Chemotherapy affects normal, healthy cells as well as breast cancer cells. This is why chemotherapy can cause hair loss, anemia, and diarrhea. In rare cases, exposing normal cells to cancer treatments such as chemotherapy and radiation therapy can cause a new, different type of cancer to develop many years after treatment.
A large study has found that women who got chemotherapy to treat breast cancer were more likely to develop leukemia within 10 years after treatment compared to women who didn’t get chemotherapy to treat breast cancer.
It’s VERY IMPORTANT to know that while the risk for leukemia was higher for women who got chemotherapy, the risk of leukemia is still very small.
The study, "Myelodysplastic syndrome and/or acute myelogenous leukemia (MDS and/or AML) after a breast cancer diagnosis: The National Comprehensive Cancer Network (NCCN) experience," was presented at the 2012 San Antonio Breast Cancer Symposium.
The researchers looked at the medical records of more than 20,500 women diagnosed with stage I to III breast cancer from 1997 to 2008.
The women received various treatments for breast cancer: some had surgery alone, some had radiation alone, some had chemotherapy alone, and some had chemotherapy plus radiation therapy.
Within 10 years after treatment, the percentages of women who developed leukemia were:
- 0.16% of women who had surgery alone
- 0.43% of women who had radiation alone
- 0.52% of women who had chemotherapy alone
- 0.54% of women who had chemotherapy plus radiation
This means that out of the 20,533 women whose medical records were reviewed, 51 of them developed leukemia.
The risk of leukemia was higher for older women. Women who developed leukemia were about 60 years old when they were treated for breast cancer and women who didn’t develop leukemia were about 54 years old when they were treated for breast cancer.
If you've had cancer treatment, it's very important that you regularly see a doctor who is familiar with your medical history and understands your special risks, and also gives you counseling, monitoring, and screening for possible complications from earlier treatment.