In a study reported in JAMA Network Open, Farris et al identified prognostic factors in patients with limited-stage small cell lung cancer (SCLC) receiving radiotherapy at two dose schedules in the CALGB 30610–RTOG 0538 trial.
Study Details
In the trial, 638 patients were randomly assigned between March 2008 and December 2019 to receive radiotherapy twice daily to a dosage of 45 Gy for 3 weeks (n = 313) or once daily to a dosage of 70 Gy for 7 weeks (n = 325). The current secondary analysis included 507 patients with sufficient data on potential prognostic factors to be included in the analysis.
Key Findings
On multivariate analysis, with a median follow-up of 4.7 years (interquartile range = 3.7–7.1 years), female sex was associated with improved overall survival vs male sex (hazard ratio [HR] = 0.73, 95% confidence interval [CI] = 0.58–0.91, P = .006). Age ≥ 70 years was associated with worse overall survival (HR = 1.50, 95% CI = 1.14–1.98, P = .004). No significant association for age or sex was observed for progression-free survival. No significant differences between treatment groups were observed for overall or progression-free survival.
Compared with patients with N1 disease, overall and progression-free survival were worse among those with N2 disease (HR = 1.64, 95% CI = 1.19–2.26, P = .002; HR = 1.36, 95% CI = 1.02–1.81, P = .04) and among those with N3 disease (HR = 2.03, 95% CI = 1.40–2.93, P < .001; HR = 1.63, 95% CI = 1.17–2.26, P = .004).
Compared with patients with stage II disease, overall survival was worse among those with stage IIIA disease (HR = 1.65, 95% CI = 1.17–2.31, P = .004) and those with stage IIIB disease (HR = 1.94, 95% CI = 1.34–2.83, P < .001).
Compared with patients treated at high-volume accrual centers, those with treatment at low-volume or middle-volume accrual centers had worse progression-free survival (HR = 1.94, 95% CI = 1.33-2.82, P < .001; HR = 1.44, 95% CI = 1.15–1.82, P = .002) and worse overall survival (HR = 1.55, 95% CI = 1.03–2.32, P = .03; HR = 1.33, 95% CI = 1.04–1.70, P = .02).
The investigators concluded: “This secondary analysis of the CALGB 30610–RTOG 0538 randomized clinical trial of patients with [limited-stage] SCLC found associations between female sex or being younger than 70 years and improved overall survival and between advanced nodal stage or treatment at low- or middle-volume accrual centers and worse outcomes. These findings suggest that stratification by nodal stage, clinical stage, and age should be considered in future randomized trials.”
Michael Farris, MD, of Wake Forest Medical University, is the corresponding author of the JAMA Network Open article.
Disclosure: The study was supported by grants from the National Cancer Institute. For full disclosures of the study authors, visit jamanetwork.com.
