The Clinical Significance of CEA, CA19-9, and CA125 in Management of Appendiceal Adenocarcinoma

ImportanceSerum tumor markers CEA, CA19-9, & CA125 have been useful in the management of gastrointestinal and gynecological cancers, however there is limited information regarding their utility in patients with appendiceal adenocarcinoma. ObjectiveAssessing the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes, pathologic, and molecular features in patients with appendiceal adenocarcinoma. DesignThis is a retrospective study with results reported in 2023. The median follow-up time was 43 months. SettingSingle tertiary care comprehensive cancer center. ParticipantsUnder an approved Institutional Review Board protocol, the Palantir Foundry software system was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least one tumor marker measured at MD Anderson between 2016 and 2023. ResultsA total of 1,338 patients with appendiceal adenocarcinoma were included, with a median age of 56.5 years. The majority of the patients had metastatic disease (80.7%). CEA was elevated in more than half of the patients tested (56%), while CA19-9 and CA125 were elevated in 34% and 27%, respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; 82% vs 95%, 84% vs 92%, and 69% vs 93% elevated vs normal for CEA, CA19-9, and CA125 respectively (all p<0.0001). Quantitative evaluation of tumor markers increased prognostic ability. Patients with highly elevated (top 10th percentile) CEA, CA19-9 or CA125 had markedly worse survival with 5-year survival rates of 59%, 64%, and 57%, respectively (HR vs. normal : 9.8, 6.0, 7.6, all p<0.0001). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease elevated CEA, CA19-9 or CA125 were all still associated worse survival (HR vs. normal : 3.4, 1.8, 3.9, p<0.0001 for CEA and CA125, p=0.0019 for CA19-9). Interestingly tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high relative to low-grade tumors (18.3 vs. 15.0, p=0.0009). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with a 11-fold increased risk of death in patients with all three tumor markers elevated relative to those with none elevated. Mutation in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9. ConclusionsThese findings demonstrate the utility of measuring CEA, CA19-9, and CA125 in the management of appendiceal adenocarcinoma. Given their prognostic value, all three biomarkers should be included in the initial workup of patients diagnosed with appendiceal adenocarcinoma. Key PointsO_ST_ABSQuestionC_ST_ABSCan serum tumor markers CEA, CA19-9, or CA125 be useful in management of patients with appendiceal adenocarcinoma? FindingsIn this single institution retrospective cohort study, elevation of CEA, CA19-9, or CA125 were associated with significantly worse 5-year survival; 82% vs 95%, 84% vs 92%, and 69% vs 93% elevated vs normal respectively. Moreover, quantitative evaluation of tumor markers increased prognostic ability. Further analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with a 11-fold increased risk of death in patients with all three tumor markers elevated relative to those with none elevated. MeaningGiven their prognostic value, all three biomarkers should be included in the initial workup of patients diagnosed with appendiceal adenocarcinoma.