Curing HER-2 positive breast cancer?

One of the biggest advances in breast cancer therapy has been in the approach to HER-2/neu positive breast cancers, which represent about 20-30% of invasive breast cancers. Historically over-expression of this oncogene used to confer a poor prognosis with women whose tumors were “HER-2/neu positive” at a higher risk of relapse and of dying from their disease, compared to those who did not HER-2/neu overexpressed. All this is now changed with the use of a HER-2/neu directed treatment, called trastuzumab. While we used to use it in women who had experienced relapse, two very large trials conducted by the National Surgical Breast and Bowel Project (NSABP) and from the North Central Cancer Treatment Group (NCCTG) demonstrated that the use of chemotherapy with trastuzumab after surgery, and then followed by a total of one year’s treatment with trastuzumab, for HER-2/neu positive breast cancer was associated with a 52% benefit in disease free survival at 4 years and a 33% improvement in overall survival. These results were first published in 2005 (1).

and then

which started with paclitaxel.

Now, from the San Antonio Breast Cancer Symposium in December 2009 comes updated results showing that at 5 years, more than 80% of women treated with adjuvant trastuzumab on the NCCTG trial are still disease free. Even more importantly, timing appeared to make a significant difference in maintaining remission. See, in the NCCTG trial there were three treatment arms. In all arms patients received doxorubicin, cyclophosphamide, and then weekly paclitaxel (AC/T). In arm I, they only received chemotherapy; in arm 2, they received chemotherapy 52 weeks of trastuzumab; in arm 3, they received 52 weeks of trastuzumab In the updated analysis presented by Edith Perez, the 84% treated in arm 3 were disease free 5 years later, compared to 80% treated in group 2, a result that was statistically significant. In overall survival, concurrent treatment (arm 3) showed a 35% improvement in overall survival as well compared to chemotherapy only (arm 1) which was not seen in the sequentially treated arm (arm 2).

This data confirms a standard of practice here at Brown, and also nationally, but I highlight it as a major breakthrough in breast cancer treatment. Hopefully the future will hold more positive news in other types of breast cancer so the same benefits can be universally realized.

References EH Romond, EA Perez, J Bryant, et al. New England Journal of Medicine 2005; 353:1673-84.