Abstract 316P
Background
Stereotactic body radiation therapy (SBRT) is an emerging management paradigm for oligometastatic breast cancer (OMBC) with the goal of improving long-term disease control or even cure. However, its implementation in treatment guidelines is still not universal. We conducted a survey to define the current practice patterns towards SBRT use in OMBC.
Methods
An online survey was conducted through OncoAlert (social media network of professionals involved in the oncology field) and local oncology societies among BC specialists from 24 March to 23 April 2021.
Results
258 BC physicians took part in the survey (65.9% were medical oncologists and 77.1% had access to SBRT); median age was 40 years. The definition of OMBC varied among respondents in terms of the number of metastases (52.3% up to 3 and 45.3% up to 5) and the number of involved metastatic sites (29.5% single site and 56.6% up to 2). BC subtype substantially impacted the choice towards the use of SBRT (38.8%), and treatment interruption before SBRT was significantly influenced by the type of systemic therapy. The main results are summarized in the table. Respondents generally preferred to continue the same systemic therapy after using SBRT for oligoprogressive and induced OMBC of initially polymetastatic disease irrespective of tumor subtypes, with the exception of SBRT for oligoprogressive triple-negative BC (TNBC) where the majority of respondents (55.8%) would change current therapy. Table: 316P
SBRT use in respect to tumor subtypes
| Hormone receptor+/HER2- BC | TNBC | HER2+ BC | P value | ||
| De novo OMBC | Yes | 70.5% | 54.3% | 64.7% | 0.001 |
| No | 14.7% | 28.3% | 53% | ||
| Uncertain | 14.7% | 17.4% | 38% | ||
| Oligoprogressive disease | Yes | 82.2% | 56.2% | 72.5% | <0.001 |
| No | 7.0% | 21.3% | 14.0% | ||
| Uncertain | 10.9% | 22.5% | 13.6% | ||
| Induced OMBC of initially polymetastatic disease | Yes | 54.3% | 39.9% | 50.8% | 0.006 |
| No | 21.7% | 34.1% | 24.4% | ||
| Uncertain | 24.0% | 26.0% | 24.8% |
Conclusions
Results of our survey showed discordance in the definition of OMBC. Even though a significant number of respondents would use SBRT for de novo OMBC, the vast majority preferred using SBRT after initial response to systemic therapy as compared to upfront SBRT. Respondents were more reluctant to use SBRT in TNBC compared with other tumor subtypes.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Oncoalert Network.
Funding
Has not received any funding.
Disclosure
I. Meattini: Financial Interests, Personal, Advisory Role: Novartis; Financial Interests, Personal, Advisory Role: Pfizer; Financial Interests, Personal, Advisory Role: Roche. M. Lambertini: Financial Interests, Personal, Advisory Role: Roche; Financial Interests, Personal, Advisory Role: AstraZeneca; Financial Interests, Personal, Advisory Role: Lilly; Financial Interests, Personal, Advisory Role: Novartis; Financial Interests, Personal, Invited Speaker: Sandoz; Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Invited Speaker: Takeda; Financial Interests, Personal, Invited Speaker: Pfizer; Financial Interests, Personal, Invited Speaker: Lilly; Financial Interests, Personal, Invited Speaker: Novartis. E. de Azambuja: Financial Interests, Personal, Invited Speaker: Roche/GNE; Financial Interests, Personal, Invited Speaker: Novartis; Financial Interests, Personal, Invited Speaker: Seattle Genetics; Financial Interests, Personal, Invited Speaker: Libbs; Financial Interests, Personal, Invited Speaker: Zodiac; Financial Interests, Personal, Invited Speaker: Lilly; Financial Interests, Personal, Invited Speaker: Piere Fabre; Financial Interests, Personal, Advisory Board: Roche/GNE; Financial Interests, Personal, Advisory Board: Novartis; Financial Interests, Personal, Advisory Board: Seattle Genetics; Financial Interests, Personal, Advisory Board: Libbs; Financial Interests, Personal, Advisory