Long-term outcomes, pathological classification and prognostic factors in localised and advanced appendiceal goblet cell adenocarcinoma following cytoreductive surgery, intraperitoneal and systemic chemotherapy.

BACKGROUND

Appendiceal goblet cell adenocarcinomas (GCAs) are rare and preferentially spread to the peritoneum. They comprise differing histological patterns with variable prognosis. Cytoreductive surgery and heated intraperitoneal chemotherapy (CRS + HIPEC) is offered in specialist centres for eradication of peritoneal metastases, but the role of systemic chemotherapy is unclear. This study aimed to evaluate the long-term outcomes and prognostic factors of GCA patients using the World Health Organisation (WHO) 2019 grading following CRS + HIPEC and the role of systemic chemotherapy.

MATERIALS AND

METHODS

Patient data from a peritoneal tumour centre were identified through a prospective database and histopathology archive (1993-2021). Patients were selected for CRS + HIPEC based on disease distribution and burden. Cases were re-reviewed for histological and two-tiered grading. Systemic chemotherapy was categorised into curative (neo/adjuvant) and palliative intent. The primary endpoint was overall survival (OS).

RESULTS

There were 210 patients with GCA who had 60% localised disease (M0) and 40% peritoneal metastases (M1) at diagnosis. CRS was carried out on 135 (64%) patients and systemic chemotherapy was given to 85 (40%) patients: 11 (13%) neoadjuvant, 9 (11%) adjuvant and 52 (61%) palliative. After multivariable analysis, positive lymph nodes, peritoneal metastasis, no perforation, no CRS and systemic chemotherapy were associated with increased risk of death (P < 0.05). Re-categorisation of the cohort into two-tiered grading showed improved stratification compared with Tang or WHO 2019 grading. Systemic chemotherapy was associated with benefit for patients with high-grade disease, positive lymph nodes and completeness of cytoreduction score CC1-3 CRS (P < 0.05).

CONCLUSION

This study represents the largest non-registry cohort of appendiceal GCA that evaluates prognostic factors. It outlines outcomes after CRS + HIPEC and provides a comprehensive analysis of the WHO 2019 grading with consideration of a two-tiered system for better risk stratification and selection of patients for systemic chemotherapy.