WEBMD: Surgery May Unleash Breast Cancer Growth

http://www.foxnews.com/story/0,2933,169301,00.html


Surgery May Unleash Breast Cancer Growth

Tuesday, September 13, 2005

By Daniel J. DeNoon



Can removing a breast cancer cause rapid growth of tumors elsewhere in
the body?

Yes, according to indirect evidence from a new analysis of clinical
trial data. The controversial theory comes from Michael Retsky, PhD,
of Children’s Hospital/Harvard Medical School in Boston, and
colleagues.

"We say this is indirect evidence; we think this is a key to
understanding the biology of breast cancer," Retsky tells WebMD. "We
certainly do not suggest any changes in clinical practice based on
this. We hope this will entice clinical and experimental people to
test these hypotheses."

However, the theory is extremely controversial. A spokesman for the
American Cancer Society says the findings are based on a misreading of
existing data.


Big Tumors Fighting Little Tumors

Retsky and colleagues looked at long-term data on breast cancer
patients treated in Italy. They saw two peaks in breast cancer relapse
among premenopausal women whose cancer had spread to their lymph
nodes. One relapse peak came very early -- just 18 months after cancer
diagnosis. The other started nearly five years after diagnosis.

This led them to a hypothesis. Cancers that relapse five or more years
after cancer surgery, they suggest, come from single cancer cells in
the body that grow slowly over time. Early relapses, they suggest,
come from tiny, dormant cancers about 1 millimeter in size.

What makes these tiny cancers grow?

Animal studies show that big tumors give off chemical signals that
keep smaller cancers from growing. When these big tumors are removed,
the smaller cancers quickly grow blood vessels and become deadly.

The same thing may happen in some women after breast cancer surgery,
Retsky says. And it's seen only in younger women, he suggests, because
reproductive hormones boost the cancer-enhancing effect.

Read Web MD's "Learn How to do a Breast Self-Exam."


Breast Cancer Screening Paradox

For more evidence, Retsky's team looked at what some call the breast
cancer screening paradox. It comes from observations in clinical
trials comparing regular mammogram screening with no screening. In the
first few years, women in their 40s who have mammograms -- but not
those in their 50s -- have a higher risk of death than those not
offered screening.

Over time, breast cancer screening shows a benefit for all women. But
why the early increase in risk? Could it be due to women with
node-positive breast cancer who suffer early relapses after surgery?
Retsky suggests that it is.

Looking at data from studies of breast cancer screening, Retsky and
colleagues saw about one excess death per 10,000 screened young women
in the third year of screening. That, he says, is just what one would
expect if his hypothesis is correct.

"It looked like surgery accelerated the disease by two years on
average, which is the usual dormancy of this [blood vessel-free] tumor
state," Retsky says. "All the data show this."

Even so, Retsky stresses, younger women with breast cancer still need
surgery. He strongly advises women to continue to seek breast cancer
screening -- and, when a cancer is found, to have it removed.

"We don't have all the answers," Retsky says. "We think our work has
pointed out that the mammography paradox is real. We are confident we
understand what causes it. We have identified a problem -- a mechanism
that is testable. We have not found a solution. But identifying the
problem is a major step in the right direction."

Retsky and colleagues report their findings in the current issue of
the International Journal of Surgery.

American Cancer Society Says It Isn't So

Don't believe any of this, says Robert A. Smith, PhD, director of
cancer screening for the American Cancer Society.

"The data don't add up to Dr. Retsky's conclusion," Smith tells WebMD.
"The idea that surgical interruption of the tumor bed will cause death
this rapidly just does not make sense."

Smith, a strong proponent of early and regular breast cancer
screening, says the apparent screening paradox does not exist.

"You do not expect mammograms to be instantly beneficial," he says.
"When you first invite women to screening, you get some with tumors
that are already advanced. And not all of the women will respond to
the invitation to screening. They may die next year or the year after,
and because they were invited, they will be counted as a death in the
screening group. So you really can't look at this pattern and make any
sense out of it."

Young women, Smith says, tend to get more aggressive breast cancers.

"So the idea these women became worse after surgery may stem from the
fact that their prognosis may have been poorer to begin with," he
says.

And Smith notes that Retsky's data are based on observations from long
ago, when breast cancer screening was in its infancy.

"The interesting thing is how beneficial modern, high-quality
mammography can be," he says. "Mammograms are quite a bit better today
than in the clinical trials that proved they saved lives."


Read Web MD's "What Women Want to Know Before First Mammogram."




By Daniel J. DeNoon, reviewed by Michael W. Smith, MD

SOURCES: Retsky, M.W. International Journal of Surgery, published
online, Sept. 12, 2005. Michael Retsky, PhD, Children’s
Hospital/Harvard Medical School, Boston. Robert A. Smith, PhD,
director of cancer screening, American Cancer Society.

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