Similar Survival Among All Subtypes of Mucinous Appendiceal Adenocarcinoma Except the Intermediate Subtype, Which Shows an Improved Survival.

Background: Limited success in the management of mucinous appendiceal adenocarcinoma (MACA) has been reported.
Methods: Cytoreductive surgery with perioperative intraperitoneal chemotherapy was used to treat a cohort of patients with peritoneal dissemination of MACA. The clinical and histopathologic variables were assessed for their impact on overall survival.
Results: The study analyzed 196 patients during a median follow-up period of 8 years. The patients had a median age was 46 years, a median survival of 12 years, and a mean survival of 12.4 years. Preoperative systemic chemotherapy and a high prior surgical score had a negative impact on prognosis. Survival was better for 37 patients (18.9%) with mucinous appendiceal adenocarcinoma-Intermediate (MACA-Int) histology than for 159 patients (81.1%) with MACA grade 1, 2, or 3, or signet ring cells (S) (p = 0.0004). Although MACA-1 and MACA-2 versus MACA-3 and MACA-S had a difference in survival of 63.9 versus 43.2 years at 5 years, with long-term follow-up evaluation, the differences in survival became insignificant (p = 0.5841).
Conclusion: The histologic subtype of MACA-Int had a 10-year survival of 81.1%, which was markedly superior to that of MACA-1, -2, -3, or -S (32.7%). With long-term follow-up evaluation, MACA-1, -2, -3, and -S did not differ significantly in survival.
(© 2022. Society of Surgical Oncology.)