PET clarifies difficult breast cancer cases
Positron emission tomography (PET) can help clinicians pinpoint a diagnosis in breast cancer patients with formerly inconclusive assessments and can predict prognosis in an aggressive form of the disease, two recent studies show.
The research projects, both published in The Journal of Nuclear Medicine, involved the use of PET and special molecular imaging techniques to provide answers in challenging cases of breast cancer. In one study (2012;53[2]:182-190), 33 women with a history of estrogen-receptor-positive breast cancer and a formerly inconclusive assessment underwent PET scanning that employed a molecular imaging technique known as 18F-FES, which offers an entirely noninvasive means of capturing estrogen receptor expression in estrogen-receptor-positive metastatic breast cancer.
In nearly all study participants (88%), 18F-FES improved diagnostic information, and prompted a change in treatment in 48%. The technique proved especially helpful in detecting bone metastases.
The second study (2012;53[2]:249-254) focused on 20 patients with an aggressive subtype of breast cancer, triple-negative. At the outset of chemotherapy and again after the second cycle of treatment, the study participants underwent 18F-FDG-PET/CT, a molecular imaging method used to gauge how metabolically active tumors are, which in term helps determine likely therapeutic response and posttreatment prognosis.
At surgery, six patients had a pathologic complete response to treatment, whereas 14 had residual tumor. The use of 18F-FDG PET/CT demonstrated that patients who exhibited less than a 42% reduction in metabolism after two cycles of chemotherapy had a 100% risk of residual tumor at surgery and a 44% risk of early relapse.
