Second-line treatment options in advanced thymic carcinoma after failure of platinum-based chemotherapy: A multicenter retrospective study

Abstract

Background: Currently there is no standard therapy recommended for second-line treatment for thymic carcinoma. Our study compared multidrug chemotherapy, single-agent chemotherapy, and PD-1 inhibitors in patients diagnosed with advanced thymic carcinoma who had previous platinum-based chemotherapy at the clinic.

Methods: The study included patients with thymic carcinoma who failed first-line platinum-based chemotherapy. Kaplan-Meier methods were applied in the study for estimating the progression-free survival (PFS) and overall survival (OS) curves. Pearson chi-square or Fisher's exact chi-square test was adopted to make comparisons of the objective response rate (ORR) between treatment groups. Cox regression was used for the multivariate analyses in PFS and OS.

Results: Among the 92 patients enrolled, multidrug chemotherapy was used in 51 (55.4%) patients for second-line therapy. Thirty-six patients (35.9%) received single-agent chemotherapy, and eight patients (8.7%) underwent PD-1 inhibitors. The multidrug chemotherapy group showed better efficacy than the other two groups, with an ORR of 35.3% (p = 0.006). The median PFS of multidrug chemotherapy, single-agent chemotherapy and PD-1 inhibitors were 5.0 months, 3.0 months, and 4.0 months, respectively (p = 0.008). Patients in the multidrug chemotherapy group also showed an advantage in OS in comparison with the other two treatment groups (p = 0.045), with a median OS of 30.4 months. Multivariate analysis showed that second-line treatment was independent factor for both PFS (p = 0.035) and OS (p = 0.037). Grade 3-4 AEs were mostly detected in patients receiving multidrug chemotherapy and were primarily hematologic. Treatment-related mortality was not found in any of the groups.

Conclusions: Multidrug chemotherapy had a trend toward a more positive response rate and outcomes in longer survival time than single-agent chemotherapy and PD-1 inhibitors. Multidrug chemotherapy is a choice worth considering for second-line therapy in patients with thymic carcinoma if tolerable.

Keywords: PD-1 inhibitor; docetaxel; platinum; second-line therapy; thymic carcinoma.