145P Real-world evidence on thymic epithelial tumours (TETs): A decade of surgical experience and recurrence outcomes

TETs are rare, diverse cancers. Treatment variations and lack of consensus on follow-up strategies require real-world data for evidence-based guidelines. We retrospectively analysed consecutive TET patients treated surgically from 2012 to 2022. Analysis included patient demographics, histological subtype, stage (International Association for the Study of Lung Cancer TNM 9th edition), treatment modalities, and recurrence patterns. The cohort comprised 198 patients with median age 64 (range 19-86), with balanced gender distribution. 17% had myasthenia gravis. The most common histological type was AB (28%). Thymoma types A and AB most commonly presented at early stage, B1 to B3 were more evenly spread across stages, while thymic carcinomas were mostly advanced at diagnosis. Neoadjuvant therapy was used in 34 patients, primarily in stages III-IV; four patients achieved complete pathological response, of whom two experienced subsequent recurrence. Complete resection was more achievable in early stages (stage I-II, 85%; stage III-IV, 44%). Stages III and IV required extensive surgeries, including pneumonectomy in 7, pleurectomy in 14, major vessel resection in 11, diaphragmatic resection in 10, and chest wall resection in 4. 27 (14%) had adjuvant radiotherapy, of whom 22 did not have clear margins. The 5-year overall survival (OS) was 89%, decreasing to 76% at 10 years. Recurrence occurred in 19 (9.6%), with the majority (11) being pleural and the highest rates noted in Type B3, followed by B2. Types A and AB had no recurrences. Seven were treated radically with further surgery or radiotherapy. Of those with recurrences, 6 are alive with disease, 6 are disease-free, and 7 died of disease. This study highlights varied treatments and outcomes in TET management. Cases of (predominantly regional) recurrent disease underscore the need for vigilant follow-up, although this could potentially be relaxed in types A and AB given a better prognosis. Our experience shows surgery's key role in advanced thymoma, leading to notable long-term survival despite surgical complexity. These findings emphasize tailored treatment strategies for improved TET patient outcomes.