Many women diagnosed with early-stage breast cancer with a high risk of recurrence (the cancer coming back) get chemotherapy after surgery to reduce the risk of recurrence. In some cases, the dose intensity of the chemotherapy may be increased.
The dose intensity of chemotherapy can be increased by:
- giving more medicine in each dose
- shortening the length of time between cycles; so, you get chemotherapy every 2 weeks instead of the standard schedule of every 3 weeks
- giving medicines one after the other (sequentially), rather than at the same time (concurrently), so a higher dose of each medicine can be given
Dose-intensified chemotherapy regimens are used more often in the United States than they are in Europe.
A study suggests that dose-intensified chemotherapy regimens decrease the risk of recurrence as well as the risk of dying from breast cancer in women diagnosed with early-stage disease.
The research was presented on Dec. 6, 2017 at the 2017 San Antonio Breast Cancer Symposium. Read the abstract of “Increasing the dose density of adjuvant chemotherapy by shortening intervals between courses or by sequential drug administration significantly reduces both disease recurrence and breast cancer mortality: An EBCTCG meta-analysis of 21,000 women in 16 randomised trials.”
This study was a meta-analysis. A meta-analysis is a study that combines and analyzes the results of many earlier studies. In this case, the results from 21,537 women from 16 studies were analyzed. All the women had been diagnosed with early-stage breast cancer.
In this analysis, the chemotherapy doses were intensified in two ways:
- 7 studies compared chemotherapy given every 2 weeks to chemotherapy given every 3 weeks (10,004 women)
- 9 studies compared sequential chemotherapy to concurrent chemotherapy (11,533 women)
Compared to women who received chemotherapy every 3 weeks, women who received chemotherapy every 2 weeks were:
- 17% less likely to have a recurrence
- 15% less likely to die from breast cancer
10 years after diagnosis.
Compared to women who received concurrent chemotherapy, women who received sequential chemotherapy were:
- 14% less like to have a recurrence
- 13% less likely to die from breast cancer
10 years after diagnosis.
“We were surprised by how strong and consistent the findings from our study were,” said Richard Gray, professor of medical statistics at the University of Oxford in the United Kingdom, who presented the research. “The results apply to most women receiving chemotherapy for early-stage breast cancer: the 15% reduction in recurrence with dose-intense chemotherapy across all trials was similar in estrogen-receptor-positive and in estrogen-receptor-negative disease, and did not differ significantly by any other patient or tumor characteristics, including age, HER2 status, nodal status, tumor size, and grade.”
Like almost all cancer treatments, chemotherapy can cause side effects, some of them severe. Common chemotherapy side effects include low red blood cell counts, which can cause anemia, and low white blood cell counts, which can lead to infection. Because dose-intense chemotherapy is more intense, some researchers have worried that the side effects would be more intense/severe.
In this analysis, the researchers found that as long as women on intense-dose chemotherapy regimens were given appropriate support medicines, such as:
- granulocyte colony stimulating factors, such as Neupogen (chemical name: filgrastim) or Neulasta (chemical name: pegfilgrastim), which helps the body make more white blood cells
- erythropoiesis stimulating factors such as Epogen (chemical name: epoetin alfa), Aranesp (chemical name: darbepoetin alfa), and Procrit (chemical name: epoetin alfa), which helps the body make more red blood cells
their side effects were not substantially more severe.
“Some centers prefer giving chemotherapy every 3 weeks and offer treatment every 2 weeks less frequently because of concerns about side effects and uncertainty about the additional benefit. Looking at the data from large numbers of women receiving dose-intense chemotherapy, we have found no evidence to justify these concerns, and the results show consistent benefit from the more intense treatments,” Gray concluded.
If you’ve been diagnosed with early-stage breast cancer that has a high risk of recurrence, it’s likely that chemotherapy will be part of your treatment plan. This and other studies suggest that an intense-dose chemotherapy regimen may offer more benefits than a standard regimen. After you consider all the characteristics of the cancer, as well as your unique situation and preferences, you and your doctor can make the best choices for you.
Visit the Breastcancer.org Chemotherapy section to learn more about what to expect during chemotherapy.