2-4), pulmonary embolism (5), trauma (6), septic shock (7), acute pancreatitis (8), hepatitis (9), stroke (10), dementia (11), metabolic syndrome (12), and respiratory diseases such as non-small cell lung cancer (NSCLC) (13,14), chronic obstructive pulmonary disease (15), interstitial pneumonia (16) and sarcoidosis (17). High RDW has been associated with increased mortality and poor pulmonary function also in the general population (18)(19)(20).The aim of this study was to investigate the prognostic impact of RDW on outcomes in elderly patients after surgery for NSCLC.
Methods
Patient cohortA total of 1,061 patients with NSCLC who underwent resection at our institute between 1998 and 2012 were retrospectively analyzed. Before the study, the Research Review Board of Tokyo University examined and approved our research protocol in accordance with the Declaration of Helsinki (project approval No. 2406). All patients undergoing surgery irrespective of this study provided written informed consent for the review of their medical charts before the surgery. A total of 69...