Cytoreductive surgery for malignant peritoneal mesothelioma: importance of patient selection using diagnostic laparoscopy.

BACKGROUND: Malignant peritoneal mesothelioma (MPM) is a rare malignancy for which cytoreductive surgery (CRS), usually combined with hyperthermic intraperitoneal chemotherapy, is considered in selected patients. However, resectability may be difficult to assess preoperatively, particularly when small-bowel or mesenteric involvement is suspected. The primary aim was to describe CRS outcomes, with a secondary exploratory aim of evaluating the role of diagnostic laparoscopy in patient selection. METHODS: We retrospectively reviewed 45 consecutive patients with MPM who underwent surgical assessment of resectability between 2008 and 2025. Surgical outcomes after CRS and overall survival were evaluated. Patient selection according to the initial surgical assessment strategy and reasons for non-CRS were also assessed descriptively. RESULTS: Eighteen patients underwent upfront exploratory laparotomy and 27 underwent diagnostic laparoscopy. CRS was ultimately performed in 22 patients: 13 after upfront laparotomy and 9 after diagnostic laparoscopy. Among patients undergoing CRS, complete or near-complete cytoreduction (CC-0/1) was achieved in 5 of 13 patients (38%) in the upfront laparotomy group and in all 9 patients (100%) selected for CRS after diagnostic laparoscopy. Among the 18 patients who did not proceed to CRS after diagnostic laparoscopy, 17 had extensive small-bowel and/or mesenteric involvement. The 5-year overall survival after CRS was 52%, and was 58% in patients with CC-0/1 cytoreduction. CONCLUSIONS: CRS was associated with encouraging long-term survival in carefully selected patients with MPM. Diagnostic laparoscopy may facilitate assessment of resectability, particularly when small-bowel or mesenteric involvement is uncertain, and may help avoid non-therapeutic laparotomy in selected patients.