Cancers we can prevent

The HPV virus in a pap smear.

One in every six cancer deaths worldwide is caused by preventable infections, a total of 1.5 million deaths yearly that could be halted by widespread vaccination programs, researchers report. 

Since 1990, that number has grown by about half a million, suggesting that vaccination programs are losing ground in the battle rather than gaining it. The vast majority of the cases are caused by three viruses and a bacterium, which are the leading causes of gastric, liver and cervical cancers. Cervical cancers account for about half of the infection-related cancers in women, while liver and gastric cancers account for about 80% of those in men.

Cervical cancers are caused primarily by the human papilloma virus (HPV), as are anal and penile tumors. Stomach cancers are caused by the bacterium Helicobacter pylori. The hepatitis B and hepatitis C viruses cause liver cancer. All such infections are readily preventable by vaccination. Other less common agents include the Epstein-Barr virus, which causes nasopharynx tumors and Hodgkin's lymphoma; human herpes virus type 8, which causes Kaposi's sarcoma, usually in conjunction with HIV; and the parasite Schistosoma haematobium, which causes bladder cancer.

The researchers reported that the worldwide average of cancers caused by infectious agents was 16.5%, with about three times more (22.9%) occurring in developing countries than in developed countries (7.4%). Rates varied widely between regions, ranging from a low of 3.3% in Australia and New Zealand to a high of 32.7% in sub-Saharan Africa. About 4% of cancers were caused by infectious agents in North America and 7% in Europe.

(Thanks, Jack Marler)

That apple a day thing

Bite me.

Eating an apple a day brings extraordinary health benefits, Kathy Freston writes.

A major review published in 2008 out of the German Cancer Research Center found that indeed, compared with those who eat less than an apple a day, those who eat one or more had less risk of oral cancer, cancer of the voice box, breast cancer, and colon, kidney, and ovarian cancer as well. 

This makes sense given new research from Cornell showing that apple peels have potent antioxidant and growth-blocking effects on human breast cancer cells examined in a petri dish, and the higher the apple concentration, the fewer the cancer cells. And apples seem to work best against estrogen-receptor-negative breast cancer, which is much harder to treat than the receptor-positive kind.

How do apples do what they do?

There are three stages of tumor formation. Carcinogens cause the initial DNA mutations (the initiation stage), and then oxidation, inflammation, and hormones cause it to grow (the promotion stage); finally, metastasis occurs, in which the cancer spreads throughout the body. Which steps have apples been found to block? All of them. Apples not only have antimutagenic, antioxidant, and anti-inflammatory effects, but they may even enhance our immune systems to help clear out any budding tumors before they get their start.

Apples will also help you lose weight, she says. Continuing eating as you do now, but eat an apple first. The special fiber in apples will make you feel full longer, and you'll eat less of everything else.

An aspirin a day keeps the apple away

Taking aspirin every day may significantly reduce the risk of many cancers and prevent tumors from spreading, according to two new studies.

Researchers at the University of Oxford found that after three years of daily aspirin use, the risk of developing cancer was reduced by almost 25 percent when compared with a control group not taking aspirin. After five years, the risk of dying of cancer was reduced by 37 percent among those taking aspirin.

A second paper that analyzed five large randomized controlled studies in Britain found that over six and a half years on average, daily aspirin use reduced the risk of metastatic cancer by 36 percent and the risk of adenocarcinomas — common solid cancers including colon, lung and prostate cancer — by 46 percent.

“What really jumps out at you in terms of prevention is the striking 75 percent reduction in esophageal cancer and a 40 to 50 percent reduction in colorectal cancer, which is the most common cancer right now,” Dr. Peter M. Rothwell, a professor of clinical neurology at the University of Oxford, said. “In terms of prevention, anyone with a family history would be sensible to take aspirin.” 

But you have to talk to your doctor, because aspirin raises the risk of gastrointestinal bleeding, but of hemorrhagic strokes.

Miracles and wonders: personal cancer meds

More evidence that the world of medicine is changing in a big way.

