Evaluation of a new staging classification and a Peritoneal Surface Disease Severity Score (PSDSS) in 229 patients with mucinous appendiceal neoplasms with or without peritoneal dissemination

Introduction: Most classifications of mucinous appendiceal neoplasms (MAN) do not take into consideration the type of primary tumor or the burden of peritoneal disease.

Materials and Methods: We conducted a retrospective evaluation of 229 patients with MAN. The severity of their disease was analyzed with the Peritoneal Surface Disease Severity Score (PSDSS) on a five-point scale that included: (1) the primary appendiceal tumor, (2) the type of peritoneal dissemination, and (3) the burden of disease. Overall survival was analyzed according to five tiers of estimated disease severity based on the above parameters.

Results: There were 19, 67, 59, 43, and 41 patients with PSDSS 0, I, II, III, and IV, respectively. One hundred seventy-three patients underwent cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Overall survival was 80.0 months in this group with 5-year survival of 100%, 79.2%, 23.3%, and 6.9% in patients with PSDSS I, II, III, and IV, respectively (P<0.001). On multivariate analysis, sex and PSDSS stage were identified as independent predictors of survival.

Conclusions: The PSDSS appears to be an important prognostic indicator in patients with MANs with or without peritoneal dissemination and may improve selection of patients for appropriate therapy from the time of diagnosis.