Multidimensional Analysis of the Learning Curve for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy in Peritoneal Surface Malignancies

Objective: To evaluate the learning curve of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in treating peritoneal surface malignancies (PSM). Summary and Background: CRS and HIPEC to treat PSM is a complex procedure with a significant morbidity. A long-lasting training program is required to acquire expertise in this type of operation. Methods: We performed CRS using peritonectomy procedures. HIPEC through the closed abdomen technique employed cisplatin and mitomycin-C or cisplatin and doxorubicin. Risk-adjusted sequential probability ratio test was used to assess the learning curve on a series of 420 cases of PSM on the basis of rates of incomplete cytoreduction and G3-5 morbidity (NCI-CTCAE v3). We determined control limits setting the type I/II error rates and unacceptable odds ratios (ORs) for the outcomes being studied. We performed the risk adjustment using logistic regression model. Results: Rates of incomplete cytoreduction, G3-5 morbidity, and postoperative mortality rates were 10.2%, 28.5%, and 2.1%, respectively. The risk-adjusted sequential probability ratio test curve crossed the lower control limit at the 137th and 149th case, respectively, for incomplete cytoreduction and G3-5 morbidity. At those points, the actual ORs are lower than the prespecified ORs for outcomes being studied. Therefore, we estimated that approximately 140 cases are necessary to ensure surgical proficiency in CRS and HIPEC. Conclusions: CRS and HIPEC to treat PSM has a steep learning curve requiring 140 procedures to acquire expertise.