Blood Test May Help Define Breast Cancer Risk in Older Women

By Barbara Bronson Gray
HealthDay Reporter

THURSDAY, Oct. 18 (HealthDay News) -- The effort to develop a blood test to reveal a woman's risk for breast cancer may be one step closer to fruition, but is still far from becoming a reality, according to a new study.

The researchers found that blood hormone tests may predict the risk for developing postmenopausal breast cancer up to 20 years after a blood sample was taken.

But the study has limitations and needs to be replicated and expanded, said Dr. Xuehong Zhang, lead author and an epidemiologist at Brigham and Women's Hospital in Boston.

If the research is confirmed by other studies, women could have their blood levels of so-called "sex hormones" such as estradiol, testosterone and the androgen DHEAS (dehydroepiandrosterone sulfate) assessed every 10 to 20 years to get a biological assessment of their breast cancer risk, Zhang explained.

"We're thinking that the addition of hormone levels to our current risk prediction models might improve our ability to find high-risk women who would benefit from additional screening or prevention," he said.

The research was scheduled for presentation Thursday at the annual cancer prevention conference of the American Association for Cancer Research (AACR) in Anaheim, Calif.

Although it has been established that levels of estrogen and androgen in the blood can be associated with the risk of postmenopausal breast cancer, researchers haven't known how far into the future that risk prediction might go, Zhang said.

Working with participants in the Nurses' Health Study, a large and long-running effort to study women's health issues, blood samples were collected in 1989 to 1990, and then again in 2000 to 2002. Only postmenopausal women not taking hormones were eligible for this study. The researchers found 796 cases of diagnosed breast cancer through June 2010.

The study showed that women with hormone levels in the top quarter for estradiol, testosterone and DHEAS had a 50 percent to 107 percent greater chance of developing breast cancer as compared to women in the lowest quarter. Elevated hormone levels were also associated with recurrent or fatal breast cancer.

Those women in the highest quarter for sex hormone-binding globulin (SHBG) -- which has been understood to reduce the cancer-causing effects of some hormones -- had a 30 percent lower risk for breast cancer compared to those with SHBG levels in the lowest quarter.

The researchers also found that elevated levels of estrogen increased a woman's risk for hormone receptor-positive breast cancer.

Tests for the levels of these hormones are available now, but the results are often uncertain because laboratories vary greatly in how they define and interpret the results, Zhang said.

A breast cancer expert urged caution in interpreting the study.

"I would ask, if you're postmenopausal and have elevated levels of these hormones, should you potentially turn off your body's hormones [to help prevent breast cancer]?" asked Dr. Julie Gralow, director of breast medical oncology at the Seattle Cancer Care Alliance.

"If the hormones are good for your bones, your heart and maybe the brain, should you do anything to reduce them if you're perceived to be at some increased risk? It could affect your health negatively [to try to reduce those hormone levels]," Gralow said.

Should such a blood test become available, Gralow said she would want women to balance their potential risk of breast cancer against the danger of other diseases and conditions, including osteoporosis and fractures, heart disease and even dementia. "This is an interesting finding that needs to be put into the perspective of the total health of the postmenopausal woman," she said.

Risk factors for breast cancer currently include aging, genetics, race and ethnicity, family history and a personal history of breast cancer, among others, according to the American Cancer Association.

Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until they are published in a peer-reviewed journal.

Copyright © 2012 HealthDay. All rights reserved. SOURCES: Xuehong Zhang, M.D., epidemiologist, Brigham and Women's Hospital, and instructor in medicine, Harvard Medical School, Boston; Julie Gralow, M.D., director, breast medical oncology, Seattle Cancer Care Alliance and professor, medical oncology division, University of Washington School of Medicine, Seattle; Oct. 18, 2012, presentation, American Association for Cancer Research cancer prevention conference, Anaheim, Calif.

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Multivitamin use among middle-aged, older men results in modest reduction in cancer, study finds

ScienceDaily (Oct. 17, 2012) — In a randomized trial that included nearly 15,000 male physicians, long-term daily multivitamin use resulted in a modest but statistically significant reduction in cancer after more than a decade of treatment and follow-up, according to a study appearing in JAMA.

The study is being published early online to coincide with its presentation at the Annual American Association for Cancer Research Frontiers in Cancer Prevention Research meeting.

