Key presentations to look out for at SABCS 2025
The upcoming San Antonio Breast Cancer Symposium (SABCS) will continue the tradition of combining principles of multidisciplinary management with basic and translational science that underpin therapeutic strategies in breast cancer. Discover key presentations in this conference report by John Benson (Cambridge University Hospitals NHS Foundation Trust, UK).
Meeting overview
The 48th meeting will be held at the Henry B Gonzales Convention Centre in downtown San Antonio, TX, USA on 9–12th December 2025. Results of several trials will be presented that are potentially practice changing and some will constitute late-breaking news, with results embargoed until presentation at the meeting.
A particular feature of the SABCS in recent years has been its relevance to daily clinical practice with the session entitled “View from the trenches” having become a popular feature. Educational sessions have been fully integrated into the main program and provide foundational knowledge and as well as updates on cutting edge translational research that is potentially practice changing. The Program Committee has representation from senior clinicians and scientists as well as patient advocates, which facilitates a comprehensive approach with a focus on standards of clinical care and survivorship issues. This patient-centric philosophy has contributed to the success of SABCS and is reflected in the number of attendees – estimated at 10,000 in 2025.
The ‘hated’ trial that transformed axillary surgery
This year’s William McGuire lecture will be delivered by Armando Guiliano (Cedars-Sinai Medical Center, CA, USA), who has been a pioneer in transforming surgical management of the axilla in early-stage breast cancer patients. Although instrumental with the introduction of sentinel lymph node biopsy techniques for clinically node negative patients, Guiliano is probably best known for the conception and execution of the seminal ACOSOG Z0011 trial that has crucially underpinned contemporary axillary management.
This trial randomized sentinel lymph node biopsy positive patients with 1 or 2 positive nodes (macrometastases or micrometastases) undergoing breast conservation therapy to completion axillary lymph node dissection (ALND) or observation only (no further axillary treatment). Surgical resection of malignant nodal tissue had been a basic tenet of breast cancer surgery for the preceding 100 years; to suggest that ALND could be omitted in biopsy-confirmed node positive patients was almost heretical and indeed considered unethical by some clinicians.
The Z0011 trial encountered much resistance from both surgeons and medical oncologists with strong emotions apparent at the time. These aspects of the trial are not widely appreciated and will be addressed by Guiliano in his lecture with insights into the personal impact of this vehement opposition to his proposed ‘hated’ trial and consequent recruitment challenges – the trial failed to achieve its accrual target.
Elucidating the link between lifestyle and breast cancer risk
The etiology of breast cancer is multi-factorial and the vast majority of cases (70–80%) are non-hereditary (sporadic) with no identifiable predisposing gene mutation. Nonetheless, environmental and lifestyle factors are important determinants of risk, which can potentially be modified to reduce overall risk of developing breast cancer. Thus, maintaining a healthy weight, undertaking regular exercise, limiting alcohol intake, avoiding/cessation of smoking and participation in regular screening may help minimize risk, with evidence that environmental and life-style factors can modify risk in those individuals with genetic predisposition.
Indeed, it has been estimated that breast cancer incidence could be reduced by up to one-third with adherence to a ‘healthy’ lifestyle. SABC 2025 will include a session entitled “Open bar and all you can eat? Impact of lifestyle in breast cancer risk and recurrence” and chaired by Seema Khan (Northwestern University Feinberg School of Medicine, IL, USA). Apart from maintenance of optimal body weight, this session will provide sobering evidence that any amount of alcohol is associated with increased breast cancer risk and low-order consumption (such as 3–4 glasses of wine per week) is not entirely risk-free. This likely relates to the influence of alcohol on the hormonal environment with increased cell membrane permeability facilitating the passage of lipids, proteins and potential mitogenic molecules into breast epithelial cells.
Relative risk increases linearly with level of alcohol consumption and there may be racial differences in susceptibility based on variation of the expression of enzymes involved in the metabolism of alcohol. This may confound epidemiological studies aiming to identify alcohol-specific effects. Social and cultural pressures combined with mental health issues in the contemporary era likely increase levels of alcohol consumption amongst women and can be modified alongside other lifestyle factors with appropriate encouragement and support. Despite the adverse effects of obesity on breast cancer risk in post-menopausal women, it will be interesting to determine whether weight-reduction drugs might affect risk independent of amounts of peripheral adipose tissue.
