The success of neoadjuvant immunotherapy trials like Niagara and those with EV-Pembro means most patients will receive immune therapy before surgery. This fundamentally shifts the clinical landscape, making the question of starting adjuvant immunotherapy less relevant as perioperative treatment becomes the standard.

In the Keynote 522 trial for early-stage TNBC, adding pembrolizumab to chemotherapy resulted in only a modest improvement in pathological complete response (pCR). Surprisingly, this small initial gain translated into much more robust and significant long-term improvements in event-free and overall survival.

Data from the KEYNOTE-671 trial demonstrates a meaningful survival benefit from perioperative pembrolizumab even in patients with PD-L1 negative (<1%) tumors. This finding supported broad regulatory approval without PD-L1 restrictions, suggesting the biomarker is not an absolute requirement for benefit in this setting.

A critical design flaw in most perioperative chemo-immunotherapy trials is the lack of a 'contribution of component' analysis. This makes it impossible to determine if the benefit comes from the neoadjuvant phase, the adjuvant phase, or both, thus complicating interpretation and clinical application.

While neoadjuvant-only immunotherapy has a strong rationale, a patient-level cross-trial comparison of CheckMate 816 (neoadjuvant) and 770T (perioperative) suggests the addition of adjuvant therapy improves event-free survival, favoring a full perioperative approach.

Instead of basing adjuvant radiation decisions on a patient's initial, pre-treatment tumor stage, clinicians should use the post-neoadjuvant pathological stage (ypTNM). Patients with a major pathologic response (e.g., downstaging from T3 to T1) may be able to safely avoid additional adjuvant radiation therapy.

Standard cancer surgery often removes lymph nodes—the factories producing immune cells. Administering immunotherapy *before* this destructive process is critical. It arms the immune system while it is still intact and capable of mounting a powerful, targeted response against the tumor.

Data from trials like CheckMate 816 shows that achieving a Pathologic Complete Response (PCR) after neoadjuvant chemo-immunotherapy is a powerful early surrogate endpoint. Patients with PCR demonstrate markedly improved overall and event-free survival.

In a neoadjuvant cemiplimab trial, only 6% of patients had a complete response based on radiographic imaging (RECIST criteria), yet 50% achieved a pathologic complete response. This major discrepancy shows clinicians should not rely solely on scans to assess treatment benefit before surgery.