Surgery, radiation, chemo, recombinant antibody combat breast cancer

March 1, 2005

BREAST CANCER is the most common cancer found in women, and the second leading cause of cancer deaths in women. More than 200,000 new cases of invasive breast cancer are diagnosed in the United States each year, approximately 77% of them in women over 50 years of age.

Direct and indirect costs associated with breast cancer in the United States total between $2.4 and $3.1 billion. Of that, almost $2 billion is for treatment of late stage breast cancer.

Treatment generally combines surgery, chemotherapy and/or radiation, depending on the location and size of the tumor. Chemotherapy following surgical removal of the tumor and affected lymph nodes has been shown to reduce 10-year mortality by 27% in women less than 50 years old, and by 11% in women between ages 50 and 69.

HORMONE THERAPY Estrogen speeds growth of a substantial proportion of breast cancers, so hormone therapy is generally used as adjuvant treatment after surgery, and for treatment of metastatic disease, in postmenopausal women with estrogen-sensitive cancers. Possible medications include tamoxifen and the aromatase inhibitors Arimidex (anastrozole), Aromasin (exemestane) and Femara (letrozole). Tamoxifen can produce side effects such as hot flashes and vaginal discharge, while aromatase inhibitors may lead to gastrointestinal disturbances and headache.

"The aromatase inhibitors have now proven themselves, and they seem to be somewhat more effective than the old stand-by tamoxifen," says Dr. Kattlove. "They will be a bit more costly, since tamoxifen is now available as a generic, but the data show a significant benefit."

"We're in the process of transition," agrees Mark Abramowicz, MD, editor of The Medical Letter on Drugs and Therapeutics, a nonprofit newsletter that critically appraises drugs. "Tamoxifen or an aromatase inhibitor have both been used as first-line hormonal treatment for metastatic breast cancer, but recently aromatase inhibitors have become the preferred treatment, since they are associated with a longer time to disease progression and lower toxicity."

HERCEPTIN In about 30% of breast cancers a protein called HER2 is overexpressed and is typically associated with more aggressive disease and shorter survival times. Herceptin (trastuzumab) is a recombinant monoclonal antibody used to inhibit growth of HER2-positive breast cancers.

It attaches itself to HER2 receptors on the cancer cells and blocks them from receiving growth signals; it also signals the immune system to destroy the cancer cells. Herceptin produces flu-like symptoms in about 40% of patients. "Herceptin should be part of initial chemotherapy for patients with HER2 overexpressing breast cancer," Dr. Abramowicz says.

MAMMOGRAPHY Undoubtedly the most effective way to combat breast cancer is to find it early, since cure rates are highest when the cancer is confined to the breast. Screening mammography can generally detect cancer one to three years before a woman can feel a lump.