Prognostic Impact of Paraneoplastic Cushing's Syndrome in Small-Cell Lung Cancer

Introduction: Paraneoplastic Cushing's syndrome (CushingPS) in small-cell lung cancer is rare but severe. Methods: We studied 383 patients with small-cell lung cancer diagnosed between 1998 and 2012. Among them, 23 patients had CushingPS, 56 had other paraneoplastic syndrome (OtherPS), and 304 had no paraneoplastic syndrome (NoPS). Results: After comparison of the three groups, we observed that CushingPS patients had more extensive disease: 82.6% versus 67.8% versus 53.3% (p = 0.005), respectively, with more than two metastatic sites: 63.2% versus 15.8% and 24.1% (p 0.001), a higher World Health Organization performance status (2-4): 73.9% versus 57.1% versus 43.7% (p = 0.006), greater weight loss (10%): 47.8% versus 33.9% versus 16.4% (p 0.001), reduced objective response to first-line treatment: 47.6% versus 74.1% versus 71.1% (p = 0.04), and poorer sensitivity to first-line treatment: 19% versus 38.9% versus 48.6% (p = 0.01). NoPS patients, with World Health Organization performance status of 3-4, had extensive disease at diagnosis, with response, sensitivity to first-line treatment, and survival similar to the CushingPS group. At relapse, the CushingPS group had no objective response to second-line treatment versus 25% versus 42.8% in OtherPS and NoPS groups, respectively (p = 0.005). The median survival of CushingPS patients was 6.6 months versus 9.2 months for OtherPS and 13.1 months for NoPS patients (p 0.001). CushingPS is a prognostic factor of death (hazard ratio, 2.31; p 0.001). Conclusion: CushingPS is the worst form of the paraneoplastic syndromes with particularly extensive tumors. Reduced objective response and sensitivity to first-line treatment and no response to second-line treatment suggest starting palliative care early at first line and exclusively at relapse.