In a nutshell
The authors aimed to identify the impact of trastuzumab on cardiac (heart) function when treatment was not specifically restricted to those with human epidermal growth factor receptor 2 positive (HER2+) breast cancer.
Some background
Trastuzumab is a type of targeted drug used to treat breast cancer. Specifically, it targets HER2+ breast cancer; it directly targets the HER2 protein on the surface of the cancer cells.
This treatment is not suitable for HER2- breast cancer, as the treatment target is the HER2+ protein. However, the effects of trastuzumab treatment for women with an unknown HER2 breast cancer status is not well studied.
Methods & findings
The aim of this study was to evaluate the risks associated with trastuzumab breast cancer treatment in relation to cardiac or heart problems.
A total of 420 women, aged 65 and over, were evaluated for diagnosis of heart problems as a result of breast cancer treatment. Of these women, 140 were allocated to a course of trastuzumab treatment, regardless of HER2 status, and 280 were allocated to chemotherapy treatment.
While there was a 28% increased chance of survival among the trastuzumab treatment group, this was not deemed to be statistically significant.
The women who received trastuzumab treatment, however, were 66% more likely to develop heart problems than the women on chemotherapy treatment only. At 3 years 77% of those who received trastuzumab had not experienced a heart problem compared to 83% of those who had received chemotherapy.
It can be assumed that the majority of the women with unknown HER2 status were likely to be HER2- (HER2+ is only seen in 20% of breast cancers).
The bottom line
Trastuzumab can increase the risk of developing heart problems such as heart failure in patients aged 65 or older in a general population; this indicates the importance of HER2 testing to ensure that trastuzumab is received only by the patients in whom it will have a survival benefit, in order to achieve a more acceptable risk-benefit profile.
The fine print
Normal heart functions can be restored within months of discontinuing trastuzumab treatment; the side effects may not be permanent.
What’s next?
If you have not yet had HER2 testing, discuss this possibility with your doctor.
Published By :
Breast Cancer Research and Treatment
Date :
Feb 21, 2014
