Aims: There is robust trial evidence for improved overall survival (OS) with immunotherapy in advanced solid organ malignancies. The real-world survival data and the predictive variables are yet to be established. The aim of this study was to evaluate the factors associated with 3-year OS for patients managed with immune checkpoint inhibitors (ICI’s).
Methods: We performed a retrospective study of patients who received ICI’s for the management of advanced solid organ malignancies in an Australia tertiary oncology centre from 2012 – 2017 and assessed the 3-year OS rates. Data regarding clinical characteristics, lines of therapy, metastatic disease burden, immune related adverse events (IRAE’s) and tumour responses were examined.
Results: Of 264 patients included in this analysis, 202 (76.5%) had melanoma, (17.4%) had NSCLC, 12 (4.5%) had RCC and 4 (1.5%) had mesothelioma. OS curves showed estimated 3-year rates of 45.9% among patients with melanoma, 58.7% among patients with NSCLC and 83.3% among patients with RCC. In a multivariable analysis, the occurrence of IRAE’s of any grade (OR 0.45; 95% CI 0.26 – 0.79; p =0.006) or ECOG of 0 or 1 (OR 2.73; 95% CI 1.54 – 4.85; p < 0.001) was associated with a higher likelihood of survival at 3 years. OS was significantly longer among patients < 65 years (median OS not reached (NR)) compared with those ≥ 65 years (median OS 24 months; 95% CI 24.29 – 47.72) (p = 0.007) and shorter in those with liver metastases (median OS 21 months, 95% CI 2.52 – 39.48) compared to those without (median OS NR) (p = 0.001). Neither gender, BMI or number of prior therapies influenced mortality.
Conclusion: Factors associated with higher rates of 3-year OS included ECOG 0-1 and occurrence of IRAE's. Older age and presence of liver metastases were associated with reduced OS.