Immunotherapy Before Surgery Boosts Breast Cancer Outcomes

A new phase 3 clinical trial has revealed that administering the immunotherapy drug nivolumab (Opdivo) before surgery significantly enhances outcomes for patients diagnosed with estrogen receptor-positive (ER+)/HER2-negative breast cancer—a form of the disease that accounts for 70% of all breast cancer cases.

Traditionally, ER+/HER2- breast cancers respond unpredictably to treatment, and carry a high risk of metastasis. This study, published by an international research team, suggests that priming the immune system before surgery could improve treatment effectiveness and reduce the risk of cancer returning.

A Game-Changer for Early-Stage Breast Cancer?

The trial included 510 patients with early-stage ER+/HER2- breast cancer, all of whom were eligible for surgery. Researchers divided the participants into two groups:

  • One group received nivolumab plus standard chemotherapy before surgery
  • The other group received chemotherapy plus a placebo before surgery

Following surgery, all participants underwent endocrine therapy, a standard treatment targeting estrogen receptors in tumor cells.

The results were compelling:

  • 25% of patients who received nivolumab had no signs of cancer at the time of surgery (a pathological complete response).
  • Only 14% of those who did not receive nivolumab achieved the same result.
  • Patients whose tumors had higher levels of PD-1—a protein targeted by nivolumab—benefited the most from the treatment.

The trial was funded by Bristol-Myers Squibb, the pharmaceutical company that manufactures Opdivo.

How Does Nivolumab Work?

Nivolumab is an immune checkpoint inhibitor that works by blocking PD-1, a protein that allows cancer cells to evade detection by the immune system. By disabling PD-1, nivolumab helps the immune system recognize and destroy cancer cells more effectively.

Administering the drug before surgery—a strategy known as neoadjuvant immunotherapy—may train the immune system to detect and eliminate cancer cells more efficiently, reducing the likelihood of recurrence.

What This Means for Breast Cancer Treatment

The study’s findings suggest that integrating immunotherapy earlier in the treatment process may be a crucial step forward for certain breast cancer patients.

Dr. Heather McArthur, co-lead author and professor of internal medicine at UT Southwestern Medical Center, emphasized the potential impact of these results.

“We hope that these findings will guide treatment decisions and, ultimately, improve cure rates for breast cancer patients.”

While more research is needed to confirm long-term benefits, this study marks a promising advancement in breast cancer treatment, offering new hope for patients battling one of the most common cancer types worldwide.