Evaluation of clinical outcomes and prognostic factors in patients with metastatic appendiceal adenocarcinoma treated with first-line chemotherapy: A multi-institutional retrospective study
Koshiro Fukuda, Hiroki Osumi, Atsuo Takashima, Takahito Awatsu, Akira Ooki, Hidekazu Hirano, Shota Fukuoka, Natsuko Okita, Shohei Udagawa, Hirokazu Shoji, Mariko Ogura, Takeru Wakatsuki, Keisho Chin, Mitsuhiro Fujishiro, Ken Kato, Narikazu Boku, Kensei Yamaguchi, Eiji ShinozakiBackground
Appendiceal adenocarcinoma (AA) is a rare cancer characterized by high incidences of mucinous histology, peritoneal metastasis, and a good prognosis. However, its chemotherapeutic efficacy and prognostic factors are unclear.
Objective
To evaluate real-world clinical outcomes and explore prognostic factors in patients with metastatic AA treated with chemotherapy.
Design
Retrospective study.
Methods
We reviewed the clinical courses of patients with metastatic AA receiving first-line chemotherapy between February 2005 and March 2023. We also explored prognostic factors using multivariate analysis.
Results
In the 66 identified patients, incidences of mucinous histology and peritoneal metastasis were 41% and 90%, respectively. Forty patients (60.6%) received an oxaliplatin-based regimen combined with bevacizumab. Median progression-free survival (PFS) was 10.9 months, and median overall survival (OS) was 23.0 months. The response rate was 22.0%, and the disease control rate was 87.8% in 41 patients with target lesions. Subsequent chemotherapy was administered to 77.4% of patients. Multivariate analysis showed that presence of the primary tumor, Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≥1, moderate to massive ascites, and elevated pretreatment carcinoembryonic antigen and carbohydrate antigen 19-9 levels were significantly associated with shorter OS. There were significant differences in OS among the three groups classified by the number of poor prognostic factors (none versus [vs.] 1-2 vs. 3-4).
Conclusions
Patients with metastatic AA showed comparable PFS and OS to those with common colorectal cancer despite a high incidence of peritoneal metastasis and a low response rate. Elevated tumor marker levels, presence of the primary tumor, ECOG PS ≥1, moderate to massive ascites were poor prognostic factors for OS. The number of these risk factors may allow exploratory prognostic stratification; however, this model is hypothesis-generating and requires external validation before clinical application.