Comparison of whole-body FDG-PET and bone scintigraphy in the evaluation of skeletal metastases in patients with breast cancer

An established standard imaging modality for detecting bone metastases in patients with breast cancer is through the use of 99mTc-hydroxymethylene diphosphonate (99mTc-IIDP) bone scintigraphy. It is clearly documented that sensitivity is generally high while specificity is often lower because of tracer uptake in non-malignant processes. The aim of this study is to evaluate the diagnostic performance of whole body 2-deoxy-2-[18F]-D- glucose positron emission tomography (18 F-FDG PET) and bone scintigraphy in the detection of bone metastasis in patients with breast cancer.METHODS: There were 232 consecutive patients who underwent FDG PET for breast cancer staging/restaging at our center during the study period. We included those who only had a bone scintigraphy within a month before or after the PET scan. The results of each image interpretation were compared retrospectively by an experienced nuclear medicine physician. Per-patient and per-lesion detection rates were collected. Bone metastasis slams was established on the basis of multimodality imaging and/or clinical follow-up for at least 6 months Weighted kappa was also calculated to determine agreement between the two modalities.RESULTS: Forty-seven patients were included in the study with ages ranging from 28-86 years. For the patient-based data, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 90%, 92.6%, 90%, 92.6%, and 91.5%, respectively, for FDG PET, and 95%, 44.4%, 55.9%, 92.3% and 66%, respectively,for bone scintigraphy. For the lesion-based data, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 66.4%, 90%, 94.7%, 50%, and 72.8%, respectively, for FDG PET, and 74.5%, 27%, 752%, 26.3% and 62.6%, respectively, for bone scintigraphy Agreement between the two modalities was slight.CONCLUSIONS: Overall, FDG PET shows to be as sensitive as bone scintigraphy in picking up bone metastases Furthermore, on both per patient and per lesion bases; PET was shown to be more confirmatory and more accurate with evidence of statistical significance. FDG PET and bone scintigraphy should play complementary roles in the detection of skeletal metastases.

The first MIBG therapy in the Philippines

Neuroblastoma is an embryonal tumor of children that frequently presents with metastases. Our patient is a 6-year-old girl who was diagnosed to have neuroblastoma with diffuse metastatic disease throughout the skeleton as seen in her 123I-MIBG scan in the United States. 18F-FDG PET/CT scan was done in the Philippines after chemotherapy and gene therapy, and before 131I-MIBG therapy. No additional lesions were seen on PET.  131I-MIBG was then performed and an 131I-MIBG with SPECT/CT thereafter, which showed an increase in size and extent of the lesion in the head and a decrease in number of the skeletal metastases. New 131I-MIBG-avid posterior cervical lymph nodes were also localized through SPECT/CT. For this patient, a follow-up 123I/131I-MIBG scan would be more cost-effective in assessing response to therapy. Sectional imaging may be done to obviate the need for sedation of this young patient.