Clinical characteristics and outcomes of patients with goblet cell adenocarcinoma of the appendix treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC): A multicenter cohort study.

Goblet cell adenocarcinoma (GCA) is a rare, aggressive type of appendix cancer (AC) often presenting with peritoneal disease (PD). While cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is standard for other AC subtypes, its role in GCA, particularly with high peritoneal cancer index (PCI), remains controversial. We conducted a retrospective analysis of two prospective databases, including patients with GCA undergoing first CRS/HIPEC. We described clinical characteristics and compared outcomes between PD patients with high (≥20) and low PCI. Progression-free (PFS) and overall survival (OS) were analyzed using the Kaplan Meier method. Prognostic factors were evaluated via multivariable Cox regression. Of 183 patients, 30 (16.4%) were non-metastatic (NM) and 153 (83.6%) had PD. In PD, median PCI was 20 (interquartile range [IQR]: 13-28). Complete cytoreduction (CC-0) was achieved in 61.4% of PD patients. Major complications (Clavien Dindo III-IV) occurred in 10% of NM and 33% of PD, with higher rates in PCI≥20 (p = 0.011). After median follow-up of 59 months, no NM recurred or died and 62.7% of PD patients recurred (77.1% intraperitoneal). Five-year PFS and OS for PD were 11.2% and 29.5%, respectively. Incomplete cytoreduction independently predicted worse PFS (hazard ratio [HR] 1.7, p = 0.009) and OS (HR 2.3, p < 0.001), while PCI≥20 did not. Five-year OS was similar in patients with high and low PCI (28.3% vs 32.0%, p = 0.551). Complete CRS/HIPEC offers promising survival in GCA with PD. NM patients at risk of PD show excellent survival. Further studies are warranted to optimize selection criteria.