8O - Outcomes for patients with appendix adenocarcinoma and the role of systemic chemotherapy

Background

Appendix adenocarcinomas (AA) are rare aggressive tumours often presenting with peritoneal metastases. The role of systemic chemotherapy remains unclear. The aim of this study was to evaluate the outcomes of patients with AA and to evaluate the role of systemic chemotherapy.

Methods

Data were collected from a prospective database (2005-2021). Cytoreduction (CRS) was described: CC0 (no residual disease, RD), CC1 (<0.25cm RD), CC2 (0.25-2.5cm RD) or CC3 (>2.5cm RD). Chemotherapy was categorised as ‘prior’ (>6 months, m, before CRS); ‘neoadjuvant’ (<6m before CRS) or ‘adjuvant’ (<6m after CC0-1 CRS) and ‘palliative’ (after CC2-3 CRS, unresectable or recurrent disease). Analyses used descriptive statistics, Kaplan-Meier and Cox regression methods.

Results

We identified 216 patients with AA: 141 mucinous, 71 not otherwise specified, 4 signet ring cell. Median age was 59 (21-81) and 58% were female. 149 (69%) patients presented with metastatic disease. 182 (84%) patients had CRS/HIPEC (76% Mitomycin C), with CC0-1 achieved in 172/182 (95%). Systemic chemotherapy (29% oxaliplatin/fluoropyrimidine) was given to 97/216 (45%) of the whole cohort (10% prior, 6% neoadjuvant, 7% adjuvant and 24% palliative); 37/46 (80%) of patients with positive nodes and 28/44 (64%) those with CC2-3 CRS. After median follow-up of 56 months (1-286), median overall survival (OS) was 122m (95% confidence interval, CI, 61-182m) and median progression-free survival (PFS) was 41m (95% CI 27-54). For patients with positive nodes, median OS was NR for those who had no chemotherapy and neoadjuvant or adjuvant chemotherapy, 81m for prior chemotherapy and 28m for palliative chemotherapy (p<0.001). After multivariate analysis, chemotherapy was associated with reduced risk of death for patients with positive nodes compared to no chemotherapy (neoadjuvant or adjuvant p=0.005, prior p=0.011 and palliative p<0.001).

Conclusions

This study represents the single largest series of patients who have AA with long term follow-up data that evaluates the role of chemotherapy in multimodality treatment. This study suggests that positive node status identifies a subgroup of patients with AA who derive the most benefit from systemic chemotherapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The Christie NHS Foundation Trust.

Funding

Has not received any funding.

Disclosure

M.C. Strach: Financial Interests, Personal, Advisory Board: Specialised Therapeutics; Financial Interests, Personal, Other, Fellowship: ESMO; Financial Interests, Institutional, Research Grant: Royal Prince Alfred Hospital; Financial Interests, Personal, Funding, Travel Fellowship: The Royal Australasian College of Physicians; Financial Interests, Institutional, Funding: The Christie Charitable Funds; Financial Interests, Personal, Funding, PhD Scholarship: Australian Government RTP Scholarship. S. O'Dwyer: Financial Interests, Institutional, Funding: Cancer Research UK; Financial Interests, Personal, Member, Academy: R&D. O. Aziz: Financial Interests, Institutional, Funding: Cancer Research UK; Financial Interests, Personal, Member, Academy: R&D. J. Barriuso: Financial Interests, Personal, Invited Speaker: Pfizer, Ipsen, NanoString, Servier; Financial Interests, Personal, Advisory Board: Nutricia; Financial Interests, Personal, Expert Testimony: AAA; Non-Financial Interests, Personal, Project Lead: EORTC; Non-Financial Interests, Personal, Invited Speaker: GETNE; Non-Financial Interests, Personal, Principal Investigator: ENETS. All other authors have declared no conflicts of interest.