WEDNESDAY, Nov. 14 (HealthDay News) -- A highly targeted biologic drug called cetuximab (Erbitux) is the first to extend the survival of patients with advanced colon cancer who have otherwise proved resistant to conventional chemotherapy, Canadian researchers confirmed.

But the drug, which costs $12,000 a month in the United States, appears to be effective in only about one-third of colon tumors, based on their specific gene profile, experts added.

"That's a significant number, but it still leaves a large proportion [of patients] who aren't benefiting," noted lead researcher Dr. Derek Jonker, assistant professor of medicine at the University of Ottawa and a medical oncologist at the Ottawa Hospital.

Nevertheless, the success of any new drug is welcome, he added.

"Until now, no anticancer therapy had demonstrated an improvement in survival in patients for whom chemotherapy was no longer effective, and for whom supportive care was the only available treatment," Jonker said. "So, cetuximab provides new hope for these patients."

The findings were reported in the Nov. 15 issue of the New England Journal of Medicine. The study was funded by the National Cancer Institute of Canada, as well as ImClone Systems and Bristol-Myers Squibb, the two companies that developed the drug.

Colorectal cancer is the third most common kind of cancer and the third leading cause of cancer death in the United States. As Jonker explained, most patients are treated with either surgery or conventional chemotherapy, which typically targets cellular DNA.

Unfortunately, almost all patients with advanced or metastasized colon cancer will develop resistance to standard chemotherapy drugs, he said.

"However, now we have a new class of drugs known as the biologically targeted therapies, such as cetuximab, and these drugs are targeted to different aspects of the tumor biology," Jonker explained. "Many of them are targeted at receptors or signals that trigger a cancer cell to grow."

In the case of cetuximab, the drug's target is the epidermal growth factor receptor (EGFR), which is found in especially high concentrations on colon cancer cells. Because biologic drugs are finely targeted to affect cancer cells and not healthy cells, they typically have fewer side effects than standard chemotherapy.

In 2004, the U.S. Food and Drug Administration granted cetuximab conditional approval for use in patients with late-stage, chemotherapy-resistant colon cancer. At the time, the agency stated that full approval hinged on the outcome of the Canadian trial.

In October, and based on the new findings, the agency followed through and gave the drug its full approval for this new indication.

In the trial, Jonker's team administered individualized doses of cetuximab to 287 colon cancer patients treated between late 2003 and August 2005. All of the patients had proven resistant to standard chemotherapy. Another 285 patients received supportive/palliative care only -- the usual option for patients in this situation.

Compared to those who didn't receive the drug, overall survival for patients receiving cetuximab improved by 23 percent, while survival without any sign of disease progression rose by 32 percent, the research team reported.

The incidence of side effects -- including skin rash -- was 78.5 percent in the cetuximab group versus about 59 percent for the control group.

One key point, however, was that increases in survival were found only among the 31.4 percent of patients who actually responded to cetuximab, meaning that their cancer stopped growing.

That's probably due to the fact that cetuximab (as well as a related drug, panitumumab) only works against a specific subtype of colon cancer cell -- those carrying an unmutated version of a particular gene called KRAS.

"Mutated KRAS almost guarantees no benefit" from cetuximab, said one expert, Dr. Axel Grothey, a professor of oncology and chairman of the colorectal cancer group at the Mayo Clinic, in Rochester, Minn.

For that reason, he said, pre-treatment gene testing may prove crucial to decisions as to whether a particular patient receives cetuximab or not.

Because it is so expensive -- the costliest drug used today against colon cancer -- and because it can induce side effects, "I would like cetuximab to be used in a more individualized way," Grothey said.

He said that most cancer centers, including the Mayo Clinic, do not yet have technologies in place to test tumors for KRAS, but many are looking into it.

Jonker agreed that, ideally, KRAS testing and the use of cetuximab would go hand-in-hand. That way, he said, "We wouldn't have to put [patients] through treatment, and we wouldn't have to suffer the cost of treatment for people who may not even respond to the drug."

Studies are already under way to see if adding cetuximab to other therapies will boost survival even further, Jonker said. "The future of cetuximab is likely to be in combination with chemotherapy or other biologically targeted therapies, where the benefits of cetuximab might be further enhanced," he said.

