PQA 02 - Lung Cancer/Thoracic Malignancies, Patient Reported Outcomes/QoL/Survivorship, Pediatric Cancer
Presenter(s)
Oded Icht, MD, MBA - Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON
O. Icht1,2, I. Nardi-Agmon3, P. Thavendiranathan3, S. Keshavjee4, J. M. Miro5, G. Liu5, J. Cho1,2, A. Bezjak1,2, and A. J. Hope1,2; 1Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada, 2Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada, 3Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, University of Toronto, Toronto, ON, Canada, 4Division of Thoracic Surgery, University of Toronto, Toronto General Hospital, Toronto, ON, Canada, 5Department of Medical Oncology, Ontario Cancer Institute, Princess Margaret Cancer Centre, Toronto, ON, Canada
Purpose/Objective(s):
Thymic malignancies, though rare, are typically managed with surgical resection followed by postoperative radiation therapy (RT). We aimed to analyze patterns of failure following treatment and evaluate long-term outcomes among patients treated with this combined modality approach. Materials/Methods:
A retrospective review was conducted of patients with thymic malignancies treated between 2004-2024 in a single tertiary center. Data collection included demographics, pathology findings, treatment parameters, RT plans, and imaging studies. Survival analysis was performed using Kaplan-Meier methods. Time to recurrence was calculated from the date of diagnosis to first radiological evidence of disease recurrence. Recurrence locations were determined via review of imaging at the time of recurrence.
Results:
Among 411 patients with thymic malignancies, 175 underwent surgery and RT with curative intent. Sixty-two patients out of those (35%) developed recurrent disease with a median follow-up of 9.7 (0.3-19.9) years. The median progression-free survival was 3.2 (2.4-4.1) years, and the median overall survival of this group was 13.4 (9.1-not reached) years. The most common Masaoka stage of patients with recurrent disease was 4A for 43.5%, and the most common thymic malignancy subtype was type B2 thymoma among 30.6% of patients (see table 1 for subtypes and staging in patients with recurrent disease). RT was delivered postoperatively in 70% of cases vs. 30% in the neoadjuvant setting, with a median dose of 50 Gy in 25 fractions. Recurrence patterns showed pleural involvement in 76% of cases, mediastinal lymph nodes in 6.5%, and lung parenchyma in 5%. Only 5% of all recurrences occurred within the radiation field, with no primary tumor bed recurrences observed. Distant extra-thoracic metastases occurred in 13% of patients. Local therapy (surgery, radiation, or both) was utilized in 66% of first recurrences. Among patients with second recurrences (54%, n=34), 76% received local therapy.
Conclusion:
The predominance of pleural recurrences outside the radiation field demonstrates excellent local control with current treatment approaches. Novel strategies to address high-risk pleural sites in select patients with advanced disease or aggressive histology should be considered.
Abstract 2384 - Table 1: Thymic malignancy subtype and stage
| Masaoka stage Thymic malignancy subtype | Stage 1 | Stage 2 | Stage 3 | Stage 4 | n/a |
| A | 0 | 0 | 0 | 1 | 0 |
| A/B | 0 | 2 | 5 | 4 | 1 |
| B1 | 0 | 0 | 1 | 0 | 0 |
| B2 | 1 | 2 | 6 | 9 | 1 |
| B3 | 0 | 3 | 4 | 9 | 0 |
| Thymic carcinoma | 0 | 0 | 5 | 5 | 1 |
| Other | 0 | 0 | 1 | 0 | 0 |
| Unknown | 0 | 0 | 0 | 0 | 1 |
