Radiological predictors of complete cytoreduction in 59 patients with peritoneal mesothelioma treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy at a UK referral centre.

OBJECTIVE: To assess the imaging features of peritoneal mesothelioma and identify key anatomical sites that aid patient selection for complete cytoreduction.

METHODS: Pre-operative imaging of 59 (32 males, 27 females) patients who underwent cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) for histologically proven peritoneal mesothelioma [36 malignant peritoneal mesothelioma, 23 cystic mesothelioma were reviewed. Imaging findings were correlated with surgical outcome. Best imaging predictors of complete cytoreduction, n = 22 and major tumour debulking, n = 12 were assessed.

RESULTS: Most patients (88.9%) had diffuse peritoneal disease with mean radiological peritoneal cancer index of 18 ± 12 (range 2-39). Disease in the lesser omentum (n = 10), porta hepatis (n = 8), perigastric area (n = 5), mesentery (n = 25), small bowel (n = 17), hydronephrosis (n = 1), concurrent pleural disease (n = 2), lymph nodes (n = 1) and abdominal wall disease (n = 4) was considered unfavourable. While 78.9% of patients who underwent complete cytoreduction had no disease at unfavourable sites, 75% of those who underwent MTD did have disease at these sites. There was significant difference in the radiological peritoneal cancer index, severity of upper abdominal disease, small bowel and mesenteric involvement between patients who underwent complete cytoreduction and MTD for malignant peritoneal mesothelioma. Complete cytoreduction was not achieved in the presence of a rind of soft tissue around the small bowel (p = 0.016) and was unlikely in the presence of large volume upper abdominal disease (p = 0.06).

CONCLUSION: Involvement of key anatomical sites such as small bowel serosa and large volume upper abdominal disease reduced the likelihood of achieving complete cytoreduction in patients with malignant peritoneal mesothelioma. Advances in knowledge: Demonstration of small bowel disease and large volume upper abdominal disease on imaging in patients with malignant peritoneal mesothelioma can be used to identify patients who may not benefit from cytoreductive surgery.