Healthy Habits - Breast Cancer and ESR1 Mutations

 

Each year more than 300,000 American patients are diagnosed with breast cancer, of whom 70% have estrogen receptor-positive (ER+), HER2-negative (HER2-) disease, the most common subtype.

 

When breast cancer spreads and becomes metastatic, it can become resistant to treatment, meaning the current treatment stops working. This can happen because cancer cells have changed, or “mutated” over time. Mutations can cause resistance to certain types of therapies, allowing the tumor to grow and progress. An ESR1 mutation is one of these kinds of resistance mutations, and may make the tumor harder to treat.

 

In fact, nearly one out of two people with ER+/HER2-metastatic breast cancer may develop an ESR1 mutation after exposure to hormone therapy, causing their disease to spread faster and make it more difficult to treat.

 

ESR1 mutations are most likely to be found when:

• Metastatic breast cancer has progressed (spread, grown, or gotten worse) on hormone therapy.
• Current hormone therapy is no longer working.
• A patient has taken hormone therapy for a year or more.
• A patient has taken multiple hormone therapies.

 

For those who have progressed on their current treatment, it becomes critically important to ask their healthcare team if they should be tested for an ESR1 mutation. A blood test should be done at each point of progression, before you begin your next treatment, so you and your healthcare team can understand what kind of treatment options may be appropriate and make an informed decision on the next course of action.

 

In this interview, Dr. Aditya Bardia, (Ah-Dee-Tee-Ah Bar-Dee-AH) MD, MPH, FASCO, Director, Breast Oncology Program, UCLA Health Jonsson Comprehensive Cancer Center, discusses how nearly one out of two people with metastatic breast cancer may develop an ESR1 mutation after progression on hormone therapy. Dr. Bardia explains why that may happen and how patients can find out about this mutation, what tests to take and the importance of patients having a dialogue with their healthcare team.

 

. Interview is courtesy: Menarini Stemline