At a time when the USA is making progress overall against cancer, a new study suggests a worrisome rise in the number of young women diagnosed with advanced, incurable breast cancer.
The number of American women ages 25 to 39 diagnosed with metastatic breast cancer -- which has already spread to other organs by the time it's found -- rose about 3.6% a year from 2000 to 2009, according to a study in today's Journal of the American Medical Association.
The trend began in the 1970s, although the most rapid increases occurred in the past decade or so, the study says. The study doesn't provide any clues about what might be driving the increase, says study author Rebecca Johnson of Seattle Children's Hospital.
"It is a big increase, and it's accelerating over time, and it's hitting the youngest women," Johnson says.
Young women shouldn't be overly alarmed, Johnson says, noting that breast cancer at any stage is relatively rare before age 40. The number of women in this age range diagnosed with advanced disease rose from about 250 a year in 1976 to about 850 a year in 2009, Johnson says.
The largest increases were in the youngest women, from ages 25 to 34, the study says. There were also slight increases in metastatic diagnoses among women ages 40 to 54, but no increase in older women.
Researchers note that their study needs to be confirmed by other researchers before doctors can be sure that rates are really increasing. It could be especially helpful to measure trends in other countries, the authors write in their study.
Studies like this "get your attention," says Len Lichtenfeld of the American Cancer Society, who wasn't involved in the research. "It may not be a big number today, but you have to wonder, 'Is this a trend that's continuing over time?' Then the numbers start to take on a new meaning."
Increases in any cancer are troubling, he says, because overall cancer deaths of all kinds have fallen about 20% in the past two decades. Breast cancer incidence rates have been stable for the past few years.
Johnson's study looked at numbers taken from a National Cancer Institute database.
It's possible that doctors and younger women are less alert to signs of breast cancer, such as a lump in the breast, because they don't expect to see the disease in anyone that young, Johnson says. Women 25 to 39 are also less likely to be insured.
Johnson, who was diagnosed with breast cancer in her 20s, says cancers in women 25 to 39 probably grow very quickly. In her case, the tumors had already spread to the bones, brain or liver by the time of her diagnosis.
Women are at increased risk of breast cancer for five years after giving birth, probably because of hormonal fluctuations that occur during pregnancy, says Patricia Ganz of the Jonsson Comprehensive Cancer Center at UCLA.
Although doctors have made important advances in treating metastatic breast cancer and prolonging women's lives, the disease is considered incurable. Although 87% of women diagnosed with earlier cancers survive at least five years, only 31% of those with metastatic disease live that long, the study says.
"It's a terrible situation," Lichtenfeld says. "These women are mothers, wives, members of families."
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