Michael Pellini fires up his computer and opens a report on a patient with a tumor of the salivary gland. The patient had surgery, but the cancer recurred. That's when a biopsy was sent to Foundation Medicine, the company that Pellini runs, for a detailed DNA study. Foundation deciphered some 200 genes with a known link to cancer and found what he calls "actionable" mutations in three of them. That is, each genetic defect is the target of anticancer drugs undergoing testing—though not for salivary tumors. Should the patient take one of them? "Without the DNA, no one would have thought to try these drugs," says Pellini.

Starting this spring, for about $5,000, any oncologist will be able to ship a sliver of tumor in a bar-coded package to Foundation's lab. Foundation will extract the DNA, sequence scores of cancer genes, and prepare a report to steer doctors and patients toward drugs, most still in early testing, that are known to target the cellular defects caused by the DNA errors the analysis turns up. Pellini says that about 70 percent of cases studied to date have yielded information that a doctor could act on—whether by prescribing a particular drug, stopping treatment with another, or enrolling the patient in a clinical trial. 

This is only the beginning.

Eat your broccoli, boys and girls

And don't cook it too much.

Broccoli has been of particular interest to scientists because it contains the highest levels of certain glucosinolates, a class of phytochemicals that many believe may reduce the risk of prostate, breast, lung and colorectal cancer. 

When eaten as a raw or lightly-cooked food, enzymes in the broccoli help to break down the glucosinolates into two valuable compounds of intensive research interest -- sulforaphane and erucin. However,

A necessary enzyme called myrosinase is missing from most of the supplement forms of glucosinolates, a valuable phytochemical in cruciferous vegetables. Without this enzyme found in the whole food, the study found that the body actually absorbs five times less of one important compound and eight times less of another. 

Intensive cooking does pretty much the same thing. If broccoli is cooked until it's soft and mushy, its health value plummets. However, it can still be lightly cooked for two or three minutes, or steamed until it's still a little crunchy, and retain adequate levels of the necessary enzyme.

Eat your enzymes, boys and girls. 

How to think about cancer screening tests

I wrote the other day of a new recommendation that men not undergo the PSA test for prostate cancer. It's still a choice, and some men, and doctors, might want the test. National statistics are not the same as your particular body.

The decision to screen for breast cancer is somewhat similar -- there are questions about whether it actually saves lives.

Dr. H. Gilbert Welch, a professor of medicine at the Dartmouth Institute for Health Policy and Clinical Practice, has written an excellent article for The New York Times explaining the difficulty of deciding, and I recommend that you read all of it.

I'll just grab a few of the highlights.

Both breast and prostate cancer screening are really difficult calls, and the statistical differences between them are only of degrees. Reasonable individuals, in the same situation, could make different decisions based on their valuation of the benefits and harms of screening.

Screening is like gambling: there are winners and there are losers. And while the few winners win big, there are a lot more losers.

False positives are really common in both breast and prostate cancer screening. Approximately 15 to 20 percent of women and men who are screened annually over a 10-year period will have to undergo at least one biopsy because of a false-positive mammogram or PSA — prostate-specific antigen — test.

Patients who are overdiagnosed are the big losers here. They undergo surgery, radiation and chemotherapy unnecessarily. And then there are the associated complications: chemotherapy can cause nausea and radiation can burn normal tissue; breast surgery can be disfiguring, and prostate surgery can lead to bladder and sexual dysfunction.

Now let’s consider the winners — those who have avoided dying from breast or prostate cancer by getting screened. While there is some debate about whether they really exist, my reading of the data is that they do, but they are few and far between — on the order of less than 1 breast or prostate cancer death averted per 1,000 people screened over 10 years. That’s less than 0.1 percent.

"The truth is that neither test works that well," he concludes. "Even with screening, most people destined to develop deadly, untreatable cancers will still do so. When it comes to breast and prostate cancer screening, there are no right answers, just trade-offs."

It's worth your time to read the whole thing.

A better test for prostate cancer

Massimo Mischi, Ph.D. helped develop the new test

Prostate cancer is the most common type of cancer among men, but its diagnosis has up to now been inaccurate and unpleasant. Now researchers have developed an imaging technology that can accurately identify tumors.

The technology is based on ultrasound, and also has the potential to assess how aggressive tumors are. This can lead to better and more appropriate treatment, and to cost savings in health care.

