THURSDAY, Nov. 5 (HealthDay News) -- A new study appears to add to growing evidence that green tea might help protect against cancer.

U.S. researchers gave 41 volunteers with pre-malignant mouth lesions green tea extract for three months at doses of 500 milligrams per meter squared (mg/m2), 750 mg/m2 or 1,000 mg/m2. The extract was taken by mouth. Other participants took a placebo.

The study found that about 59 percent of people taking the highest dose of the green tea extract showed a clinical response, compared with 18 percent of those who took a placebo. The researchers also noted a trend toward improvement in certain biomarkers that could predict cancer development.

During the study period of about 28 months, 15 people developed oral cancer. People who took the green tea extract and those who didn't were equally likely to develop the cancer. However, people who had mild to moderate dysplasia, or abnormal cell growth, at the start of the study took longer to develop oral cancer if they took the green tea extract.

Study author Dr. Vassiliki Papadimitrakopoulo, a professor in the department of thoracic/head and neck medical oncology at the University of Texas M.D. Anderson Cancer Center, said the findings were encouraging but did not provide definitive proof that green tea can prevent cancer.

"This is a phase 2 study with a very limited number of patients who took what would be the equivalent of drinking eight to 10 cups of green tea every single day. We cannot with certainty claim prevention benefits from a trial of this size," Papadimitrakopoulo said in a news release from the American Association for Cancer Research.

"The goal of this kind of research is to determine whether or not these supplements have long-term prevention effects," Papadimitrakopoulo noted. "More research, including studies in which individuals at high risk are exposed to these supplements for longer time periods, is still needed to answer that sort of question."

The findings were released online in advance of publication in the November print issue of the journal Cancer Prevention Research.

More information

The U.S. National Center for Complementary and Alternative Medicine has more about green tea.

WEDNESDAY, Nov. 4 (HealthDay News) -- A shorter, more intense course of whole-breast radiation works as well as the traditional six-week course, at least for some early-stage breast cancers, a new study shows.

"This concept of a shorter length of treatment is gaining acceptance," said Dr. Manjeet Chadha, associate chair of radiation oncology at Beth Israel Medical Center and associate professor of radiation oncology at Albert Einstein College of Medicine, both in New York City. Chadha led the study and is scheduled to present the results Wednesday at the American Society for Radiation Oncology annual meeting, in Chicago.

Researchers previously have tried to investigate whether they can alter the duration of radiation therapy or the volume, Chadha said. "My study focuses on the duration of it," she said.

In her three-week treatment -- called accelerated hypofractionated whole breast irradiation -- a woman gets the entire affected breast irradiated and receives a ''boost,'' or extra dose, at the site where the tumor was removed. Other approaches include giving a boost dose after the entire radiation treatment to the whole breast is completed.

Chadha's study is ongoing, but she planned to report on 122 patients with early-stage breast cancers who underwent lumpectomies followed by the accelerated treatment. They were then tracked for a median of two and a half years (half followed longer, half less). The patients' median age was 66.

No relapses were noted, and the three-year survival rate was nearly 95 percent, Chadha said.

''It sounds encouraging," she said of her results. To further evaluate the accelerated treatment, she compared the first 50 patients on the briefer approach to a matched group of 70 patients who got the more traditional six-week radiation treatment.

Side effects, such as skin irritation and redness, were similar, she found. ''There was no difference in fatigue or breast edema [swelling]," she said. The cosmetic results were satisfactory, too.

The new study adds some valuable information for doctors trying to decide for individual women which radiation treatment approach might be best, said Dr. Nayana Vora, a professor of radiation oncology and associate member of the developmental cancer therapeutics program at the City of Hope Comprehensive Cancer Center in Duarte, Calif.

''It's a short follow-up,'' she said, noting that some side effects may surface later. But, she noted that a study outside the United States that looked at the briefer treatments has followed patients for up to 12 years with results similar to Chadha's study.

''Very few studies have been documented in the U.S. with external whole beam [to the whole breast] and a concomitant boost," Vora said. ''It tell us that, yes, patients can be treated with a short course of radiation treatment. Will it become the standard of care? I don't know."

While Vora typically offers her patients the six-week treatment unless they can't commit to that time period because of transportation problem or other obstacles, she said she now may consider the shorter treatment.

In another study to be presented at the oncology meeting, researchers reported that breast cancer patients who have a mastectomy and then receive radiation to the lymph nodes behind the breast bone (the internal mammary lymph nodes) do not live longer than those who don't get those nodes treated.

The study evaluated 1,334 women with stage 1 or 2 breast cancers that had spread to the axillary lymph nodes under the arms or whose original tumor was in a central, internal location. All got radiation to the chest wall and nodes above the collar bone. But half got the internal mammary radiation and half did not.

After a decade, survival differences between the groups were small, with 60 percent of those who didn't get the extra radiation still alive, and 63 percent of those who got it surviving.

Most radiation oncologists are reluctant to radiate the internal mammary nodes, Vora explained, because of their proximity to the heart.

More information

To learn more about radiation therapy, visit the U.S. National Library of Medicine.

WEDNESDAY, Nov. 4 (HealthDay News) -- A vaccine that targets human papillomavirus (HPV) is able to stop precancerous lesions in the vulva from progressing into full-blown malignancies, Dutch researchers report.

Two other vaccines -- Gardasil and Cervarix -- have been approved for young women to prevent infection with HPV, which is also thought to spur precancerous lesions in the cervix and cause 70 percent of cervical cancers.

But the vaccine used in this study, published in the Nov. 5 issue of the New England Journal of Medicine, is not the same as the two existing vaccines.

