A retrospective study conducted at the University of Texas M.D. Anderson Cancer Center has demonstrated that the utilization of FDG-PET/CT for the initial staging of inflammatory breast cancer (IBC) may allow clinicians to provide a better prognosis for patients with this aggressive form of breast cancer. The study appeared in the February issue of the Journal of Nuclear Medicine.
According to the American Cancer Society, IBC accounts for approximately 1 to 3 percent of all breast cancers diagnosed in the United States. It tends to occur in younger women—African-Americans appear to be at higher risk—and its incidence is increasing. The disease gained its name because the affected breast displays the same symptoms that occur with inflammation.
However, the symptoms of IBC are not caused by infection or injury, but by cancer cells blocking lymph vessels in the skin. Patients often do not have a breast lump, and symptoms may not show up on a mammogram. Because it does not look like typical breast cancer, the disease can be harder to diagnose.
“The standard treatment for IBC is neoadjuvant chemotherapy followed by modified radical mastectomy and radiation therapy,” the research team wrote. “Multiple investigations, including chest radiography, whole-body bone scintigraphy (WBS), CT, and MRI, are conducted to exclude distant metastasis before therapy.”
IBC tends to grow more quickly and aggressively than the more common types of breast cancer. Upon diagnosis, it is already considered to be at least stage IIIB (locally advanced) and even stage IV if it has spread to distant parts of the body. Because of this, IBC has been harder to successfully treat than other types of breast cancer. Knowing the extent of the disease at the start could have a great impact on the outcome for many patients
For the study, researchers reported findings in 41 women between the ages of 25 and 71 (mean age, 50 years) with unilateral primary IBC who had originally presented with swelling, some pain and skin changes, such as rash and skin discoloration between July 2005 and July 2007. A palpable mass was not evident on physical examination in 63 percent of patients, which is not unusual in this form of breast cancer, and 90 percent had no symptoms of distant metastasis (disease spread beyond the breast).
Each patient underwent a whole-body FDG-PET/CT exam on a GE Healthcare Discovery ST PET/CT system. The scans showed that nearly half of the patients (49 percent) had distant metastasis, and 27 percent had disease in multiple sites. Neither finding had been previously detected by conventional imaging. These results were confirmed by biopsy and supplementary imaging.
“The preliminary results of this retrospective study demonstrate that PET/CT shows an exceedingly high percentage of ipsilateral axillary (90 percent), and subpectoral (44 percent) nodal (N3) disease,” the authors wrote.
One of the more intriguing possibilities suggested by the research is utilizing PET/CT as a first-line imaging modality in cases of suspected IBC. Although the modality is currently not allowed for this purpose, the study outcomes support further investigation of this diagnostic course.
“If validated, the cost of a PET/CT study in these patients may be equivalent to the total cost of imaging multiple organs and allow a single hospital visit and decreased imaging time, when compared with the time required for a battery of staging studies,” the authors wrote.