vendredi 30 octobre 2015

US Breast Cancer Deaths Falling Steadily — But Black Women Increasingly At Risk

US Breast Cancer Deaths Falling Steadily — But Black Women Increasingly At Risk

The American Cancer Society has issued newly revised guidelines on mammography and breast cancer screening. Here a woman is screened in Los Angeles in 2010. (Damian Dovarganes/AP/File)

The American Cancer Society has issued newly revised guidelines on mammography and breast cancer screening. Here a woman is screened in Los Angeles in 2010. (Damian Dovarganes/AP/File)

By Richard Knox

With all the recent controversy over how often women should get mammograms, you might not realize that breast cancer is becoming an ever more-survivable disease.

But, alas, that’s not the case among black women in this country. Historically they’ve had the highest risk of dying if they get breast cancer among any ethnic group. And now, data from the American Cancer Society show that African-Americans have nearly caught up with whites over the past three years in their risk of getting breast cancer in the first place.

Given black women’s higher risk of dying from breast cancer, that’s particularly bad news.

Breast cancer accounts for one in every three malignancies among US women — it’s the most common type if you don’t count non-melanoma skin cancers, which are usually inconsequential. More than 230,000 American women will get a breast cancer diagnosis this year, and about 40,000 will die of the disease.

But over the past 26 years, the overall US breast cancer death rate has dropped by more than a third, according to recent research. That’s nearly a quarter-million living women who would have died from breast cancer at rates that prevailed among their mothers’ generation.

“Whether people realize it or not, breast cancer mortality rates have been dropping since about 1990,” says Carol DeSantis of the American Cancer Society, lead author of an update on the disease published Thursday in CA: A Cancer Journal for Clinicians.

Part of that success is due to widespread mammograms, which can find breast cancers at an early stage, although the contribution of regular mammogram screening is unclear.

“Screening has clearly contributed to lowering mortality, but we can’t say by how much,” DeSantis says.

Better treatments are clearly a big part of this success story — more effective chemotherapy, the estrogen-blocking drug tamoxifen, and drugs targeted at the protein HER2 and other growth promoters on the surface of some women’s breast cancer cells.

Put it together with our aging society — more women reaching the most breast cancer-prone years, and fewer women dying of the disease — and the result is record numbers of breast cancer survivors.

More than 3.1 million American women with a history of breast cancer are alive today, and the great majority of them are cancer-free, DeSantis says.

The number of survivors will reach four million within the coming decade.

But a closer look at the numbers shows that not all women are benefitting equally. Black women with breast cancer are 42 percent more likely to die of it than whites, the new report notes. In some US cities, the black-white disparity in breast cancer mortality is even wider, according to a study published last year and cited by the New York Times. In Memphis, for example, the mortality risk among black women is more than 200 percent higher than among whites; in Los Angeles, their risk is about 70 percent higher.

And while breast cancer mortality has been dropping among black women, “their rate is not dropping as much,” DeSantis says. “We think probably some of the advances in treatment are not getting to them.”

Black women report in national surveys that they get regular mammograms about as often as their white counterparts. Still, black women are more likely to have a later stage of cancer at diagnosis.

This may be a sign that when a black woman has a suspicious mammogram, she’s less likely to get prompt followup care.

In this context, the news that African-Americans are catching up to Caucasians in the incidence of breast cancer — their risk of getting breast cancer in the first place — is especially disturbing. “Historically, black women have had lower incidence rates than white women,” DeSantis says. “Now we see they have very similar incidence.”

The historical gap probably has something to do with blacks’ lower socioeconomic status. Among other things, that’s associated with earlier child-bearing and more pregnancies, both of which protect against breast cancer.

The growth of a black middle class may have something to do with increasing breast cancer incidence among African-American women. But DeSantis thinks another factor may be more potent: Strikingly higher obesity among black women.

“Fifty-eight percent of black women are clinically obese, compared to 33 percent of white women,” she says. “In seven states where breast cancer incidence is higher in black women than in whites, these are southern states which tend to have a larger proportion of women who are obese.”

DeSantis also notes that obesity in white women has leveled off in recent years — and so has their incidence of breast cancer, which has been stable since 2004. Breast cancer incidence is also stable among Hispanics and Native Americans.

But in black women, both obesity and breast cancer incidence have continued to increase in tandem.

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