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Vienna, Austria

ESTRO 2023

Session Item

Lung
Poster (Digital)
Clinical
Risk factors for intracranial metastasis in stage III NSCLC after chemoradiation
Stephane Thibodeau, Canada
PO-1332

Abstract

Risk factors for intracranial metastasis in stage III NSCLC after chemoradiation
Authors:

Stephane Thibodeau1, Mahbuba Meem1, Simran Sandhu2, Wilma Hopman3, Geneviève Digby4, Shahad Al-Ghamdi4, Timothy Owen1, Allison Ashworth5, Andrea Fung6, Adi Kartolo7, Andrew Robinson6, Osbert Zalay8, Fabio Ynoe de Moraes1

1Queen's University, Department of Oncology, Division of Radiation Oncology, Kingston, Canada; 2Queen's University, Faculty of Medicine, Kingston, Canada; 3Queen's University, Department of Public Health Sciences, Kingston, Canada; 4Queen's University, Department of Medicine, Division of Respirology, Kingston, Canada; 5Queen's University , Department of Oncology, Division of Radiation Oncology, Kingston, Canada; 6Queen's University, Department of Oncology, Division of Medical Oncology, Kingston, Canada; 7McMaster University, Department of Oncology, Division of Medical Oncology, Hamilton, Canada; 8University of Ottawa, Department of Radiology, Division of Radiation Oncology, Ottawa, Canada

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Purpose or Objective

Around 30% of patients with non-small cell lung cancers (NSCLC) are diagnosed with stage III disease at presentation, of which about 85% are treated with definitive chemoradiation (CRT). Approximately 40% of patients will eventually develop intracranial metastases (IM), though associated risk factors are not clearly described. We report survival outcomes and risk factors for development of IM in a cohort of patients with stage III NSCLC treated with CRT at a tertiary Cancer Centre.

Material and Methods

We identified 195 patients with stage III NSCLC treated with CRT from January 2010 to May 2021. Multivariable logistic regression was used to generate odds ratios for covariates associated with development of IM. Kaplan-Meier analysis with the Log Rank test was used for unadjusted time-to-event analyses. P-value for statistical significance was set at < 0.05 with a two-sided test.

Results

Out of 195 patients, 108 (55.4%) had stage IIIA disease and 103 (52.8%) had adenocarcinoma histology. The median age and follow-up (in months) was 67 (IQR 60-74) and 21 (IQR 12-43), respectively. 148 patients (75.9%) were treated with 60 Gy in 30 fractions concurrent with chemotherapy. Of the 77 patients who received treatment since immunotherapy was available and standard at our Cancer Centre, 45 (58.4%) received at least one cycle. During follow-up, 84 patients (43.1%) developed any metastasis, and 33 (16.9%) developed IM (either alone or with extracranial metastasis). 150 patients (76.9%) experienced a treatment delay (interval between diagnosis and treatment > 4 weeks). Median OS was not reached for the overall cohort, and was 43.1 months for patients with IM and 40.3 months in those with extracranial-only metastasis (p=0.968). Factors associated with developing any metastasis included higher overall stage at diagnosis (p=0.013) and higher prescribed dose (p=0.022). Factors associated with developing IM included higher ratio of involved over sampled lymph nodes (p=0.001) and receipt of pre-CRT systemic or radiotherapy for any reason (p=0.034). On multivariate logistical regression, treatment delay (OR 4, p=0.032) and overall stage at diagnosis (IIIA vs. IIIB/IIIC) (OR 2.4, p=0.034) predicted development of IM.

Conclusion

In patients with stage III NSCLC treated with definitive CRT, the risk of intracranial metastasis appears to increase with overall stage at diagnosis and, importantly, treatment delay (> 4 weeks). Survival was better in patients without metastases. No difference in survival was observed between patients who developed either intracranial (alone or with extracranial metastasis) or extracranial-only metastasis. Metastatic disease remains the primary life-limiting prognostic factor in patients with stage III NSCLC treated with CRT. Further research is needed to better understand factors associated with survival and development of metastasis after CRT in the immunotherapy era.