Board: Zodiac; Financial Interests, Personal, Advisory Board: Lilly; Financial Interests, Personal, Advisory Board: Piere Fabre; Financial Interests, Personal, Other, Travel grants: Roche/GNE; Financial Interests, Personal, Other, Travel grants: GSK/Novartis; Financial Interests, Institutional, Research Grant: Roche/GNE; Financial Interests, Institutional, Research Grant: AstraZeneca; Financial Interests, Institutional, Research Grant: GSK/Novartis; Financial Interests, Institutional, Research Grant: Servier. A. Prat: Other, Personal, Other: Novartis; Financial Interests, Personal, Stocks/Shares: Reveal Genomics; Financial Interests, Personal, Invited Speaker: Pfizer; Financial Interests, Personal, Invited Speaker: Novartis; Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Invited Speaker: MSD Oncology; Financial Interests, Personal, Invited Speaker: Lilly; Financial Interests, Personal, Invited Speaker: Daiichi Sankyo; Financial Interests, Personal, Invited Speaker: Amgen; Financial Interests, Personal, Invited Speaker: Guardant Health; Financial Interests, Personal, Advisory Role: Amgen; Financial Interests, Personal, Advisory Role: Roche; Financial Interests, Personal, Advisory Role: Novartis; Financial Interests, Personal, Advisory Role: Pfizer; Financial Interests, Personal, Advisory Role: Bristol Myers Squibb; Financial Interests, Personal, Advisory Role: Boehringer Ingelheim; Financial Interests, Personal, Advisory Role: PUMA; Financial Interests, Personal, Advisory Role: Oncolytics Biotech.; Financial Interests, Personal, Advisory Role: Daiichi Sankyo; Financial Interests, Personal, Advisory Role: Abbvie; Financial Interests, Personal, Advisory Role: AstraZeneca; Financial Interests, Personal, Advisory Role: NanoString Technologies; Financial Interests, Institutional, Research Grant: Roche; Financial Interests, Institutional, Research Grant: Novartis; Financial Interests, Institutional, Research Grant: Incyte; Financial Interests, Institutional, Research Grant: Puma Biotechnology; Financial Interests, Personal, Ownership Interest: PCT/EP2016/080056: HER2 as a predictor of response to dual HER2 blockade in the absence of cytotoxic therapy; Financial Interests, Personal, Ownership Interest: WO/2018/096191. Chemoendocrine score (CES) Based on PAM50 for breast cancer with positive hormone receptors with an intermediate risk of recurrence; Financial Interests, Personal, Ownership Interest: HER2DX filing; Financial Interests, Personal, Ownership Interest: methods for breast cancer treatment and prediction of therapeutic response (US 63/023785); Financial Interests, Personal, Other, Travel, Accommodations, Expenses: Daiichi Sankyo; Financial Interests, Personal, Other: Oncolytics; Financial Interests, Personal, Other: Peptomyc S.L. P.G. Aftimos: Financial Interests, Personal, Advisory Role: Boehringer Ingelheim; Financial Interests, Personal, Advisory Role: Macrogenics; Financial Interests, Personal, Advisory Role: Roche; Financial Interests, Personal, Advisory Role: Novartis; Financial Interests, Personal, Advisory Role: Amcure; Financial Interests, Personal, Advisory Role: Servier; Financial Interests, Personal, Advisory Role: Radius; Financial Interests, Personal, Advisory Role: Deloitte; Financial Interests, Personal, Invited Speaker: Synthon; Financial Interests, Personal, Invited Speaker: Amgen; Financial Interests, Personal, Invited Speaker: Novartis; Financial Interests, Personal, Invited Speaker: Gilead; Financial Interests, Personal, Other, Travel grants: Amgen; Financial Interests, Personal, Other, Travel grants: MSD; Financial Interests, Personal, Other, Travel grants: Pfizer; Financial Interests, Personal, Other, Travel grants: Roche; Financial Interests, Institutional, Research Grant: Roche; Financial Interests, Personal, Advisory Role: G1 Therapeutics. All other authors have declared no conflicts of interest.