Treatment of Early Invasive Breast Cancers

By Kurt Ullman Adjuvant chemotherapy plays an important role in the treatment of early invasive breast cancers. Recent trials comparing a combination of docetaxel and cyclophosphamide (TC) with doxorubicin and cyclophosphamide (AC) suggests the TC regimen may have important therapeutic advantages.

Adjuvant chemotherapy plays an important role in the treatment of early invasive breast cancers. Recent trials comparing a combination of docetaxel and cyclophosphamide (TC) with doxorubicin and cyclophosphamide (AC) suggests the TC regimen may have important therapeutic advantages.

“What has changed many people’s thinking over the last couple of years are the results of a large randomized trial that looked at outcomes and adverse effects,” said Lee Schwartzberg, MD, medical director of The West Clinic and clinical professor at the University of Tennessee Health Sciences Center in Memphis. “The findings indicated that TC surpassed AC in both disease-free and overall survival with comparable acute toxicities. Importantly, there were no long-term cardiac risks for TC, [which] are sometimes seen in AC.”

The trial, presented at the most recent San Antonio Breast Cancer Symposium, included 1,016 women with Stage I to Stage III breast cancer. Half received four every-three-weeks cycles of TC (75/600 m2 ), and half received four cycles of AC (60/600 mg/m2 ) in a similar dosing. Women who were candidates for radiation therapy and/or hormonal therapy also received these treatments. At the time of the presentation, participants had been followed for a median of seven years.

Overall survival was 87% among patients treated with TC and 82% among patients treated with AC. Disease-free survival was 81% for those in the TC group and 75% for those treated with AC. The 26% reduction in the risk for cancer recurrence among women treated with TC was statistically significant. More in-depth analyses showed a benefit for TC that was not changed due to age, hormonal status, or Her2 status.

“AC was a common—but by no means the only—combination treatment for breast cancer,” said Dr. Schwartzberg. “The main benefits seen from the TC regimen are less risk of heart problems and at least as good, if not better, efficacy.”

However, Dr. Schwartzberg also stresses the need for caution in discarding AC because of the results of this one large and well conducted study. He points out that many trials have been published over the years looking at AC and a large part of that evidence shows the benefits obtained from that combination.

In addition, since the side effect profiles are not identical, there are some individuals that should not be exposed to TC. One example would be a person who already has problems with neuropathy. In this instance, the use of the AC regimen might be counter-indicated since neuropathy is also an established side effect of taxanes.

“I would not yet say that AC is a regimen that should not be used,” he said. “”However, I do think that we have a very good alternative and many people believe that the overall risk/benefit analysis favors TC. But on the basis of just one study, you can’t say the other regimen should not be used.”