The drug might also work better if given earlier in the disease process, before patients have developed resistance to chemotherapy.

In any case, the Canadian trial does give colon cancer patients some new reason for hope, Grothey said. "We need this drug," he said, "and we probably need it even earlier."

More information

There's more on colon cancer at the American Cancer Society  .

TUESDAY, Nov. 13 (HealthDay News) -- In mice, a low-carbohydrate diet slowed prostate tumor growth, possibly because fewer carbohydrates leads to a drop in insulin production, U.S. researchers say.

"This study showed that cutting carbohydrates may slow tumor growth, at least in mice. If this is ultimately confirmed in human clinical trials, it has huge implications for prostate cancer therapy through something that all of us can controls, our diets," lead researcher Dr. Stephen Freedland, a urologist at Duke University Medical Center, said in a prepared statement.

Previous studies linked insulin and a related substance called insulin-like growth factor (IGF) with the growth of prostate tumors in mice. Freedland and his colleagues theorized that reducing levels of these substances might slow prostate tumor growth.

They compared tumor growth in mice eating either a low-carbohydrate diet; a low-fat but high-carbohydrate diet; or a Western diet high in fat and carbohydrates.

Mice fed the low-carbohydrate diet had the smallest tumor size and longest survival, the team found.

""Low-fat mice had shorter survival and large tumors , while mice on the Western diet had the worst survival and biggest tumors. In addition, though both the low-carb and low-fat mice had lower levels of insulin, only the low-carb mice had lower levels of the form of IGF capable of stimulating tumor growth," Freedland said.

The study is published in the Nov. 13 online edition of the journal Prostate.

Freedland is currently organizing a clinical trial to examine the impact of a low-carbohydrate diet on prostate tumor growth in men.

More information

The American Cancer Society has more about prostate cancer  .

FRIDAY, Nov. 9 (HealthDay News) -- Women taking oral contraceptives are at a slightly increased risk for developing cervical cancer, but a decade after stopping the pill even this very small risk disappears, a new British study suggests.

However, that finding doesn't change the recommendation for women to continue getting screened for cervical cancer, experts say.

"This is good news," said lead researcher Dr. Jane Green, an epidemiologist in the Cancer Epidemiology Unit at the University of Oxford. "We have been able to estimate the lifetime risk of cervical cancer for women on the pill and find it's really quite small," she said.

"The small increase in cervical cancer we see in women who are taking oral contraceptives starts to fall once pill use stops and has really gone away by 10 years after stopping use," Green said.

"The pill has many other benefits, including reducing the risk of other cancers, such as ovarian cancer and womb cancer," Green added.

The report is published in the Nov.10 issue of The Lancet.

In the study, Green and her colleagues from the International Collaboration of Epidemiological Studies of Cervical Cancer collected data on almost 16,600 women with cervical cancer and more than 35,500 women without cervical cancer. These women had participated in a total of 24 studies.

Green's team confirmed that the risk of cervical cancer among women who use oral contraceptives does increase over time. But this increase in risk is very small -- women who take contraceptives for five years or more have only about twice the risk compared with women who never took the pill.

In absolute terms, that means that a 20-year-old woman living in a developed country who uses an oral contraceptive for 10 years increases her odds of developing cervical cancer by age 50 from 3.8 cases per 1,000 women (without Pill use) to 4.5 per 1,000 women after using oral contraception. In less developed countries, where access to cervical cancer screening is more limited, that risk rises from 7.3 to 8.3 cases per 1,000 women, the researchers estimated.

Similar risk was seen for invasive and localized cancer and in women who have the human papillomavirus (HPV), which causes about 70 percent of all cervical cancers, Green noted.

Although the risk for cervical cancer associated with the Pill is small, Green advised women to still be screened for the disease. "Screening for cervical cancer is effective," she said. "The advice is to go for regular screenings."

Eventually, Green hopes that the vaccination against the human papillomavirus will go a long way to preventing many cases of cervical cancer.

One expert agreed that the findings showed the risk for cervical cancer from oral contraceptives was very small.

"This is reassuring news for women," said Dr. Peter Sasieni, from the Wolfson Institute of Preventive Medicine at Queen Mary University of London and author of an accompanying journal comment. "There is really a minimal risk from oral contraceptives, and that risk disappears fairly soon when you stop taking them," he said.

