Vitamin C and Cancer

The Food and Drug Administration doesn’t require proof that dietary supplements are safe or effective, as long as they don’t claim that the supplements can prevent, treat, or cure any specific disease; and most supplements have not been tested to find out how they interact with medicines, foods, or other herbs and supplements.  Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects aren’t often available.
Vitamin C supplements are generally considered safe.  Doses higher than 1,000 mg can cause diarrhea, nausea, heartburn, belly pain, and stomach cramps in some people, but the safe upper limit of vitamin C for adults is considered to be about 2,000 mg.  Most oncologists routinely recommend that people with cancer avoid gram-size doses of vitamin C during treatment.
Vitamin C is an essential vitamin the human body needs to function well.  It is a water-soluble vitamin that cannot be made by the body, and must be obtained from foods or other sources. Many studies have shown a link between eating foods rich in vitamin C, such as fruits and vegetables, and a reduced risk of cancer.
Vitamin C is also an antioxidant, a compound that helps block the action of unstable molecules known as free radicals, which can damage cells.  Vitamin C is thought by some to enhance the immune system by stimulating the activities of natural killer cells and anti-cancer agents.  Some claim that the vitamin can prevent a variety of cancers from developing, including lung, prostate, bladder, breast, cervical, intestinal, esophageal, stomach, pancreatic, and salivary gland cancers, as well as leukemia and non-Hodgkin’s lymphoma.  Vitamin C is also said to prevent tumors from spreading, help the body heal after cancer surgery, enhance the effects of certain anti-cancer drugs, and reduce the toxic effects of other drugs used in chemotherapy.
Vitamin C is water-soluble, which means that the body uses what it needs and eliminates the rest.  Small amounts of vitamin C are needed for healthy skin, tendons, ligaments, bones, cartilage, and blood vessels, and for the healing of wounds and injuries.  It also helps to body absorb iron from foods.  A shortage of vitamin C causes scurvy, a disease marked by fatigue, fragile blood vessels bleeding, which can be fatal if not treated.  Vitamin C deficiency is very rare among people who eat a reasonably balanced diet.
Many scientific studies have shown that diets high in fruits and vegetables reduce the risk of developing cancers of the pancreas, esophagus, larynx, mouth, stomach, colon and rectum, breast, cervix, and lungs.  Many of these studies show people who eat foods to get a high level of vitamin C have about half as much cancer as those who have a low intake of these foods. Likewise, people with higher blood levels of vitamin C tend to have a lesser risk of developing cancer than do people with lower levels.  However, studies that observed large groups or people and clinical trials of vitamin C supplements have not shown the same strong protective effects against cancer.
Some oncologists believe that taking high doses of antioxidant vitamins may actually interfere with the effectiveness of radiation and some chemotherapy drugs.  However, no randomized clinical trials have yet been done in humans to test the effect of Vitamin C supplements during radiation therapy or chemotherapy.  Although high doses of vitamin C have been suggested as a cancer treatment, the available evidence from clinical trials has not shown any benefit.
The American Cancer Society recommends eating a variety of healthful foods, with most of them coming from plant sources, rather than supplements. It’s best to get vitamins and minerals from foods but supplements may be helpful for some people, such as pregnant women, women of childbearing age, and people with restricted food intakes.   If a supplement is taken, choose a balanced multivitamin/mineral supplement that contains no more than 100% of the “Daily Value” of most nutrients.

