Real-World Outcomes of Relapsed and Refractory Systemic Therapy in the Canadian SCLC Database (CASCADE)

Small cell lung cancer (SCLC) accounts for 15% of all lung cancer cases, with one-third of patients presenting with limited disease (LD). This form of SCLC has the potential for cure through the use of concurrent chemoradiation therapy, followed by prophylactic cranial irradiation (PCI). However, relapses are frequent, and the overall survival (OS) rates remain unsatisfactory. The recently published ADRIATIC trial (NCT03703297) has shown that the addition of consolidation durvalumab after chemoradiation can enhance OS and progression-free survival (PFS). This study aimed to assess the real-world treatment approaches and outcomes for LD-SCLC in Canada, thereby providing context for emerging therapeutic strategies.

The Canadian SCLC Database (CASCADE) is a multi-institutional real-world database of patients with SCLC from 9 academic institutions across Canada. Demographics, diagnostics, treatments, and outcomes were obtained from CASCADE. Patients with a de novo diagnosis of LD-SCLC between January 2001 and December 2022 were included. The data cutoff was June 2023. The primary outcome was OS.

The overall population consisted of 1319 patients, with 1024 patients who received curative treatment and 295 patients who received palliative treatment. In the overall population, the median age at diagnosis was 68 years and 54% were female. A total of 54% of patients treated with curative intent received PCI. The median follow-up for OS was 66.1 months. In the curative intent arm, the most common treatment approach was concurrent chemoradiation (60%); in the palliative intent arm, the most common treatment approach was palliative chemo with or without radiation. The median OS for patients in the curative arm was 24.9 months and was 9.6 months for patients in the palliative arm. A total of 36% of patients receiving concurrent chemoradiation met basic eligibility to participate in the ADRIATIC trial. The median OS of patients who were ADRIATIC eligible was 30.3 months versus 21.7 months for patients who were not eligible for the ADRIATIC trial.

Treatment strategies for LD-SCLC exhibit considerable diversity, with 22% of patients receiving therapy aimed at palliative care. The predominant treatment modality employed was concurrent chemoradiation. Despite the application of curative intent therapies, LD-SCLC is associated with a dismal prognosis, highlighting a significant gap in effective treatment options.

Source: Moore S, Zhan LJ, Gill J, et al. Relapsed and refractory systemic therapy real-world outcomes in the Canadian small cell lung cancer database (CASCADE). Barcelona, Spain, & online: presented at ESMO Congress 2024; abstract 1789P.