"Multivitamins are the most common dietary supplement, regularly taken by at least one-third of U.S. adults. The traditional role of a daily multivitamin is to prevent nutritional deficiency. The combination of essential vitamins and minerals contained in multivitamins may mirror healthier dietary patterns such as fruit and vegetable intake, which have been modestly and inversely associated with cancer risk in some, but not all, epidemiologic studies. Observational studies of long-term multivitamin use and cancer end points have been inconsistent. To date, large-scale randomized trials testing single or small numbers of higher-dose individual vitamins and minerals for cancer have generally found a lack of effect," according to background information in the article. "Despite the lack of definitive trial data regarding the benefits of multivitamins in the prevention of chronic disease, including cancer, many men and women take them for precisely this reason."

J. Michael Gaziano, M.D., M.P.H., of Brigham and Women's Hospital and Harvard Medical School, Boston, (and also Contributing Editor, JAMA), and colleagues analyzed data from the Physicians' Health Study (PHS) II, the only large-scale, randomized, double-blind, placebo-controlled trial testing the long-term effects of a common multivitamin in the prevention of chronic disease. The trial includes 14,641 male U.S. physicians, initially age 50 years or older, including 1,312 men with a history of cancer at randomization, who were enrolled in a multivitamin study that began in 1997 with treatment and follow-up through June 1, 2011. Participants received a daily multivitamin or equivalent placebo. The primary measured outcome for the study was total cancer (excluding nonmelanoma skin cancer), with prostate, colorectal, and other site-specific cancers among the secondary end points.

PHS II participants were followed for an average of 11.2 years. During multivitamin treatment, there were 2,669 confirmed cases of cancer, including 1,373 cases of prostate cancer and 210 cases of colorectal cancer, with some men experiencing multiple events. A total of 2,757 (18.8 percent) men died during follow-up, including 859 (5.9 percent) due to cancer. Analysis of the data indicated that men taking a multivitamin had a modest 8 percent reduction in total cancer incidence. Men taking a multivitamin had a similar reduction in total epithelial cell cancer. Approximately half of all incident cancers were prostate cancer, many of which were early stage. The researchers found no effect of a multivitamin on prostate cancer, whereas a multivitamin significantly reduced the risk of total cancer excluding prostate cancer. There were no statistically significant reductions in individual site-specific cancers, including colorectal, lung, and bladder cancer, or in cancer mortality.

Daily multivitamin use was also associated with was a reduction in total cancer among the 1,312 men with a baseline history of cancer, but this result did not significantly differ from that observed among 13,329 men initially without cancer.

The researchers note that total cancer rates in their trial were likely influenced by the increased surveillance for prostate-specific antigen (PSA) and subsequent diagnoses of prostate cancer during PHS II follow-up starting in the late 1990s. "Approximately half of all confirmed cancers in PHS II were prostate cancer, of which the vast majority were earlier stage, lower grade prostate cancer with high survival rates. The significant reduction in total cancer minus prostate cancer suggests that daily multivitamin use may have a greater benefit on more clinically relevant cancer diagnoses."

The authors add that although numerous individual vitamins and minerals contained in the PHS II multivitamin study have postulated chemopreventive roles, it is difficult to definitively identify any single mechanism of effect through which individual or multiple components of their tested multivitamin may have reduced cancer risk. "The reduction in total cancer risk in PHS II argues that the broader combination of low-dose vitamins and minerals contained in the PHS II multivitamin, rather than an emphasis on previously tested high-dose vitamins and mineral trials, may be paramount for cancer prevention. … The role of a food-focused cancer prevention strategy such as targeted fruit and vegetable intake remains promising but unproven given the inconsistent epidemiologic evidence and lack of definitive trial data."

"Although the main reason to take multivitamins is to prevent nutritional deficiency, these data provide support for the potential use of multivitamin supplements in the prevention of cancer in middle-aged and older men," the researchers conclude.

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The above story is reprinted from materials provided by JAMA and Archives Journals.

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Journal Reference:

Gaziano J, Sesso HD, Christen WG, et al. Multivitamins in the Prevention of Cancer in Men: The Physicians' Health Study II Randomized Controlled Trial. JAMA, 2012; DOI: 10.1001/jama.2012.14641

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

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