The use of trastuzumab, chemotherapy and surgery among women with HER2-positive metastatic breast cancer significantly improves survival from the time central nervous system metastases are diagnosed, according to a study published in Clinical Cancer Research.
“We clearly now know that these women should get trastuzumab, and potentially chemotherapy, even if cancer spreads to the brain,” said lead researcher Adam Brufsky, Professor of Medicine at the University of Pittsburgh Cancer Institute.
“Women with HER2-positive breast cancer have a reasonable chance of living a long time with their disease and they should be given aggressive therapy where appropriate.”
According to the findings, 10-16 per cent of women with advanced breast cancer develop central nervous system metastases.
Brufsky and colleagues evaluated the incidence, potential risk factors and outcomes for patients with HER2-positive breast cancer, considering how patients with HER2-positive breast cancer develop brain metastases, before following them to examine what happens thereafter.
Of the 1,023 women newly diagnosed with HER2-positive metastatic breast cancer, 377 had central nervous system metastases.
Patients with central nervous system metastases were younger and more likely to have hormone receptor–negative disease and higher disease burden compared with those whose cancer did not spread to the brain.
In addition, for those patients without central nervous system metastases at initial diagnosis, cancer progressed to the brain about 13 months after diagnosis.
For those diagnosed with central nervous system metastases, treatment with trastuzumab, chemotherapy or surgery was each associated with a significant improvement in overall survival: trastuzumab, 17.5 months vs. no trastuzumab, 3.8 months; chemotherapy, 16.4 months vs. no chemotherapy, 3.7 months; surgery, 20.3 months vs. no surgery, 11.3 months.
“It is surprising that chemotherapy/trastuzumab adds to these women’s survival,” Brufsky said.
“We thought that the brain metastases would be dominant in this regard no matter what therapy.”