Treatment response after induction therapy in advanced thymic tumors: results from the Italian nationwide TYME...

Induction therapy (IT) prior to surgery is a key strategy to improve resectability in advanced thymic tumors (ATTs). This study aimed to assess prognostic factors and the impact of IT on clinical outcomes.

We retrospectively analyzed 64 patients with TNM-stage II-IV ATTs treated with IT and surgery between January 2002 and December 2024, using data from the TYME multicenter Italian database. Radiological response (RR) was defined by RECIST v1.1. Statistical comparisons were performed using Chi-square, t-test, or Wilcoxon rank-sum test. Univariate and multivariate logistic models evaluated associations between variables and outcomes.

Mean age was 52 years; 58 % were male. Most tumors (83.4 %) were stage III-IV, with thymoma as the predominant histology (79.7 %). Radiological signs of mediastinal or vascular invasion and tumor diameter > 5 cm were present in over 86 % of cases. Platinum-based chemotherapy was administered in 96.9 %, with CAP regimen used in 62.5 %. Partial response was achieved in 69 % (Responders, RE), while 31 % had stable/progressive disease (Non-responders, NRE). Extended surgery was performed in 84.4 %, with R0 resection in 76.3 %. Adjuvant therapy was administered in 66.7 % of cases. Relapse occurred in 78.6 % (local) and 21.4 % (distant). No significant differences were found between RE and NRE in clinical, radiological, or pathological features. Five-year OS (88 % vs 93 %) and RFS (45 % vs 43 %) were similar between groups. ECOG performance status was the strongest independent predictor of better RFS (OR 7.18), while ASA score was associated with RR (OR 0.20).

The TYME database analyses revealed no significant outcome differences between RE and NRE following IT in ATTs, underscoring the complexity of predicting long-term outcomes based on RR alone. This study also suggests the prognostic value of physical status via ASA score and ECOG PS. Further studies with varied chemo regimens are needed to improve response rates in multimodal ATT therapy. Accepted as poster presentation at ESMO Congress 2025, October 17-21, 2025 - Berlin.