📬 Breast Cancer Intelligence Digest — Week 2026-W32

I-SPY2 dual PD-1/LAG-3 blockade raised pCR to 44% in ERBB2-negative disease, RxPONDER ovarian-reserve analysis showed AMH predicts chemotherapy benefit, an international Delphi consensus set criteria for second breast-conserving therapy, and TROPION-Breast01 safety/PRO data, the ASPIRE and DARVIN trials, REaCT-ZOL and brain-imaging surveillance drove the week's discussion.

⚡ TL;DR

📄 Publications

Cemiplimab and Fianlimab With Neoadjuvant Chemotherapy in Early-Stage High-Risk ERBB2-Negative Breast Cancer: The I-SPY2 Randomized Clinical Trial. — 78 participants were randomized to the intervention group and 350 to the historical control population

🐦 Twitter / 🦋 Bluesky

ASPIRE: chemotherapy-free anastrozole, palbociclib and dual HER2 blockade reaches 24.9-month PFS in first-line HR+/HER2+ disease — In first-line HR+/HER2+ metastatic breast cancer, a chemotherapy-free regimen of anastrozole, palbociclib, trastuzumab and pertuzumab achieved a median PFS of 24.9 months
RxPONDER ovarian reserve analysis: baseline AMH separates premenopausal patients who benefit from chemotherapy from those who do not — In premenopausal patients under 55, AMH >=10 pg/ml was associated with a ~54% reduction in recurrence risk with chemoendocrine therapy (HR 0.46), while AMH <10 pg/ml showed no chemotherapy benefit (HR 1.27)
Brain imaging surveillance in metastatic breast cancer: clinicians and patient advocates push to rewrite guidelines — An editorial argues screening for brain metastasis is associated with clinically relevant rates of detection of asymptomatic disease and leads to diagnosis of smaller and fewer lesions before neurologic symptoms
International Delphi consensus and a SEER analysis converge on repeat lumpectomy plus reirradiation for second ipsilateral events — Consensus was reached for 78 (80%) of 97 items, with 100% agreement that second breast-conserving therapy is a reasonable option for selected patients
ctDNA in early breast cancer: a JAMA Oncology review meets MRD assay data in TNBC — A JAMA Oncology review on circulating tumor DNA in early breast cancer was published by the Dana-Farber group

Full details below ↓

📄 What's Being Published

Manuscripts:

Local management of second ipsilateral breast cancer events after primary breast-conserving therapy: an international Delphi consensus. — Hannoun-Levi Jean-Michel et al., Lancet Oncol

After two rounds, consensus was reached for 78 (80%) of 97 items. Panellists agreed unanimously that patient preferences are central to decision making (100%) and that a second breast-conserving therapy is a reasonable option for selected patients (100%). Criteria favoring second breast-conserving therapy included an interval between surgeries of at least 60 months, low-risk accelerated partial breast irradiation classification, luminal molecular profile, and no grade 3 late toxicity related to the first breast-conserving therapy; where mastectomy was chosen, immediate autologous reconstruction was preferred (94%) over implant-based approaches (75%).

Clinical bottom line: A second breast-conserving therapy with tumour bed reirradiation is a legitimate option for carefully selected patients with a second ipsilateral event, and HER2-positive or triple-negative biology alone should not push a patient to mastectomy.

Read full article →

Cemiplimab and Fianlimab With Neoadjuvant Chemotherapy in Early-Stage High-Risk ERBB2-Negative Breast Cancer: The I-SPY2 Randomized Clinical Trial. — Isaacs Claudine et al., JAMA Oncol

A total of 78 participants were randomized to the intervention group and 350 to the historical control population. The dual PD-1/LAG-3 regimen graduated in all clinical signatures, with pCR rates versus control of 44% (95% CI, 34%–53%) versus 21% (95% CI, 17%–25%) in all ERBB2-negative disease, 53% (95% CI, 39%–67%) versus 29% (95% CI, 22%–36%) in triple-negative, and 36% (95% CI, 23%–49%) versus 14% (95% CI, 9%–19%) in HR-positive/ERBB2-negative disease. Among total participants, 16 (21%) experienced adrenal insufficiency, including hypophysitis (11% grade 3 or 4), mostly occurring after immunotherapy completion.

Clinical bottom line: Adding cemiplimab plus fianlimab to neoadjuvant chemotherapy roughly doubles pCR across ERBB2-negative subtypes, but a 21% rate of adrenal insufficiency means the ImPrint immune signature must be used to select who is exposed to dual checkpoint blockade.

