Recurrence of breast cancer in the central nervous system (CNS) associated with trastuzumab treatment

This large analysis determined the risk of CNS metastases as the first site of recurrence in patients with HER2-positive breast cancer who received trastuzumab (herceptin).

Breast cancer recurrence (return of the cancer) may occur near the site of the original cancer, or at other distant locations. The central nervous system (CNS), consisting of the brain and the spinal cord, has been reported as the site of breast cancer recurrence in some cases.

Trastuzumab is a common drug used to treat patients with human epidermal growth factor 2 positive (HER2+) breast cancer. The HER2 complex, when present on cancer cells, promotes rapid growth and division. Trastuzumab locks on to the HER2 complex and inhibits its' action. Since the approval of trastuzumab the survival of patients with HER2+ breast cancers has improved dramatically. However, trastuzumab has been recently suspected to increase the risk of CNS recurrence.

4 trials, including a total of 9020 patients were included in this meta-analysis (an analysis of data combined from several similar trials). 4921 patients received trastuzumab as cancer treatment in addition to surgery and/or chemotherapy for a period of one year, while the remaining 4099 patients did not receive trastuzumab. 2.56% of patients receiving trastuzumab developed CNS metastases as the first site of breast cancer recurrence, compared to only 1.94% of patients not receiving trastuzumab. This correlates to a 35% increase in the risk of CNS recurrence.

Trastuzumab was shown to increase the risk of CNS recurrence in HER2+ breast cancer patients.

The results of this meta-analysis should be weighed against the proven benefits of trastuzumab treatment.

Consult with your physician regarding the risks and benefits of trastuzumab in the treatment of HER2+ breast cancer.