Breast Cancer Survivors and Heart Failure

There is higher rate of heart failure among breast cancer survivors than has previously been reported. 12,000 women were studied, and a report found that the women had a 20 percent risk of developing heart failure over just five years if they got a common chemotherapy regimen.  This is compared to just 3.5 percent of breast cancer patients who did not get chemo.
Clinical trials of breast cancer patients have shown that the drugs can damage the heart and cause higher rates of heart failure. They generally demonstrate about a 4 percent increase in heart failure over three to five years for women getting chemo. Clinical trials usually involve a select group of patients who are healthy in other ways.
Each drug raised the risk on its own, but the combination greatly raised heart failure rates.
It is important to note that these rates do vary by age.  The rates are much lower in the younger women. More than 40 percent of the women over the age of 75 who got a combination of an anthracycline and Herceptin also developed heart failure within five years and 13.7 percent of the breast cancer patients that age who did not get chemo developed heart failure.
The study highlights a growing problem. The American Cancer Society estimates there are 12 million cancer survivors alive in the United States now. As many cancer patients survive their disease and lead ever-longer lives, they find they must fight second battles against the long-term effects of the treatments that saved their lives. Even so-called targeted therapies, which were designed to better target tumor cells while leaving healthy tissue alone, have been shown to cause long-lasting damage.
And as they leave the care of a specialized oncologist and return to day-to-day care, they may not know they’re at special risk of other conditions – and their primary care doctors may not be aware, either. The American Society of Clinical Oncology has been warning about the problem for years, and released research at its annual meeting last June showing that 94 percent of primary care doctors didn’t know about the potential long-term effects of drugs commonly used to treat breast and prostate cancer.
Breast cancer is the leading cancer killer of U.S. women, after lung cancer. It is diagnosed in more than 220,000 women a year, according to the American Cancer Society, and will kill nearly 40,000 this year. About 20 percent of cases are a kind called HER-2 positive, and Herceptin was formulated to especially target this kind. It’s very effective and has saved thousands of lives, but it was known to also damage the heart, although doctors don’t understand just how.
Heart failure is also very common. The National Heart, Lung and Blood Institute estimates 4.8 million Americans have congestive heart failure, which is a chronic condition in which the heart doesn’t pump blood effectively. Half of patients with heart failure die within five years, and 400,000 people get newly diagnosed every year.
So what can women do if they’ve had chemo for breast cancer and want to watch their hearts?
Cardiologist Dr. Larry Allen of the University of Colorado in Denver, who also worked on the study, said they first of all need to be educated about what drugs they have taken and what the side-effects are.
“Second, patients should ask about what heart tests may be indicated before, during, and after treatment,” Allen said in a statement. These may include tests of how well the heart is pumping blood – tests that most women won’t get during a routine physical or well-woman visit.
“Third, in addition to allowing doctors to monitor for heart problems, patients can monitor themselves for worsening heart function by understanding how heart problems may present — including shortness of breath especially when lying flat, leg swelling, palpitations/heart fluttering, and exercise intolerance (these symptoms can represent non-heart disease too, but generally warrant additional evaluation),” Allen added.
“Unfortunately, it is unknown if medications that are typically used to treat heart failure (such as beta-blockers and ACE inhibitors) might protect against heart damage from certain chemotherapy drugs.

Breast Cancer Screenings

Mammography false alarms linked with later tumor risk
The American Cancer Society recommends breast cancer screenings for women who are in good health starting at age 40. But, a growing number of researchers have questioned the benefits of annual mammograms since 2009 when the United States Preventive Services Task Force first recommended that screening be done every two years and be generally restricted to women aged 50 to 74.
Now, a new study shows women with mammograms that produce false positives have a heightened risk of being diagnosed with breast cancer years later, but the reason why this is–is uncertain.
An increased risk of breast cancer among women with false positive mammograms has been reported before. The new sturdy attempts to estimate the extra risk while taking into consideration that doctors may have missed the cancer in the previous diagnosis. According to the lead author in the new study, physician mistakes regarding missing cancers are only is a small percentage of the increased risk.
A mammogram is considered false positive when it suggests possible breast cancer but additional screenings or a biopsy fails to find it. The increased risk of breast cancer occurring, does not explain most of false-positive mammograms. Radiologists reread the original mammograms and found that doctors had actually missed the cancer in 72 of the 295 women, for a false-negative rate of 1.5 percent. Even after taking those missed cancers into account, however, the researchers found that women with false-positive mammograms were still 27 percent more likely to be diagnosed with breast cancer years later, compared to women with only negative test results.
The risk was slightly higher in women who had surgical biopsies that turned out to be negative. The risk of a false-positive test over 10 mammograms ranges from 58 percent to 77 percent in the U.S.
There are those that wonder if there is an inherent biology of the breast makes it suspicious and it puts a woman at higher risk, but no one knows for sure.
Should women who get false-positive mammograms be followed more closely by their doctors, or if false-positive patients should be screened differently.
Some now believe that the excess rate of breast cancer among women who have had false-positive mammograms points to the need to personalize screening programs for women.
A risk calculator app, to guide women in deciding how often to get mammograms, is being developed at the University of California. The calculator considers a range of factors, including age, race, previous breast cancer, family history and breast density. The average five-year breast cancer risk for a 50-year-old white woman with no prior family history of breast cancer is 1.25 percent, the calculator shows. It ranges from less than 1 percent, to 2.70 percent, depending upon breast density, for the same woman with a history of a prior breast biopsy, regardless of whether the biopsy was positive or negative.
Getting a mammogram every other year instead of annually did not increase the risk of advanced breast cancer in women ages 50 to 74, according to a study that was published last year. The recommendation to reduce the frequency and delay the start of mammography screening was based on research showing the risk of false-positive results – which needlessly expose women to the anguish of a possible breast cancer diagnosis and the ordeal of further testing – outweighed the benefits of detecting cancers earlier.