Neoadjuvant treatment and survival outcomes by pathologic complete response in HER2-negative early breast cancers.

Response to treatment before surgery indicates better outcomes in breast cancer patients. To understand how well cancer treatments work, patients are compared on their overall survival. This measures the number of people in a study or treatment group who are still alive after a certain amount of time from when they were diagnosed or started treatment. Overall survival shows how well patients are doing in their cancer journey, but it takes time to understand how good treatments are when using this measure. In women with early-stage breast cancer, a quicker way to understand how well patients react to their treatment is called pathologic complete response (pCR). Some people have whole-body treatments such as chemotherapy before surgery (known as neoadjuvant treatment). For these patients, pCR may occur after neoadjuvant treatment, meaning all signs of cancer are gone when they have surgery. In real-life clinical settings, little research has been done to understand how pCR can measure breast cancer survival. In this study, the authors investigate whether women who had a pCR were more or less likely to have their cancer become worse or experience death than those who did not achieve pCR. The health records of 496 women diagnosed with early breast cancer over an eight-year period were assessed. The results show that women who did not have a pCR were more likely to have their cancer become worse or die. This means that pCR could be a better way than overall survival to identify which treatments work well in early breast cancer, and importantly, change the course of a patient's journey.