Some Staging Studies Not Beneficial in Early Breast Cancer Work-Up
?San Francisco, CA—Three frequently used radiologic tests rarely detect metastases in patients with a new diagnosis of breast cancer and should not be routinely performed, according to a comprehensive literature review presented at the 2012 Breast Cancer Symposium.
Bone scan, liver ultrasound, and chest x-ray are often used as first-line screening modalities for potential metastases. However, no established protocol is available for such costly screening, and no solid evidence justifies its use—which now is often accompanied by computed tomography (CT), positron-emission tomography (PET), and magnetic resonance imaging (MRI), said Stuart-Allison Moffat Staley, MPH, a medical student at the University of North Carolina School of Medicine, Chapel Hill.
“Our literature analysis suggests that these 3 tests are of little use in screening women for metastases, and likely result in a lot of false-negatives in early-stage disease,” Ms Staley said at a press briefing. “The relevant topic is cost containment. When you look at the cost of these 3 tests, they are significantly less expensive than other more advanced imaging options; however, when they are used routinely in thousands of new breast cancer patients annually, collectively they become costly to the healthcare system,” she indicated.
Ms Staley noted that as a tertiary care center, her institution receives many referrals from community oncologists. “Many patients do come in having had staging evaluations, and physicians are using chest x-ray and liver ultrasound in many cases,” she stated.
Test Outcomes Vary by Disease Stage
The investigators asked whether bone scan, liver ultrasound, and chest x-ray help to determine the extent of metastatic disease in asymptomatic, newly diagnosed patients with breast cancer. Using detection rate (defined as the number of patients with an abnormal test result divided by the total number of patients tested) as the primary outcome, 8 studies met the inclusion criteria.
The primary outcome measure ranged from <0.9% to approximately 4%. As expected, the rates were highest for patients with stage III disease. By modality and by stage, the detection rates were:
- Bone scan: 1.29% for stage I, 3.09% for stage II, and 12.5% for stage III, for an average of 4.18%
- Ultrasound of the liver: 0.47% for stage I, 1.0% for stage II, and 4.2% for stage III, for an average of 1.46%
- Chest x-ray: 0% for stage I, 0.42% for stage II, and 4.57% for stage III, for an average of 0.87%.
“These very low detection rates, particularly in stage I and II disease, make us question the utility of these 3 modalities for an adequate staging evaluation,” Ms Staley noted.
Detection rates of metastases were higher for women with stage III disease than for women with stage I or II breast cancers, particularly as detected by bone scans (12.5%), suggesting that this modality may still have a role in this subgroup.
However, the researchers suggested that these 3 particular imaging tests may be unnecessary even in these women, when the patients are also assessed with more sensitive imaging, such as PET, CT, or MRI scans.
Andrew Seidman, MD, a medical oncologist at Memorial Sloan-Kettering Cancer Center, New York, commented on the findings. “It strikes me that we are living in a time when we move quickly to embrace new, more sensitive technologies, but the elephants in the room are the false-positives. The ‘Choosing Wisely’ campaign, which ASCO [American Society of Clinical Oncology] participates in, recommends that we back off from examinations that are really not evidence-based and which, in many cases, do more harm than good.”
Extensive Testing Is Futile in Low-Risk Patients
The results of this study are consistent with other findings suggesting that extensive testing is futile in patients with a very low risk of distant metastases, pointed out Dr Seidman. “Doing extensive imaging, looking for something that has a very low yield and little impact on health, can lead to unnecessary procedures, biopsies, complications, and costs,” he noted.
The higher yield in patients with stage III disease probably exempts this group from such restrictions, Dr Seidman added. He said that for patients with stage I and II cancer, he does not order these imaging tests, nor does he order PET scans. “I reserve these for patients at high risk, which includes stage III breast cancer,” he said.