Real-world outcomes of breast cancer patients with brain metastases treated with radiotherapy in Ontario: A population-based study.
Bibliographic record
Abstract
2027 Background: Brain Metastases (BrM) are a major cause of morbidity and mortality in patients with metastatic breast cancer (MBC). Real-word data regarding time to development of breast cancer BrM and survival outcomes is lacking. Methods: We conducted a retrospective, observational population-based cohort study to assess treatment patterns and outcomes of patients with de-novo MBC who received radiotherapy for intracranial metastatic disease between January 2009 and December 2018. We used population health administrative databases in Ontario held at ICES, an independent, non-profit research institute. Primary endpoints were i) cumulative incidence of radiotherapy for BrM accounting for the competing risk of death, and ii) time from MBC diagnosis to brain radiotherapy. Secondary endpoints included overall survival (OS) and radiation therapy toxicity. Data were censored if patients were alive on the same therapy at last available follow-up with the last cut-off date being March 31, 2019. Kaplan-Meier analyses were performed for the time to event endpoints and compared using the log-rank test. Cumulative incidence of radiotherapy for BrM from the diagnosis of MBC was calculated using the Cumulative Incidence Function (CIF), accounting for the competing risk of death using a competing risk analysis. Multivariable regression models were used to account for confounding variables. Results: 3,916 patients with de-novo MBC were identified, among whom 549 (14%) developed BrM requiring radiotherapy; cumulative incidence of BrM at 7-year follow-up was highest among patients with HER2+/HR- (34.7%) and HER2+/HR+ (28.1%) disease, followed by triple negative MBC (21.9%) and HR+/HER2- (12.1%) subtypes. The median time from diagnosis of MBC to first radiotherapy treatment for BrM was 7.5 months, 15.0 months, 16.8 months and 19.8 months, in TNBC, HER2+/HR-, HR+/HER2- and HER2+/HR+ subtypes, respectively. The median OS from radiotherapy among patients with breast cancer BrM was 5.1 months in the overall cohort. When analyzed by subtype, the median OS was 2.6 months, 4.8 months, 8.7 months, and 9.4 months in TNBC, HR+/HER2, HER2+/HR+ and HER2+/HR- subtypes, respectively. In a multivariable Cox regression model, a triple negative or HR+/HER2- breast cancer subtype, treatment with WBRT, age > 60 and a high-income quintile (4 or 5) were independently prognostic for shorter OS after adjustment for the index year at diagnosis. Patients treated with stereotactic radiosurgery (SRS) had lower 30-day mortality (6.4% vs. 18.9%, p = 0.003) and lower likelihood of hospitalization within 30 days of therapy (9.6% vs. 20.2%, p = 0.015) compared to patients treated with WBRT. Conclusions: Approximately 1 in 7 patients with MBC will require radiotherapy for BrM. Our data support the use of SRS when clinically indicated and provide insights regarding the time to development of BrM by breast cancer subtype.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".