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St. Joseph Hospital in Nashua touts new 3-D mammography machines

New technology in medicine is a good thing except when it’s not, and sometimes it is hard to tell the difference.

Consider the newest high-profile addition to St. Joseph Hospital: tomosynthesis, commonly called 3-D mammography. This technology, approved by the government for use just two years ago, is unquestionably a good thing.

Mammography now takes a single, two-dimensional X-ray, and some small, tumors can be hard to see through masses of healthy tissue.

Tomosynthsis takes a whole range of X-rays in “slices” through the breast, which can be examined separately or assembled into a digital three-dimensional picture. The hospital has three of the machines, two in Nashua and one in its Milford Medical Center, and is prominently touting them with billboards and other publicity.

The technology allows doctors to spot possible tumors that would be hidden in a 2-D picture, said Dr. Ophelia Chang, medical director of breast care services at St. Joseph Hospital.

“See that? It’s a very subtle architectural distortion,” Chang said, pointing at a radiograph, or X-ray picture, of a 45-year-old woman’s breast. On a 2-D image, nothing could have been detected.

Even displayed on the specialty computer monitor, with such high resolution that it costs far more than most computers, the distinction would have escaped a layperson, but Chang said a follow-up biopsy found that the irregularity was a very early tumor. It was treated and the patient, who gave permission for her case to be discussed with the press, is doing fine.

The discovery, Chang said, “could be the difference between dying of breast cancer at age 50, and dying of cardiovascular disease when she’s 85.”

So what’s the downside?

Most obviously, there’s cost. The three machines by the firm Hologic, which replaced 2-D mammogram machines, cost about $1 million total. While there’s no extra charge to patients so far, Chang said, St. Joseph Hospital or insurers have to find the money somewhere at some point, which eventually means it will have to be paid by patients.

This is a common issue with medical technology, which is often more expensive than the technology it replaces, and is one of the major drivers to soaring health care costs.

Tomosynthesis also involves about twice as much radiation exposure to patients as 2-D mammograms, Chang said.

That raises exposure back to the level before mammograms switched to digital within the past decade. Levels are still very low and safe for patients, the National Cancer Institute said.

And for those hoping it might be more comfortable, the 3-D mammography still requires compression of the breasts, Chang said.

But there’s another, more subtle, potential downside to improved medical technology, Chang noted.

Although it goes against intuition, more detailed cancer detection is not always a plus for patients because it can produce unintended consequences known as “false positives.”

Most famously, in May of last year, the U.S. Preventative Services Task Force, a national group that examines the effect of new medical technologies and practices, recommended against the most common type of prostate cancer testing for most men.

The task force said the benefits of detecting and removing early cancers had proved to be less than the harm done by unnecessary follow-up tests and surgeries. Too many of the tumors spotted by the testing were false positives that would not have been a problem during the patient’s lifetime, so treating them was actually harmful to patients. In that case, the task force says, it’s better to not do any detection at all.

As any man knows who has discussed the issue with his doctor recently, the topic remains controversial. But false positives mean that apparent improvements sometimes do more harm than good.

Chang can quantify her response to that concern, taken from research before the technology was approved: 40 percent. “There is a 40 percent reduction in callbacks with tomosynthesis,” she said.

In other words, 3-D mammography’s improved ability to determine whether an abnormality is a concern means 40 percent fewer women had to be called back in to have a second mammogram.

“That means less stress, less worry for them,” she said.

St. Joseph Hospital has only had the new machine for a few weeks, so it doesn’t have its own data yet, but Chang said the research is solid and she expects the numbers to hold true in Nashua.

St. Joseph Hospital performs about 11,000 mammograms a year, Chang said, and has about a 10 percent callback rate.

Cutting that callback figure by 40 percent over the course of a year would mean that at least 400 women won’t have the worry of being told they need to come back into the office because something suspicious was seen on their mammogram.

If that holds true, it’s a definite advantage for patients. However, it could mean a reduction in income for the hospital unless the improved technology can draw more patients, which helps explain St. Joseph Hospital’s advertising.

There’s also another subtle cost: More detail in the images means more work for doctors to examine them, so as not to miss anything captured by the technology.

But Chang, who says she is regularly pitched by companies selling new devices, said the 3-D mammography is worth it for patients and the community.

“I see a lot of technology that isn’t worth the cost, but this makes a real difference,” she said.

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