"This provides a therapeutic effect to a lesion that's already there," explained Dr. Eugene P. Toy, an associate professor of obstetrics and gynecology in the division of gynecologic oncology at the University of Rochester Medical Center.

"This shows that it is possible to vaccinate against chronic disease, as well as treat HPV-induced premalignance," added study co-author Sjoerd H. van der Burg, of the experimental cancer immunology and therapy section at the Leiden University Medical Center in the Netherlands and ISA Pharmaceuticals, which helped fund the study and has licensed the patent for the vaccine from Leiden University Medical Center.

Eventually, clinicians hope the two HPV vaccines on the market will reduce the incidence of vulvar precancerous lesions.

Right now, though, said Dr. Kristine Zanotti, a gynecologic oncologist with University Hospitals Case Medical Center in Cleveland, "there are a lot of potential therapeutic challenges with HPV-related problems, especially vulvar dysplasia, which are multi-focal [they crop up in different places] and recurrent. [This vaccine] is a very exciting tool."

The HPV-16 virus is implicated in 75 percent of cases of these vulvar lesions. A sexually transmitted pathogen, HPV has also been linked to rare cancers of the throat, genitals and anus, as well as genital warts.

For vulvar lesions, the existing treatments are unpleasant and not altogether effective.

"What we typically do is ablative therapies that destroy the lesion. That involves a surgical procedure or topical agents that essentially slough off the lining of the affected tissue," Toy explained.

"Complete response rates [from these therapies] are disappointingly low, and we don't know if they last," added Zanotti.

For this study, 20 patients with vulvar dysplasia were vaccinated three or four times against certain cancer-related proteins associated with HPV-16.

Three months after the last vaccination, 60 percent of patients reported some kind of response along with fewer symptoms. For the same time period, five women (25 percent) saw their lesions disappear completely and four women had no more signs of HPV-16.

After a year, 79 percent of patients had experienced some kind of response while almost half had a complete response, which lasted at least 24 months, according to the report.

All of the patients showed immune responses to the vaccine.

Unlike Gardasil and Cervarix, which only affect the outside of the virus, the vaccine explored in this study was "trained to sense the proteins that are produced by the virus inside the cell. As such, they can recognize virally infected or virally transformed cells," van der Burg explained.

Also exciting is the possibility, mentioned in the paper, that the new vaccine could be combined with imiquimod cream to completely erase all signs of the infection and tainted cells.

Next, the researchers want to figure out why the vaccine did not have a complete effect in all patients and they would also like to improve the vaccine so it works in patients with actual cancer or even other, non-HPV-related cancers, van der Burg said.

"In principle, this vaccine gives an enormous stimulation of the immune response against the HPV antigens expressed in infected and transformed cells. As such, it should do the same in patients with other types of HPV-16-induced (pre-)malignancies. However, in cancer patients, other forces may work against the efficacy of this vaccine. These need to be tackled, too, in order to make the vaccine do its job," van der Burg added.

More information

The U.S. National Cancer Institute has more on human papillomavirus.

TUESDAY, Nov. 3 (HealthDay News) -- Low blood cholesterol levels reduce the risk not only of heart disease but also of cancer, two new studies show.

The findings should help ease longstanding fears that low cholesterol is associated with an increased risk of cancer, said Dr. Demetrius Albanes, a senior investigator at the U.S. National Cancer Institute, and an author of one of two reports in the November issue of Cancer Epidemiology, Biomarkers and Prevention.

"These results should help dispel any lingering thoughts that low cholesterol may help cause cancer," said Eric Jacobs, strategic director of pharmacoepidemiology at the American Cancer Society, who wrote an accompanying editorial.

Data from a study that has followed more than 29,000 Finnish men for 18 years showed both the reason for fears that low cholesterol levels raised the risk of cancer and the reason why those fears were unjustified, Albanes said.

Cholesterol levels below the generally recommended 200 milligrams per deciliter were associated with an 18 percent higher overall risk of cancer, but the increased risk applied only to cases diagnosed in the early years of the study. "The finding supports the idea that lower cholesterol levels are the results of undiagnosed cancers," Albanes explained.

And higher levels of HDL cholesterol, the "good" kind that protects coronary arteries, were associated with a 14 percent lower risk of all cancers over the entire length of the study, he said.

In addition, data on the more than 5,500 men enrolled in the Prostate Cancer Prevention Trial showed that those with cholesterol levels lower than 200 had a 59 percent lower risk of developing the most dangerous form of that cancer, said a second report in the same issue of the journal.

Low cholesterol levels were more likely to be seen in men whose prostate cancers had high Gleason scores, a measure of the disruption of the prostate gland's normal structure caused by the malignancy, the study found. Prostate cancers with the highest Gleason scores are regarded as the most difficult to treat.

Cholesterol levels had no significant effect on the overall incidence of prostate cancer in the study, said study leader Elizabeth Platz, co-director of the cancer prevention and control program at the Johns Hopkins Kimmel Cancer Center.

But the association between low cholesterol levels and a reduced incidence of aggressive disease "is a notable reduction which is not often seen for prostate cancer," she said.

It is still not known whether statins, which help prevent heart disease by lowering blood levels of "bad" LDL cholesterol, can reduce the risk of cancer, Albanes said.

"We did not collect information in detail on cholesterol-lowering efforts," Albanes said. "It may be premature to read from our findings that such efforts to actively lower cholesterol levels can achieve a cancer benefit. Our results don't speak to that point."

Nevertheless, "evidence continues to mount that the use of statins is inversely correlated with the risk of prostate cancer," Platz said.

But both agreed that further research is needed to both prove the point and identify the molecular mechanisms behind the association.

More information

A guide to cholesterol is offered by the American Heart Association  .