Before breast tomosynthesis, or 3-D mammography, there was digital 2-D mammography, before digital 2-D, there was film. Though tomosynthesis is still being tested in clinical studies, radiologists across the country are optimistic about this new technology and what it could mean for the future of breast cancer screening.

Shoshannah Roth, manager of health technology assessment information services at ECRI Institute in Plymouth Meeting, Pennsylvania, draws an analogy between the breast and a book, and how 2-D mammography takes the breast information and puts it all on one page, which can be difficult for some radiologists to read. Tomosynthesis, on the other hand, allows radiologists to look at the breast in slices, or multiple pages.

“Radiologists can look at a couple of pages at a time and flip through the book,” says Roth. “This allows them to see certain features easier because they’re no longer covered up or obscured by surrounding tissue.” In 2014, a study involving 139 doctors from 13 U.S. academic and community-based hospitals and led by Dr. Sarah M. Friedewald of the Caldwall Breast Center at Advocate Lutheran General Hospital in Illinois, looked at 281,187 conventional mammograms and compared them to 173,663 tomosynthesis exams.

The findings, published in the Journal of the American Medical Association (JAMA), illustrated that tomosynthesis detected 41 percent more invasive breast cancers (and 29 percent more breast cancers overall) than 2-D mammography. Additionally, the study showed a 15 percent decrease in women recalled for additional screening, a 49 percent increase in positive predictive value for a recall and a 21 percent increase in positive predictive value for biopsy.

A follow-up study was conducted earlier this year, in which 278,906 conventional mammograms were compared to 173,414 tomosynthesis exams. That study, also published in JAMA, found a 50 percent increase in invasive cancer detection and a 14 percent reduction in recall rate.

“Our study answered the critical question of who should be imaged with tomosynthesis, providing compelling evidence that all women undergoing mammographic screening should be imaged with tomosynthesis, regardless of their breast density,” Dr. Elizabeth Rafferty, the lead investigator of the study, told HealthCare Business News, at that time.

A European study led by Dr. Per Skaane, Ph.D., from the department of radiology at Oslo University Hospital in Norway, compared full-field digital mammography (FFDM) to FFDM combined with tomosynthesis in 25,547 women between the ages of 50 and 69. Those results showed a 30 percent overall relative increase in cancer detection when combining the exams.

“With 2-D mammography, approximately 10 percent of women are recalled from screening, which results in lots of extra tests and anxiety for patients,” says Dr. Liane Philpotts, chief of breast imaging at Yale-New Haven Hospital. “With 3-D mammography, those false positives are reduced by 30 to 40 percent. You [can] see many benign things with tomosynthesis that you weren’t seeing before, such as cysts or benign masses, and you have to learn how to disregard many of them. You have to learn how to let some things go, but also train your eyes to notice subtle malignant masses.”

Although Philpotts says scrolling through all of the images that are part of a tomosynthesis exam can be tiring and requires a certain learning curve, she believes that anyone who starts using tomosynthesis prefers it.

Drawbacks of tomosynthesis
Though physicians have lauded the benefits that 3-D mammography brings to the field, there are some disadvantages that can be found in this screening method. The studies being conducted mainly focus on the sensitivity of the test for breast cancer screening. Jonas Rehn, senior product manager of mammography solutions and global diagnostic X-ray at Philips Healthcare, believes that the reason 2-D is still preferred over 3-D in current screening programs lies with the limitations of studies being conducted.

“There are no studies to date on the impact of tomosynthesis on mortality. The studies that are available focus on surrogate endpoints such as cancer detection rates and in very few cases interval cancer detection rates,” he says. Up until last year, there was no code for tomosynthesis, so there was no reimbursement.

It was in January 2015 when a code for tomosynthesis became available for reimbursement at approximately $57, although the range can be from $25 to $125, depending on specific hospitals. CMS does cover the cost, but many private insurers do not. ECRI’s Roth credits this to a mixed pot of evidence — some showing tomosynthesis increases the recall rate, some showing that it decreases the recall rate and others showing that tomosynthesis does nothing at all.

Yale-New Haven’s Philpotts thinks that there are more than enough studies consistently showing positive results in terms of increased cancer detection and reduced recalls for private companies to reimburse. “[Private insurers] are still trying to hold out and say that it’s ‘experimental’ and ‘investigational,’” she says, “and this is troubling since there are five years or more of data that are consistently showing positive results. I think it’s only a matter of time before they’re forced to pay. While the equipment is more costly, even with the added cost of $57 to a mammogram, it will still save money. Ultimately, down the line, [tomosynthesis] saves money in terms of reduced recalls, fewer diagnostic exams and fewer biopsies.”

