August 19, 2012
Contralateral breast cancer refers to cancer that develops in the opposite breast after an initial diagnosis of breast cancer. According to a study published in Breast Cancer Research and Treatment, the likelihood of contralateral breast cancer may vary by the hormone receptor status and HER2 status of the initial breast cancer.
For breast cancer survivors, the likelihood of developing another cancer in the opposite breast is higher than the likelihood of a woman developing a first breast cancer. Awareness of the risk of contralateral breast cancer allows women and their physicians to take steps to manage the health of the opposite breast. Women may undergo regular screening, for example, in order to detect contralateral breast cancer at the earliest stage possible.
To explore whether the frequency of contralateral breast cancer varies by the hormone receptor status and HER2 status of the initial breast cancer, researchers collected information about 482 women who had developed a contralateral breast cancer and 1,506 women who had not developed a contralateral breast cancer.
- Compared with women whose initial breast cancer was estrogen receptor-positive and progesterone receptor-positive (ER+/PR+), women with hormone receptor-negative breast cancer (ER-/PR-) were 60% more likely to develop a contralateral breast cancer.
- When HER2 status was also considered, the risk of contralateral breast cancer appeared to be highest among women with cancer that was ER-negative but HER2-positive (ER-/HER2+). These women were twice as likely to develop contralateral breast cancer as women with ER+/HER2- cancer. Because of the relatively small number of women with ER-/HER2+ breast cancer, however, these results should be interpreted with caution.
- Women with triple-negative breast cancer were 40% more likely to develop contralateral breast than women with ER+/HER2- cancer. This finding was not statistically significant, however, suggesting that it could have occurred by chance alone.
Although this study suggests that the likelihood of contralateral breast cancer may vary by the hormone receptor status and HER2 status of the initial cancer, additional, larger studies will be required before firm conclusions can be drawn. Furthermore, even if some groups of women are found to have a lower risk of contralateral breast cancer than others, attention to the health of the opposite breast will remain important for all breast cancer survivors.