Survival difference in NSCLC and SCLC patients with diabetes mellitus according to the first-line therapy

The aim of this study was to examine the survival difference between non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) patients with diabetes mellitus (DM) according to the first-line therapy. All patients with lung cancer diagnosed at our hospitals between April 1999 and March 2011 were retrospectively analyzed. The definition of DM was strictly determined and included fasting plasma glucose and HbA1c levels. The patients were divided into 2 groups: those with DM (DM group) and those without DM (non-DM group). For each treatment type, the survival of these 2 groups was evaluated. For NSCLC patients overall, the difference in survival between the DM group and the non-DM group was not significant (p = 0.112). However, in surgically treated NSCLC patients, the difference in survival between the 2 groups was significant (p = 0.022). In chemotherapy-treated NSCLC patients, the difference in survival between the 2 groups was not significant (p = 0.942). On the other hand, for SCLC patients overall, the difference in survival between the DM group and the non-DM group was significant (p = 0.012). In chemotherapy-treated SCLC patients, the difference in survival between the 2 groups was significant (p = 0.026). The influence of DM may differ between NSCLC and SCLC patients. At the current treatment level for unresectable NSCLC, the influence of DM might not be the same for NSCLC patients treated with surgery as for SCLC patients treated with chemotherapy. Elucidation of the mechanism by which hyperglycemia influences the progression of lung cancer will improve survival in lung cancer patients with DM.