Factors Associated with Bone Scintigraphy Positivity in Cholangiocarcinoma

Abstract

Objective: To examine factors associated with bone scintigraphy (BS) positivity in cases with cholangiocarcinoma (CCA) to help assess appropriate utilization of BS in CCA patients. Material and Methods: This cross-sectional study enrolled CCA patients who underwent BS for detection of bone metastasis between January 2012 and July 2020. The BS images were reviewed by two nuclear medicine physicians to assess BS positivity. Factors including tumor location, T stage, regional lymph node metastasis, other distant metastases, and serum carbohydrate antigen 19-9 (CA19-9) were evaluated. Associations between covariates and positive BS were analyzed using bivariate and multiple logistic regressions. Results: Among 158 CCA patients, 70 (44.3%), 84 (53.2%), and 4 (2.5%) had positive, negative, and equivocal BS, respectively. Of all 70 positive cases, 50 cases (71.4%) had multiple metastatic lesions. The spine was the most common metastatic site (n=55, 78.6%). After exclusion of equivocal cases, 154 were included in the regression models. In bivariate logistic regression, the factors associated with BS positivity were intrahepatic tumor location (OR=2.18, p-value=0.039) and other distant metastasis (OR=2.08, p-value=0.028). Further analysis using multiple logistic regression showed only other distant metastasis was associated with positive BS (OR=2.66, p-value=0.008). Conclusion: There was a significant association between other distant metastasis and BS positivity in CCA patients. This factor should be considered as a clinical indication for requesting BS in this group of patients.