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

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.