Why Don’t Patients Know the Truth about Mammography?

WASHINGTON, D.C.-Breast cancer claims precipitate the greatest number of malpractice suits in the U.S., according to Bonnie Rush, president, Breast Imaging Specialists, as presented at AHRA 2014.

This is, in large part, due to the public’s lack of understanding of mammography’s abilities and limitations, and therefore heightened expectations of its effectiveness. This isn’t exactly the public’s fault, Rush confessed.

“All we’ve been doing is trying to defend mammography, we are defending mammography as though it is the only thing in the world that can find cancer; it is not,” she said.

The appeal of mammography screening is early detection, which leads to greater chance of survival and increased quality of life. The problem with promoting mammography as an early detection screening tool is that it is not as effective in detecting cancer in women with dense breasts, and, according to Rush, these women make up 40 percent of the screening population.[[{"type":"media","view_mode":"media_crop","fid":"27014","attributes":{"alt":"","class":"media-image media-image-right","id":"media_crop_7419651757247","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"2584","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 83px; width: 249px; border-width: 0px; border-style: solid; margin: 1px; float: right;","title":" ","typeof":"foaf:Image"}}]]

Radiologists have recognized for a long time, but infrequently disclosed to patients, that the sensitivity of the screening mammogram decreases with increasing breast tissue density, Rush said.

Rush noted that 70 percent of breast cancers are in women with dense breasts, most of which are interval cancers, which are cancers diagnosed after a negative mammogram but before the next screening period.

Extensive density can hide tumors, referred to as masking, Rush likened it to “Trying to find a snowball in a snowstorm.” An American College of Radiology Imaging Network/National Cancer Institute found that in women with greater than 50 percent breast density, the ability of the radiologist to see an abnormality that may be cancer is directly affected, offering only 60 percent sensitivity with high breast density.

The increased risk posed by breast density is significant. Rush reported that dense breasts create a risk factor of having breast cancer equivalent to the risk of someone who has a personal history of breast cancer, or a genetic mutation, like BRCA 1 or BRCA 2.

The ACR took notice of the severity of the issue and, in 1992, recommended that the mammography report begin with a description of breast composition, and when the breast tissue is greater than 50 percent dense, a disclaimer should be included regarding the decreased sensitivity of the study, Rush explained.

“What good is a disclaimer statement if you know that there is something else that can find the cancer? It doesn’t hold water,” Rush said.

The disclaimer protects the radiologist and passes the baton, providing the referring clinician with the responsibility of determining the next steps.

“[The referring physician] is not ignorant unless you can educate them, it’s our job. We are trying to pass the buck to the referring physician, that is not where it should go,” Rush said.

Education needs to start within the radiology industry, though. ACR published a BI-RADS breast density description, with grades A through D rating how dense breasts are. Rush stated that subjective scoring is unreliable between the two “middle” categories: B and C, as only 62 percent of radiologists looking at the same images agreed with the breast density scoring. An objective solution could be found in density quantifying software, Rush said.

In 2012, the ACR recognized the need for standardization of breast density, telling Diagnostic Imaging that unless all radiologists use a standard categorization, they won’t be completely effective.

Legislation has stepped in and currently 19 states have passed laws requiring that information about a patient’s breast density, and what it means to have dense breasts, be included on a mammography report that is sent to the patient.

A federal bill with the same mandate was also introduced in July, with proposed text recommending individuals with breast cancer consult with their physicians about questions pertaining to breast density.

Often, women with dense breasts are recommended to undergo supplemental breast cancer screening. A 2014 survey completed by Diagnostic Imaging and ObGyn.net found that the largest majority of providers recommended ultrasound as a supplemental screening modality, followed by MRI.