Large Breast Cancer Tumors Rise in '90s

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Large Breast Cancer Tumors Rise in '90s

Study Finds Unexpected Increase of Large Tumors in Women With Breast Cancer

During '90s

 

The Associated Press

 

 

Nov. 18 — A new analysis shows a small but surprising upswing during the 1990s

in the proportion of women with newly diagnosed breast cancer who have unusually

large tumors, which are more likely to prove fatal.

Experts are uncertain why this happened, but they speculate that both obesity

and hormone replacement therapy may have fueled the growth of larger cancers,

even during a time when the discovery of small tumors rose dramatically as a

result of widespread mammography.

 

 

 

The analysis, prepared by the American Cancer Society, found that the incidence

of large tumors increased by just over 2 percent a year between 1992 and 2000,

but only in white women.

 

" The great majority of tumors in white women are small and at a localized

stage, " said Dr. Michael Thun, senior author of the report. " But we were

surprised to see there has been an increase in tumors of five centimeters or

more. "

 

The analysis is based on the National Cancer Institute's Surveillance,

Epidemiology and End Results program, a database of cancer incidence and

survival data that covers about 14 percent of the U.S. population. It was

published in the latest issue of the cancer society's journal CA.

 

In 2000, there were 6.3 cases of breast cancer larger than five centimeters for

every 100,000 white women in the United States, compared with 5.6 cases in 1992.

Still, smaller tumors are much more common. In 2000, there were 90 tumors size

two centimeters or smaller per 100,000 and 34 that were between two and five

centimeters.

 

Large tumors are about twice as common in black women. The cancer society

attributes this to less access to high-quality screening, particularly for poor

women. In 2000, there were 12 cases of large tumors for every 100,000 black

women, a figure that changed little throughout the 1990s.

 

Overall, breast cancer survival is improving. Since about 1990, the breast

cancer death rate has been falling by 2 1/2 percent annually for whites and 1

percent for blacks. Experts say they think better treatment, including

widespread use of the drug tamoxifen, as well as mammogram screening are

responsible for the improvement.

 

However, cancer can take many years to kill after it is discovered, and the

increase in newly diagnosed large tumors is worrisome, because they are more

likely to have spread and are harder to cure.

 

" I'm not sure what to make of it. It's a surprise, " says Dr. Phyllis Wingo, an

epidemiologist at the Centers for Disease control and Prevention. She said other

studies that follow women's health for long periods of time could help confirm

the finding as well as help doctors figure out its cause.

 

The hormone estrogen can fuel the growth of breast cancers. Thun said the most

likely explanation for the rising tumor size is increases in women's estrogen

levels resulting from obesity and hormone replacement therapy, or HRT, after

menopause.

 

Fat tissue itself makes estrogen. About two-thirds of U.S. women over 50 are

overweight. The cancer society estimates weight contributes to between one-third

and one-half of all breast cancer deaths among older women.

 

The use of hormone replacement pills, which include estrogen, has fallen since

last year, when a study showed that the widely used treatment after menopause

increases the risk of breast cancer, heart attacks and stroke. That study found

breast tumors were slightly larger, on average, among the hormone users.

 

" Is it biologically tenable that HRT and obesity could have contributed? The

answer is clearly yes, " said Dr. Larry Norton, deputy physician-in-chief for

breast cancer programs at Memorial Sloan-Kettering Cancer Center in New York

City.

 

Dr. Daniel Kopans, director of breast imaging at Massachusetts General Hospital,

noted that breast cancer deaths began to decline five to seven years after

mammograms became widespread.

 

" I am at a loss to understand why there was the blip in very large cancers, " he

said. " I can speculate that women who do not want to be screened also neglect to

bring their cancers to their doctor's attention and delay seeking care even

longer than before screening was available. "

 

Dr. Cheryl Perkins, senior clinical adviser at the Susan G. Komen Breast Cancer

Foundation, said the push during the 1990s to increase mammography, especially

among poorer women, may have led to the discovery of large tumors in those who

had never been screened before.

 

" If you bring new women into the screening arena, you may find larger tumors

initially, " she said. " If you continue to screen, you will find smaller ones. "

 

 

 

EDITOR'S NOTE: Medical Editor Daniel Q. Haney is a special correspondent for The

Associated Press.

 

 

 

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Copyright 2003 The Associated Press. All rights reserved. This material may not

be published, broadcast, rewritten, or redistributed.

 

 

 

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