Comparing neoadjuvant options for HER2+ breast cancer

This study aimed to compare the pathological complete response (pCR) rates of two neoadjuvant therapy combinations for HER2 positive (HER2+, dependent on HER2 for growth) breast cancer.

This study concluded that the combination of pertuzumab (Perjeta), trastuzumab (Herceptin) and chemotherapy resulted in higher pCR rates than trastuzumab and chemotherapy alone. 

Early stage HER2+ breast cancer is often treated with surgery to remove the tumor while still small. Neoadjuvant therapy can be used before surgery to shrink the tumor to allow easier removal. Pertuzumab and trastuzumab are monoclonal antibodies that work by binding to the cancer cells, targeting them for destruction. Both pertuzumab and trastuzumab can be used in combination with standard chemotherapy drugs as neoadjuvant therapy in HER2+ breast cancer patients.

It was not known wheter a pertuzumab, trastuzumab and chemotherapy combination would be more effective than a trastuzumab and chemotherapy combination.  

This study involved 297 HER2+ breast cancer patients who had neoadjuvant treatment prior to surgery. 60% of patients received the trastuzumab and chemotherapy combination (T-CT). 40% received the trastuzumab, pertuzumab and chemotherapy combination (T-P-CT). The study measured the pathologic complete response (pCR) rate in each group. The pCR is the absence of any invasive cancer.

Two systems were used to classify the subtype of HER2+ breast cancer – the BluePrint system and the clinical subtype system. The pCR rate was also measured in relation to these groups.

The overall pCR rate was 47%. Patients who received T-P-CT had higher pCR rates when compared to those who received T-CT.

Patients classified as the HER2+ subtype by the BluePrint system had an overall pCR rate of 65%. Patients classified as luminal subtype (tumors were also dependent on the hormone estrogen for growth) by the BluePrint system had a pCR rate of 31% when treated with T-P-CT compared to 8% when treated with T-CT. The highest pCR rate (76%) was seen in BluePrint classified HER2 type patients treated with T-P-CT. 

This study concluded that the combination of P/T/CT was associated with increased pCR rates for most HER2+ patients when compared to the combination of T/CT.

Consult your physician about the best neoadjuvant therapy option for you.