Here's why this is important.

After determining the PSA (prostate-specific antigen) level in the blood, biopsies are performed to see if there are tumors in the prostate. However the PSA level is not a very good indicator: two-thirds of all biopsies turn out to have been unnecessary.

The biopsies also have disadvantages; for example they are not targeted, but instead tissue is sampled randomly using 6 to 12 needles. The chance that the needles will miss a tumor is high, causing a false negative result. In around one-third of cases with negative biopsies, tumors are later found to be present. Furthermore doctors often operate after a positive biopsy, but find a tumor so small that it would have been better not to operate.

Current state of the art is in the Dark Ages. Here's how the new test works.

The new technology uses the injection of microbubbles of a contrast agent with no side-effects. The response of the tiny bubbles to ultrasound is different from that of human tissue or blood. This makes the bubbles traceable from the outside, right into the smallest blood vessels. The pattern of blood vessels in tumors is different from that in healthy tissue. The researchers can recognize this pattern from advanced analysis of the bubble concentrations. And because tumors need blood -- and hence new blood vessels -- to grow, the researchers expect to be able to see how aggressive the cancer is from the pattern of the blood vessels.

Tell your doctor.

MRI's may help those at high risk of breast cancer

For women with a high risk of breast cancer because of genetic mutations or family history, yearly M.R.I. scans in addition to mammograms and breast exams may save lives, a new study finds.

The study, the first to measure survival in a large number of high-risk women receiving M.R.I.’s, found that after six years of follow-up, 93 percent of mutation carriers with cancer were still alive, compared with 74 percent alive at five years in earlier studies. In the new study, all of the women at high risk because of family history were still alive after six years. 

“Carefully screened with M.R.I., clinical breast examination and mammography, even women at high risk for the development of breast cancer may make a rational decision not to have prophylactic mastectomy as a risk-reducing intervention,” said Dr. Andrew D. Seidman, a breast cancer specialist at Memorial Sloan-Kettering who was not involved in the study. 

Breast M.R.I. is not recommended for most women, who have only an average risk of breast cancer, because the scans find too many possible abnormalities and lead to repeat scans and biopsies for things that turn out to be harmless. Even in this study of high-risk women, about 10 percent of the suspicious M.R.I. findings turned out to be false positives.

CT scans may prevent lung cancer deaths

A huge government study has found that annual CT scans of current and former heavy smokers reduced their risk of death from lung cancer by 20 percent.

Equally interesting, the scans seem to reduce the risks of death from other causes as well, suggesting that the scans could be catching other illnesses. “What we also have found is that low-dose CT scan gives information on cardiovascular disease, emphysema” and other pulmonary diseases, said Dr. Claudia Henschke, a clinical professor of radiology at Mount Sinai Medical Center .

Patients wishing to get a CT lung screen will most likely have to pay the roughly $300 charge themselves, since few insurers pay for such scans unless an illness is suspected. The federal Medicare program will soon reconsider paying for such screens, a Medicare official said. 

Another caution: One-quarter of those given CT scans were found to have anomalies, nearly all of which were benign. These false signals generally led to more worry, more CT scans and sometimes to lung biopsies and thoracic surgery.

The medical community is still debating whether such scans should become routine. They don't yet know which patients would be best suited for the test. Nevertheless, if you're worried, it's a good thing to discuss with your doctor.

More evidence for mammograms

Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s. But their results were greeted with skepticism by some experts who say they may have overestimated the benefit. 

Last year the United States Preventive Services Task Force, an independent group that issues guidelines on cancer screening, questioning the benefit of screening women younger than 50. 

The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. 

The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening. 

Other experts were not convinced. 

One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties. 

It is an important distinction, Dr. Gotzsche said, because screening finds many cancers that do not need to be treated or found early. With more harmless cancers being found in the screened group, it will look like the chance of surviving breast cancer is greater in that group. “The analysis is flawed,” he said.

The new study is here. This sounds like the controversy surrounding PSA screening for prostate cancer: screening finds a lot more cancers, but they may not all be lethal. You have to read up and talk to your doctor about your particular case.

