Ready for Prime Time?

The portable Dilon 6800 Gamma Camera provides the ability to image up to the chest wall and mimic all mammographic views.

The medical community is quick to adopt some new technologies while others take a long time to gain acceptance and utilization. Breast specific gamma imaging (BSGI) ranks among the latter.

According to experts and information conveyed by Dilon Technologies LLC, Newport News, Va (the manufacturer that pioneered the technology), BSGI has been around for about 10 years, but has only become a routine procedure for about the past 3 years. Many breast surgeons and radiologists are still a bit skeptical about BSGI. And yet research shows the technology offers great promise for detecting more breast cancers in high-risk women with normal mammograms.

“Personally, I am excited about BSGI and believe there is a great future for it,” said Rose Heller-Savoy, MD, board-certified breast radiologist and director of mammography services at Montclair Breast Center in Montclair, NJ. “I’ve been watching the technology for a long time, but I don’t think it’s ready for prime time.” Heller-Savoy (like a handful of specialists this reporter spoke with) is in the cautiously optimistic camp.

BSGI is a novel molecular imaging approach that uses the Dilon 6800, high-resolution small-field-of-view gamma camera and a radiotracer. Emitted gamma rays are converted into images showing “hot spots.” According to Dilon Technologies, this molecular imaging technique can help physicians more reliably differentiate cancerous from non-cancerous cells.

“The majority of imaging is anatomically based; it asks the question: What does cancer look like?” said Rachel Brem, MD, professor of radiology, vice chairman of radiology, and director of breast imaging at George Washington University (GW). “BSGI asks a different question: How does breast cancer function differently than normally surrounding breast tissues?” While other adjunct modalities such as MRI and ultrasound image the physical structure of the breast, BSGI captures the cellular functioning of breast tissue.

Brem, who by all accounts is considered one of the world experts in the technique, has been using BSGI before it was FDA-approved as she participated in the clinical trials more than 10 years ago. Not surprisingly, Brem is a major proponent of BSGI. “It is absolutely astonishing the number of cancers we find using it, that we would not otherwise know about,” Brem said. “It helps to diagnose more cancers, especially in high-risk women with normal mammograms.”

According to Brem, the team at GW has found new cancers in “10% to 15% percent of patients that we did not know about prior to using BSGI.” Results like those raise the question: Why aren’t more breast specialists and radiologists adopting BSGI?

WORKING OUT THE KINKS

When asked about why BSGI is “not ready for prime time,” Heller-Savoy cited several reasons. First, she said that to her knowledge, Dilon provides excellent equipment for diagnosing, but there is no device on the market that can integrate the biopsy. “The technology can image, but the biopsy add-on is not yet FDA-approved as far as I know,” she said. “Like all technologies it is still evolving and has proved it is worthwhile, but there are limitations.”

Simply put, many in the women’s health field believe that there are still kinks in the armor when it comes to BSGI. Another limitation, Heller-Savoy said, is that BSGI offers a broad spectrum of how results are manifested. “It’s not just normal versus abnormal; it’s more complicated than that,” she said. And, she continued, “BSGI doesn’t always get back to the chest wall as well as MRI.”

On the upside, Heller-Savoy points to several advantages with BSGI. She noted that the technology can certainly save the radiologist time. Unlike other breast imaging modalities that may result in 1,000 images, BSGI provides four to eight images; that’s “a lot less images for the radiologist to look at,” Heller-Savoy said. Moreover, BSGI is a lot more comfortable than breast MR for the patient. Finally, she said studies have “shown that BSGI is seeing a lot more smaller stuff” than other modalities—and therein lies the technology’s greatest advantage.

A LOOK AT THE LATEST RESEARCH

A new study about BSGI was published in the June issue of Radiology. Brem was one of the key people involved in the study that enrolled 146 women, all of whom underwent BSGI and breast biopsy. According to Brem, “It was the largest study to date to look at sensitivity of breast cancers with BSGI.” The findings, as stated by Brem: BSGI helped to detect 98% of invasive cancers and 96% of all cancers.

But Brem is quick to point out that the data gathered was not intended to be a comparison of BSGI and MRI. Rather, the goal was to look at BSGI’s sensitivity, regardless of the grade and size of the malignancy. According to the research, BSGI helped to detect hidden cancer in six study participants that had not been caught by mammography or ultrasound.

Heller-Savoy (who was not involved in the study) noted that while MRI is “incredibly sensitive,” it also provides numerous false positives. According to experts, sometimes MRI is almost “too specific.” As one physician noted, every time they do a breast MRI it gives the specialist a laundry list of things to double check. Not the case, says Heller-Savoy and other experts, with BSGI. “There will definitely be a future with this technology,” Heller-Savoy said. “It is less expensive than breast MRI, and those that cannot qualify as ‘high-risk’ enough for MRI will turn to BSGI.”

REASONS FOR WAITING?

“In general, I am an early adopter for new advances in breast technologies, and as we move forward here we may find a role for BSGI in addition to—or instead of—breast MRI,” said Pat Whitworth, MD, director, Nashville Breast Center, and immediate past chairman of the board and chairman of the research committee of the American Society of Breast Surgeons.

High-risk patients with dense breast tissue are benefiting from BSGI.

But presently, Whitworth is still waiting. Why? Whitworth thinks good things are worth the wait.

“I am intrigued because two or three studies say BSGI is as sensitive as breast MRI,” Whitworth said. He admits he is not an expert on the subject, and that is one reason he is not utilizing the technology in his practice. But in addition, Whitworth notes that all physicians need to look at the economics. “On order of magnitude, I believe BSGI is less expensive. But reimbursement is not that great from what I understand.” While Brem says GW is being reimbursed for BSGI, Whitworth points out that many specialists have already invested heavily in breast MRI equipment. For a breast center or hospital, investing in new technology is a hefty financial commitment … and something of a quandary when new techniques emerge. You want the best, but you can only afford so much. It is simply a reality of doing business in today’s medical arena.

But the big reason Whitworth believes BSGI is still underutilized has more to do with human nature than bottom lines. “Dilon is producing very credible results. BSGI is less expensive overall, more comfortable for the patient, and according to studies, it’s as sensitive and as specific as breast MRI,” Whitworth said. “But for the medical community, that’s hard to believe. It’s like moving a giant tanker ship and getting it to turn.” Says Whitworth, it will simply take time and more data.

Then there is Brem—on the front lines, tending to patients, spearheading studies, and saving lives. She believes the primary reason BSGI has not yet been fully embraced is quite simple: It’s all about mind-set. “Breast imaging and nuclear medicine were always fields apart,” Brem said. “It’s just taking some time for breast imagers to accept this technology.”

But Brem couldn’t be more optimistic. She says implementation is increasing, it takes less time than MRI, the procedure is getting reimbursed, there is no body weight limitation, and the overall cost of the technology is a “fraction of MRI.” “BSGI is easily integrated into clinical practice, extremely well-tolerated, and the fact is, it is both exciting and vitally important,” Brem said.

—Marianne Matthews