Real-world predictors of survival in patients with extensive-stage small-cell lung cancer in Manitoba, Canada: a retrospective cohort study.

Background

Extensive-stage small-cell lung cancer (ES-SCLC) is an incurable cancer with poor prognosis in which characteristics predictive of long-term survival are debated. The utility of agents such as immune checkpoint inhibitors highlights the importance of identifying key characteristics and treatment strategies that contribute to long-term survival and could help guide therapeutic decisions.

Objective

This real-world analysis examines the characteristics, treatment patterns, and clinical outcomes of patients receiving chemotherapy without immunotherapy for ES-SCLC in Manitoba, Canada.

Methods

A retrospective cohort study assessed patient characteristics, treatment, and survival duration (short: <6 months; medium: 6-24 months; long: >24 months) using the Manitoba Cancer Registry and CancerCare Manitoba records. Eligible patients were aged >18 years with cytologically confirmed ES-SCLC diagnosed between January 1, 2004, and December 31, 2018, and received cytotoxic chemotherapy (CT). The one-, two-, and five-year probabilities of overall survival (OS) were assessed relative to patient, disease, and treatment characteristics using Kaplan-Meier methods and Cox proportional hazards models.

Results

This analysis included 537 patients. Cisplatin was used in 56.1% of patients, 45.6% received thoracic radiotherapy (RT), and few received prophylactic cranial irradiation (PCI). In the overall cohort, one-, two- and five-year OS rates were 26%, 8%, and 3%, respectively. For patients with Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0, OS rates at one, two, and five years were 43%, 17%, and 10%, respectively, vs. 27%, 8%, and 2% for those with ECOG PS 1-2, and 16%, 3%, and 3% for those with ECOG PS 3-4. In long-term survivors, ECOG PS scores were lower and abnormal laboratory test results were less frequent. Overall, 74.4% of long-term survivors received thoracic RT and 53.5% received PCI. Known poor prognostic factors - including brain/liver metastases, high lactate dehydrogenase (LDH), abnormal sodium, and low hemoglobin levels - were less common but still seen in long-term survivors.

Conclusion

Although rare, patients with ES-SCLC may experience long-term survival with CT ± thoracic RT ± PCI. Factors predicting long-term survival include traditional prognostic factors such as ECOG PS, LDH level, and receipt of thoracic RT or PCI. These findings support current treatment algorithms for ES-SCLC and provide baseline survival estimates to assess the real-world impact of adding immune checkpoint inhibitors in the future.

Informations de copyright

Copyright © 2023 Dawe, Rittberg, Syed, Shanahan, Moldaver, Bucher, Galloway, Reynolds, Paul, Harlos, Kim and Banerji.

Déclaration de conflit d'intérêts

IS and MS are employees and shareholders of AstraZeneca. DM was an employee of AstraZeneca at the time of this study. DD reports advisory board attendance for Merck Canada, Novartis, Jazz Pharmaceuticals, Pfizer, and AstraZeneca, honoraria for education content from Boehringer-Ingelheim and Bristol Myers Squibb, grants from Canadian Institutes of Health Research, CancerCare Manitoba Foundation, and Manitoba Medical Services Foundation. RR reports grant funding received from AstraZeneca. SB reports advisory board attendance for AstraZeneca, Bayer, Bristol Myers Squibb, Jazz Pharmaceuticals, Merck Canada, Novartis Janssen, Pfizer, and Roche, clinical trial funding from AstraZeneca, Bayer, and Roche, grants from Canadian Institutes of Health Research, grants from CancerCare Manitoba Foundation, and grants from Genome Canada, outside the submitted work. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study received funding from AstraZeneca Canada. The funder had the following involvement with the study: study design, writing of this article, data interpretation and decision to submit it for publication. The funder was not involved in data analysis and did not have access to patient data.