Upper abdominal procedures were performed in 100% and 61.1% of the patients in the PDS and NACT–IDS arms, respectively (P = 0.0001). The percentages of optimal residual tumor (RT ≤ 1 cm) at PDS and IDS were 91% and 90% respectively, with a rate of complete cytoreduction (RT = 0) of 45.0% and 60.0%, respectively (P = 0.158)