Oral Bisphosphonates May Significantly Reduce Breast Cancer

Results of a new analysis of data from the Women's Health Initiative (WHI) observational study showed that women who used bisphosphonates, which are commonly prescribed bone-strengthening pills, had significantly fewer invasive breast cancers than women who did not use bisphosphonates. These findings were presented at the CRTC-AACR San Antonio Breast Cancer Symposium.

In the 150,000-plus cohort of generally healthy postmenopausal women, the researchers found that women who used bisphosphonates, mostly alendronate, which is sold as Fosamax (alendronate sodium) by Merck, had 32% fewer cases of invasive breast cancer compared to women who did not use such drugs.

"The idea that bisphosphonates could reduce breast cancer incidence is very exciting because there are about 30 million prescriptions for these agents written annually in the United States targeting bone health, and more could easily be used to counteract both osteoporosis and breast cancer," said the study's lead investigator, Rowan Chlebowski, M.D., Ph.D., medical oncologist at the Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles Medical Center.

The concept arose from findings in a report on an adjuvant breast cancer trial where use of the bisphosphonate zoledronic acid given intravenously every six months resulted in fewer contralateral breast cancers.

"It appeared to make bone less hospitable to breast cancer," Chlebowski said.

However, since bisphosphonates are prescribed for women with low bone mineral density and low bone mineral density has been associated with lower breast cancer incidence, a means to control for potential differences between women prescribed bisphosphonate and those not prescribed bisphosphonate in the cohort was needed.

Given that, Chlebowski and colleagues devised a way to control for use of bisphosphonates in the WHI. About 10,000 of the participants had bone mineral density analysis as part of the study, and for the rest they used a 10-item hip fracture predictive score to measure bone density. The researchers were able to correlate the findings from the women who had bone mineral density tests to findings from the predictive score in order to correct for any potential difference in bone density in women using bisphosphonates compared to non-users.

Studying 2,216 WHI participants who were using bisphosphonates when they entered the study, the researchers found that only 64 women developed breast cancer, and most of those cases (50) were estrogen receptor positive. Overall, there was a mean 32 percent fewer breast cancers in women using bisphosphonates compared to women who did not. There were 30 percent fewer estrogen receptor-positive cancers and 34 percent fewer entry receptor-negative cancers in bisphosphonate users. The latter finding was not statistically significant as there were very few receptor-negative cases.

"Bisphosphonates reduce angiogenesis and stimulate immune cells responsible for tumor cell surveillance as potential mediators," Chlebowski said. "This association needs to be studied further. While we currently have several options for reducing receptor-positive breast cancers, none are available for receptor-negative cancers."

Several ongoing adjuvant breast cancer trials evaluating oral and intravenous bisphosphonate will be available in the near future to provide randomized clinical trial evidence regarding their influence on new contralateral breast cancer risk, Chlebowski said.

For more information:

•  Onco'Zine - The International Cancer Network

Targeted Breast Ultrasound Can Reduce Biopsies for Women under Forty

Targeted breast ultrasound of suspicious areas of the breast, including lumps, is a safe, reliable and cost-effective alternative to invasive biopsies for women under age 40, according to the findings of two studies presented at the 95th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA).

"By performing high-quality breast ultrasound, we can reduce the number of expensive and avoidable invasive diagnostic procedures in young women," said senior author Constance D. Lehman, M.D., Ph.D., professor and vice chair of radiology at the University of Washington and director of imaging at the Seattle Cancer Care Alliance. "We don’t want to be overly aggressive with this population."

The researchers conducted two studies in which targeted ultrasound was used to distinguish between potentially cancerous masses and benign findings in young women who had detected breast lumps or other focal (specific) areas of concern in their breasts. The first study included 1,123 ultrasound examinations of women under age 30, while the second included 1,577 ultrasound examinations of women ages 30 to 39.

Across both studies, all instances of cancer at the site of the clinical concern were positively identified through targeted ultrasound. In addition, all negative ultrasound findings correctly identified benign changes in the breast. The only malignant mass not identified by ultrasound was an unsuspected lesion outside of the targeted examination area. That cancer was identified by a full breast mammogram.

The incidence of malignancy among women in their 30s was 2%. The incidence of malignancy among women younger than 30 was 0.4 percent.

Fig 1. A breast ultrasound image showing a benign mass.

