Routine X-Rays, Bone Scans Show Low Detection Rate for Spotting Breast Cancer Spread
By Charlene Laino
WebMD Health News
Reviewed by Louise Chang, MD
Sept. 12, 2012 (San Francisco) -- Tests often performed to look for cancer spread in women with early-stage breast cancer are generally unnecessary, new research suggests.
Analysis of pooled data from eight published studies involving about 1,700 women with breast cancer shows that bone scans, liver ultrasounds, and chest X-rays very rarely detect the spread of cancer in newly diagnosed patients without symptoms.
"The findings reinforce the message we sent out to members regarding the lack of utility of almost any X-ray in low-risk patients -- that is, those with Stage 1 or Stage II breast cancer. Additionally, we showed the cost-effectiveness of ordering bone scans, PET, and CT imaging is so low that they should not be done," says American Society of Clinical Oncology (ASCO) spokesman Andrew Seidman, MD. He is a medical oncologist at Memorial Sloan-Kettering Cancer Center in New York City.
"If doctors would heed the recommendations, we would save an enormous amount of money and spare patients from unnecessary invasive procedures, overtreatment, unnecessary radiation exposure, and misdiagnosis," he says.
The problem: Old habits die hard, particularly among doctors who are afraid of missing potentially treatable cancer spread outside the breast area if they don't order the tests, Seidman says. He was not involved with the study, presented at a news briefing in advance of the 2012 Breast Cancer Symposium, which starts Thursday.
Low Detection Rates
An estimated 226,870 new cases of invasive breast cancer are expected to occur in women and 2,190 cases in men in the U.S. in 2012. An additional 63,300 cases of in situ (non-invasive) breast cancers are expected to occur in U.S. women, totaling more than 290,000 new cases. Non-invasive breast cancer means the cancer has remained in the milk ducts or lobules of the breast, whereas invasive cancer means it has grown into the healthy breast tissue.
In Europe and Canada, it is common for newly diagnosed patients to get a bone scan, a liver ultrasound, and chest X-ray to look for signs of cancer spread, says researcher Stuart-Allison Moffat Staley, MPH, a medical student at the University of North Carolina School of Medicine.
In the U.S., patients typically get one or two of the tests, followed in many cases by more sophisticated imaging screening with CT, PET, or MRI.
There's no set cost for tests -- a chest X-ray runs from $200 to $900, she says. Bone scan and liver ultrasounds also cost hundreds of dollars, while the more advanced imaging tests cost thousands. "But even if the cost of a test is only $100, the total cost is huge when you multiply by thousands of breast cancer patients," she says.
Despite their pervasiveness, there is no solid evidence showing the routine use of these tests to spot metastatic disease, or cancer spread outside the breast area, improves patients' health. So the researchers posed the following question: "Among women with newly diagnosed breast cancer that are otherwise asymptomatic (without symptoms), does evaluation with bone scanning, liver ultrasound, and chest radiograph help to determine the extent of metastatic disease?"
The answer: Not really.
The tests had very low detection rates of cancer spread, particularly for the 1,482 women with stage I and II cancer: 2.43% for bone scans, 0.82% for liver ultrasound, and 0.51% for chest X-ray.
In the 400 women with stage III cancer, the detection rates were somewhat higher, particularly with bone scans: 12.5%, vs. 4.2% and 4.57% for liver ultrasound and chest X-ray, respectively.
"We must rethink the utility of these tests. Are they saving lives? How many false positives are there? How many false negatives? Likely a lot. Women with early-stage cancer may not need any of these tests," Staley says. "And we don't even know which tests are best for women with stage III cancer."
Although she and Seidman don't have the answers, they agree a head-to-head comparison of these radiological tests with more sensitive imaging, such as CT or PET, looking at effectiveness and cost, is a logical next step.
ASCO isn't the only medical group taking a long hard look at whether procedures and tests work and work well enough to justify their cost. The American Board of Internal Medicine Foundation's Choosing Wisely campaign, for example, developed a list of commonly used tests or treatments whose necessity is not supported by high-level evidence.
These findings were presented at a medical conference. They should be considered preliminary, as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.
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SOURCES: 2012 Breast Cancer Symposium, news briefing, Sept. 11, 2012. Andrew Seidman, MD, attending physician, medical oncology, Memorial Sloan-Kettering Cancer Center, New York City. Allison Moffat Staley, MPH, medical student, University of North Carolina School of Medicine, Chapel Hill. Schnipper L. et al, Journal of Clinical Oncology, April 3, 2012 online.
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