Study: Preoperative estrogen-blocking therapy may preempt need for mastectomy

March 23, 2012

Preoperative treatment with aromatase inhibitors increases the likelihood that postmenopausal women with estrogen receptor-positive breast cancer will be able to have breast-conserving surgery rather than a mastectomy, according to the results of a national clinical trial presented today at the Society of Surgical Oncology annual meeting in Orlando, Fla.

"We found that half of the postmenopausal women in the study who initially faced having a were able to have breast-conserving after being treated for four months with an aromatase inhibitor. Preoperative therapy with aromatase inhibitors significantly increases surgical options for women with estrogen-rich cancers," says John A. Olson, Jr., M.D., Ph.D., professor and vice chairman of the Department of Surgery at the University of Maryland School of Medicine and chief of general and oncologic surgery at the University of Maryland Medical Center in Baltimore.

Dr. Olson is co-principal investigator of the Phase II trial, which was conducted by the American College of Surgeons (ACOSOG). He presented the results at a plenary session at the Society of Surgical Oncology's national meeting. Matthew J. C. Ellis, M.D., B.Chir., Ph.D., of Washington University in St. Louis, is the principal investigator.

Aromatase inhibitors, which stop the production of estrogen that fuels the growth of , are widely used to treat postmenopausal women with hormone-responsive breast cancer. A University of Maryland scientist, Angela H. Brodie, Ph.D., professor of pharmacology and , pioneered the development of these drugs, which also have shown promise in helping to prevent breast cancer in high-risk patients.

Breast-conserving surgery, or , means that surgeons remove only the tumor and surrounding tissue, sparing a woman's breast. Mastectomy requires removal of the entire breast. Many women, especially those with larger tumors, are treated with chemotherapy to shrink the cancer before surgery in hope of avoiding mastectomy. There is growing evidence that hormone therapy with aromatase inhibitors may be more effective than chemotherapy in older women with hormone-responsive cancers. About 80 percent of postmenopausal women with breast cancer have tumors that express hormone receptors, such as the receptor for estrogen.

E. Albert Reece, M.D., Ph.D., M.B.A., vice president of medical affairs at the University of Maryland and dean of the University of Maryland School of Medicine, says, "This clinical trial, co-led by Dr. Olson, clearly demonstrates the benefit of neoadjuvant treatment with aromatase inhibitors for with facing often-difficult decisions about whether to have breast-conserving surgery or mastectomy. We are very pleased that Dr. Olson, who recently joined our faculty, will be continuing this important area of research at the University of Maryland School of Medicine, augmenting the extraordinary work being done here on aromatase inhibitors by Dr. Angela Brodie."

In the ACOSOG study, researchers analyzed results from 374 patients with larger, Stage II and III-grade, estrogen receptor-positive tumors. Of these, 45.7 percent were considered candidates for mastectomy, 53.2 percent for breast conservation surgery and 1.1 percent were deemed inoperable. The women were selected at random to receive one of three approved the U.S. Food and Drug Administration: anastrozole, letrozole or exemestane.

After treatment for 16 weeks, 352 women had surgery. Of these, 241 women (68.5 percent) had breast-conservation surgery and 111 had a mastectomy. The group that had breast conservation therapy included 84 of 163 women (51.5 percent,) who were deemed to require mastectomy by their surgeon at the outset.

"We found it particularly interesting that about one-fourth of the patients who had a mastectomy after being treated with an aromatase inhibitor had evidence of a relatively small tumor when we examined their breast tissue in the laboratory, suggesting that a mastectomy might not have been necessary," Dr. Olson says.

He adds, "Giving aromatase inhibitor therapy preoperatively allows breast conservation surgery in a substantial proportion of patients with estrogen receptor-rich tumors who would otherwise be considered candidates for mastectomy. If we had better techniques to determine how much cancer remains after preoperative treatment and surgeons were willing to attempt breast-conservation surgery in patients with responsive tumors, perhaps we could improve the rates of successful breast-conservation therapy for these patients."

In 75 percent of the cases, the final determination on what type of surgery to have was based on the recommendation of the surgeon. The remaining 25 percent was based on the patient's preference.

Explore further: Estrogen-lowering drugs reduce mastectomy rates for breast cancer patients

Related Stories

Estrogen-lowering drugs reduce mastectomy rates for breast cancer patients

May 9, 2011
In the first large trial of its kind in the United States, researchers have shown that estrogen-lowering drugs can shrink tumors and reduce mastectomy rates for patients with stage 2 or 3 breast cancer.

New clinical trial to test novel approach to treat triple-negative breast cancer

June 2, 2011
A multicenter clinical trial led by a researcher at the University of Maryland Marlene and Stewart Greenebaum Cancer Center will evaluate a new approach to treat triple-negative breast cancer, an often-aggressive type of ...

Young women with early breast cancer have similar survival with breast conservation, mastectomy

September 7, 2011
Young women with early-stage breast cancer have similar survival rates with a lumpectomy and radiation treatment, known as breast-conservation therapy, as with mastectomy, a new study conducted at the University of Maryland ...

Recommended for you

Shooting the achilles heel of nervous system cancers

July 20, 2017
Virtually all cancer treatments used today also damage normal cells, causing the toxic side effects associated with cancer treatment. A cooperative research team led by researchers at Dartmouth's Norris Cotton Cancer Center ...

Molecular changes with age in normal breast tissue are linked to cancer-related changes

July 20, 2017
Several known factors are associated with a higher risk of breast cancer including increasing age, being overweight after menopause, alcohol intake, and family history. However, the underlying biologic mechanisms through ...

Immune-cell numbers predict response to combination immunotherapy in melanoma

July 20, 2017
Whether a melanoma patient will better respond to a single immunotherapy drug or two in combination depends on the abundance of certain white blood cells within their tumors, according to a new study conducted by UC San Francisco ...

Discovery could lead to better results for patients undergoing radiation

July 19, 2017
More than half of cancer patients undergo radiotherapy, in which high doses of radiation are aimed at diseased tissue to kill cancer cells. But due to a phenomenon known as radiation-induced bystander effect (RIBE), in which ...

Definitive genomic study reveals alterations driving most medulloblastoma brain tumors

July 19, 2017
The most comprehensive analysis yet of medulloblastoma has identified genomic changes responsible for more than 75 percent of the brain tumors, including two new suspected cancer genes that were found exclusively in the least ...

Novel CRISPR-Cas9 screening enables discovery of new targets to aid cancer immunotherapy

July 19, 2017
A novel screening method developed by a team at Dana-Farber/Boston Children's Cancer and Blood Disorders Center—using CRISPR-Cas9 genome editing technology to test the function of thousands of tumor genes in mice—has ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.