Neoadjuvant Radiotherapy for Locally Advanced Unresectable Thymoma

Overview

The goal of this prospective, randomized, controlled phase II clinical study is to evaluate the efficacy and safety of neoadjuvant radiotherapy in patients with locally advanced unresectable thymoma. The main questions it aims to answer are: 1. Which treatment method is more effective in improving the radical resection rate: neoadjuvant chemoradiotherapy or neoadjuvant radiotherapy ? 2. The safety and adverse reactions of neoadjuvant radiotherapy? Does the addition of neoadjuvant chemotherapy have an impact on this? Participants will be randomly divided into two groups: one group will receive neoadjuvant radiotherapy, and the other will receive neoadjuvant chemoradiotherapy. The primary endpoint of the study is to evaluate the radical resection rate (R0) of two groups. The secondary endpoints will include the pathological complete response rate (pCR), 3-year progression-free survival, and safety and toxicities. In addition, this study will explore the feasibility and completion rate of minimally invasive surgical resection.

For patients with thymoma, surgery is the optimal choice, and it has been proven to improve the survival rate of patients with thymoma. For locally advanced unresectable thymoma, direct surgical resection is associated with significant trauma, a high incidence of surgical complications, and a risk of postoperative recurrence. The application of neoadjuvant therapy is expected to reduce tumor volume and downstage the tumor, thereby increasing the rate of complete tumor resection (R0). Clinical practice has confirmed that thymic tumors are sensitive to both radiotherapy and chemotherapy. However, neoadjuvant chemotherapy regimens for thymoma have not been unified, and the available evidence recommends cisplatin based combination regimens. Earlier retrospective studies mainly targeting locally advanced unresectable thymoma suggested that neoadjuvant radiotherapy could achieve an R0 resection rate of about 50%-75% in these patients. In recent years, neoadjuvant chemoradiotherapy has shown promise in terms of objective response rate and R0 resection rate in patients with thymoma. There is still controversy over how to choose an appropriate neoadjuvant treatment protocol for such patients, and there is a lack of randomized prospective controlled studies. In this prospective randomized controlled study, participants will be randomly assigned in a 1:1 ratio into two groups. One group will receive neoadjuvant radiotherapy alone, while the other group will receive the same radiotherapy regimen in combination with concurrent cisplatin chemotherapy. Participants in both groups will undergo standard surgery based on efficacy assessment. The purpose of this study is to evaluate the impact of these two approaches on the R0 resection rate in patients and to comprehensively assess the safety of the treatment modalities. This study also aims to provide clinical evidence for neoadjuvant treatment strategies in locally advanced unresectable thymoma.