🌸 Breast Cancer — 2026-W36

What this page is. Every paper the week's monitor reviewed — including the ones that did not go into the digest. Material marked “Not selected” was reviewed and deliberately left out. It has not been fact-checked to digest standard and is not endorsed. For the curated read, see the digest itself.

ASCO Living Guideline update in JCO providing systematic, evidence-based recommendations on neoadjuvant/adjuvant chemotherapy, endocrine therapy, immunotherapy, and targeted therapy for stage I-III HR-positive, HER2-negative breast cancer. Directly informs treatment selection, sequencing, and duration decisions in routine practice.

Updated analysis of the phase 3 OlympiA trial in gBRCA-mutated, HER2-negative high-risk early breast cancer, published in Annals of Oncology. Confirms sustained invasive disease-free survival, distant disease-free survival, and overall survival benefit with adjuvant olaparib, reinforcing its role as standard adjuvant therapy in this population.

Narrative review in JAMA Oncology on systemic therapy decision-making for older adults with early-stage breast cancer, covering chemotherapy, CDK4/6 inhibitors, and neoadjuvant immunotherapy. Offers guidance to balance overtreatment and undertreatment risks in this underrepresented population.

Large multicentre phase 1 trial of a novel nectin-4-directed antibody-drug conjugate in pretreated advanced solid tumors including NSCLC and HR+/HER2- breast cancer, published in Lancet Oncology. Establishes safety, dosing, and preliminary activity for a new ADC that may inform future development in these tumor types.

Substantive review in Lancet Oncology from the International Immuno-Oncology Biomarker Working Group on tumour-infiltrating lymphocytes as biomarkers linked to radiotherapy and systemic therapy response in breast cancer. Calls for standardized TIL reporting to guide future biomarker-driven individualization of treatment.

Cross-sectional claims-based analysis of women with germline pathogenic variants in breast cancer susceptibility genes, published in JCO Precision Oncology. Shows low uptake of risk-reducing surgery, breast MRI, and pancreatic screening, highlighting gaps in guideline-concordant management after genetic testing.

Secondary analysis from a large single-arm phase 2 trial (EA1181/CompassHER2) in stage II/IIIa HER2-positive breast cancer, published in JCO. Reports pathologic complete response rates and clinicopathologic predictors of response to neoadjuvant taxane/trastuzumab/pertuzumab, informing which patients might benefit from de-escalated regimens pending survival data.

Secondary biomarker analysis of the phase 3 APHINITY trial in early-stage HER2-positive breast cancer, published in Lancet Oncology. Compares manual, digital, and AI-based TIL scoring methods and links TIL levels to outcomes and pertuzumab benefit, potentially refining how immune infiltrate is used to stratify treatment benefit.

Independent validation study comparing AI-derived versus pathologist-scored tumor-infiltrating lymphocytes as a prognostic marker in early-stage triple-negative/HER2-positive breast cancer, using pooled data from randomized adjuvant trials, published in Lancet Oncology. Supports potential use of automated TIL scoring for prognostication but does not establish a specific treatment-selection role.

Single-arm phase 1b/2 umbrella trial in Clinical Cancer Research testing elacestrant plus everolimus in ER-positive/HER2-negative advanced breast cancer after prior endocrine therapy and CDK4/6 inhibitor. Shows a modest progression-free survival signal with a manageable safety profile, offering an additional post-CDK4/6i combination option pending further validation.