Most U.S. women have relatively easy access to mammography and breast ultrasound, but breast MRI presents a greater challenge, especially for Native American women and those in rural areas, according to a new study published online in the Journal of the American College of Radiology.
Breast MRI is currently the most sensitive test for breast cancer, and it's recommended as an annual adjunct to mammography for screening high-risk women, according to Tracy Onega, PhD, of Dartmouth College and colleagues. Lack of access to the modality could negatively affect women's health.
Tracy Onega, PhD, from Dartmouth College."Geographic access may determine both the availability and uptake of breast imaging services, which in turn may influence treatment decisions and ultimately outcomes," Onega's team wrote.
The researchers used 2004-2008 Medicare claims data to identify ZIP codes in which breast imaging occurred, and they estimated travel times for each modality for 215,798 census block groups. They characterized estimates of travel time by social and demographic factors for 92.8 million women age 30 years or older, as well as subgroups of age, race/ethnicity, rurality, education, and median income (JACR, May 30, 2014).
Overall, most women have relatively easy access to breast imaging services, the group found: 85% of women had travel times of 20 minutes or less to the nearest mammography or ultrasound service, and 70% had travel times of 20 minutes or less for breast MRI.
"We were pleasantly surprised to find that access to mammography and breast ultrasound was good overall," Onega told AuntMinnie.com.
But some subgroups' access was more limited. Native American women had median travel times two to three times longer for all three modalities compared to women of other racial/ethnic groups. Rural women's median travel times to breast imaging services were four- to eightfold longer than those of urban women, the team found.
| Population with travel time > 30 min to nearest breast imaging service | |||
| Mammography | Ultrasound | Breast MRI | |
| Asian | 2.2% | 2.4% | 7.4% |
| Black | 6.4% | 7% | 26.1% |
| Native American | 39.6% | 42.8% | 84.2% |
| Pacific Islander | 7.2% | 7.5% | 21.3% |
| White | 12.6% | 14% | 46.5% |
| Small town and isolated rural | 27.9% | 31.9% | 86.1% |
Travel time to MRI services increased as rurality increased -- a phenomenon likely to be even more pronounced with new advanced technologies such as digital breast tomosynthesis, Onega's team wrote. Why? One reason is that equipment costs for new technology tend to be high, and there are fewer staff members available with expertise in it.
Whatever the reason, it's important to address the access problem, particularly because rural women have been shown to have a greater likelihood of advanced-stage breast cancer than their urban counterparts, according to the researchers.
"Variation in geographic access by race/ethnicity and rurality has potential implications for ... underlying disparities in healthcare utilization and outcomes," the group wrote. "Approximately 2.5 million women aged 30 years and older who live more than 30 minutes from the nearest breast imaging facility of any kind may be disadvantaged for early detection of breast cancer."
Is the answer to put breast MRI scanners in every county? That's probably not practical, Onega said.
"There are going to be areas with relatively poorer access to advanced technologies, so it's more a matter of figuring out how to better get women to those technologies," she said. "But perhaps there's also a way that the market and the government could work together to create incentives for allocating resources more fairly across the population, not based solely on financial concerns."
