Taxotere-Based Chemotherapy Significantly Improved Overall Survival Compared In Breast Cancer

Armen Hareyan's picture
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For women with early stage breast cancer who have had surgery, treatment with the investigational chemotherapy combination of Taxotere (docetaxel) Injection Concentrate and cyclophosphamide significantly improved overall survival compared to standard chemotherapy. The presentation reports results with a median follow-up of seven years and has been updated since the last report was published with 5.5 years median follow-up [Jones S et al. J Clin Oncol, 2006, 24:5381-7]. This latest report has also been updated from the abstract submitted to SABCS 2007.

In the updated analysis, overall survival at seven years was statistically higher among women treated with Taxotere and cyclophosphamide (TC) versus those treated with doxorubicin and cyclophosphamide (AC): 87% versus 82% (HR: 0.69, [95% CI, 0.50, 0.97]). The 31% reduction in the risk of death was statistically significant (p=0.032). At seven years, the disease-free survival (DFS) was also statistically greater among women treated with TC than those treated with AC: 81% versus 75% (HR: 0.74, [95% CI, 0.56, 0.98]). The 26% reduction in the risk of cancer recurrence among women treated with TC was statistically significant (p=0.033). The disease-free survival benefit seen in the elderly patients (aged 65 years or older; 31% risk reduction of recurrence) is consistent with that in the overall patient population.

Principal study investigator Dr. Stephen Jones, medical director and co-chair, breast cancer research committee of US Oncology, helped develop the regimen combining the anthracycline doxorubicin with cyclophosphamide, which became a foundation of breast cancer chemotherapy for more than 30 years.

"The investigational Taxotere combination significantly increased the percentage of women living with no signs of cancer at seven years, as compared to the anthracycline combination," said Dr. Jones.

US Oncology Adjuvant Trial 9735 Protocol

USO Adjuvant Trial 9735 was designed primarily to evaluate disease-free survival among women with node-positive and node-negative early breast cancer. Node-positive indicates that the cancer has spread to the lymph nodes under the arm, while node-negative breast cancer means that the lymph nodes are clear of cancer. Secondary endpoints included overall survival and safety. The investigators also explored the efficacy and safety of the treatments based on the age of patients and the biologic characteristics of their tumors.

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All patients taking part in the study had received surgery for Stage I-III invasive breast cancer, meaning that the cancer was either localized to the breast or had spread to the lymph nodes under the adjacent arm.

A total of 1016 patients were randomized between June 1997 and December 1999; 48% of patients had node-negative disease and 16% were age 65 years or older. After surgery, patients were randomized to receive four cycles of either standard-dose of anthracycline doxorubicin 60 mg/m2 and cyclophosphamide 600/mg/m2 (n=510) or Taxotere 75 mg/m2 and cyclophosphamide 600mg/m2 (n=506), administered by intravenous infusion every three weeks. After chemotherapy was completed, patients were treated with radiation therapy if indicated. Patients with hormone receptor positive disease also received hormonal therapy (tamoxifen).

In the TC group, there were 88 DFS events (17%) and 58 deaths (12%). The AC group had 118 DFS events (23%) and 84 deaths (17%). Exploratory analyses showed benefit of TC irrespective of age, hormonal status or Her2 status.

Grade 3-4 neutropenia occurred in 60% of younger (<65 years) and 52% of older (greater than or equal to 65 years) women in the TC group, and in 54% and 59% of younger and older women, respectively, in the AC group. Among younger patients, the frequencies of Grade 3-4 febrile neutropenia were 4.4% with TC and 2.3% with AC, while in older patients the frequencies were 7.7% and 3.7% for TC and AC, respectively. Grade 3-4 nausea was less common among women in both age groups treated with TC (<65: 2%, greater than or equal to 65: 3%) than those given AC (<65: 7%, greater than or equal to 65: 5%). In the TC group, additional Grade 3-4 adverse events reported among women <65 and greater than or equal to 65 were fever in 4% and 6% and infection in 7% and 6%, respectively, while in the AC arm the rates of Grade 3-4 fever were 3% and 4% and Grade 3-4 infections were 10% and 2% for younger and older women, respectively.

Breast Cancer, the Most Common Cancer in Women

Breast cancer is the most frequently diagnosed cancer in women throughout the world. The American Cancer Society estimates that one in eight women will develop breast cancer within their lifetime. By the end of 2007, more than 178,000 American women will have learned they have invasive breast cancer. In the European Union, more than 429,900 new cases were diagnosed in 2006. Age is the biggest risk factor, and one in 26 women over 70 will have breast cancer in her lifetime.

In the U.S., breast cancer is the third-leading cause of cancer death in women. More than 40,000 women in the U.S. will die of breast cancer this year; more than half are 65 or older. In the EU, breast cancer is the leading cause of cancer death among women; an estimated 132,000 died from breast cancer in 2006.

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