THURSDAY, March 6 (HealthDay News) -- New research shows that women who experienced a recurrence of their breast cancer had almost twice as much estrogen in their blood as women who remained cancer-free after treatment.

This indicates that circulating estrogen levels contribute to a recurrence as much as the initial malignancy does.

That information is not entirely new, said Dr. Jennifer Wu, an obstetrician/gynecologist at Lenox Hill Hospital in New York City. "That's the reason we use drugs that help to lower estrogen levels. Estrogen causes increased cell division; we think it can perhaps start breast cancer," she said. "But this is a good study in that it has a lot of patients and proves that they have a demonstrable increase in estrogen levels over patients who don't have a recurrence."

Where there's a problem, there's also often a solution.

"Anti-estrogen drugs can only have so much impact," said study author Cheryl Rock, a professor of family and preventive medicine at the University of California, San Diego, School of Medicine. "There are two things apart from these drugs that can help to lower estrogen, or we believe it can, because it can in the general population. One is moderate to vigorous exercise, and the other is healthy weight management, achieving an ideal weight."

The hormone estrogen is produced not only by the ovaries, but also by fat tissue.

Previous research has shown that estrogen contributes to the risk of primary breast cancer in postmenopausal women, but there has been less evidence of the role of estrogen in cancer recurrence.

"The relationship between circulating estrogen and risk for primary breast cancer is very well-established, but there were surprisingly few studies in which estrogen levels have been measured in breast cancer survivors," Rock explained.

This study, published in the March issue of Cancer Epidemiology, Biomarkers & Prevention, followed 153 pairs of women who had had breast cancer (one in each pair experienced a recurrence, while one did not) for more than seven years.

Two-thirds of the participants were using tamoxifen, a drug which interferes with estrogen's activity in the body.

In the end, women with more circulating estrogen were more likely to have a recurrence.

There may be other factors at play also, Rock said. For instance, sex hormone-binding globulin basically makes estrogen available to get into tissue. "If estrogen is bound to that protein, it's not going to float right over to the cell," Rock said. "When people are overweight, they have higher blood levels of insulin, which suppresses synthesis of that protein, so exercise not only is related to actually helping weight management but, because it lowers insulin, it might make the hormonal situation look better."

And don't rule out existing anti-estrogen drugs, experts added.

"This study justifies the use of drugs that help decrease estrogen levels like tamoxifen and aromatase inhibitors," Wu said. "[In the future], we may want to titrate different levels of anti-estrogen medications. Right now, we have a standard dosage for everyone, whereas women who are heavier or other women who may have higher estrogen levels for one reason or another may need larger doses."

More information

Visit the National Cancer Institute for more on breast cancer.

WEDNESDAY, March 5 (HealthDay News) -- Although it's a much more targeted treatment than standard chemotherapy, the effective and much-touted leukemia drug, Gleevec, isn't without side effects.

In women still in their reproductive years, imatinib (Gleevec) might damage the chances of having a baby in the future, according to a case report published as a letter in the March 6 issue of the New England Journal of Medicine.

"Although the odds are not known, it is possible that imatinib and drugs with a similar mode of action may impair fertility," said one of the letter's authors, Dr. Constantinos Christopoulos, deputy director of the 1st department of internal medicine at Amalia Fleming General Hospital in Athens, Greece. "It is not known whether imatinib-induced infertility is reversible."

However, Christopoulos was also quick to point out that this was only a single case report of premature ovarian failure, and it can be difficult to establish the exact cause of the condition.

"Imatinib is a very effective drug that has revolutionized the treatment of chronic myeloid leukemia (CML), but knowledge of the effects of its long-term administration is still limited, and close medical surveillance of patients receiving the drug is mandatory," he said.

The patient Christopoulos and his colleagues reported on was a 28-year-old female who had Philadelphia chromosome-positive CML. Each year in the United States, just under 5,000 people are diagnosed with this type of cancer, according to the Leukemia and Lymphoma Society.

She was initially given 400 milligrams of Gleevec daily. About one year into her treatment, the dose of Gleevec was increased to 600 milligrams per day, because she still had some cancer cells. She didn't have any severe side effects due to the treatment, though she experienced some skin discoloration and muscle cramping. During the first two years, she also reported having regular menstrual cycles.

About two years after she first started taking Gleevec, and about six months after the dose was increased, the woman reported that she was having irregular menstrual cycles and then her periods ceased altogether.

Doctors confirmed premature ovarian failure. While it's not possible to definitively prove that Gleevec caused premature menopause, Christopoulos said that based on the timing, the lack of other causes, and the drugs' mode of action, it's the most likely culprit.

Gleevec works by targeting tyrosine kinases, which are proteins that are very active in cancer cells. However, these proteins are also expressed by the ovaries.

"There are about 60 tyrosine kinases. Can Gleevec be so specific that it only interacts with one of the 60? This drug is pretty good at targeting and hitting the bull's-eye, but it's not perfect," said Dr. Bart Kamen, chief medical officer of the Leukemia & Lymphoma Society.

