Prevalence of Malignancy on Contrast-Enhanced Computed Tomography of the Abdomen and Pelvis in Patients With Unexplained, Unintentional Weight Loss.

OBJECTIVE: The aim of the study was to evaluate the prevalence of malignancy on contrast-enhanced computed tomography (CT) of the abdomen and pelvis in patients with unexplained, unintentional weight loss (UUWL). METHODS: This is a retrospective review of 999 adult outpatient contrast-enhanced CT of the abdomen and pelvis for UUWL. Patients were stratified into 2 groups: (1) weight loss only (WLO, n = 222) and (2) UUWL with additional symptoms (UUWL+, n = 777). χ2 test was performed to compare malignancy detection rate in the WLO and UUWL+ groups. RESULTS: Prevalence of malignancy was 5.3% (95% confidence interval [CI], 4.2%-7.1%; 55 of 999). Prevalence of malignancy in the WLO group was 2.3% (95% CI, 0.7%-5.2%; 5 of 222), lower than the prevalence of 6.2% (95% CI, 4.6%-8.1%; 48 of 777) in the UUWL+ group (P = 0.02). Prevalence of malignancy was lower in patients younger than 60 years in all patients and in the UUWL+ subgroup (P < 0.01 in both cases). CONCLUSIONS: There is low prevalence of malignancy on contrast-enhanced CT of the abdomen and pelvis in patients with UUWL, particularly in younger patients and those without additional symptoms.