PET/CT May Improve Inflammatory Breast Cancer Prognosis

For patients diagnosed with inflammatory breast cancer (IBC), fluorodeoxyglucose (FDG) PET/CT may be helpful for staging the disease earlier than conventional imaging, according to a recent study.

Homer A. Macapinlac, M.D. The University of Texas

Researchers at The University of Texas M.D. Anderson Cancer Center in Houston said that by using PET/CT, they were able to define the location and the extent of disease in patients with IBC, which can help improve prognosis by helping physicians find the most appropriate treatment.

"The standard thinking is that the cancer is local, but for patients diagnosed with this rare and aggressive form of breast cancer, PET helps see beyond the breast and may reveal more extensive disease," said Homer A. Macapinlac, M.D., co-author of the study and professor and chair of nuclear medicine at M.D. Anderson. "We rely on PET to call our attention to areas for potential biopsy, to establish the extent of the disease and to envision regional imaging that may need to be done."

The retrospective study, published in the February 2009 issue of The Journal of Nuclear Medicine, included records from July 2005 through July 2007. The study is the largest to date to evaluate PET/CT in the initial staging of IBC, said Dr. Macapinlac. "We looked at 41 women between the ages of 25 and 71, all patients newly diagnosed with unilateral primary IBC," he said.

The women had originally presented with breast swelling and pain or skin changes such as rash and skin discoloration. A palpable mass was not evident on physical examination in 26 patients (63 percent), which is not unusual in IBC. Ninety percent had no symptoms of distant metastases.

A 52-year-old woman with biopsy-proven right IBC. (a) Maximum intensity-projection reconstruction of CT-attenuation corrected PET image shows multiple areas of 18F-FDG uptake consistent with extensive metastasis. (b) Axial PET/CT shows 18F-FDG uptake in right breast, with associated diffuse skin thickening (short arrows), and uptake in bilateral hilar nodes (long arrows), axial skeleton (curved arrow), and pulmonary nodules (arrowheads). A 52-year-old woman with biopsy-proven right IBC. (a) Maximum-intensity-projection reconstruction of CT-attenuation-corrected PET image shows global hypermetabolic uptake in right breast (star), right subpectoral nodes (arrow), and right internal mammary nodes (arrowheads) and bilobar liver metastases (curved arrows). (b) Coronal PET/CT shows right subpectoral (arrow) and right breast (star) uptake. Images reprinted with permission of The Journal of Nuclear Medicine (JNM). Co-authors of "Retrospective Study of 18F-FDG PET/CT in the Diagnosis of Inflammatory Breast Cancer: Preliminary Data" include Selin Carkaci, Homer A. Macapinlac, Massimo Cristofanilli, Osama Mawlawi, Eric Rohren, Ana M. Gonzalez Angulo, Shaheenah Dawood, Erika Resetkov, Huong T. Le-Petross and Wei-Tse Yang, all of the M.D. Anderson Cancer Center in Houston. JNM, February 2009.

Each patient underwent a whole-body FDG PET/CT exam. Scans showed that nearly half of the patients (49 percent) had distant metastases and 27 percent had disease in multiple sites. The metastases had not been previously detected by conventional imaging modalities in 35 percent of those with distant disease. Results were confirmed by biopsy and supplementary imaging.

"The results were significant—in nearly half of these patients we identified distant metastatic disease," said Dr. Macapinlac. "Eleven of the 20 had disease in two or more organ sites, indicating extensive disease to begin with, which probably correlates with the poor prognosis."

In IBC, the cancer cells block the lymph vessels in the skin of the breast, causing swelling and redness. IBC accounts for 1 to 3 percent of all breast cancer cases in the U.S. and tends to be diagnosed in younger women when compared to non-inflammatory types. The disease occurs more frequently and at a younger age in African-Americans than in Caucasians. Like other types of breast cancer, IBC can occur in men, but usually at an older age than in women. Some studies have shown an association between family history of breast cancer and IBC.

When diagnosed, IBC is already considered to be at least stage IIIB and in some cases stage IV if it has spread to distant parts of the body. That is why knowing the extent of the disease up front may have great implications for patient outcome, said Dr. Macapinlac.

"The median survival is one to three years, but the good news is there are many new clinical trials that can be offered to these patients," he said. "These treatments show very good promise, which is why I think this study is particularly important. In addition, in the future we will be investigating how this technique will be useful in assessing response to these new therapies."

A PET/CT procedure for IBC patients could be less than or equivalent to the cost of separately imaging multiple organs and would require a single hospital visit and decreased imaging time when compared to the time required for several regional staging studies, Dr. Macapinlac added.

David A. Mankoff, M.D., Ph.D., said this study is one of the first specifically examining inflammatory breast cancer and one of a number of studies of FDG PET and PET/CT showing that PET/CT is beneficial as part of initial staging in locally advanced breast cancer. Still more investigation is needed, he said.

"M.D. Anderson is one of the centers leading the way on this research," said Dr. Mankoff, a professor of radiology at the University of Washington and Seattle Cancer Care Alliance. "This study is part of a growing body of literature that shows that PET/CT for patients who present with what looks like locally advanced breast cancer can be very helpful.

"You can identify a subset of patients who may have more widespread disease than you would have suspected without PET," Dr. Mankoff continued. "The other important thing this study shows is that PET is very helpful in identifying spread to regional lymph nodes, which is important for determining treatment."

Previous studies have not supported the use of PET/CT for early stage breast cancer, said Dr. Mankoff.

"In early stage breast cancer, from a variety of viewpoints including cost-effectiveness, PET/CT is not recommended," he said. "But with locally advanced breast cancer, the studies have generally supported and found that PET is very helpful. This study helps to show which patients benefit from PET/CT at their initial staging."