Some Chemotherapy Is More Toxic Than Others

Researchers at the University of Texas MD Anderson Cancer Center compared six breast cancer chemotherapy regimens to determine which caused more toxic side effects by requiring the patients to be hospitalized for infections, fever, dehydration or low blood counts.

In order, from the regimen that caused the most hospitalizations among 12,894 patients who were treated for early stage breast cancer, to the one that caused the fewest, the chemotherapies were:

• Docetaxel and cyclophosphamide cycled every three weeks (TC)
• Doxorubicin and cyclophosphamide cycled every three weeks (AC)
• Docetaxel, doxorubicin and cyclophosphamide cycled every three weeks (TAC)
• Doxorubicin and cyclophosphamide cycled every three weeks, followed or preceded by docetaxel cycled every three weeks (AC+T)
• Doxorubicin and cyclophosphamide cycled every two weeks, followed or preceded by paclitaxel cycled every two weeks (ddAC+P)
• Doxorubicin and cyclophosphamide cycled every three weeks followed or preceded by weekly paclitaxel (AC+wP)

The treatments are interchangeable, says the study’s lead author, Dr. Carlos Barcenas, from the department of Breast Medical Oncology at MD Anderson, so knowing which ones are associated with more toxicity may help some patients and doctors to choose more tolerable therapies. Other factors may also play a role; the TC regimen, for example, is linked to the most hospitalizations but that’s because it involves more intensive doses of chemotherapy in half the time – 12 weeks – of all of the other options, which are spread out over 24 weeks. For women who prefer to have their chemotherapy finished sooner, the higher risk of side effects may be worth the time savings.

Women with heart disease also have to use the TC regimen, since the others include a drug that is toxic to the heart.

The results, published in the Journal of Clinical Oncology, should help patients to be more informed about their chemotherapy options, says Barcenas, and prompt more research into ways that the right treatments can be matched to the right patients.

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