Cytoreductive surgery plus perioperative intraperitoneal chemotherapy in pseudomyxoma peritonei: Aspects of the learning curve

Background: Cytoreductive surgery (CRS) plus perioperative intraperitoneal chemotherapy is a highly invasive treatment of peritoneal metastasis and requires many surgical procedures before mastering. The aim of this study was to estimate how many procedures are needed before stabilization can be seen in surgical outcome (R1 surgery, adverse events and bleeding) in patients with pseudomyxoma peritonei (PMP). Patients and methods: All 128 patients with PMP who were treated with CRS alone or CRS plus perioperative intraperitoneal chemotherapy between 2003 and 2008 at the Uppsala University Hospital, Uppsala, Sweden, were included. The learning curve was calculated using the partial least square (PLS) and cumulative sum control chart (CUSUM) graph. Two groups were formed based on the results of the learning curve. The learning curve plateau was considered the same as the stabilization in the CUSUM graph. Group I consisted of patients included during the learning period (n = 73) and Group 11 of patients treated after the learning period ended (n = 55). Comparisons between the groups were made on surgical outcome, survival and adverse events. Results: Stabilization was seen after 220 +/- 10 procedures. A higher occurrence of R1 surgery was seen in Group H (80%) compared to Group I (48%; P = 0.0002). Overall survival increased at four years after surgery in Group H compared to Group I (80% vs. 63%; P = 0.02). Conclusion: CRS plus perioperative intraperitoneal chemotherapy is a highly demanding procedure that requires more than 200 procedures before optimisation in surgical outcome is seen. (C) 2014 Elsevier Ltd. All rights reserved.