Research Shows PET/CT Spots Spread of Inflammatory Breast Cancer Earlier
The spread of an extremely aggressive form of breast cancer can be detected earlier by using a combination of two imaging modes, researchers at The University of Texas M. D. Anderson Cancer Center reported at the Radiological Society of North America annual meeting.
Combining computed tomography (CT) with positron emission tomography (PET) enables researchers to more quickly and accurately pinpoint the location of metastases from inflammatory breast cancer. About 40 percent of women with the disease survive for five years.
"Our results showed that PET/CT allows non-invasive evaluation and accurate cancer staging throughout the body in a single examination," says Selin Carkaci, M.D., assistant professor in M. D. Anderson's Department of Diagnostic Radiology, who presented the research at the meeting.
"PET/CT is able to detect disease in its earliest stages, when changes are happening at a functional and cellular level, which is quite different from other imaging modalities that identify disease when there is distortion of normal anatomy," Carkaci says. Early identification of metastases allows earlier treatment.
The study presented in Chicago included 41 women newly diagnosed with inflammatory breast cancer who each underwent a whole-body PET/CT exam. Metastases were found in 20 patients (49 percent) and were confirmed by biopsy or correlative imaging. Two false positives identified disease when none was present, resulting in an accuracy rate of 95 percent. PET/CT scans were 98 percent accurate in identifying cancer that had spread to the local lymph nodes.
Currently CT, whole body bone scan, ultrasound and MRI are most often used imaging modalities for detecting disease spread to distant sites. FDG PET/CT has an emerging role in the comprehensive staging of inflammatory breast cancer.
CT provides a detailed image of the body's organs, bones, other tissues and tumors. PET reflects what the tumors are doing - metabolically and chemically.
A patient receiving a PET/CT, is first injected with a radioactive drug consisting of F-18 tagged glucose. The CT scanner takes a series of x-ray pictures to create an extremely detailed image of the size and shape of the abnormal cancerous growths. A PET scan then detects where the glucose has gathered, literally lighting up areas of concentration. Because fast-growing tumors more readily absorb glucose than normal cells, they show up as bright spots on the PET scan that tip off their location and concentration in the affected organs.
Some recent studies showed that the use of PET/CT early in the course of the systemic therapy could quickly determine whether a treatment regimen is working or should be changed. Whether or not PET/CT should become the clinical standard for evaluation of response to therapy awaits more research.
"Large-scale trials addressing the clinical utility of PET/CT may lead to a change in the routine diagnostic algorithm and follow-up protocols for patients with inflammatory breast cancer," Carkaci says.
Inflammatory breast cancer is rare - representing just 1-5 percent of all breast cancers diagnosed. Unlike other breast cancers that present as a lump, inflammatory breast cancer is a more diffuse disease that spreads throughout the breast tissue. Symptoms include: redness, swelling, and warmth in the breast, skin that is reddish, purple or bruised, has ridges and/or appears pitted like an orange.
Because the symptoms are ambiguous, women with IBC are more likely than other women with breast cancer to be misdiagnosed, and ultimately diagnosed after the disease has metastasized.
Earlier this year, M. D. Anderson opened the world's first clinic devoted to treating the disease, the Morgan Welch Inflammatory Breast Cancer Research Program and Clinic. The clinic sees more cases of inflammatory breast cancer than any institution in the United States.
Co-authors with Carkaci are senior author Homer A. Macapinlac, M.D., chair of M. D. Anderson's Department of Nuclear Medicine; H.T. Le-Petross, M.D., of M. D. Anderson's Department of Diagnostic Radiology; Massimo Cristofanilli, M.D., of M. D. Anderson's Department of Breast Medical Oncology and director of the Welch Clinic; and A. M. Angullo-Gonzalez, M.D., of M. D. Anderson's Department of Breast Medical Oncology and W.T. Yang, M.D., of M. D. Anderson's Department of Diagnostic Radiology, Chief of Breast Imaging Section.