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Mutsaers A, Li G, Fernandes J, Ali S, Barnes E, Chen H, Czarnota G, Karam I, Moore-Palhares D, Poon I, Soliman H, Vesprini D, Cheung P, Louie A. Uncovering the armpit of SBRT: An institutional experience with stereotactic radiation of axillary metastases. Clin Transl Radiat Oncol 2024; 45:100730. [PMID: 38317679 PMCID: PMC10839264 DOI: 10.1016/j.ctro.2024.100730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 02/07/2024] Open
Abstract
Purpose/objectives 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 to 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. Results We 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 40 Gy (interquartile range (IQR): 35-40) in 5 fractions, (BED10 = 72 Gy). 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. Conclusion Using 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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Affiliation(s)
- A. Mutsaers
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - G.J. Li
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - J.S. Fernandes
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - S. Ali
- Department of Radiation Therapy, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - E.A. Barnes
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - H. Chen
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - G.J. Czarnota
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - I. Karam
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - D. Moore-Palhares
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - I. Poon
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - H. Soliman
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - D. Vesprini
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - P. Cheung
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
| | - A.V. Louie
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Hospital, University of Toronto, Canada
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