EVALUATION OF SKELETAL METASTASES RELATED TO PRIMARY CANCERS USING BONE SCINTIGRAPHY AND SPECT/CT

Abstract

Bone metastasis is a clinically significant complication of advanced malignancy, and its prompt and accurate identification is essential for staging, treatment planning, and the prevention of skeletal-related events. Technetium-99m (^99mTc) bone scintigraphy is the most widely used technique for whole-skeleton assessment, but planar images have limited specificity; hybrid single photon emission computed tomography/computed tomography (SPECT/CT) combines functional and anatomical information to improve lesion localization and characterization. This study aimed to evaluate skeletal metastases related to primary cancers using bone scintigraphy and SPECT/CT. A cross-sectional observational study was conducted over two months at the Combined Military Hospital (CMH), Lahore. Using convenience sampling, 59 adult patients with known primary malignancies referred for bone scintigraphy were enrolled; patients with primary bone tumors, severe renal impairment, recent trauma, fracture or orthopedic surgery, and pregnant or lactating women were excluded. Data were analyzed in SPSS version 26 using descriptive statistics, the chi-square test, Fisher’s exact test, and McNemar’s test. The mean age was 60.37 ± 15.36 years and the mean body weight 69.80 ± 7.72 kg, and 52.5% of patients were female. Breast (30.5%) and prostate (28.8%) cancers were the most common primary malignancies, and 69.5% of patients reported bone pain. Planar bone scintigraphy detected abnormalities in 44 patients (74.6%), whereas SPECT/CT detected abnormalities in 53 (89.8%). Every scintigraphy-positive patient was also positive on SPECT/CT, and SPECT/CT identified abnormalities in 9 of the 15 patients with negative planar scans. The spine, ribs, and pelvis were the most frequently involved sites. The association between the two modalities was statistically significant (χ² = 19.59, p < 0.001), and McNemar’s test confirmed a significant difference in detection (p = 0.004). These findings indicate that bone scintigraphy remains a valuable screening tool, while the addition of SPECT/CT improves the detection, localization, and characterization of skeletal lesions and supports more accurate staging and treatment planning.