Though accounting for only a small fraction of all breast cancers, the more aggressive types found in younger women tend to kill at higher rates when treatment is delayed, greatly affecting poor and minor women.

Researchers in California found that Latinas, African Americans, and poor women lacking health insurance were far more likely to die of breast cancer after delaying treatment past 6 weeks of detection. Using data from the California Cancer Registry database, investigators from the University of California, Irvine and Children's Hospital of Orange County focused on patients ages 15 to 39, who typically account for only 5 to 6 percent of breast cancer cases. The team found 8,860 women who had been diagnosed between 1997 and 2006, comparing those who began chemotherapy or received surgery within 6 weeks to those who did not.

Within 5 years, 22 percent who delayed treatment were dead, compared to 16 percent who began treatment within two weeks and 17 percent who began within 2 to 4 weeks. The researchers found that nearly 18 percent of poorer women in that age group delayed treatment for at least 6 weeks, compared to a much lower rate of 8 percent for all women.

Twenty-eight percent of the poor women died within 5 years, compared to 11 percent of more affluent women.

A woman's treatment decision and, therefore, health outcome was also linked to whether she had good health insurance. Of young women with either public or no health insurance, 18 percent delayed treatment for 6 weeks or more, with 31 percent of them dying within 5 years. The numbers for young women with private insurance were much lower, with only 10 percent delaying treatment for that long, with 14 percent dying within 5 years.

The 5-year survival rate among breast cancer patients was lowest among black women at 57 percent, followed by Hispanic women at 74 percent, Asian women at 81 percent, and whites at 86 percent.

The researchers published their findings this month in JAMA Surgery, writing: "Surgical delay time was a significant risk factor for reduced survival after breast cancer diagnosis independent of race/ethnicity, cancer state at diagnosis, age, insurance type and [socio-economic status]. It may be difficult for a physician to make arrangements for surgery because of barriers such as a patient's lack of insurance," they wrote.

However, one online reviewer criticized the study for manipulating data in ways making it hard to isolate treatment delay as the causal culprit. "In the end, in this analysis, we have continued evidence of disparities in health care that lead to decreased survival, whether the disparity is a function of race, income, or delays in receiving treatment," wrote Dr. Leigh Neumayer of the University of Utah School of Medicine in Salt Lake City.

Neumayer said he supported eliminating disparities cited in the study for "the health of our nation."

See also: Teen Pregnancy Cuts Breast Cancer Risk By 50%.

Below is a video on breast cancer symptoms and treatment: