According to an article published in the journal Cancer, treatment with Arimidex® (anastrazole) prior to surgery provides greater anticancer responses than treatment with tamoxifen (Nolvadex®) in women with hormone-positive breast cancer.
The majority of women with breast cancer have cancer that is stimulated to grow from contact with the female hormones estrogen and/or progesterone. This type of cancer is referred to as hormone-positive breast cancer.
An important component of treatment of hormone-positive breast cancer is hormone therapy, which prevents or reduces the ability of estrogen to stimulate the growth of cancer cells.
Tamoxifen is an agent that reduces the ability of estrogen to bind to cancer cells. Arimidex is an agent that prevents the body from forming the active form of estrogen.
Neoadjuvant therapy in breast cancer is therapy that is used prior to surgery. Neoadjuvant therapy reduces the size of the cancer in the breast, allowing some patients who would have otherwise had to have a mastectomy (complete removal of the breast) to undergo breast-conserving surgery (removal of the cancer and surrounding tissue). Furthermore, the shrinking of cancer with neoadjuvant therapy sometimes allows patients who were considered inoperable to undergo the surgical removal of their cancer.
Neoadjuvant therapy also begins to fight cancer immediately as opposed to waiting until the patient has recovered from surgery to begin treatment.
Researchers from several countries recently conducted a clinical trial to directly compare tamoxifen to Arimidex as neoadjuvant therapy in women with hormone-positive breast cancer. This trial included 451 patients treated at 81 medical centers. The women were considered postmenopausal. Their breast cancer was considered operable or potentially operable. Patients were treated with either tamoxifen or Arimidex for three months prior to surgery.
- Among patients who were considered inoperable prior to therapy and those who were eligible for a mastectomy but not breast-conserving surgery, those treated with Arimidex had significantly greater reduction in size of their cancer than those treated with tamoxifen.
- Patients who were considered inoperable prior to therapy had a significantly greater chance of becoming operable after treatment with Arimidex compared to treatment with tamoxifen.
- The overall anticancer response rate was significantly higher after three months of treatment with Arimidex compared with three months of treatment with tamoxifen.
- Both agents were generally well tolerated.
The researchers concluded that neoadjuvant treatment with Arimidex appears superior to that of tamoxifen in postmenopausal women with hormone-positive breast cancer. Longer follow-up is necessary to determine if neoadjuvant treatment with either of these agents results in differences in long-term outcomes.
Reference: Cataliotti L, Buzdar A, Noguchi S, et al. Comparison of Anastrozole versus Tamoxifen as Preoperative Therapy in Postmenopausal Women with Hormone Receptor-Positive Breast Cancer. Cancer. 2006; 106: 2095-2103.