Peritoneal disseminations from appendiceal vs. colorectal mucinous adenocarcinoma. An Italian multicentric comparative study
In brief
Appendiceal cancer had 59% five-year survival after cytoreductive surgery and heated chemotherapy
In a 402-patient Italian cohort treated with cytoreductive surgery and heated chemotherapy in the abdomen, five-year overall survival was 59% for appendiceal tumors versus 35% for colorectal tumors; distant relapse was also less common with appendiceal cancer (28% versus 43%). The retrospective comparison shows different outcomes, but cannot establish that tumor origin caused the survival gap or clarify the role of perioperative chemotherapy.
- Journal
- European journal of surgical oncology : the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology (Q1)
- Published
- 6 October 2026
- Study design
- Cohort / observational study
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Dario Baratti, Mario Valle, Marco Tonello, Andrea Di Giorgio, Piero Vincenzo Lippolis, Manuela Robella, et al.
- PMID
- 42868949
- DOI
- 10.1016/j.ejso.2026.112182
Why clinicians should know about it
- Picked for Surgery (paper of the day, 18 October 2026): CRS/HIPEC outcomes better for appendiceal vs colorectal mucinous cancer
Abstract
BACKGROUND: We compared baseline characteristics, outcomes and patterns of failure between patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for peritoneal disseminations from appendiceal (MACA) or colorectal mucinous adenocarcinoma (MCRC), in order to assess clinical and prognostical differences. METHODS: Prospectively collected data for 402 patients treated for MACA (n = 218) or MCRC (n = 184) in 17 Italian centers were retrospectively analyzed. RESULTS: Colorectal origin was associated with lower peritoneal cancer index (PCI) (P < 0.001), lower rates of signet-ring cells histology (P = 0.016), T4a/b primaries (P < 0.001), negative nodes (P < 0.001), synchronous metastases (P < 0.001), microsatellite stability (P = 0.009), wild-type KRAS (P < 0.001) and BRAF (P < 0.001), but not wild-type NRAS (P = 0.999), incomplete cytoreduction (P = 0.014), and perioperative systemic anticancer treatments (s-ACT) (P < 0.001). Median follow-up was 70.5 months (95% confidence interval [CI] = 45.8-92.3) for MACA, and 40.2 months (95%CI = 35.4-55.2) for MCRC. Five-year overall survival was 58.9% (95%CI = 51.3-67.5) for MACA, and 35.4% (95%CI = 27.1-46.2) for MCRC (P < 0.001). Appendiceal origin correlated with better prognosis at multivariate analysis (hazard-ratio 2.52; 95%CI = 1.50-4.25; P < 0.001). Five-year cumulative incidence of distant relapses was higher for MCRC: 42.6% (95%CI = 30.8-52.4) vs. 28.1% (95%CI = 19.7-35.7) (P = 0.032). Incidence of peritoneal relapse was not different (P = 0.706). PCI correlated with survival in MCRC (P < 0.001), but not in MACA. Perioperative s-ACT correlated with worse prognosis in MACA (P = 0.024), but not in MCRC (P = 0.920). CONCLUSIONS: Peritoneal disseminations from MACA are associated with distinct clinical-biological features, better prognosis and lower incidence of systemic relapses, suggesting that MCRC and MACA are different entities. MACA should not be excluded from CRS/HIPEC based only on higher PCI. The role of s-ACT remain unclear.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.