Real-world efficacy and safety of capecitabine with oxaliplatin in patients with advanced adenocarcinoma of the ampulla of Vater

Abstract Background Adenocarcinoma of the ampulla of Vater (AoV) is one of the rare periampullary cancers, and due to its anatomical location, it is categorized into various histologic subtypes. Its rarity and diversity pose challenges in treatment decision-making for patients with advanced AoV carcinoma. This study investigated the efficacy and safety of the combined regimen of capecitabine and oxaliplatin (CAPOX) in a real-world clinical setting. Methods This investigation encompassed patients with advanced AoV carcinoma who underwent CAPOX treatment. Histologic phenotypes were identified through a combination of histopathological analysis and protein expression markers, including MUC1, CDX2, CK20, and MUC2. The correlation between histopathological determinants and survival outcomes was explored, in addition to an evaluation of the safety profile of CAPOX therapy. Results From January 2010 to June 2023, 42 patients received CAPOX. Of these, 14 patients (33.3%) had not received any prior palliative chemotherapy, while 28 patients (66.7%) had undergone one prior line of chemotherapy. At a median follow up of 9.0 months, the median progression-free survival (PFS) was 4.38 months (95% CI, 2.78–5.69) and the median overall survival (OS) was 9.57 months (95% CI 7.56–11.6). The objective response and disease control rates were 38.1% and 61.9%, respectively. Patients who received CAPOX as a second-line treatment had poorer PFS (HR = 2.62; 95% CI, 1.49–4.90, p = 0.003) and OS (HR = 2.82, 95% CI, 1.47–5.38, p = 0.001) compared to those who received CAPOX as a first-line chemotherapy. There were no statistically significant differences in PFS ( p = 0.185) and OS ( p = 0.097) between groups based on histologic subtypes. Neutropenia (14.3%) emerged as the predominant grade 3–4 toxicity. Notably, treatment cessation occurred in select instances owing to grade 3 fatigue (9.5%) and peripheral neuropathy (9.5%). Conclusions This study confirmed the therapeutic efficacy and safety of CAPOX in a real-world setting, consistent with prior phase II trial results. While CAPOX proved feasible for advanced AoV carcinoma regardless of histologic subtype, its reduced effectiveness in second-line settings necessitates further research to determine its optimal palliative use.