When breast cancer spreads from its primary location to other parts of the body, the bone is often the first site in which secondary tumors, known as metastases, are detected.
Identifying such metastases often involves extensive and redundant testing. Typically, physicians obtain images using bone scan, magnetic resonance imaging (MRI), computed tomography (CT), or positron emission tomography (PET), and then piece this information together to determine whether the cancer has spread.
In the future, much of this redundant testing may be avoided. A Memorial Sloan-Kettering study now suggests that patients can receive faster and more accurate diagnoses by a method in which PET and CT are performed simultaneously and on one machine.
The investigators compared this method, called integrated PET/CT, to bone scan — the traditional way of detecting bone metastases — by analyzing the clinical history of 163 women with breast cancer who had been examined with both methods.
The two tests were found to be comparable in many instances, but did not agree in about one-fifth of patients. “As we learned by analyzing samples of bone tissue obtained from some of these patients, PET/CT seems to be more accurate at detecting bone metastases,” explained Patrick Morris, a medical oncology fellow and the lead author of the study.
He added that integrated PET/CT is a more convenient option for patients since it allows several organs to which breast cancer commonly spreads — including the bone, liver, and lungs — to be imaged simultaneously. In contrast, bone scan can only be used to locate bone metastases.
The investigators cautioned that further trials are needed to establish whether the development of integrated PET/CT has made bone scans obsolete, an issue subject to some controversy.
“If our findings hold true, the issue can be laid to rest, and PET/CT could replace CT plus bone scan in patients for whom we are concerned about metastatic breast cancer to bone,” noted Maxine S. Jochelson, Director of Radiology for the Breast and Imaging Center and a co-author of the study, which was published in June in the Journal of Clinical Oncology. [PubMed Abstract]
Other senior authors included medical oncologist Heather L. McArthur and Clifford A. Hudis, Chief of the Breast Cancer Medicine Service.