Major study finds early-stage breast cancer patients can safely skip chemotherapy

The majority of women who have been diagnosed with a common form of early-stage breast cancer are able to skip chemotherapy, according to a landmark study.  The impact of this news is huge as not only do these women not need treatment beyond surgery and hormone therapy but skipping chemotherapy does not hurt their chances of beating back the disease.  The results from this study most likely will accelerate the decline in chemotherapy for the disease.

Funded by the National Cancer Institute, results from the study were presented at the American Society of Clinical Oncology conference in Chicago and published by the New England Journal of Medicine. 

One of the biggest causes of side effects in many cancer patients is chemotherapy.  For women with breast cancer, there are many ramifications for their health depending on the type of chemotherapy used.  Examples of side effects - some of which can be long-term - women may suffer include early menopause, weight gain, hair loss, infections, decreased bone density, nausea and vomiting, extreme fatigue, and in rare cases, more serious complications of leukemia and heart failure.

This is why researchers have been looking into other means of treatment that do not involve harsh chemotherapy drugs that result in major side effects.  In recent years, there have been various regimens of gene-targeting therapies, hormone blockers, and immune system treatments to help get cancer in remission without the use of chemotherapy.  If chemotherapy has to be used, many doctors are using it only for short periods of time or using lower doses of it to lessen the effect of side effects. 

The study’s purpose

This new study’s purpose was to determine if using chemotherapy on women with early-stage breast cancer that had not yet spread to lymph nodes, is hormone-positive (meaning its growth is fueled by estrogen or progesterone) and is not the type that the drug Herceptin targets.   Usual protocol for this type of breast cancer is surgery followed by years of a hormone-blocking drug.  However, because of the possibility of any stray cancer cells that could have been missed, many women are recommended to have chemotherapy as an additive protective treatment. 

The study gave 10,273 patients a test called Oncotype DX, which uses a biopsy sample to measure the activity of 21 genes involved in cell growth and response to hormone therapy, to estimate the risk that a cancer will recur.  Previous studies have shown that women with low scores could skip chemotherapy but women with high scores should still be treated with chemotherapy. 

The question has always been, what about women who fall into the midrange scores – do they still need chemotherapy?  

Results from the study

To answer this question, researchers randomly assigned more than 6,700 (67% of the participants) women with intermediate risk or having scores of 11 to 25 to two groups.  After surgery, one group received endocrine therapy only, while the other group received endocrine therapy plus chemotherapy.  After nine years of follow-up, the data showed that 94 percent of both groups were still alive, and about 84 percent were alive without signs of cancer, therefore demonstrating that having additional chemotherapy treatment would have made no difference in their outcome. 

About 17 percent of the women with high-risk scores were advised to use chemotherapy while 16 percent of women with low-risk scores are now being told they can skip chemotherapy. 

The one exception however, were women age 50 or younger.  Women within this age group who had a recurrence score of 16 or higher did get a “substantial” boost from using chemotherapy and are being advised to consider using it. 

The results from this study show that researchers are getting much closer to being able to personalize treatment when it comes to cancer. In the old days, there were always a specific medical protocol followed for anyone who was diagnosed with any cancer – everyone would be treated the same with no regard for individualization.  Now it is possible to look at subtypes of cancer by looking at the genes and then determining the right treatment to be given to the right patient at the right time. 

Studies such as this one will help make tremendous strides in being able to treat cancer in the most effective way possible personalizing each person’s treatment reducing side effects while improving their chance of survival.