"Is it worth that risk? You better believe it," Kamen said. "The side effects of Gleevec compared to what else we do in cancer treatment is mild. It has a wonderful risk-to-benefit ratio."

"The advantages of this drug clearly outweigh the disadvantages," said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La.

Brooks also pointed out that most women with CML are long past their reproductive years. According to the American Cancer Society, the average age of CML diagnosis is about 67.

While most women are already counseled about the risks to their fertility before undergoing any cancer treatment, Christopoulos said that women of reproductive age receiving Gleevec should know that they shouldn't become pregnant while taking the drug, and they may want to freeze some of their eggs before treatment.

More information

The American Cancer Society has more on Gleevec  .

TUESDAY, March 4 (HealthDay News) -- While the majority of colon cancers were thought to develop from polyps, a new study challenges that assumption and points out that so-called non-polypoid (flat or depressed) lesions in the colon are also likely to turn into cancer.

A study in the March 5 issue of the Journal of the American Medical Association reports that such lesions were present in almost 10 percent of people screened for the study, and that these lesions were 10 times more likely to be cancerous than polyps were.

"Colorectal cancer is common, it is preventable, and it can be prevented even better," said the study's lead author, Dr. Roy Soetikno, chief of gastroenterology at the Veterans Affairs Palo Alto Health Care System in California. "Not all colon cancers are created equal, and doctors will now start looking for those that aren't so obvious."

Soetikno said it's like when you cross the street: You look left, and you look right before you cross, but "you never look carefully for the pothole on the street. This study is saying that doctors need to look at everything, including the potholes, to do a much better job."

The good news is that with current colonoscopy technology, doctors can find and remove these lesions. The bad news is that virtual colonoscopy (CT colonography) is not yet sensitive enough to pick up these dangerous lesions.

Previously, experts believed that these non-polypoid lesions were mainly found in people of Japanese descent, and U.S. doctors weren't specially trained to look for them. Soetikno and his colleagues underwent special training with specialists from Japanese endoscopy centers to learn to better detect these potentially pre-cancerous lesions.

Using their new knowledge, the U.S. researchers searched for non-polypoid lesions among 1,819 veterans who were already scheduled to undergo standard colonoscopy. The average age of the study participants was 64, and 95 percent were male. And, most -- 79 percent -- were white.

The researchers found that 764 people (42 percent) had at least one unusual colorectal growth. One hundred and seventy (9.35 percent) had non-polypoid colorectal lesions. Eighty-one of these people had both polyps and non-polypoid lesions.

Soetikno said that in a general screening, the chance of finding a polyp is about 30 percent, and that doctors are about five times more likely to find polyps than non-polypoid lesions. But, non-polypoid lesions are far more likely to be cancerous than polyps are. The new study found the odds were 9.78 times higher that a non-polypoid lesion would be cancerous than a polyp.

Generally, non-polypoid lesions can be removed at the time of a colonoscopy. If the center where you have your colonscopy done doesn't have the expertise yet, you may have to undergo a second procedure to have the lesion removed. Also, Soetikno said that if the lesion is completely flat, you'll probably need to go to a more experienced center to have it removed.

Dr. David Lieberman is chief of the division of gastroenterology at Oregon Health and Science University and the Portland VA Medical Center, and author of an accompanying editorial in the journal. He said, "I think this study will be very enlightening for the [gastroenterology] community. It points out that the non-polypoid lesions are found in the U.S., and that they can be somewhat ominous because they carry a reasonably high risk of cancer."

Both Soetikno and Lieberman stressed that this study's findings don't mean that a colonoscopy isn't useful. It definitely is, at both screening for and preventing colorectal cancer, the second leading cause of cancer death in the United States.

"Colonoscopy is a very good tool. It's not perfect, but it's a good tool," Lieberman said. "This study emphasizes the need for a high-quality examination with a fully-trained endoscopic technician," he added.

More information

To learn more about colonoscopy, visit the American Gastroenterological Association  .

FRIDAY, Feb. 29 (HealthDay News) -- There may be a link between rising rates of carbohydrate intake and obesity and the increasing number of esophageal cancer cases in the United States, a new study says.

Researchers noted that cases of esophageal cancer increased from 300,000 in 1973 to 2.1 million in 2001, which closely mirrors increases in carbohydrate intake and obesity over the same time.

Obesity is a major risk factor for many types of cancer, and a diet high in calories from refined carbohydrates is a common contributor to obesity, the researchers noted. They also said no other studied nutrients were found to correlate with esophageal cancer rates.

"If we can reverse the trends in refined carbohydrate intake and obesity in the U.S., we may be able to reduce the incidence of esophageal cancer," study senior author Dr. Li Li, an assistant professor in the department of family medicine and the Case Comprehensive Cancer Center at Case Western Reserve University/University Hospitals Health System, said in a prepared statement.

The study was published in a recent issue of The American Journal of Gastroenterology.

The causes of esophageal cancer are largely unknown, and despite recent advances, patients with this type of cancer have a poor prognosis. The five-year survival rate is less than 20 percent.

More information

The American Cancer Society has more about esophageal cancer  .