When compared with other types of breast cancer, lobular breast cancer has distinct characteristics and management challenges. For example, it has a distinct growth pattern, may respond differently to therapies, and may demonstrate unconventional recurrence patterns. And, in fact, lobular breast cancer is more common than many may think.

“Lobular breast cancer is absolutely not a rare disease, accounting for up to 15% of all patients with breast cancer, and as an important type of breast cancer, it should be studied and recognized as such,” said Christine Desmedt, PhD, head of the Laboratory for Translational Breast Cancer Research and associate professor at KU Leuven.

At the 2026 San Antonio Breast Cancer Symposium®, Dr. Desmedt will moderate a special session, Lobular Breast Cancer: Not a Rare Disease, on Wednesday, December 9, from 4:30 to 6 p.m. CT in Hemisfair Ballroom 1-2 at the Henry B. Gonzalez Convention Center. The presentations will offer diverse updates on the diagnosis, understanding, treatment, and monitoring of lobular breast cancer.

Fresia Pareja, MD, PhD, a pathologist at Memorial Sloan Kettering Cancer Center, will explore the challenges of diagnosing lobular breast cancer and what artificial intelligence may offer to improve the pathologic diagnosis and classification of this type of breast cancer.

Christos Sotiriou, MD, PhD, research director of Fonds de la Recherche Scientifique-FNRS, Chef de Clinique at the Institut Jules Bordet, and director of the Bordet Cancer Research Laboratories, will discuss the use and application of gene expression-based assays for patients with lobular breast cancer.

“Although these prognostic assays have been used now for many years, they were never developed specifically for patients with lobular breast cancer,” Dr. Desmedt said. “Dr. Sotiriou is well placed to review the current evidence and propose where we feel comfortable and where we should be careful when applying these assays to patients with lobular breast cancer.”

Caroline Malhaire, MD, PhD, a radiologist at Institut Curie, will discuss the challenges associated with diagnostic imaging of lobular breast cancer and offer recommendations on its use.

“This is an area where we need to do better with imaging for these patients,” Dr. Desmedt said. “Lobular breast cancer grows in a very different way than other breast cancers, and as such, it may be more difficult to detect and monitor on imaging.”

Then, Dr. Desmedt will summarize recent biological insights with regard to lobular breast cancer—both in the early and metastatic settings. She will also highlight which of those findings may have clinical relevance in both the short and long term for these individuals.

Claire Turner, founder of Lobular Breast Cancer UK, will provide a patient advocacy perspective.

Session titles, times, and locations are subject to change. For the most up-to-date SABCS 2026 program information, please visit the Program page at SABCS.org.