Special to The American
About one-third of women diagnosed with early-stage breast cancer will have their cancer travel, or metastasize, to other parts of the body, with the bone being the most common site of initial detectable spread. Controversy surrounds the question of whether CT and bone scans should be standard in evaluating patients for these metastases, or whether a combination of PET/CT scanning might be more effective at detecting breast tumors that have reached nearby bones.
Currently, bone scans, positron emission tomography (PET), and computed tomography (CT) all continue to be used alone or in combination for the detection of breast cancers suspected to have spread. Each has its own strengths. A PET scan uses a radioactive chemical and a special camera to look at biochemical activity in the body. Cancer cells typically have higher activity. A CT scan uses multiple X-rays to make detailed pictures of structures inside of the body and can analyze the size and shape of tumors. A bone scan is a nuclear scanning test that can identify new areas of bone growth or breakdown including areas of cancer metastases.
A recent retrospective study conducted by Memorial Sloan-Kettering Cancer Center investigators suggests that PET/CT scanning might offer the most efficient and effective detection of newly diagnosed breast cancer that has spread to the bone. The new findings may mean less stress and more timely therapy for patients, and could make the longtime use of radionuclide bone scans for breast cancer unnecessary in this setting.
With one machine, simultaneous PET/CT draws on the strengths of each tool to both detect and locate abnormal and potentially cancerous cells. Further, its diagnostic reach can go beyond the bone. “In contrast with bone scans, which are only able to detect bone metastases, PET/CT has the advantage of concurrently imaging other common sites of breast cancer metastases such as the liver and lungs,” says lead author Patrick Morris, a breast cancer specialist at Memorial Sloan-Kettering.” Therefore, PET/CT may not only be superior to bone scan for the detection of bone metastases, it may also be more convenient for patients.”
Researchers identified 163 women with suspected metastatic breast cancer who had been evaluated by both PET/CT and bone scans between January 2003 and June 2008. The study, published in the June issue of the Journal of Clinical Oncology, compared the images and, when possible, correlated them with confirmatory biopsy results.
The majority of the dual tests were in agreement, leaving just 31 cases (19 percent) conflicting. A majority of the 31 represented cases of a PET/CT catching tumors that a bone scan missed. Dr. Morris estimates that some metastases could have been discovered by up to three or four months earlier using PET/CT instead of a bone scan. Further, PET/CT uncovered cancer’s spread outside the bone in 62 percent of patients in the study.
This improved accuracy and efficiency over older imaging approaches may help patients and their clinicians save time and money, as well as emotional and physical pain. “False positive radiology findings without a biopsy confirmation can lead to inappropriate therapeutic interventions and significant distress for the patient,” Morris says. “False negative findings, on the other hand, may result in delayed therapy, symptoms, and altered quality of life. Therefore, the development of a simple, reliable, and convenient test for imaging patients with suspected metastatic breast cancer is desirable.”