Real-world experience of postoperative adjuvant chemoimmunotherapy in patients with pancreatobiliary subtype ampullary adenocarcinoma.

Background: The efficacy and safety of chemotherapy combined with programmed cell death protein-1 (PD-1) inhibitors in postoperative adjuvant therapy of pancreatobiliary subtype ampullary adenocarcinoma (AAC) are uncertain. This study aims to evaluate the effect of such treatment on the survival of this patient population.

Methods: We retrospectively collected patients with pancreatobiliary subtype AAC who underwent surgical treatment at the Sun Yat-sen Memorial Hospital from January 2018 to December 2022. Patients with high-risk recurrence factors after surgery were divided into surgery alone group, adjuvant chemotherapy group, and adjuvant chemoimmunotherapy group. The Kaplan-Meier method was used to plot survival curves, and the Log-Rank method was used to compare the differences in overall survival (OS) and recurrence-free survival (RFS) between groups.

Results: A total of 71 people were enrolled, including 24 patients received surgery alone, 31 patients received adjuvant chemotherapy, and 16 patients received adjuvant chemoimmunotherapy. The median time of clinical follow-up was 17.8 [IQR 8.3-28.4] months. The 1-year OS rates of the surgery alone group, adjuvant chemotherapy group, and adjuvant chemoimmunotherapy were 41.7%, 71.0%, and 93.3%, respectively. The 2-year OS rates were 28.6%, 47.7%, and 84.0%, respectively. The median OS was 6.8 months and 22.1 months, but the adjuvant chemoimmunotherapy group did not reach (P = .0002). The median RFS was 4.7 months, 15.7 months, and 14.8 months, respectively, but the differences were not statistically significant (P = .0613). Univariate and multivariate Cox analysis results showed that tumor size >2.3 cm (HR = 2.06, 95% CI, 1.06-4.04; P = .034) and the treatment regimen were independent factors affecting prognosis, compared to surgery alone and adjuvant chemotherapy (HR = 0.521, 95% CI, 0.26-1.04; P = .065), adjuvant chemoimmunotherapy (HR = 0.106, 95% CI, 0.02-0.47; P = .003) significantly improves patient survival. There was no statistically significant difference in any complications between the 3 groups (P > .05). Compared with the adjuvant chemotherapy group, patients in the adjuvant chemoimmunotherapy group are more likely to experience hypothyroidism (P = .044) and pruritus (P = .022). There is no statistically significant difference in other AEs between the 2 groups (P > .05).

Conclusion: Compared with surgery alone or adjuvant chemotherapy, patients with pancreatobiliary subtype AAC who received adjuvant chemoimmunotherapy showed better OS, and the drug-related toxicity was acceptable.