"Surgical excision or needle biopsy of tissue can be painful, expensive and frequently unnecessary in these age groups, which have very low rates of malignancies," Dr. Lehman said. "In most cases, monitoring with targeted ultrasound is a very safe alternative."

She added that ultrasound should be the diagnostic tool of choice for young women seeking care for breast lumps and other suspicious focal signs and symptoms. "It is time we used ultrasound to reduce unnecessary morbidity and costs associated with more aggressive invasive approaches," Dr. Lehman said.

Also see Abstracts:
- Outcomes of Targeted Ultrasound Evaluation in Women Under 30 Years of Age with Focal Breast Signs or Symptoms. Presented by Dr. Vilert Loving, MD
- Contribution of Mammography to Ultrasound Evaluation of Women 30 to 39 Years of Age with Focal Breast Signs or Symptoms . Presented by Michael Portillo, MD

For more information:
- Onco'Zine - The International Cancer Network

Annual Screening with Breast Ultrasound or MRI Could Benefit Some Women

Results of a large-scale clinical trial presented presented at the 95th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA) provide the first strong evidence of the benefit of annual screening ultrasound for women with dense breasts who are at elevated risk for breast cancer. In addition, the study confirmed that MRI is highly sensitive in depicting early breast cancer.

"We found that annual screening with ultrasound in addition to mammography significantly improves the detection of early breast cancer," said lead researcher Wendie A. Berg, M.D., Ph.D., breast imaging specialist at American Radiology Services, Johns Hopkins — Green Spring Station in Lutherville, Md., "and that significantly more early breast cancer can be found when MRI is performed, even after combined screening with both ultrasound and mammography. However, both ultrasound and MRI increase the risk of false-positive findings."

Women who are at high risk for breast cancer need to begin screening at a younger age, because they often develop cancer earlier than women at average risk. However, women below age 50 are more likely to have dense breast tissue, which can limit the effectiveness of mammography as a screening tool.

Multicenter trials have shown that MRI enables radiologists to accurately identify tumors missed by mammography and ultrasound. The American Cancer Society recommends that some groups of women with a high risk of developing breast cancer should be screened with MRI in addition to their yearly mammogram beginning at age 30. However, MRI is not for everyone.

"Because MRI is a very expensive test and requires intravenous contrast, it is something we only recommend for screening the approximately 2% of women who are known or likely carriers of BRCA1 or BRCA2 gene mutations or have other unusual circumstances that put them at very high risk for breast cancer," Dr. Berg said.

"There are another 10 to 15% of women who are at some increased risk because of personal history of breast cancer, family history of breast cancer and/or dense breast tissue," she added. "For many of these women, MRI is not currently justified, but annual ultrasound would be appropriate in addition to mammography."

Fig 1. This breast MRI showing focus of enhancement in left breast, negative on mammography and screening ultrasound. Pathology proven infiltrating ductal carcinoma

The researchers studied 612 women, mean age 55 years, at elevated risk of breast cancer enrolled at 14 sites in the American College of Radiology Imaging Network (ACRIN) 6666 trial funded by the Avon Foundation and the National Cancer Institute. Women underwent baseline screening mammography and ultrasound with follow-up exams at 12 and 24 months and then a single, contrast-enhanced MRI at 24 months.

Sixteen women were diagnosed with breast cancer. Twelve of the cancers were invasive, and four were ductal carcinoma in situ (DCIS). Over the course of the study, 50 to 56 percent of cancers were shown on mammography. Adding ultrasound allowed detection of 70 to 94% of cancers. Adding MRI allowed for detection of additional cancers at their earliest stage.

Fig 2. Ultrasound showing 9-mm benign mass (arrows) in upper inner quadrant

The study also found that supplemental screening with ultrasound or MRI significantly increased the risk of false-positive findings, leading to unnecessary biopsies in some women.

"It is important that women are advised of the increased potential of undergoing an unnecessary biopsy as a result of screening with ultrasound or MRI," Dr. Berg said, "but we hope this study motivates women and their doctors to learn more about their risk factors and to consider supplemental screening in addition to mammography where indicated."

Also see Abstracts:
Supplemental Yield and Performance Characteristics of Screening MRI after Combined Ultrasound and Mammography: ACRIN* 6666 *American College of Radiology Imaging Network.