Validation of Pretreatment Prognostic Factors and Prognostic Staging Systems for Small Cell Lung Cancer in a Real-World Data Set

Prognostic significance of body mass index and serum albumin as the indicators of nutritional status in small cell lung cancer

BACKGROUND

Body mass index (BMI) and serum albumin (ALB) level are long-established markers that reflect the nutritional status and eventually the prognosis of cancer patients. The objective of the study was to determine the clinical significance of these factors and specify their roles in outcomes compared with performance status (PS) and weight loss (WL), which are considered the most significant patient-related prognostic factors in small cell lung cancer (SCLC) treated with platinum-etoposide-based chemotherapy.

METHODS

A total of 378 patients with SCLC were enrolled in the study and analyzed retrospectively.

RESULTS

BMI values were similar by clinical stage, whereas the percentages of the patients with WL, low serum ALB, and particularly poor (≥2) PS were significantly higher in patients with extended disease SCLC (ED-SCLC) compared to those with limited disease SCLC (LD-SCLC). In LD-SCLC, patients with poor PS lived for a significantly shorter time than patients with good PS (HR: 7.791, p = 0.0001); however, BMI (HR: 1.035, p = 0.8), WL (HR: 0.857, p = 0.5), and ALB (HR: 0.743, p = 0.3) had no significant effect on the outcome. In ED-SCLC, PS (HR: 4.257, p = 0.0001), WL (HR: 1.677, p = 0.001), and ALB (HR: 0.680, p = 0.007) had an impact on survival, but BMI did not (HR: 0.791, p = 0.08). In LD-SCLC, the univariate analysis showed that only poor PS was correlated with increased mortality (HR: 7.791, p = 0.0001); yet it lost significance in multivariate analysis. In ED-SCLC, poor PS (HR: 4.257, p = 0.0001), WL (HR: 1.667, p = 0.001), and a low ALB level (HR: 0.680, p = 0.007) were shown to be factors for poor prognosis in the univariate analysis; yet only PS remained significant in multivariate analysis (HR: 2.286, p = 0.001).

CONCLUSION

Even though BMI and serum albumin showed no prognostic value in SCLC patients treated with chemotherapy, PS was found to be the most significant prognostic factor in both LD- and ED-SCLC stages.

Long-Term Survival and Stable Disease in a Patient with Extensive-Stage Small-Cell Lung Cancer after Treatment with Carboplatin, Etoposide and Atezolizumab

Survival beyond 2 years is rare in patients with extensive-stage small-cell lung cancer (ES-SCLC) treated with chemotherapy alone. We describe a patient with ES-SCLC who was treated with carboplatin, etoposide and the programmed death-ligand 1 inhibitor atezolizumab in the IMpower133 study (ClinicalTrials.gov registration: NCT02763579) and who achieved exceptionally long-term survival. Treatment-naïve patients with ES-SCLC (n = 403) were included in the IMpower133 study, and the identified patient had been randomised to the investigational treatment arm, where patients received induction therapy with carboplatin and etoposide plus atezolizumab for four 21-day cycles, followed by ongoing maintenance therapy with atezolizumab. The patient had achieved a partial response after induction therapy, and then received seven cycles of atezolizumab maintenance therapy until immune-related toxicities necessitated discontinuation. The patient was alive with an ongoing response and excellent performance status more than 6 years after starting treatment and 5 years after discontinuing atezolizumab maintenance. In conclusion, this patient with ES-SCLC from the IMpower133 study is a rare example of ongoing survival more than 6 years beyond diagnosis and the start of treatment with first-line atezolizumab. This demonstrates the potential durability of response with immunotherapy.