Capecitabine after treatment for early triple-negative breast cancer reduces risk of recurrence

Adding a year of capecitabine (Xeloda) after standard treatment resulted in fewer people with early-stage, triple-negative breast cancer having a recurrence, according to a study presented at the ASCO Annual Meeting on May 29. The results show promise, but more research will need to look into how capecitabine can best be used with recent changes in how treatment is given.

Background

Between 15 and 20 percent of breast cancer diagnoses are triple-negative, meaning the cancer doesn’t use estrogen or progesterone or the HER2 protein to grow, and doesn’t respond to targeted therapies that treat those subtypes. Triple-negative breast cancers respond to chemotherapy, which is standard treatment for this diagnosis. But unlike people with other types of breast cancers who can take targeted medicines after surgery to reduce risk for recurrence, those with triple-negative disease have no access to ongoing therapy.

Capecitabine is a chemotherapy pill. It is approved by the Food and Drug Administration for use in metastatic breast cancer and has fewer and less severe side effects than chemotherapy given by vein. It has been studied as an ongoing treatment in past clinical trials for people with early-stage triple-negative breast cancer. The SYSUCC-001 trial looks at adding capecitabine after standard therapy to reduce the risk of recurrence for women with triple-negative breast cancer.

The study assigned 443 women who had completed treatment for early-stage, triple-negative breast cancer to two groups:

• one year of maintenance therapy with twice-daily capecitabine
• observation, which is the standard approach

Results

The main goal for the study was disease-free survival: the difference between capecitabine and observation in how likely people were to go without breast cancer returning. The number of women who were without cancer returning 5 years after the study started was

• 83 percent of the capecitabine group
• 73 percent of the observation group

The study also looked at how many women went without cancer metastasizing, or traveling to other parts of the body

• 85 percent of the capecitabine group
• 76 percent of the observation group

Both results were statistically significant, meaning they are likely not the result of chance. Fewer women in the capecitabine group had died 5 years after the study, but that result was not statistically significant.

The most common side effect reported in the trial was hand-foot syndrome. It occurred in 45.2 percent of women given capecitabine, and required medical care in 7.7 percent of women in that group.

Another common side effect was low blood cell counts, and 6.8 percent of people had diarrhea. No other side effect reached a level that required medical care.

Importantly, Naamit K. Gerber, MD, who led the response discussion to this study, noted that 93 percent of women received chemotherapy after breast surgery. Today, giving chemotherapy before surgery is the more common course of treatment for triple-negative breast cancer. Pre-surgery chemotherapy treatment provides more information on whether the breast cancer has responded to chemotherapy or not. This allows doctors to see who is likely to go without cancer returning and who might benefit from more treatment.

What this means for you

SYSUCC-001 adds to data that capecitabine can lead to people going longer without cancer returning when added to standard treatment, and do so with relatively few side effects. But because it is based on a treatment order that is falling out of use, the effect on treatment may be limited. Dr. Gerber suggested capecitabine may be an option for people who get chemotherapy after surgery despite the trend, and only after this study is reviewed and published.

Most people diagnosed with early-stage triple-negative breast cancer will likely have to wait for more information on the best schedule and dose for capecitabine in this use and how it fits with current treatments. Seeing how cancer reacts to chemotherapy may help doctors tell who will benefit from extra treatment.