Paclitaxel combos useful as breast cancer adjuvant therapy

NEW YORK (Reuters Health) - In women with high risk breast cancer, adjuvant regimens involving paclitaxel and doxorubicin with or without cyclophosphamide provide comparable results, researchers report in a May 17th online paper in the Journal of Clinical Oncology.

Overall 6-year survival rates were 82% with a cyclophosphamide regimen and 87% with dose-dense paclitaxel. Corresponding disease-free survival was 79% to 80% in both groups.

Dr. David Loesch, of Oncology Clinical Trials and Services, Phoenix, Arizona, and colleagues note that common themes in recent studies of adjuvant therapy for breast cancer have been dose intensity and sequential drug administration.

In this vein, the researchers studied more than 1800 women with histologically confirmed, stage I to III adenocarcinoma of the breast. All had undergone primary surgery and had no residual tumor. Their median age was 52 years, 52% had estrogen receptor and progesterone receptor-positive disease and 46% had one to three positive nodes. They were enrolled between 2000 and 2002.

About half were randomized to doxorubicin 60 mg/m2 plus cyclophosphamide 600 mg/m2 every 3 weeks for four cycles followed by paclitaxel 175 mg/m2 every 3 weeks for four cycles. The remaining patients received dose dense therapy with doxorubicin 50 mg/m2 plus paclitaxel 200 mg/m2 every 3 weeks for four cycles followed by paclitaxel 80 mg/m2 weekly for 12 weeks.

The most frequent toxicities were hematologic, including neutropenia and leucopenia, followed by neuropathy, myalgia, nausea, and fatigue. Thirteen percent of the cyclophosphamide patients had study treatment withdrawn because of toxicity compared to 20% of the dose dense group.

Thus, the researchers point out, "a dose-dense paclitaxel regimen is as efficacious as doxorubicin plus cyclophosphamide followed by paclitaxel; however, the substitution comes at a price of increased peripheral neuropathy."

They also say that "many patients with early stage, hormone receptor-positive disease are best treated with anti-hormone therapy alone."

In the current study, there was no difference in time to progression or overall survival between the arms. Therefore, the team concludes, "any increased neuropathy seems unwarranted for this subgroup."

http://jco.ascopubs.org/cgi/content/abstract/JCO.2009.24.1000v1

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