"When making a decision about what from of contraception to use, women shouldn't worry about cervical cancer," Sasieni concluded. "It's not an issue," he said.

However, he believes that taking oral contraceptives is another good reason to get screened regularly for the disease. "By going for regular screenings, a women can reduce her risk by 80 percent," Sasieni said.

Another expert agreed that women shouldn't worry about the Pill and cervical cancer risk.

"I don't think women are basing their decision of which form of contraception to use on the risk for cervical cancer," said Debbie Saslow, director of breast and gynecologic cancer at the American Cancer Society. "People who want to use oral contraceptives should not be alarmed over the slight increase in cervical cancer risk," she said.

However, women -- whether they take oral contraceptives or not -- should be getting regular cervical cancer screening, Saslow said.

More information

For more on cervical cancer, visit the American Cancer Society  .

THURSDAY, Oct. 25 (HealthDay News) -- What's good for your diet may also guard against skin cancer.

Scientists have discovered that an extract of broccoli sprouts protects the skin against the sun's harmful ultraviolet rays.

That's not the same as calling the extract a sunscreen, however.

"This is not a sunscreen, because it does not absorb the ultraviolet rays of the sun," explained Dr. Paul Talalay, a professor of pharmacology and molecular sciences at Johns Hopkins University School of Medicine in Baltimore. "We don't want people covering their bodies with broccoli and going to the beach. They will have no protection whatsoever."

Exposure to ultraviolet or UV rays is the primary cause of most skin cancers. The incidence of skin cancer in the United States is on the rise as men and women who had too many sunburns earlier in life get older and develop the disease.

Talalay started working on skin cancer prevention about 25 years ago. "Cells contain an elaborate network of protective genes that code for proteins that protect against four principal injurious processes to which all of our cells are exposed and which are the causes of cancer, degenerative disease and aging," he explained.

Those four processes are: oxidation; DNA damage; inflammation and radiation, namely ultraviolet radiation.

The cells' protective system normally operates at about one-third capacity, so the real question is what would ramp up that system.

"Our strategy has been to find things that will boost the system," Talalay explained. Broccoli, in particular, has previously reported to have some anti-cancer effects.

"We looked in vegetables, and it turned out they had a rather large quantities of a compound that induced this system, particularly in cruciferous vegetables such as broccoli, cabbage, Brussels sprouts, et cetera," Talalay said.

The compound, called sulforaphane, is found in broccoli sprout extracts and was first identified by Talalay and his colleagues more than 15 years ago. Sulforaphane has been shown to inhibit tumor development in animals.

For this study, Talalay and his colleagues tested the compound in both mice and humans.

The human experiments involved six healthy volunteers. Each participant was exposed to UV radiation on two circles on their back that were either treated or not treated with different doses of broccoli extract.

The highest doses of the extract reduced UV-induced redness and inflammation (erythema) by an average of 37 percent, although protection varied from 8 percent to 78 percent.

"If you apply an extract of broccoli sprouts that contains high levels of sulforaphane to regions of human skin, you can protect them very substantially," Talalay said. "We believe, to the best of our knowledge, that this is the first demonstration of protection against a known human carcinogen in humans."

One expert was excited by the discovery.

"There is some interesting data here," said Dr. Vijay Trisal, an assistant professor of surgical oncology at the City of Hope Cancer Center, in Duarte, Calif. "Sulforaphane compounds have been known to boost the immune system locally. This has some basic science behind it."

"The same thing happens with interferon, which we use for melanoma. It boosts the natural killer cells," Trisal explained.

The findings do need to be replicated, Talalay noted.

"It's going to take a little while to work out how this should be applied," Talalay said. "We would need to have a preparation rich in sulforaphane that would be easily absorbed through the skin, and this is not yet a reality. But, since we're dealing with a food, we're not dealing with anything likely to have a toxicity."

The study is published in this week's issue of the Proceedings of the National Academy of Sciences. Talalay and a co-author are unpaid consultants to Brassica Protection Products LLC (BPP), which licenses the technology to produce broccoli sprouts. These two authors, along with Johns Hopkins University, are equity owners in BPP. Antony Talalay, son of Paul Talalay, is chief executive officer of BPP.

More information

Visit the National Cancer Institute for more on skin cancer.