Stereotactic body radiation therapy for the treatment of pleural metastases in patients with thymoma: a retrospective review of 22 patients

Spatial Distribution Patterns of Pleural Dissemination in Patients With Thymoma and Survival Analysis

Background: Thymoma is a common malignancy with low incidence, and pleural metastases are common pattern of recurrence. It is necessary that the spatial location of pleural metastatic lesions be analyzed. This study aimed to analyze the spatial distribution patterns of pleural dissemination in patients with thymoma and evaluate the variables that influence the survival of pleural metastasis in this population. Methods: This retrospective study investigated hospital admissions of patients diagnosed with pleural metastasis from thymoma. The spatial distribution pattern and visualization of the pleural metastases were analyzed after establishing a coordinate system. We further analyzed the survival and influencing factors in patients with pleural metastases from thymoma. Results: The analysis included 56 patients with a cumulative count of 365 pleural metastases, with 351 metastases from Zones 1-5 finally included in the analysis. The spatial distribution of the 285 initially diagnosed pleural metastases was significantly concentrated in Zones 3 and 4 near the lateral half of the spine (56.5%), followed by Zone 5 (17.5%). Collectively, these two components accounted for 74.0% (211/285) of all initial metastatic lesions. The survival rates at 5 years for those who underwent surgery versus nonsurgical treatment were 68.3% and 37.1%, respectively (p=0.015). Univariate Cox regression analysis showed that surgical intervention reduced the risk of death by 61%. Conclusions: The distribution of pleural metastatic lesions exhibited a nonuniform pattern, primarily concentrated on the spinal aspect below the aortic arch of the costal pleura and the spinal aspect of the diaphragmatic pleura.

Stereotactic Ablative Radiation Therapy for Sacral Bone Metastasis in Recurrent Type A Thymoma: A Two-Year Follow-Up Demonstrating Pain Reduction and Local Control

A 74-year-old Asian man presented with sacral bone metastasis-related pain caused by a metastatic thymoma. Computed tomography revealed an approximately 6-cm sacral mass, which was confirmed as a metastatic thymoma. The patient was referred to our department and underwent stereotactic ablative radiation therapy (SABR) using volumetric modulated arc therapy and received a total dose of 35 Gy in five fractions. One year after SABR, the sacral lesion had decreased in size, and the pain medication was reduced. After two years, the patient no longer required pain medication, indicating successful management of bone metastases in recurrent Type A Thymoma.

Postoperative radiotherapy results in 192 epithelial thymic tumours patients with 10 years of follow-up

PURPOSE

To assess the prognostic factors and patterns of failure of patients consecutively treated with surgery and postoperative radiation therapy (PORT) for thymic epithelial tumours (TET).

PATIENTS AND METHODS

Data from 192 TET patients who were operated and received PORT at a single centre from 1990 to 2019 was retrospectively analysed.

RESULTS

Most patients had thymoma (77 %, B247%), were classified Masaoka-Koga stage III (35 %) or IV (32 %) and had a R0 (75 %) resection. Radiotherapy was delivered at a median dose of 50.4 Gy (range, 42-66 Gy; ≥ 60 Gy in 17 %), 63 (33 %) patients were treated by intensity-modulated radiation therapy and elective nodal radiotherapy was used for 37 %. At a median follow-up of 10.9 years, the 10-year overall survival (OS) and progression-free survival (PFS) rates were 62 % (95 % CI: 54-70 %) and 47 % (95 % CI: 39-55 %), respectively. Locoregional recurrence (LRR) occurred in 72/192 (38 %) patients, distributed as 6 local, 45 regional and 21 both local and regional. LRR were mainly located to the pleura: 66/72 (92 %) and 16/72 (22 %; 16/192 in total, 8 %) were in-field. Distant relapse (DR) were observed in 30 patients (16 %), resulting in 10-year locoregional (LRC) and distant control rates of 58 % (95 % CI: 50-66 %) and 82 % (95 % CI: 77-88 %), respectively. In the multivariate analysis, Masaoka-Koga stage (HR [hazard ratio]: 1.9; p = 0.001), thymic carcinomas/neuroendocrine tumours (TC) (HR: 1.6; p = 0.045) and ECOG PS > 1 (HR: 1.9; p = 0.02) correlated with poorer OS. Higher Masaoka-Koga stage (HR: 2.6; p < 0.001) associated with a decreased LRC but not R1 status (HR: 1.2; p = 0.5) or WHO histology classification. TC (HR: 3.4; p < 0.001) and a younger age (HR: 2.5; p = 0.02) correlated with DR.

CONCLUSION

Approximately one-third of the TET in our study experienced a LRR, mainly to the pleura, and 8% in total were in-field. The place of radiotherapy should be better defined in higher risk thymoma patients within prospective randomized studies.