February 26, 2013 | by Roberta Nichols
Breast cancer has long been a frightening specter for women as they approach middle age and their risk of the disease rises. Now new research has yielded what seems to be alarming data about younger women.
A study published in the Feb. 27 issue of Journal of the American Medical Association finds that cases of advanced breast cancer are increasing among 25- to 39-year-old women in the United States.
The data emerged from a study in which researchers were studying why young women with breast cancer tend to experience more aggressive disease than older women and have lower survival rates.
Researchers led by Rebecca H. Johnson, M.D., of Seattle Children’s Hospital and University of Washington, reviewed national trends in breast cancer incidence in the U.S, mining data from the U.S. Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. They obtained incidence and survival rates on women with breast cancer as of 2009. Data spanned the years 1973 to 2009, 1992 to 2009 and 2000 to 2009.
The team found a small but statistically significant increase in the incidence of breast cancer with distant involvement (metastases to bone, brain, lung, etc.) between 1976 and 2009 for women age 25 to 39 years – without a corresponding increase in older women.
“Since 1976, there has been a steady increase in the incidence of distant breast cancer at diagnosis in 25- to 39-year-old women, from 1.53 per 100,000 in 1976 to 2.90 per 100,000 in 2009,” according to researchers. This represents an average compounded increase of 2.07 percent per year over the 34-year span.
“The trend shows no evidence for abatement and may indicate increasing epidemiologic and clinical significance,” researchers wrote.
The numbers don't bode well for new patients diagnosed with breast cancer.
“The trajectory of incidence trend predicts that an increasing number of young women in the U.S. will present with metastatic breast cancer in 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,” wrote Johnson.
This increased incidence of metastatic disease for 25- to 39-year-olds affected all races and ethnicities evaluated, especially non-Hispanic white and African-American, in both metropolitan and nonmetropolitan areas.
Johnson concedes that more work need to be done. “Our finding requires corroboration and, if confirmed, further study of potential causes,” she said.
Courtney A. Vito, M.D., assistant professor in the Division of Surgical Oncology at City of Hope, who was not involved in the study, agrees that more research is needed before definitive conclusions can be drawn.
“This is a very well-done study, but as with all large database studies, it is impossible to show cause and effect, and clearly more study is needed to understand this trend,” Vito said.
The increase may be due to increasingly sophisticated diagnostic testing over the years, she suggested.
“Systemic staging scans are more sensitive now, and smaller amounts of systemic disease are now more easily detectable (especially via PET/CT) and therefore patients with very minimal systemic disease are now able to more readily be classified as Stage IV which may explain some of the increase but most likely not all.
“We now have more sensitive detection for younger women who present with symptoms,” she continued. “Breast MRI (newer technology) has superior sensitivity compared to mammogram (mainstay technology in 1970s, 1980s) in young, dense breasts which may accelerate rates of diagnosis (i.e., we are better at finding breast cancer in younger women), and I would have expected that we were able to actually see more prompt, earlier stage diagnosis as time went on."
This demographic group also has significantly changed since the 1970s, she points out.
Women age 25 to 39 in 1976 were born in the 1950s and earlier, and have significantly different risk profiles than women age 25 to 39 in 2006.
“Today’s younger women have had earlier menses, higher body mass index, older age at the birth of their first child or no children at all, and more variable rates of breast feeding, all of which are risk factors for breast cancer," Vito said. "This increase is most likely not due to one or two specific causes but is most likely multifactorial. More investigation into the differences in overall lifestyles, health choices, access to care and medical/demographic information of young women over time in this country is needed.
“This study shows an alarming trend, but it must be kept in perspective,” cautioned Vito. “Overall, the total number of young women 40 and younger diagnosed with breast cancer remains low compared to older women over 40, and it is appropriate that mass screening efforts be focused on this older age group. However, breast cancer awareness with high importance placed on education and access to care for younger women is paramount to combat this relatively uncommon but devastating disease.
“This study clearly shows that younger women are presenting with Stage IV breast cancer at higher rates, and therefore physicians need to maintain their vigilance and act promptly when addressing breast-related complaints in younger women.”