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'Micro' Spreading of Breast Cancer Needs Treating, Study Urges

Other research cautions against too much screening for lung cancer

MONDAY, June 1, 2009 (HealthDay News) -- Researchers are now recommending that doctors treat women with breast cancer who have tiny metastases in the so-called sentinel lymph nodes.

That's because leaving these cancers untreated appears to result in a higher rate of cancer recurrence, according to a new study.

Skipping additional treatment for the tiny metastases, known as micrometastases or micromets, could actually result in more deaths, said the study's lead author, Dr. Vivianne Tjan-Heijnen, a professor of medical oncology at Maastricht University Medical Center in the Netherlands.

She presented the findings Monday at a press briefing at the annual meeting of the American Society of Clinical Oncology in Orlando, Fla.

About 10 percent of doctors are not following up with these micromets, the study also found.

On the flip side, another study being presented at the meeting found that too many CT screening tests for lung cancer are being performed, resulting in an inordinately high number of false-positives, with no clear benefits for patients.

For the breast cancer study, Tjan-Heijnen explained that the sentinel lymph node is important in detecting the spread of cancer because it "is the first on which the breast [and thus breast cancer] drains."

"If it's negative, no further treatment is required," she said. "But to prevent false-negative results, it is important that the sentinel node is intensively examined. This has led to an increased detection of isolated tumor cells and micrometastases."

The big question was whether these cells end up causing problems down the line.

Apparently they can, the study found. Over five years, cancer appeared in additional lymph nodes at a rate 4.5 times higher in women who did not receive additional treatment than in those who had surgery or radiation.

The new study "doesn't change the standard of care for node-positive disease, even when there is microscopic disease," noted Dr. Rick Bleicher, a breast surgeon at Fox Chase Cancer Center in Philadelphia. "It reinforces the standard of care, which is axillary dissection," meaning the removal of affected nodes nearest the breast, he said.

But in cancer treatment, there may be such a thing as too much intervention as well, which the new lung cancer study suggests.

Researchers from the U.S. National Institutes of Health concluded that the use of low-dose CT as a screening tool for lung cancer results in many false-positives -- a full 33 percent after two screenings. And that, they said, makes an already unclear benefit seem simply not worth the downside, in terms of patient anxiety and expense.

"We'd seen some increasing promotion of low-dose CT scans as a screening tool, mostly individual hospitals, some direct-to-consumer advertising, some suggesting that the value of these scans can alleviate anxiety," said Dr. Jennifer M. Croswell, acting director of the NIH Office of Medical Applications of Research. "But there was no good evidence that if you get screened you actually have fewer deaths. The potential burdens of screening are underexamined."

Finding such a high false-positive rate in the pilot trial -- part of a larger lung-cancer screening trial of former and current smokers -- means that "we need continued investigation before continued promotion to the public," she continued.

Another expert agreed. "We need to wait for the [full] results of the national lung screening trial so we can figure out if there is a survival benefit and, if there is and it's powerful, we'll accept the false-positives," said Dr. Julie Gralow, an associate professor of oncology at the University of Washington who moderated a news conference to report the findings.

In the meantime, she said, efforts to curb lung cancer rates should be directed toward reducing or eliminating tobacco use.

"In my opinion," added Dr. George Simon, director of thoracic oncology at the Fox Chase Cancer Center, "lung cancer screening should not be done outside the setting of a clinical trial, and this abstract highlights one of the reasons why. When you do a CT scan of the lungs, you could find the small nodules in the lung and many of them could be benign. And the detection of benign, asymptomatic, inconsequential nodules will lead to invasive procedures to diagnose what it is."

"Lung cancer screening can cause a lot of stress, financial and psychological consequences that are unintended," he said.

A final analysis presented at the news briefing addressed challenges in the cancer research field. Specifically, cancer trials that take a long time to develop tend to recruit fewer participants, a new study found -- making it less likely that the trial will succeed in reporting meaningful results.

"The development of a clinical trial is a lengthy and laborious process, consuming, on median, 2.4 years and in excess of 370 steps internally to develop," explained the study's lead author, Steven K. Cheng, a postdoctoral fellow at the Center for Management Research in Healthcare at the Oregon Health & Science University.

Overall, 40 percent of nonpediatric therapeutic trials did not achieve their minimum projected patient accrual and, for important phase 3 trials, three of five did not meet their accrual objectives, he said.

Trials that took nine to 15 months to develop were more likely to get the participants they needed, whereas just 22 percent of those that took 27 or more months met their minimum recruitment goals.

The study did not look at whether the trials succeeded despite this limitation.

"We must pursue ways to improve efficiency," Cheng said, citing corporate models that might be adopted by the health-care community.

More information

The U.S. National Cancer Institute has more on lung cancer.

SOURCES: June 1, 2009, news conference with Julie Gralow, M.D., associate professor, oncology division, University of Washington School of Medicine, Seattle; Jennifer M. Croswell, M.D., acting director, NIH Office of Medical Applications of Research, Bethesda, Md.; Vivianne Tjan-Heijnen, M.D., Ph.D., professor of medical oncology, Maastricht University Medical Center, the Netherlands; Steven K. Cheng, Ph.D., postdoctoral fellow, Center for Management Research in Healthcare, Oregon Health & Science University, Portland, Ore.; American Society of Clinical Oncology 2009 annual meeting, Orlando, Fla.
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