Postoperative Radiation Therapy for Thymic Carcinoma: An Analysis of the International Thymic Malignancy Interest Group/European Society of Thoracic Surgeons Database

Therapeutic management of patients with advanced thymic malignancies: A review for clinicians

Thymic epithelial tumors (TETs) are a heterogeneous group of rare tumors that arise from thymic epithelial cells in the anterior mediastinum. They can be divided into three different histological subtypes: thymomas, thymic carcinomas (TC), and neuroendocrine carcinomas (TNET). TCs and TNETs are rarer but more aggressive entities with frequent distant metastasis. Thymomas occur in 90 % of cases in a localized/locally advanced stage, on the other hand about 70 % of TCs are locally advanced at the time of diagnosis. Surgery plays a primary role in the management of patients in whom complete resection is feasible. The benefit of post-operative radiotherapy (PORT) is still controversial, since it could be related to stage, histotype, and preoperative chemotherapy. If the tumor is unresectable at diagnosis, radiotherapy or concurrent chemoradiotherapy is the most commonly used approach. Cisplatin and anthracycline-based regimens are standard of care in patients with unresectable or metastatic thymomas, but, at the same time, regimens with carboplatin and paclitaxel are the most widely used especially in patients with contraindications to cisplatin/anthracyclines, due to better tolerance. Recently, the anti-VEGFR antibody Ramucirumab has shown promising activity in combination with carboplatin plus paclitaxel in previously untreated advanced TCs. Several clinical trials with chemotherapy combination, target therapy and immunotherapy are still ongoing to define the best therapeutic strategy in this disease, also for the second line treatment, for which in daily practice there is currently no standard of care for patients who went into progression to the first line.

Thymic tumors: radiotherapy experience for single institute

PURPOSE

The aim is to evaluate treatment outcomes and prognostic factors in patients with thymic epithelial tumor (TET) treated with radiotherapy (RT).

METHODS

Sixty-four patients were treated between 2000 and 2023. The median age was 52 years (20-83), and 81% of underwent R0 resection. The stage (s) distribution for I, II, III, and IV were 5%, 61%, 26%, and 8% by Masaoka-Koga and 63%, 11%, 17%, and 9% by TNM, respectively. WHO types A/AB/B/C and thymic neuroendocrine tumors were seen in 5%, 22%, 64%, 6%, and 3% of patients, respectively. The median RT dose was 5040 cGy (1620-6596). Survival was calculated from the beginning of RT.

RESULTS

The median follow-up was 70 months (1.5-268). The median time to recurrence was 30 months (6.5-106), seen in 23% of patients. Mean overall (OS), progression-free survival (PFS) and 5‑year local control were 141, 138 months, and 82.4%, respectively. In univariate analysis, the presence of organ invasion and TNM stage were significant as new prognostic factors for survival (p < 0.05). In multivariate analysis, the high-risk group (B2/B3/C) and another surgical center (p < 0.05) for OS, and KPS ≤ 80, thymic carcinoma, and Masaoka-Koga sIII-IV (p < 0.05) for PFS were identified as unfavorable prognostic factors.

CONCLUSION

Recurrence in TET can occur over a longer period. In this study, 5‑year local control of 82.4% was achieved. The prognostic importance of KPS, histology, Masaoka-Koga stage, risk group, and surgical center was demonstrated. Advances in the diagnosis, staging, and treatment of TET will enable more personalized treatment.

Postoperative radiotherapy for completely resected thymoma and thymic carcinoma: A systematic review and meta-analysis

BACKGROUND

The role of postoperative radiotherapy (PORT) after complete tumor resection in patients with thymoma or thymic carcinoma remains controversial. We performed a meta-analysis to identify groups that would benefit from PORT.

METHODS

Multiple scientific databases were systematically searched for studies comparing overall survival (OS) and/or disease-free survival (DFS) between PORT and surgery alone in patients with completely resected thymomas or thymic carcinomas until April 10, 2024. A random-effects model was used for the statistical analysis.

RESULTS

A total of 31 studies with 10543 patients were included (17 studies involving 4763 patients with thymoma, seven studies involving 1045 patients with thymic carcinoma, and seven studies involving 4735 patients with mixed histological types). Notably, PORT significantly prolonged OS (hazard ratio [HR] = 0.73, 95% confidence interval [CI]: 0.59-0.91) and DFS (HR = 0.62, 95% CI: 0.43-0.89). Similar results were also observed when the multivariate-adjusted HRs were used as the measure of effect (OS: HR = 0.60, 95% CI: 0.43-0.83; DFS: HR = 0.48, 95% CI: 0.29-0.79). In subgroup analyses, PORT was associated with a longer OS and DFS for thymoma (HR = 0.73, 95% CI: 0.56-0.96 and HR = 0.65, 95% CI: 0.46-0.93), thymic carcinoma (HR = 0.72, 95% CI: 0.49-1.07 and HR = 0.38, 95% CI: 0.19-0.77), and stage 3-4 disease (HR = 0.50, 95% CI: 0.34-0.74 and HR = 0.44, 95% CI: 0.27-0.70), but not for stage 2 disease (HR = 0.81, 95% CI: 0.55-1.19 and HR = 0.97, 95% CI: 0.51-1.83).

CONCLUSIONS

PORT is likely to improve OS and DFS in patients with completely resected stage 3-4 thymoma or thymic carcinoma; however, the value of PORT for stage 2 disease requires further evaluation in large-scale studies.