A focus on reproductive considerations for young breast cancer patients
A special session at SABCS2025 will be dedicated to breast cancer in young women and chaired by Ann Partridge (Dana-Farber Cancer Institute, MA, USA); although the majority of early stage breast cancer occurs in older, post-menopausal women, absolute numbers of younger women with the disease are increasing globally and present therapeutic challenges in terms of innate biology and poorer prognosis, but also psychosocial problems when pregnancy-associated or a breast cancer diagnosis precedes a first pregnancy. Although TNBC is more common amongst pre-menopausal women, disparities in clinical outcomes between younger and older women are greatest for hormone receptor-positive disease.
Results of the prospective randomized POSITIVE trial were presented at SABCS in 2022 and revealed that temporary interruption of endocrine therapy amongst women who become pregnant after breast cancer did not appear to have any adverse impact on clinical outcomes with short term follow up after initial treatment for 18–30 months. Changes in reproductive behavior due to demands of career have led to increasing numbers of pre-menopausal women developing hormone receptor positive breast cancer before childbirth. It was emphasized at the time that “patient-centered reproductive healthcare should be incorporated routinely in the care of young women with breast cancer” and this will be reiterated during this session at SABCS 2025.
Cracking the lobular carcinoma code
There is often much deliberation at tumor board meetings on the optimal management of lobular carcinoma (ILC), which represents about 15% of invasive breast cancers. Lobular cancers have been diagnosed more frequently in recent years with widespread use of hormone replacement therapy and magnetic resonance imaging (MRI) [1]. There is a perception that ILC is unresponsive to chemotherapy and should not be employed in the neoadjuvant setting for post-menopausal women with larger biopsy-confirmed node positive luminal type tumors. However, ILC represents a heterogeneous group of cancer subtypes that likely arise from the same cell type as ductal carcinoma but have distinct biological characteristics, prognosis and response to therapeutic intervention.
An update on lobular-specific clinical trials will be presented at SABCS 2025 and moderated by Steffi Oesterreich (University of Pittsburg Medical Center, CA, USA) and Marleen Kok (Netherlands Cancer Institute). Robust and well-designed trials of ILC have been more difficult to conduct due to relatively small numbers of patients with limited longer term follow up data available for this cancer type, which has a tendency for late recurrence after 15–20 years. The use of CDK 4/6 inhibitors and/or antibody drug conjugates (ADC) may be effective in reducing any proclivity for late recurrence and underline the urgent need for clinical trials in this population to identify appropriate biomarkers.
There is much pressure from patient advocacy groups (e.g. the Lobular Breast Cancer Alliance [LBCA]) to encourage earlier diagnosis with up to half of ILC cases having a delay of 12 months or more in diagnosis (according to a patient survey to be presented at SABCS2025). About 10% of these cancers are occult on mammograms but visualized with MRI and patients are particularly concerned about the optimal modality for radiological surveillance in these cases. Moreover, due to lack of a key cell-adhesion molecule (e-cadherin), these cancers are permeative within breast tissue rather than forming a distinct mass and may be dismissed at initial clinical presentation.
The potential of ctDNA
Despite being in the era of personalized medicine, many patients continue to be over-treated in efforts to maximize breast cancer-specific survival rates. SABCS 2025 will include a session dedicated to adaptive therapy in breast cancer. Circulating tumor DNA (ctDNA) is a technology that offers the prospect for liquid biopsies to guide personalized management strategies by stratification of recurrence risk and detection of minimal residual disease (MRD) using ultrasensitive assays.
Several oral presentations and posters at this year’s meeting will address the potential clinical utility of ctDNA, which continues to be a major focus of research interest around the world. Liquid biopsy can monitor disease response and the measurement of ctDNA in adaptive clinical trials can identify patients for whom therapies should be intensified (to eradicate resistant clones) and those where toxic treatments can be safely omitted without significant oncologic detriment.
Key clinical trial presentations to bookmark
Results of several trials of metastatic breast cancer (MBC) will be presented during the SABCS meeting that have evaluated use of newer biological agents as a combinatorial first line standard of care (SOC) maintenance therapy approach rather than being introduced at a later stage of disease relapse.
