Date of publication: January, 2013
Among women with metastatic breast cancer, those who do not have evidence of tumor cells in their bloodstream tend to have better outcomes. This was found for women with triple-negative breast cancer as well as women with other types of breast cancer. These results were published in Breast Cancer Research and Treatment.
Among women with metastatic breast cancer (cancer that has spread to other sites in the body), detection of cancer cells in the bloodstream has been linked with shorter time to cancer progression and shorter survival. Less is known, however, about whether this finding varies by type of breast cancer.
To evaluate the impact of circulating tumor cells by type of breast cancer, researchers conducted a study among 486 women with metastatic breast cancer. The median age of the women was 55 years, and 18% had triple-negative breast cancer.
- Overall, circulating tumor cells (at least 5 cells per 7.5 ml of blood) were detected in 42% of women. The likelihood of testing positive for circulating tumor cells did not vary substantially by type of breast cancer: circulating tumor cells were detected in 46% of women with hormone receptor-positive/HER2-negative breast cancer, 37% of women with HER2-positive breast cancer, and 36% of women with triple-negative breast cancer.
- Women who tested negative for circulating tumor cells tended to have better outcomes than women who tested positive. Among women with triple-negative breast cancer, time to cancer progression was 5.8 months among women without circulating tumor cells and 3.1 months among women with circulating tumor cells. Overall survival was also better among who tested negative for circulating tumor cells.
- Similar results were found among women with hormone receptor-positive/HER2-negative breast cancer: the absence of circulating tumor cells was linked with better progression-free and overall survival. Among women with HER2-positive breast cancer, the absence of circulating tumor cells was linked with better overall survival, but did not significantly affect progression-free survival.
These results suggest that circulating tumor cells provide information about the prognosis of several different subtypes of metastatic breast cancer, including triple-negative breast cancer. Research in this area continues and could eventually help guide treatment decisions.