Day One: International Summit on Breast Cancer

Triple negative breast cancer used to be the subtype with the fewest moves. In this ASCO 2026 read-out, Professor Hope Rugo makes the case that the field now has too many good options and not enough answers about how to sequence them.

Professor Rugo walks through the practice-changing and practice-shaping data across the neoadjuvant and metastatic settings. She starts with the long-term KEYNOTE-522 follow-up, moves through trials that try to prime the immune response and drop anthracyclines, and then turns to the antibody-drug conjugates that are reshaping first-line metastatic care. Her recurring theme is that biology and order now matter as much as the agents themselves, and that the era of a chemotherapy-only control arm in higher-risk disease is over.

Key points for clinicians:

• KEYNOTE-522 at 7.8 years of median follow-up sustains the event-free and overall survival benefit of adding pembrolizumab, with the largest gains in patients who did not achieve pCR and a shift toward lower residual cancer burden. PD-L1 predicts chemotherapy sensitivity, not pembrolizumab benefit.

• The TRAD phase 2 trial used radiation plus pembrolizumab as induction and increased T-cell infiltration and pCR, supporting the idea of turning cold tumors hot.

• HELEN-011 showed camrelizumab added to a non-anthracycline docetaxel-carboplatin backbone improves pCR regardless of PD-L1 status, reinforcing that immunotherapy-free control arms no longer belong in T2 or node-positive TNBC.

• In I-SPY 2.2, four doses of rilvegostomig, an anti-PD-1/TIGIT bispecific, plus T-DXd produced a 72 percent pCR rate overall, with 62 percent of responders reaching pCR chemotherapy-free and 97 percent without anthracyclines, a model for response-adaptive de-escalation.
  

In metastatic disease, ASCENT-04 positions sacituzumab govitecan plus pembrolizumab as a potential new first-line standard for untreated PD-L1-positive TNBC, while ASCENT-03 and TROPION-Breast02 extend the case for TROP2 ADCs, and PFS2 signals across trials suggest treatment order matters.

• Among newer agents, the HER2xEGFR bispecific izalontamab showed a striking PFS hazard ratio of 0.29 and improved overall survival in pretreated disease, with cytopenias that will require careful management.

The most useful thing about a tumor board is watching experts disagree in good faith. In this session, an international panel takes two early-stage breast cancer cases and works them the way a real team would, out loud, with the tension left in.

Moderated by Professor William Gradishar, the panel walks a 35-year-old with BRCA1-associated triple-negative breast cancer and a 50-year-old with HER2-positive, hormone-receptor-positive breast cancer from diagnosis through surgery, systemic therapy, and the decisions in between. What comes through is how much thoughtful practice varies across the United States, Europe, and Asia, and how often the right answer is a shared decision rather than a protocol.

Key points for clinicians:

• Case 1 covers nodal clipping, neoadjuvant KEYNOTE-522 chemoimmunotherapy, PARP inhibition for BRCA carriers, and de-escalation of axillary surgery after an excellent response.

• Fertility preservation is treated as part of the plan, with egg or embryo harvesting and GnRH agonists during chemotherapy in a young patient.

• The panel openly disagrees on prophylactic bilateral mastectomy in a BRCA1 carrier, weighing contralateral risk against the limits of the survival evidence.

• Case 2 examines neoadjuvant therapy thresholds for HER2-positive disease, THP versus more intensive regimens, and where antibody-drug conjugates such as T-DXd are indicated before or after after surgery.

• Regional differences in mastectomy rates and de-escalation, across the US, South Korea, and China, show how the same case is managed differently around the world.