Low Vitamin D a Problem for Women with Breast Cancer
Women with breast cancer who have a vitamin D deficiency at
the time of diagnosis are more likely to have a recurrence or to die from their
disease, say researchers at an American Society of
Clinical Oncology (ASCO) meeting.
Surprisingly, the researchers also found that only 24
percent of the patients had adequate levels of vitamin D when they were
diagnosed.
"This study found that vitamin D deficiency is very common
among women with breast cancer, and it suggests that vitamin D deficiency is
linked to poorer outcomes in these women," says Dr. Nancy Davidson at the Johns
Hopkins Kimmel Cancer Center in Baltimore, Maryland.
Nevertheless, the evidence is not strong enough to suggest
women with breast cancer take more of the vitamin.
"It's premature to tell all women diagnosed with breast
cancer that they should take vitamin D supplements over and above what's
recommended for bone health," says study author Dr. Pamela Goodwin at Mount
Sinai Hospital in Toronto, Ontario, Canada.
"If you're a woman with breast cancer, it's probably
worthwhile having vitamin D levels checked,” she notes.“If they're deficient,
they should take more to get it in the range that we think is beneficial.”
The optimal levels of vitamin D associated with breast
cancer risk in this study do overlap with optimal levels for bone health, adds
Dr. Goodwin.
Prior research has suggested that vitamin D levels may be
associated with breast cancer risk, an idea that is biologically plausible.
"We know from basic science studies that breast cancer
cells have vitamin D receptors and can interact with vitamin D," explains Dr.
Goodwin.
There is, however, a lot of confusion about the different
health benefits of vitamin D and, the authors say, daily allowance
recommendations vary greatly around the world.
The study involved 512 women newly diagnosed with localized
breast cancer (confined to the breast and arm pit) between 1989 and 1995. All
participants had had blood taken at the time of diagnosis and had also filled
out a questionnaire on diet. Vitamin D levels were measured by radioimmunoassay.
The women, whose age averaged about 50, were followed for
just under 12 years. Of the total, 37.5 percent were deficient in vitamin D (the
lowest levels), 38.5 percent had insufficient levels of vitamin D (not deficient
but not quite healthy levels), and 24 percent had levels in the healthy range.
Women who were premenopausal, weighed more, had high
insulin levels, and had more aggressive tumors were all more likely to have low
vitamin D levels.
"Fat tissue acts as a trap for vitamin D," says Dr.
Goodwin. "Levels were also lower in younger women, which was a bit of a
surprise, until we realized older women were taking more supplements."
The risk of breast cancer spreading was almost double in
women with deficient levels of vitamin D at diagnosis, compared with women whose
levels were healthy.
The risk of dying of breast cancer was 75 percent higher in
women with too-low levels of vitamin D versus women in the optimal range.
However, there was no survival difference between women
with healthy levels and insufficient levels.
The data also suggested that there may be a small increased
risk of metastasis or death if vitamin D levels are high, but not a
statistically significant effect, says Dr. Goodwin.
"This suggests that there's a healthy level for vitamin D
and, if you are deficient, you have an increased risk of metastasis, but if you
go above [a certain point], your risk of death goes up again," she says.
Although it is not a firm conclusion, Dr. Goodwin adds, the
finding "is raising a red flag. It's probably not safe to take very high levels
and get vitamin D levels up really high."
And the findings are consistent with another study which
found that men with prostate cancer who took vitamin D died earlier than those
taking a placebo.
Always consult your physician for more information.
|
Routine care is the best way to keep you and your
breasts healthy. Although detecting breast cancer at its earliest stages is
the main goal of routine breast care, other benign conditions, such as
fibrocystic breasts or cysts, are often discovered during routine care.
Breast cancer is the most common type of cancer among
women in the US, other than skin cancer.
According to the National Cancer
Institute (NCI), when breast cancer is found early and is still
localized (restricted to the site of origin, without evidence of spread),
the relative survival rate, when measured at five years, is 98 percent.
When breast cancer is found at a late stage (cancer
that has spread to distant parts of the body), the survival rate at five
years is 26 percent.
Although the incidence of breast cancer is beginning to
decrease, one out of eight women will develop invasive breast cancer at some
point in their lives. Mortality rates have decreased over the past several
years due to early detection and improved treatment.
If you are diagnosed with breast cancer, the most
important thing for you to remember is that it is not a hopeless condition.
Early detection and modern therapy with a combination of surgery, radiation,
medications, or hormones can help many patients.
Step 1. Breast Self-Examination
(BSE)
A woman should begin practicing breast self-examination by the age of 20 and
continue the practice throughout her life - even during pregnancy and after
menopause. BSE should be done regularly at the same time every month.
Regular BSE teaches you to know how your breasts normally feel so that you
can more readily detect any change. Changes may include:
- development of a lump
- a discharge other than breast milk
- swelling of the breast
- skin irritation or dimpling
- nipple abnormalities (i.e., pain, redness, scaliness, turning
inward)
If you notice any of these changes, see your healthcare
provider as soon as possible for evaluation.
Step 2. Clinical Examination
A breast examination by a physician or nurse trained to evaluate breast
problems should be part of a woman's physical examination.
The American Cancer Society
(ACS) recommends between the ages of 20 and 39, women should have a
clinical breast examination by a health professional every three years.
After age 40, women should have a breast examination by
a health professional every year. A physical breast examination by a
physician or nurse is very similar to the procedures used for breast
self-examination. Women who routinely practice BSE will be prepared to ask
questions and have their concerns addressed during this time.
Step 3. Mammography
Mammography is a low-dose x-ray of the breasts to find changes that may
occur. It is the most common imaging technique. Mammography can detect
cancer or other problems before a lump becomes large enough to be felt, as
well as assist in the diagnosis of other breast problems. However, a biopsy
is required to confirm the presence of cancer.
According to the National Cancer Institute, women in
their 40s and older should begin having a screening mammogram on a regular
basis, every one to two years. But, the American Cancer Society recommends
that by age 40, women should have a screening mammogram every year. (A
diagnostic mammogram may be required when a questionable area is found
during a screening mammogram.)
Both organizations suggest that women who may be at
increased risk for breast cancer should talk with their physicians about
whether to begin having mammograms at an earlier age.
Always consult your physician for more information.
|