Dr. Debra Monticciolo, fellow of the American College of Radiology, and chair of the American College of Radiology Breast Imaging Commission, agrees and says that insurers will eventually have to respond to the demand for a better technology, and when something has proven benefits, there will be pressure from women themselves saying “this is the technology we want.”

Options in the market
Manufacturers are making strides to ensure they bring increasingly effective breast imaging technology to the marketplace so providers can achieve better outcomes for their patients. A report from analysts at MarketsandMarkets estimates breast imaging will become a $4.14 billion market by 2021, at a compound annual growth rate of 8.5 percent from 2016 to 2021. Hologic’s Affirm prone biopsy system received FDA approval in April, and became the first 2-D/3-D imaging-guided prone biopsy system to enter the U.S. market. The system allows doctors to better handle biopsies for subtle lesions or faint calcifications that are only identifiable using 3-D exams.

A review conducted by the York Health Economics Consortium, a consultancy and research company, confirmed that the Hologic system is more accurate than just a 2-D exam, with doctors being able to screen for breast cancer with 41 percent more accuracy. Additionally, patients had a 40 percent less chance of being called back for additional screening.

The radiation dose that a woman receives during screening can possibly double if she undergoes a 2-D and 3-D mammography exam. To address this, software can be used to create a 2-D image from the 3-D image, and this synthetic 2-D takes the place of a 2-Donly exam, resulting in lower dose to a patient. Hologic has a product that received FDA approval in 2013 — C-View 2-D imaging software. C-view images are generated from the 3-D tomosynthesis data acquired during the mammography exam, so a patient does not have additional 2-D exposure.

In 2014, GE received FDA approval for SenoClaire, a breast imaging with 3-D tomosynthesis solution. The SenoClaire performs a low-dose short X-ray sweep around the breast taking nine exposures in what the company calls a “step-and-shoot” method of acquisition — that means the tube is stationary at the time of acquisition, which may improve image sharpness.

Siemens Healthineers announced in May that its Mammomat Inspiration and Mammomat Inspiration PRIME edition digital mammography systems can be used as standalone 3-D mammography systems. All other mammography systems on the market require a combination of 2-D and 3-D exams. It is the first and only 3-D digital breast tomosynthesis system to receive FDA approval as a standalone screening and diagnostic tool, according to Jennifer Okken, women’s health product manager at Siemens Healthineers.

“As part of the FDA approval, 31 readers read through all types of breast tissues and demonstrated increased detection rate,” she says. “These readers, all trained on tomosynthesis and the interpretation of these images, evaluated 330 screening FFDM and tomosynthesis cases consisting of 105 malignant cases and 225 non-malignant cases. “From the study conducted, the recall rate decreased by an average of 19 percent without the need for a 2-D image.” Philips Healthcare received FDA clearance for its MicroDose spectral-imaging mammography system in 2013, which is a fullfield digital mammography system. The MicroDose SI uses a slim detector that “scans” the breast and counts the X-ray photons one-by-one with no scattered radiation, resulting in a low radiation dose while keeping the same image quality.

As for a tomosynthesis modality, Kalavathi G V, business leader of mammography at Philips Healthcare, says that the company is in the process of developing one. “Philips is developing spectral tomosynthesis using the photon-counting technology as in the current MicroDose SI product,” she says. “The technology is currently in clinical testing.”

Will 2-D-only go extinct?
Approximately 20 to 30 percent of health care facilities in the U.S. use tomosynthesis, and ACR’s Monticciolo does not believe that standard 2-D acquisition will disappear in the near future since she thinks that 2-D imaging is excellent and cost-effective — but not everyone agrees with this sentiment. “We are aware of clinician enthusiasm for [tomosynthesis], so this certainly can drive the adoption of the technology,” says Diane Robertson, director of health technology assessment information services at ECRI Institute. “If you have radiologists and breast cancer physicians who are enthused and excited about tomosynthesis, they will request it from their health system.”

Rehn predicts that given the development of second-generation tomosynthesis systems such as low-dose techniques, better interpretation tools and protocols, 3-D screening will become the new standard. According to Philpotts, the future will be tomosynthesis combined with the synthesized 2-D images so that radiologists can reduce radiation dose, but still benefit from getting all the information in the 3-D portion. “Tomosynthesis is such a positive trend in so many ways: reducing recalls; increasing cancer detection; fewer patients needing follow ups; and better positive predictive value for biopsy. It’s a much better technology. It’s more accurate for a better interpretation,” says Philpotts.