Uncovering the armpit of SBRT: An institutional experience with stereotactic radiation of axillary metastases
Bibliographic record
Abstract
Purpose/Objective(s): The growing use of stereotactic body radiotherapy (SBRT) in metastatic cancer has led to its use in varying anatomic locations. The objective of this study was to review our institutional SBRT experience for axillary metastases (AM), focusing on outcomes and process.Materials/Methods: Patients treated with SBRT to AM from 2014-2022 were reviewed. Cumulative incidence functions were used to estimate the incidence of local failure (LF), with death as competing risk. Kaplan-Meier method was used to estimate progression-free (PFS) and overall survival (OS). Univariate regression analysis examined predictors of LF.ResultsWe analyzed 37 patients with 39 AM who received SBRT. Patients were predominantly female (60%) and elderly (median age: 72). Median follow-up was 14.6 months. Common primary cancers included breast (43%), skin (19%), and lung (14%). Treatment indication included oligoprogression (46%), oligometastases (35%) and symptomatic progression (19%). A minority had prior overlapping radiation (18%) or surgery (11%). Most had prior systemic therapy (70%).Significant heterogeneity in planning technique was identified; a minority of patient received 4-D CT scans (46%), MR-simulation (21%), or contrast (10%). Median dose was 40Gy (interquartile range (IQR): 35-40) in 5 fractions, (BED10=72Gy). Seventeen cases (44%) utilized a low-dose elective volume to cover remaining axilla.At first assessment, 87% had partial or complete response, with a single progression. Of symptomatic patients (n=14), 57% had complete resolution and 21% had improvement. One and 2-year LF rate were 16% and 20%, respectively. Univariable analysis showed increasing BED reduced risk of LF. Median OS was 21.0 months (95% [Confidence Interval (CI)] 17.3-not reached) and median PFS was 7.0 months (95% [CI] 4.3-11.3). Two grade 3 events were identified, and no grade 4/5.ConclusionUsing SBRT for AM demonstrated low rates of toxicity and LF, and respectable symptom improvement. Variation in treatment delivery has prompted development of an institutional protocol to standardize technique and increase efficiency. Limited followup may limit detection of local failure and late toxicity.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".