Metastatic Breast Cancer on the Rise in Women Over the Past Three Decades, Possibly Linked to Rising Obesity Rates

A national study found that the number of young women being diagnosed with metastatic breast cancer, meaning it has metastasized or spread to other parts of the body, has been slowly but steadily rising over the past three decades.  

Among women ages 25 to 39, incidents crept upward by 2.1 percent per year between 1976 and 2009, according to Dr. Rebecca Johnson of Seattle Children's Hospital and the University of Washington in Seattle, and colleagues.

The upward trend was not seen among older women in the analysis of the Surveillance, Epidemiology, and End Results (SEER) database, published in the Feb. 27 issue of the Journal of the American Medical Association.

 The findings are worrying for an "age group that already has the worst prognosis, no recommended routine screening practice, the least health insurance, and the most potential years of life," the researchers pointed out.

However, as to why more young women have tumors that already spread to bone, brain, lungs, or other distant sites isn't clear, they noted, is not quite so clear yet. 

Rising obesity rates, changes in alcohol and tobacco use, and genetics are possible causes, according to Dr. Thomas Julian, director of surgical oncology at Allegheny General Hospital in Pittsburgh.

"That's a problem because we don't usually screen before age 40 unless you know there are genetics in the family or a strong family history," he said.

Researchers have noticed that the steepest uptick for changes have occurred in the most recent era from 2000-2009, during which incidence rose 3.6 percent per year. As another point of evidence according to ABCNews.com, metastatic presentation rose as a proportion of all invasive breast cancer in the 25 to 39 age group from 4.4 percent in the 1970s to 7.2 percent after the turn of the century.

And trends can be noted among all races and ethnicities, according to reports-in both urban and non-urban areas alike.