HER2CLIMB-05 is a double-blind randomized study that has investigated the tyrosine kinase inhibitor tucatinib as earlier first line SOC maintenance therapy in HER2 positive MBC and follows on from the original HER2CLIMB study [2]. Patients with no or asymptomatic brain metastases received tucatinib or placebo (1:1) in combination with trastuzumab plus pertuzumab and a taxane (once every 21 days). Data will be presented at SABCS 2025 confirming that this trial met its primary endpoint and showing a statistically significant delay in time-to-progression and extended progression-free survival from the addition of tucatinib in the first line maintenance setting. A particularly exciting prospect of this upfront anti-HER2 therapy is that up to 20% of patients had a complete response and some may be cured of their disease.
DESTINY-BREAST09 is another trial that has investigated the use of a novel anti-HER2 agent in the first line setting for the treatment of advanced or metastatic HER2 positive breast cancer. The ADC trastuzumab deruxtecan (T-DXd) in continuous combination with pertuzumab was compared with the standard regimen of a taxane combined with trastuzumab and pertuzumab (THP) as per the CLEOPATRA trial [3]. T-DXd improved progression-free survival by 13.8 months at a median follow-up of 29 months and hence a 44% reduction in risk of progression or death [HR 0.56; 95% CI 0.44 – 0.71 (p<0.00001)]. These impressive results from upfront T-DXd have prompted health authorities in the United States to seek regulatory approval and further trials are planned that compare THP with T-DXd as monotherapy.
The Phase III ASCENT-04 trial has yielded clinically meaningful and statistically significant results demonstrating that the ADC sazituzumab-govitecan is potentially synergistic with the immune-check point inhibitor pembrolizumab. Progression-free survival for PDL-1 positive TNBC was improved compared with SOC chemotherapy and is the preferred choice in the first line setting, although it remains unclear whether overall survival results should be awaited prior to any practice change (there was potential for cross-over in the trial).
Finally, another promising ADC has been explored in the TROPION-Breast01 study for the treatment of unresectable or metastatic hormone receptor-positive HER2 negative/low (not IHC 3+) breast cancer in patients previously exposed to endocrine therapy and chemotherapy for MBC. Datopotamab deruxtecan (Dato-DXd) is an ADC with novel linkers that are tumor selective and exhibit the bystander effect after release of the cytotoxic payload. Results to-date has shown improved progression-free survival (4.5 versus 6.9 months) and lower risk of death [HR 0.64] compared to standard chemotherapy. This median increase of 2.3 months in progression-free survival is relatively modest compared with T-DXd and there was no difference in median overall survival (but this was a linked primary endpoint).
Registration guidance and the full program are available through the official SABCS website.
Author profile:
In addition to serving as a Consultant Breast Surgeon in the Cambridge Breast Unit (UK), John Benson holds academic positions as an Associate Lecturer at the University of Cambridge, a Visiting Professor at the School of Medicine, Anglia Ruskin University and an Honorary Lecturer at the University of East Anglia (UK).
He co-convenes the Advanced Skills in Breast Disease Course, now hosted by Selwyn College Cambridge (UK) after its transition from the Royal College of Surgeons of England. Additionally, he serves as the Module Lead for the Masters in Oncoplastic Breast Surgery, a program jointly run by the University of East Anglia and the Royal College of Surgeons of England. His clinical practice at Addenbrooke’s Hospital is exclusively dedicated to managing patients with breast diseases.
The opinions expressed in this interview are those of the author and do not necessarily reflect the views of Oncology Central or Taylor & Francis Group.
References:
[1] Batra H, Mouabbi JA, Ding Q, Sahin AA, Raso MG. Lobular carcinoma of the breast: A comprehensive review with translational insights. Cancers (Basel) 15(22):5491 (2023).
[2] Murthy RK, Loi S, Okines A et al. Tucatinib, trastuzumab, and capecitabine for HER2-positive metastatic breast cancer. N. Engl. J. Med. 382(7):597-609 (2020).
[3] Swain SM, Baselga J, Kim SB et al. Pertuzumab, trastuzumab, and docetaxel in HER2-positive metastatic breast cancer. N. Engl. J. Med. 372(8):724-34 (2015)