Should Adjuvant Herceptin Treatment for Breast Cancer Last 6 or 12 Months?

Breast cancer is the most common cancer in women. HER2-positive breast canceraccounts for 20% of all breast cancers. In the past, overexpression of the HER2 receptorwas associated with frequent disease recurrence and shorter survival. Today, however, combining chemotherapy with molecularly targeted medicines that inhibit the HER2 receptor has substantially improved disease outcomes.

HER2 is a receptor on the membrane of our cells and a member of the epidermal growth factor protein family. Normal cells have 20 thousand HER2 receptors, whereas this number is 2 million in HER2-positive breast cancer.

Our HER2-targeted medicine Herceptin (active ingredient trastuzumab) binds to the HER2 receptor, preventing it from interacting with other receptors and sending signals into the cell. It also marks the cancer cell, helping the body’s immune cells recognize and destroy it. Herceptin’s adjuvant (protective treatment after surgery) duration is 1 year.

A study seeking to answer whether this duration could be shortened compared 6 months with 12 months of trastuzumab. It evaluated 4088 patients with early-stage HER2-positive breast cancer. Patients were followed for a total of 5 years. The study found that 6 months of Herceptin was as effective as 12 months. Only a 0.4% difference in disease-free survival was found between 6 months and 12 months of treatment. In addition, cardiac toxicity (a side effect) associated with trastuzumab occurred 4% less frequently.

Details of this eagerly awaited study, significant for both shorter treatment duration and reduced toxicity, will be presented in June at the 2018 American Cancer Congress (ASCO18). We will follow the study’s details for you, together with commentary from leading cancer scientists worldwide.