A recent study suggests that in staging of breast cancer, bone scintigraphy analysis may not be necessary for detection of bone metastasis when positron emission tomography/computed tomography (PET/CT) imaging has been performed. Results of the study were published in the journal The Oncologist.
The prospective study included patients seen at a comprehensive cancer center in Porto, Portugal, between 2014 and 2020. PET/CT and bone scintigraphy were used for staging, with the 2 types of images obtained within 60 days of each other for each patient. Two or more senior nuclear medicine physicians evaluated imaging results. The researchers compared findings from PET/CT and bone scintigraphy analyses for each patient, and by anatomical region, to determine accuracy, sensitivity, and specificity in identifying bone metastasis with these approaches.
The study population included 410 patients, mean age was 54 years, and 79.5% of the patients had ductal carcinoma. Cancers presented as grade 3 in 69.0% of patients. Slightly less than half (47.1%) of patients had T2 tumors, 36.8% had N1 status, and 72.7% had M0 status. Among 112 (27.3%) patients with distant metastasis, bone metastasis was reported in 81 patients (72.3%).
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In patient-based analysis, the accuracy of PET/CT was calculated to be 98.05%, compared with 95.61% for bone scintigraphy (P =.0775). Sensitivity in detecting bone metastasis was 93.83% with PET/CT and 81.48% with bone scintigraphy (P =.0442). Specificity, which reflects the ability to minimize false positives, was 99.09% with each technique (P =.6831).
Comparisons between PET/CT and bone scintigraphy were also performed across several anatomical regions. In most cases, the accuracy and sensitivity of PET/CT were significantly greater than bone scintigraphy. These included evaluations of the pelvis and sacrum, the sternum, the spine, the humerus, the clavicle, and the scapulae. However, bone scintigraphy showed significantly greater accuracy and sensitivity in evaluations of the cranium. Measurements of the rib cage, the femur, and the tibia and fibula produced similar accuracy and sensitivity results for both techniques.
In analyses of receiver operating characteristic (ROC) curves for each technique, the area under the curve was 0.9509 with PET/CT, compared with 0.7969 with bone scintigraphy. Overall, analyses of ROC curves suggested greater sensitivity and consistency across bone segments with PET/CT than with bone scintigraphy.
“PET/CT surpasses [bone scintigraphy] in the detection of [breast cancer] bone metastases and must be the technique of choice to stage these patients,” the study investigators concluded.
Reference
Santos JC, Abreu MH, Santos MS, et al. Bone metastases detection in patients with breast cancer: does bone scintigraphy add information to PET/CT? Oncologist. Published online April 8, 2023. doi:10.1093/oncolo/oyad087