An apple a day

I eat one everyday, because I like apples and I have the vague notion that they're good for me. "An apple a day keeps ... " and all that. Well, there is some truth to it.

Not only can apples keep the doctor away by helping your immune system with healthy food but studies at the University of Ulster have found that apple phenols protect the DNA in colon cancer cells: "Our results indicate that a crude extract of apple phenolics can protect against DNA damage." Researchers at Cornell University have found that up to six apples a day can prevent breast cancer in primates and believe this can be extrapolated to humans. "Consumption of apples may be an effective strategy for cancer protection," say the researchers.

A quick search found evidence of this: scientists are reporting isolation of chemical compounds from apple peel that may be involved in the apple's beneficial health effects.

And this. And this.

A common diabetes drug may prevent cancer

There's growing evidence that metformin, a drug commonly prescribed for diabetes, may also help prevent some cancers. Researchers reported this week that it hold promise as a way to keep smokers from developing lung cancer.

Metformin has been shown to switch on an enzyme that blocks mTOR -- a protein that helps tobacco-induced lung tumors grow.

They said metformin prevented lung tumor growth in mice exposed to a cancer-causing agent found in tobacco smoke, and because it is already widely used in people, it may be worth further study.

"Although smoking cessation is the most important step for current smokers, over half of lung cancer cases are diagnosed in former smokers, raising the importance of identifying those at highest risk and identifying effective preventive treatments," said Dr. Philip Dennis of the National Cancer Institute, part of the National Institutes of Health. The findings were so strong the team now wants to test it in smokers to see if it can keep then from developing tumors.

Other studies have shown that metformin can cut diabetics' risk of pancreatic and breast cancers, and it has also been investigated for a role in preventing prostate cancer.

The problem with all these studies is that metformin is now a generic drug, so there is no incentive for pharmaceutical companies to launch an expensive clinical trial to demonstrate the drug's utility when they would not be the exclusive beneficiary of their findings.


"Among the various treatment options for Type 2 diabetes, if all other things are equal, early evidence that metformin might have benefit on the oncology side may play a role in decision making," said Dr. Michael Pollak, a medical oncologist at McGill University in Montreal, who surveyed recent metformin research in an article in the journal Cancer Prevention Research.

Another breakthrough in cancer research

A multidisciplinary research group at UCLA has now teamed up to not only visualize a virus but to use the results to adapt the virus so that it can deliver medication instead of disease.

The work provides critical structural information for researchers around the world attempting to modify the adenovirus for use in vaccine and gene-therapy treatments for cancer.

"If our work is successful, this therapy could be used to treat most forms of cancer, but our initial efforts have focused on prostate and breast cancers because those are the two most common forms of cancer in men and women, respectively," said Lily Wu, a UCLA professor of molecular and medical pharmacology.

A breakthrough in cancer treatment

Advances in genetic technologies have allowed scientists to study the genetic mutations that underlie cancer in much greater detail. The result has been a new approach to drug design. Unlike chemotherapy, which can affect both healthy and cancerous cells and often triggers serious side effects, genetically targeted drugs act selectively on cancer cells that carry the mutation.

Now comes news of an experimental drug designed to block the effects of a genetic mutation often found in patients with malignant melanoma, a deadly cancer with few existing treatments, Technology Review reports.

The drug significantly shrank tumors in about 80 percent of those who carried the mutation. The findings signal a major success for so-called targeted cancer therapies, which are designed to block the effects of genetic mutations that drive the growth of cancer cells.

"This study is a major breakthrough in cancer treatment, and for metastatic melanoma," says Matthew Meyerson, an oncologist and researcher at the Dana Farber Cancer Institute in Boston. "It's a spectacular example of how genome-targeted therapies are beginning to help cancer patients."

In this study, 37 of 48 patients with the mutation responded to the new experimental drug, with their tumors shrinking by more than 30 percent. Tumors completely disappeared in three of those patients. About 30 percent of patients who took the drug the longest developed a specific type of squamous cell carcinoma, a tumor that usually doesn't spread and typically resolves on its own. 

Image: A PET scan of one melanoma patient shows a significant decrease in the size and number of tumors (shown in black) 15 days after treatment with an experimental drug.