Read full article →

🔗 Also discussed on social media →

Investigation of a prostate cancer radiation response signature in the breast cancer SweBCG91RT randomized trial. — Zhao Shuang G et al., Clin Cancer Res

PORTOS scores were calculated from gene expression profiles of 765 tumor samples from SweBCG91RT, a randomized trial of adjuvant whole-breast radiotherapy versus observation following breast-conserving surgery in node-negative stage I–IIA breast cancer. A significant interaction (P = 0.049) between PORTOS and radiotherapy was observed for 10-year cumulative incidence of any recurrence. Patients in the top 75% of PORTOS scores derived substantial benefit from radiotherapy (SHR = 0.46, P < 0.001), compared to those in the bottom 25% (SHR = 0.73, P = 0.24).

Clinical bottom line: A 24-gene radiation response signature developed in prostate cancer identifies the early breast cancer patients who gain from adjuvant radiotherapy and those at higher risk of radiation-related breast pain, making it a cross-tumor candidate biomarker for radiotherapy omission trials.

Read full article →

🗣️ What People Were Discussing This Week

How these are chosen: filtered for clinical relevance, grouped by the new development discussed, then ordered by engagement (bookmarks and reposts).

ASPIRE: chemotherapy-free anastrozole, palbociclib and dual HER2 blockade reaches 24.9-month PFS in first-line HR+/HER2+ disease

In the first-line treatment of HR+/HER2+ metastatic breast cancer, a chemotherapy-free regimen of anastrozole, palbociclib, trastuzumab, and pertuzumab achieved a median PFS of 24.9 months. Clinicians discussed this alongside the FDA approval of maintenance palbociclib plus trastuzumab, with or without pertuzumab, and endocrine therapy for HER2-positive breast cancer. The active debate centers on whether a chemotherapy-free CDK4/6-plus-dual-HER2-blockade induction is a reasonable first-line alternative to taxane-based therapy in HR+/HER2+ metastatic disease.

Discussed by: @stolaney1, @DFCI_BreastOnc, @OncLive

→ View representative tweet

RxPONDER ovarian reserve analysis: baseline AMH separates premenopausal patients who benefit from chemotherapy from those who do not

In premenopausal patients aged under 55 with HR+/HER2-negative, RS ≤25 disease, baseline AMH ≥10 pg/ml was associated with approximately a 54% reduction in recurrence risk with chemoendocrine therapy (HR 0.46), while AMH <10 pg/ml showed no chemotherapy benefit (HR 1.27). Premenopausal patients with low baseline AMH <10 pg/ml did not have IDFS or DRFS improvement with chemotherapy, and baseline estradiol, progesterone, LH, and FSH were not predictive of chemotherapy benefit; ultrasensitive inhibin B measured in the pg/ml range was also predictive of chemotherapy benefit. Commentators noted that baseline AMH outperformed age and menopausal status in predicting chemotherapy benefit, framing the question of whether AMH is ready for routine measurement before recommending chemotherapy to premenopausal women with node-positive, RS ≤25 disease.

Discussed by: @Dr_ElvinaA, @Dr_Oncologista, @OncoAlert, @kazuki_nozawa, @stolaney1

→ View representative tweet

Brain imaging surveillance in metastatic breast cancer: clinicians and patient advocates push to rewrite guidelines

An editorial argues that screening for brain metastasis is associated with clinically relevant rates of detection of asymptomatic disease and leads to diagnosis of smaller and fewer lesions before the development of neurologic symptoms. In advanced TNBC and HER2-positive breast cancer, clinicians and patient advocates argue that for many patients brain metastases are a question of when, not if, and that early detection can preserve cognitive function and reduce rates of catastrophic complications. Survey data compound this position: 85% of patients wanted brain imaging surveillance and 91% wanted more information about brain metastases, yet only 13% of physicians routinely discuss brain metastasis — a disconnect that is driving calls to revise current guidelines before an overall survival benefit is formally demonstrated.

Discussed by: @Dr_RShatsky, @DFCI_BreastOnc, @JaniceTNBCmets

→ View representative tweet

International Delphi consensus and a SEER analysis converge on repeat lumpectomy plus reirradiation for second ipsilateral events

The Lancet Oncology Delphi consensus established that 78 (80%) of 97 items reached agreement, with 100% consensus that a second breast-conserving therapy is a reasonable option for selected patients; key suitability criteria included an interval between surgeries of at least 60 months, low-risk accelerated partial breast irradiation classification, and luminal molecular profile. Oncologists also noted that HER2-positive or triple-negative biology alone are not absolute contraindications to repeat breast-conserving therapy. A SEER analysis of 4,651 patients with ipsilateral breast tumor recurrence found that re-BCS plus re-RT achieved OS, breast cancer-specific survival, and local control comparable to salvage mastectomy, while re-BCS alone increased 10-year second ipsilateral breast tumor recurrence (5.04% vs 0.36%), sharpening the debate over when salvage mastectomy remains the right choice.

