Background: Radiologic tests to determine the size and location of cancer on peritoneal surfaces are needed for patient management and for clinical research activity.
Methods: Computed tomography (CT) of the abdomen and pelvis were obtained on 45 patients with a diagnosis of peritoneal carcinomatosis before implementation of a complete exploratory laparotomy with biopsy or resection of all tissues suspicious of malignancy. CT findings and surgical findings were recorded and the data analyzed by dividing the abdomen into 9 regions or into 15 anatomic sites.
Results: In an overall patient analysis, the sensitivity was 79%. In the nine different abdominal regions, sensitivity was greater than 80% in the right flank, left flank, and right lower and left lower abdominal regions. Sensitivity was lowest in the pelvis (60%). Negative predictive value in the pelvis was 20%. The volume of tumor present within an abdominal region or anatomic site greatly influenced the sensitivity. A sensitivity of only 28% was recorded when tumor nodules were less than 0.5 cm in thickness. This increased to 90% when nodule thickness was greater than 5 cm.
Conclusions: CT is not a reliable diagnostic test for low volume tumor on peritoneal surfaces, and the greatest inaccuracies were recorded in the pelvis. Its diagnostic value increased as tumor volume increased.