Can photoacoustic ultrasound detect breast cancer earlier?

Breast cancer death rates have fallen by more than half over the past 50 years, in part due to better screening methods that help clinicians detect and treat the disease earlier.

For women with dense breast tissue, there is still room for improvement. Mammograms do not always detect abnormalities in women with dense breasts. Meanwhile, women under 40, who are more likely to have dense breasts, are not eligible for cancer screening under current guidelines.

A new startup called BeSound is trying to expand access to more comfortable breast cancer screening options, including an imaging approach called photoacoustic ultrasound. The company says ultrasound can detect cancer earlier than traditional screenings, even in people with dense breasts.

Where mammograms fail to detect breast cancer

Mammography, an X-ray test, is currently the gold standard for breast cancer screening. It helps radiologists identify areas of dense tissue that could signal a tumor.

However, mammograms don’t always detect lumps in dense breast tissue. About 10% of women have extremely dense breasts, putting them at a much higher risk of cancer, while 40% of women have a mixture of fatty and dense breast tissue. Mammograms fail to detect approximately 25 to 50% of breast cancers in these patients, depending on the density of their breasts.

Using mammography to detect abnormalities in dense breast tissue is like driving a boat through a fog bank, said Robert Smith, PhD, senior vice president of early detection science at the American Cancer Society.

“Are you heading straight in, figuring there’s probably nothing there?” Smith told Verywell. “That’s kind of what happened to women for years, when their doctors said their mammogram was normal, but half the breast was obscured by dense breast tissue. You couldn’t tell if there was cancer or not.”

What is photoacoustic ultrasound and is it better than mammography?

Ultrasound imaging is approved by the FDA for breast cancer screening and several other procedures. It uses non-ionizing radiation and therefore does not pose the same health risks associated with radiation from x-rays and mammograms. A review of studies finds that ultrasound can detect up to 7.7 more cases of breast cancer per 1,000 women than mammography.

“Although we know that ultrasound can detect many more cancers in women with dense breasts, many women are not able to have this ultrasound because their offices do not offer it,” said Rachel Brem, MD, consultant at BeSound and vice chair of radiology at George Washington University School of Medicine.

However, ultrasound imaging tends to detect many more false positives than other major types of screening. To check whether a lump is benign or cancerous, BeSound uses a technology called photoacoustic imaging. This measures oxygen and blood flow to tissues using light and sound.

The FDA cleared photoacoustic imaging in 2021, meaning it considers it safe and effective for its intended use.

However, Brem said BeSound has not clinically tested whether the combination of ultrasound and photoacoustic imaging works as well or better than contrast-enhanced MRI or mammography.

Smith said it was crucial to compare the effectiveness of the test to that of mammography.

“Since we’ve been screening women for breast cancer, tests have been marketed – electrical impedance and thermal scanning – all kinds of things that are touted as comfortable, without radiation or compression. But they can’t say they’re as good as traditional imaging tests. They just compare the characteristics of the scan, not its accuracy,” he added.

No major medical organization recommends stand-alone ultrasound imaging for breast cancer screening in women, regardless of their risk level. For some people with dense breasts, the Centers for Disease Control and Prevention (CDC) recommends talking with your doctor about your breast cancer risk factors and other tests, such as an MRI.

Who should have a photoacoustic ultrasound?

BeSound hopes to appeal to women under 40, who are more likely to have dense breast tissue than older women.

About 85% of breast cancers occur in women with no family history of the disease. However, health insurance generally only covers screening mammograms for women ages 40 to 74, based on recommendations from the U.S. Preventive Services Task Force.

Women under 40 can get the test if they have a family history of breast cancer or have symptoms, but they must be willing to pay out of pocket.

BeSound imaging is accessible to any asymptomatic woman aged 25 and over. The company is opening its first clinic in California this fall, with several more across the country soon to follow.

“There really is no downside and a huge opportunity for upside to finding early, curable breast cancer in younger and younger women,” Brem said.

How much does it cost?