Screening for breast cancer with mammography isn't perfect -- and neither are the modalities used to track women already diagnosed with the disease. At the recent American Society of Clinical Oncology (ASCO) Breast Cancer Symposium (BCS) in San Francisco, researchers discussed ways to find and track breast cancer more effectively.
A group from Kentucky discussed how mobile mammography units can affect screening compliance in uninsured women, while researchers from New York City shared results from a study that points to PET/MR as a better way to track breast cancer metastases than PET/CT.
Does mobile mammo boost compliance?
Historically, mobile mammography has improved the use of breast cancer screening among uninsured women, according to Dr. Elizabeth Riley from the University of Louisville in Kentucky. In a previous study, Riley and colleagues found that women's insurance status predicted whether they would return for screening at a mobile mammography unit; for this study, the team examined whether access to mobile mammography influences uninsured women to get screened.
"To our knowledge, this is the largest database of mobile mammography encounters reported in the literature," Riley's group wrote in an ASCO abstract.
The researchers included data from January 2001 through December 2010. During that time, 48,324 screening mammograms were performed in Jefferson County, which includes the city of Louisville and is the largest county by population in Kentucky. Of 21,587 women who received these exams, 9,422 (44%) were uninsured.
Riley's team parsed the data by age, race/ethnicity, insurance status, and location of encounter; locations included public health clinics, health fairs, and churches. The group defined "utilization" as women receiving screening one or more times in the 10-year period.
White women were most likely to get screened (63.9%), followed by black women (29.1%), Hispanic women (3.8%), and women in other racial or ethnic categories (3%), according to the researchers.
Uninsured women were most likely to make use of mobile mammography, at 43%, followed by women with private insurance (36%), those with Medicare coverage (16.1%), and those with Medicaid (4.7%).
Within the uninsured group, race was an independent predictor of repeat utilization of mobile mammography units; however, race was less significant in the uninsured group than in the entire dataset, suggesting that insurance type is a stronger predictor of whether women will come back for screening, whatever their race, Riley's team concluded.
Which is better: PET/MR or PET/CT?
In another study presented at ASCO BCS, researchers from NYU Langone Medical Center compared differences in the detection of breast cancer metastases using PET/CT and PET/MR. They found that PET/MR outperformed PET/CT in detecting metastases in the liver, brain, lymph nodes, and bone -- good news for patients, since PET/MR delivers less radiation than PET/CT.
"PET/MR is still new, and there's not a lot of clinical data on its performance," presenter Dr. Eleonora Teplinsky told AuntMinnie.com. "PET/CT is used to follow patients with metastatic disease, but it has more than a few limitations, including the double radiation dose and misregistration of images due to motion. We wanted to explore whether PET/MR could address those limitations."
Forty-eight patients underwent PET/CT and PET/MR after a single FDG injection. Both the PET/CT and the PET/MR images were read by a radiologist blinded to prior exams or reports who recorded the number of metastases per organ. Two experienced radiologists who had access to previous imaging and pathology reports served as the reference standard.
Twenty patients had no distant metastases on the exams. In the remaining 28 patients, the radiologists detected nine liver, 18 bone, seven lung/pleura, five brain, and 10 lymph node metastases; some patients had more than one metastatic site.
PET/CT missed two metastases found by the reference radiologists, while PET/MR identified all of them, Teplinsky's group found.
| PET/CT vs. PET/MRI | ||
| Metastases found by reference standard | Metastases found by PET/CT | Metastases found by PET/MRI |
| 49 | 47 | 50* |
PET/MR technology could offer a good alternative to PET/CT, though it needs more clinical study, Teplinsky said.
"The technology is pretty exciting," she told AuntMinnie.com. "For a long time, the two modalities couldn't be combined because of the detectors. But since they have been, we're seeing that it has advantages over PET/CT that could make it a good option for tracking breast cancer patients with metastases."
