Some Staging Studies Offer No Benefit in Early Breast Cancer Workup

TON - November 2012, Vol 5, No 10 — November 15, 2012

Three commonly used radiological tests rarely detect metastases in newly diagnosed breast cancer patients and should not be routinely performed, according to a comprehensive literature review presented at the American Society of Clinical On­cology (ASCO) 2012 Breast Cancer Symposium, held in San Francisco, California.1

Bone scan, liver ultrasound, and chest x-ray are often used as first-line screening for potential metastases. However, there is no established protocol for this costly screening—which is often accompanied now by advanced imaging such as CT, PET, and MRI—and there is no solid evidence to justify its use, said Allison M. Staley, MPH, a medical student at the University of North Carolina School of Medicine in 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,” 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 said.

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 said.

Literature Review Examined Tests’ Utility
The study asked whether bone scans, chest x-rays, and liver ultrasounds help to determine the extent of metastatic disease among newly diagnosed asymptomatic breast cancer patients. The researchers searched publications from 1990 to the present for articles that used detection rate—defined as the number of patients with an abnormal test result divided by the total number of patients tested—as their primary outcome of interest. Eight studies of 232 met the investigator’s criteria.

The primary outcome measure, pooled detection rates, ranged from <0.5% to approximately 4%. As ex­pected, they were highest for patients with stage III disease. Per modality and by stage, the detection rates were as follows:

  • Bone scan: stage I (1.29%), stage II (3.09%), stage III (12.5%), for an average of 4.18%
  • Liver ultrasound: stage I (0.47%), stage II (1.0%), stage III (4.2%), for an average of 1.34%
  • Chest x-ray: stage I (0%), stage II (0.42%), stage III (4.57%), 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,” she said.

Rates of metastases were higher for women with stage III disease than for those with stage I or II breast cancer, particularly as detected by bone scans (12.5%), suggesting this modality may still have a role in this subgroup. However, the authors suggested that these 3 particular imaging tests may be unnecessary even in these women, when the patients are also assessed with more sensitive imaging.

Andrew Seidman, MD, of 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 elephant in the room are the false-positives. The ‘Choosing Wisely’ campaign, which ASCO 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.”

This study is consistent with other findings suggesting that extensive testing is futile in patients with a very low risk of distant metastases, he said. “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 stage III patients probably exempts this group from such restrictions, he added. Seidman said 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.

Reference

  1. Moffat Staley A-S. Staging evaluation with bone scan, liver ultrasound, and chest radiograph in patients with primary breast cancer: a systematic review. Presented at: American Society of Clinical Oncology 2012 Breast Cancer Symposium; September 13-15, 2012; San Francisco, CA. Abstract 4.

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