Pancreatic cancer in patients with chronic calcifying pancreatitis: Computed tomography findings - a retrospective analysis of 48 patients

Objective: Chronic calcifying pancreatitis (CCP) is a risk factor for pancreatic cancer (PC). Symptoms of PC are non-specific in patients with CCP, and diagnostic imaging can be difficult. Some studies have shown that diagnosis may take several months, leading to delays in treatment (Lin et al., 2015; Lennon et al., 2014) [2,3]. The aim of this study was to describe the radiological signs of PC in patients with CCP.

Methods: This retrospective, single-center study was conducted between January 2004 and December 2014. Patients with CCP who were being monitored for PC were included. Each patient diagnosed with PC was matched with two CCP controls who did not develop PC.

Results: We studied 48 patients with CCP (30 men (62%) and 18 women (38%), mean age 69.4 years). Sixteen patients (with 18 tumor sites) who developed PC (1.52%) were compared with 32 controls who did not develop PC. A hypodense mass was observed in all of the patients with PC, predominantly in the pancreatic head (61.2%). No such masses were observed in the controls (p<0.001). The average mass size was 36.3mm, and the masses were observed to push aside the calcifications in all patients (p<0.001). Calcifications were very abundant (>10) in 33.3% of the patients with PC and in 71.9% of the controls (p=0.0076). The main pancreatic duct (MPD) was dilated in all of the patients with PC (average diameter 8.6mm; homogeneous in 83.3%) and in only 46.9% of the controls (average 7.4mm; homogeneous in 37.5%) (p>0.05). Dilation of the intrahepatic bile ducts and common bile duct was observed in 15 (94.4%) of the patients with PC and in none of the controls (p<0.0001). The average alcohol consumption was 1g/day (0-5g/day) in the PC group and 4.6g/day (0-20g/day) in the control group. In addition, the average smoking history was 14.25 pack-years (0-40 PY) in the PC group and 27.70 PY (0-60 PY) in the control group.

Conclusion: The presence of a pancreatic mass in a patient with CCP is suggestive of malignancy, especially when few pancreatic calcifications are observed (that are pushed aside by the tumor) and when the tumor causes dilation of the common bile duct and main pancreatic duct.