Evaluating the prognostic significance of significant weight loss in patients with stage III non-small cell lung cancer (NSCLC) undergoing definitive chemoradiation (CRT) after FDG-PET staging.

Abstract

e20045 Background: In the pre-PET era, weight loss is a harbinger of occult metastatic disease in patients with stage III NSCLC. Identifying the relationship between weight loss and pattern of relapse (POR), may enable stratification of patients into prognostic groups associated with increased risk of relapse. We sought to identify if weight loss remains a negative independent prognostic factor after FDG-PET staging. Methods: A retrospective audit (using web-based and electronic databases) was conducted in all patients with stage III NSCLC treated with definitive CRT between 01/07/2013 and 30/06/2018 at the Royal Brisbane and Women’s Hospital and The Prince Charles Hospital, Queensland, Australia. A descriptive analysis was applied to describe the primary end-point of PFS and secondary end-points of OS and POR, in relation to the percentage of pre-treatment weight loss (0-10% vs > 10-20% vs > 20%). A subset analysis looked at other prognostic factors identified in NSCLC to account for potential confounders. Results: Of the 127 patients (mean age 65 years, mean weight 76kg, 57% male, 42% current smokers) who commenced treatment during the study period, 24% lost > 10% and 3% lost > 20% weight. Median TTP for the entire cohort was 9 months. Based on multivariable modelling, risk of PD or death was 45% higher with > 10% loss of body weight (p = 0.004), and risk of death was 36% higher with > 10% of body weight (p = 0.05). Of the 54% that died during follow-up, 31 had distant PD, 18 had locoregional PD, 6 had local PD, and 10 had no PD. Males were at increased risk of PD. Conclusions: A prognostic link continues to be identified between significant (> 10%) weight loss and risk of progressive disease or death in stage III NSCLC treated with definitive CRT despite pre-treatment FDG-PET. These findings identify a sub-group of patients where weight loss could still be a surrogate for micro-metastases not detected on PET, or other adverse prognostic markers. Other treatment strategies or improved diagnostic strategies are warranted.