The Value of Positron Emission Mammography (PEM) in Management of Breast Cancer

Abstract

To determine the value of few key parameters measured from 3D-PEM breast images in breast cancer management. One hundred nine, pathology proven, female breast cancer patients with mean age of 66 ± 11 (ranging from 28 to 83) years underwent PEM imaging for surgical planning at our institute. Ten mCi of 18-flourodeoxy glucose (FDG) was administered intravenously. One hour post-injection, multiple tomographic sections of the right and left breast were obtained in medio-lateral, oblique and cranio-caudal (cc) positions. Retrospectively, lesion depth (using cc image), lesion size, lesion shape (ovoid, circular, irregular ovoid, irregular circular, ring-like, linear) and maximum standard uptake value (SUVmax) of FDG in lesion and normal fatty breast area was evaluated. The ratio of SUVmax of lesion to normal fatty breast area was computed. Whole body PET/CT FDG images were used for staging the breast cancer. Out of 109 patients 53.0% had left sided lesion and 47.0% were right sided. Seventy six percent of the patients had a single lesion and the remaining 24.0% had multiple lesions. The most common shape was found to be circular for 42.4% of the patients, 23.6% irregular circular, 21.2% irregular ovoid, 8.3% ovoid, 3.0% linear and 1.5% ring like. Less than 2.0% had a lesion depth of ≤ 0.7 cm. Remaining 98% had lesions at depths ranging from 0.9 cm to 10.8 cm with mean depth of 3.8 ±1.9 cm. All patients with lesions ≥ 0.7 cm were candidates for treatment with single lumen balloon catheter using Xoft E-brachytherapy system for accelerated partial breast irradiation (APBI). Patients with lesion depths ≤ 0.7 cm were candidates for multi-lumen balloon catheter. The average value for maximum PEM SUV (SUVmax) in the lesion was 1.49 ± 1.09 (ranging from0.46 to 7.48) and in normal fatty breast tissue was 0.25 ± 0.13(ranging from 0.07 to 0.90). The mean ratio of SUVmax of lesion to normal tissue was 6.35 ± 4.04 (ranging from 0.88 to 24.1). The number of metastatic lesions was determined from PET/CT images. Preliminary findings suggest a correlation of this ratio with staging of the breast cancer determined from whole body PET/CT scan of these patients. PEM imaging may provide valuable parameters such as accurate lesion depth measurement which in turn helps decipher the selection of single vs multi-lumen catheter for APBI. In addition to this the ratio of SUVmax may help predicting the stage and hence, prognosis and management of breast cancer.