Discussed by: @stolaney1, @stolaney1, @DrOyeniyi

→ View representative tweet

ctDNA in early breast cancer: a JAMA Oncology review meets MRD assay data in TNBC

A JAMA Oncology review on circulating tumor DNA in early breast cancer was published by the Dana-Farber group. Separately, a substudy evaluating a whole-exome sequencing, tumor-informed ctDNA MRD assay in TNBC after neoadjuvant chemotherapy entered the discussion. Clinicians also raised the possibility that biomarkers including HER2DX, ctDNA, PET response, and molecular subtype may soon guide treatment de-escalation in neoadjuvant HER2-positive disease, with the core debate being whether ctDNA-detected molecular residual disease is ready to change adjuvant management or should remain a trial-enrollment tool.

Discussed by: @DFCI_BreastOnc, @Dr_ElvinaA, @OncLive

→ View representative tweet

TROPION-Breast01 final safety and patient-reported outcomes: Dato-DXd shifts toxicity from myelosuppression to mucosal and ocular events

Final safety data from TROPION-Breast01 show grade ≥3 treatment-related adverse events of 22.2% with Dato-DXd versus 45.6% with physician's choice chemotherapy. The Dato-DXd toxicity profile was characterized by stomatitis 51.4% (grade ≥3: 6.4%), nausea 51.9% (grade ≥3: 1.4%), ocular events and dry eye, and ILD 3.9% overall (grade ≥3: 0.8%, one grade 5 event). Patient-reported outcome data showed Dato-DXd delayed time to deterioration in global health status/QoL, pain, and physical functioning compared with chemotherapy, centering the discussion on whether a lower grade ≥3 rate with a distinctly mucosal and ocular side-effect profile changes how clinicians choose between Dato-DXd and chemotherapy in previously treated HR+/HER2-negative disease.

Discussed by: @OncoAlert, @stolaney1, @stolaney1, @JaniceTNBCmets

→ View representative tweet

DARVIN: dalpiciclib plus endocrine therapy in HR+/HER2- visceral crisis challenges reflex chemotherapy

DARVIN, a multicenter phase II trial, evaluated dalpiciclib plus endocrine therapy in 53 women with HR+/HER2-negative advanced breast cancer and visceral crisis, reporting a 6-month survival of 92.5%, ORR of 26.4%, DCR of 79.2%, and median PFS of 11.2 months, with median OS not reached. In an IPTW-adjusted external comparison, median PFS favored dalpiciclib plus endocrine therapy over chemotherapy at 11.2 versus 4.6 months (HR 0.30, P < 0.0001), though grade ≥3 neutropenia occurred in 77.4% of patients. Clinicians are weighing how to balance efficacy against quality of life in this setting, and debating whether a single-arm phase II with an external control is sufficient to justify replacing chemotherapy with CDK4/6 inhibition in selected patients presenting in visceral crisis.

Discussed by: @stolaney1, @OncLive

→ View representative tweet

I-SPY2: dual PD-1/LAG-3 blockade with neoadjuvant chemotherapy doubles pCR in ERBB2-negative breast cancer

In I-SPY2, cemiplimab plus fianlimab added to neoadjuvant chemotherapy achieved pCR rates versus control of 44% (95% CI, 34%–53%) versus 21% (95% CI, 17%–25%) in all ERBB2-negative disease, 53% (95% CI, 39%–67%) versus 29% (95% CI, 22%–36%) in triple-negative, and 36% (95% CI, 23%–49%) versus 14% (95% CI, 9%–19%) in HR-positive/ERBB2-negative disease, with the greatest benefit observed in ImPrint biomarker-positive patients. Among participants, 16 (21%) experienced adrenal insufficiency, including hypophysitis (11% grade 3 or 4), mostly after immunotherapy completion. Commentators confirmed that the pCR improvement extended to both triple-negative and HR-positive disease, with the central question being whether dual checkpoint blockade should be restricted to ImPrint-positive patients given the 21% rate of adrenal insufficiency.

Discussed by: @Dr_Oncologista, @StephenVLiu, @JAMAOnc, @StephenVLiu

→ View representative tweet

🔥 Top Ranked Tweets

MV Chandrakanth @ChandrakanthMv

The MONARCH Trials — The Complete Abemaciclib Story

From metastatic HR+/HER2− breast cancer to high-risk early breast cancer, HER2-positive disease, and CDK4/6 inhibitor continuation beyond progression, the MONARCH program has defined the clinical role of abemaciclib across the breast cancer continuum.

This infographic provides a one-glance visual summary of the key MONARCH trials and their major clinical take-home messages.

What trial from the MONARCH program has had the greatest impact on your clinical practice?

#BreastCancer #bcsm #Oncology #MedTwitter #Abemaciclib #CDK46 #MONARCH #MedicalEducation #MVOnco

🔖 53 ❤️ 86 🔁 37 👁 3,265