Vitamin D and breast cancer
Using mice, researchers at Georgetown University Medical Center found that doses of vitamin D significantly reduced development of estrogen receptor-positive (ER+) breast cancer, but had no effect on estrogen receptor-negative (ER-) cancer. Supplementation of the vitamin also reversed insulin resistance in obese mice. Vitamin D may reverse the action of genes that promote inflammation and cell proliferation. A report was presented at the Annual Meeting of the American Association for Cancer Research in April.
Estrogen plus progestin more dangerous than thought
A new analysis of a randomized trial involving over 16,000 women (randomly chosen to receive either estrogen-plus-progestin or a placebo) confirms that women who use combined hormone therapy have a higher risk of developing breast cancer and that the cancers are more likely to be fatal. The report, published in the Journal of the American Medical Association, concludes that estrogen plus progestin is associated with greater breast cancer incidence, the cancers are more commonly node-positive, and breast cancer mortality also appears to be increased.
Aggressive breast cancer needs better screening
According to researchers based at Cancer Care Ontario, interval cancers – that is, cancers that were not detectable on a previous mammogram – are more likely to be both aggressive and have a poor prognosis. These are different from “missed” cancers due to observer error or misinterpretation. True interval cancers make up about 75% of missed tumours and are more likely to grow rapidly in the time between mammograms, to be estrogen receptor negative (ER-), to have tumour cells that divide rapidly and to have a less common type and arrangement of cancer cells. The problem can only be overcome with advances in imaging technologies to detect such fast-growing tumours.
(Tumor Characteristics Associated With Mammographic Detection of Breast Cancer in the Ontario Breast Screening Program, J Natl Cancer Inst (2011) 103(12): 942-950)
Normal stem cells made to act like cancer stem cells
Researchers in North Carolina have isolated normal stem cells and given them the properties of stem cells associated with an aggressive type of breast cancer (triple negative breast cancer, or TNBC). TNBC is a highly recurrent form that spreads aggressively, carries a poor prognosis and accounts for approximately 15% of all breast cancer cases. It is diagnosed more frequently in younger women, women with BRCA1 mutations, among African-Americans and Hispanics, and those having recently given birth. By isolating the mutant stem cells, the researchers hope to map cell activity leading to more effective treatments.
Tamoxifen works only in half of high-risk women
A prominent epidemiologist in Britain has suggested that 10% of women could benefit from taking tamoxifen as a preventative to breast cancer. This is based on a clinical trial that found that high-risk women (family history, dense breasts) on tamoxifen were a third less likely to develop breast cancer. However, a reanalysis of the data demonstrates that only 46% of the women saw a change in breast density and a consequent reduction in risk, nor does this take into account other short- or long-term effects.
Enzyme fuels potentially deadly breast cancer
Researchers have found an enzyme (17ß-hydroxysteroid dehydrogenase type 7, or HSD17B7) that converts a weak form of estrogen, estrone, into the highly potent form, estradiol, that drives breast cancer. (Estrone is produced by the adrenal glands and continues to be present after the ovarian form of estrogen, estradiol, is no longer produced.) Because breast cancer tumours with this enzyme are likely to be much more aggressive and potentially deadly, identifying the enzyme and how it is turned on gives researchers potential targets for disrupting the lethal production of estradiol in breast cancers.
Approval of a new test for HER2 genes in breast tumours
In the U.S., the Food & Drug Administration has approved a new test for HER2 genes that can be performed using a standard microscope, making it easier to identify patients who would benefit from Herceptin. The new test, known as the Dual ISH system, was 86% sensitive in identifying HER2+ tumour samples.
Estrogen’s role in breast cancer can fluctuate
According to an editorial in Cancer Prevention Research, estrogen can be both a friend and a foe. While estrogen is necessary for cancer cells to grow and multiply, when cancer cells develop in an environment where estrogen hasn’t been present for some time (as in post-menopause), they can often be killed off by an unexpected flood of the hormone. In such a situation, a short burst of estrogen therapy can be effective. Oncologists judge the situation based on a woman’s menopausal status, presence or absence of ovaries, and other factors.
A blood test for breast cancer?
An article in Cancer Research suggests that the identification and measurement of a biomarker might lead to early detection of cancer using a simple blood test. The findings focus on using antibodies towards a common non-human sugar molecule obtained primarily through a diet of red meat and dairy. A blood test of antibodies to one specific Neu5Gc-containing sugar chain could be used to diagnose breast cancer as effectively as the standard PSA test used to test for prostate cancer.
Gamma imaging better than ultrasound for dense breasts
Breast-specific gamma imaging (BSGI) relies on a tracing agent that emits gamma radiation after it is injected and taken up by all cells of the body. BSGI detects increased metabolic activity of cancerous cells as compared to surrounding tissues and can discover very early stage cancers independent of tissue density. Compared with mammography and ultrasound, BSGI offers greater sensitivity and fewer false positives, particularly for women with dense breasts. However, when used on younger women (aged 40), a single BSGI scan involves a lifetime risk for fatal cancer that is perhaps 20 to 30 times greater than that of digital mammography.
New review of silicone breast implants
After five years of marketing, the U.S. Food & Drug Administration reviewed safety issues linked to silicone breast implants – connective tissue disease, reproductive issues, breast cancer or other new side effects. Twenty percent of women who get implants for aesthetic reasons, and 50% who have breast reconstruction, will need the devices removed within ten years because of complications. ”The risks and complications, though frequent, are well understood,” according to the director of the FDA’s Center for Devices and Radiological Health.
Hypnosis and local anaesthesia speed breast cancer recovery
Two European anaesthesiologists, specializing in hypnosis, followed 78 women destined for breast surgery (partial mastectomy, node biopsy and axillary dissection), of whom 18 chose to have hypnosis and a local rather than a general anaesthetic. The women who chose hypnosis and a local spent a few minutes more in the operating room but needed fewer painkillers and spent shorter times in the recovery room and hospital. This option, for other kinds of surgeries in addition to breast surgery, could have an impact on health costs.