Table 1.

Summary of the stages of surgical innovation according to the IDEAL paradigm (adapted from references 2 and 5), with description of the interpretation of these stages in this review relating to published work on pressurized intraperitoneal aerosol chemotherapy

Stage of innovation	Description	No. of patients	Proposed method of investigation	Studies in this stage included in this review
0 – Idea	Preclinical work in vitro and in animals	None	Varied	Preclinical studies in animals (in vivo and post‐mortem models) and in vitro
1 – Idea	First human applications: proof of concept and small safety studies	Very few	Structured case reports	Case reports and small case series. Occupational health and safety studies. Scientific studies of clinical samples Data presented relate to safety and/or initial feasibility/proof of concept Prospective or retrospective data collection
2a – Development	Major technical details defined but technique remains experimental	Few, selected	Prospective development studies	Larger case series, and single‐arm non‐randomized studies. Scientific studies of clinical samples Prospective or retrospective data collection
2b – Exploration	Individual learning curves progressing quickly, with resulting increase in patient accrual and broadening of indication. Effectiveness still not demonstrated formally	Many, mixed	Research database, explanatory or feasibility RCT	Large case series from a prospectively maintained database, and RCTs. Scientific studies of clinical samples. Prospective study relating to a new indication for the technique Primary outcomes are efficacy‐related. Prospective data collection
3 – Assessment	Procedure is part of many surgeons' practice and becoming the standard of care	Many, variable	RCT	RCT with primary outcome relating to efficacy
4 – Long‐term	Procedure is routine practice and long‐term outcomes and late/rare complications can be monitored	Almost all	Registry, rare case reports	Not applicable