After surgery to remove early-stage breast cancer, chemotherapy often is given to destroy any breast cancer cells that may remain in the body and reduce the risk of the cancer coming back (recurrence). Doctors call chemotherapy given after surgery adjuvant chemotherapy.
A number of chemotherapy medicines, given alone or in combination, are used as adjuvant chemotherapy, including a class of medicines called anthracyclines.
Interim results from an analysis of several studies suggest that chemotherapy regimens that include an anthracycline may be better than a regimen that doesn’t include an anthracycline for women diagnosed with early-stage, HER2-negative breast cancer with a high risk of recurrence.
The interim results were presented at the 2016 American Society of Clinical Oncology Annual Meeting on June 7, 2016. Read the abstract of “Interim joint analysis of the ABC (anthracyclines in early breast cancer) phase III trials (USOR 06-090, NSABP B-46I/USOR 07132, NSABP B-49 [NRG Oncology]) comparing docetaxel + cyclophosphamide (TC) v anthracycline/taxane-based chemotherapy regimens (TaxAC) in women with high-risk, HER2-negative breast cancer.”
Anthracycline chemotherapy medicines are:
- Adriamycin (chemical name: doxorubicin)
- Ellence (chemical name: epirubicin)
- Doxil (chemical name: doxorubicin)
- daunorubicin (brand names: Cerubidine, DaunoXome)
- mitoxantrone (brand name: Novantrone)
Anthracyclines work by damaging cancer cells’ genes and interfering with their reproduction.
Like all chemotherapy medicines, anthracyclines may cause serious side effects, including heart damage, which can lead to heart failure. Doctors also are concerned about a higher risk of leukemia in women who have been treated with Adriamycin. Because of these concerns, many doctors started using a chemotherapy regimen that did not include an anthracycline after surgery. These concerns are probably why there has been a decrease in anthracycline use.
Still, doctors wanted to be sure that they were treating women with the most effective chemotherapy regimen possible.
The studies included 4,130 women who had had surgery to remove early-stage, HER2-negative breast cancer with a high risk of recurrence. The women were randomly assigned to receive one of two chemotherapy regimens:
- 2,052 women were treated with Adriamycin, Cytoxan (chemical name: cyclophosphamide), with Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel) -- the anthracycline regimen, called TaxAC for short
- 2,078 women were treated with Taxotere and Cytoxan -- the non-anthracycline regimen, called TC for short
The women were followed for about 3 years. The researchers recorded how long the women lived without a recurrence of invasive breast cancer, called invasive disease-free survival.
Overall, 3-year invasive disease-free survival rates were:
- 92.4% for the TaxAC regimen
- 91.7% for the TC regimen
This suggests that the anthracycline regimen is slightly better than the regimen without an anthracycline.
The researchers had planned to issue an early report if the Taxotere-Cytoxan regimen seemed to be less effective than the Adriamycin-Cytoxan-Taxol/Taxotere regimen. This happened, which is why the researchers presented the report at the ASCO Annual Meeting.
The researchers also looked at how effective each regimen was based on the characteristics of the cancer. These results, while early, may help women and their doctors make decisions about chemotherapy regimens.
For triple-negative disease (estrogen-receptor-negative, progesterone-receptor-negative, and HER2-negative), 3-year invasive disease-free survival rates were:
- 89.6% for the TaxAC regimen
- 86.6% for the TC regimen
For hormone-receptor-positive disease, 3-year invasive disease-free survival rates were:
- 93.7% for the TaxAC regimen
- 94.1% for the TC regimen
The researchers also looked at even more specifically defined cancer characteristics to see if there were certain groups of women who would do well without an anthracycline in the regimen or groups of women who would get more benefits from a regimen that included an anthracycline:
- For women with estrogen-receptor-positive disease with no cancer in the lymph nodes (node negative), the two regimens offered about the same benefit.
- For women with estrogen-receptor-positive disease with one to three positive nodes, the TaxAC regimen reduced recurrence risk by 2% to 2.5% more than the TC regimen.
- For women with triple-negative disease with no cancer in the lymph nodes, the TaxAC regimen reduced recurrence risk by 2% to 2.5% more than the TC regimen.
- For women with estrogen-receptor-positive disease with four or more positive nodes or women with triple-negative disease with one or more positive nodes, the TaxAC regimen reduced recurrence risk by about 6% to 11% more than the TC regimen.
“I don’t think these early results change practice, but they validate what many of us have been doing,” said Paul Gilman, M.D., chief of the Hematology/Oncology Division at Lankenau Hospital. Dr. Gilman is a member of the Breastcancer.org Professional Advisory Board. “The results give us guidance on which women seem to benefit from anthracycline chemotherapy and which women will do just as well with the TC regimen.”
It’s important to know two things about this study:
- The regimen of Taxotere and Cytoxan was given for six cycles; four cycles is usually the timing of this regimen.
- These are preliminary results; more follow-up is needed to see if these early results continue over time.
You and your doctor will consider several important factors when deciding on a chemotherapy regimen:
- The characteristics of the cancer: The cancer’s stage, hormone-receptor status, HER2 status, and lymph node status will influence the chemotherapy regimen your doctor recommends.
- Your age, menopausal status, and general health: Your doctor will take into account your age, general health, and menopausal status when recommending a chemotherapy regimen. If you have high blood pressure, are older than 60, and have a history of heart problems, your doctor will probably recommend a chemotherapy regimen that doesn’t include an anthracycline.
Deciding on the best chemotherapy regimen can be a bit of a balancing act. You want a combination that offers the most benefits with the least risks and side effects. It’s important to remember that while there are many standard chemotherapy regimens, each person’s treatment plan will be unique because each cancer is unique.
If you’ll be having chemotherapy to treat breast cancer, it’s a good idea to ask your doctor why a specific regimen is recommended for you. If your recommended regimen doesn’t include an anthracycline and you have no history of heart problems or high blood pressure, you might want to ask your doctor why. Together, you and your doctor will make the best decision for your unique situation.