"Radiotherapy for thymic epithelial tumors: What is the optimal dose? A systematic review."

Area of Science:

• Oncology
• Radiation Oncology
• Thoracic Surgery

Background:

• Thymic epithelial tumors (TETs) are rare thoracic malignancies often managed with multimodal therapy, including surgery, radiation therapy (RT), and chemotherapy.
• Current radiotherapy guidelines for TETs lack robust evidence, primarily relying on older studies using 2D RT techniques.
• The optimal radiation dose for TETs, especially with modern RT modalities, is not clearly established.

Purpose of the Study:

• To systematically review recent literature on radiation doses for thymic epithelial tumors (TETs) using modern RT techniques.
• To identify the optimal radiation dose for patients with TETs undergoing adjuvant or primary radiotherapy.
• To synthesize evidence regarding RT doses in the context of advanced techniques like 3D-CRT, IMRT/VMAT, and proton therapy.

Main Methods:

• A systematic literature search was performed across four databases adhering to PRISMA guidelines.
• Studies were screened for relevance, excluding those with fewer than 20 patients, 2D RT only, or short follow-up periods.
• Data from eligible studies were analyzed using the Synthesis Without Meta-analysis (SWIM) method, stratifying by prognostic factors.

Main Results:

• Only two studies met initial strict inclusion criteria; loosening follow-up allowed evaluation of three additional studies, totaling 193 patients.
• The heterogeneity and limited number of studies resulted in controversial findings regarding optimal RT doses.
• No definitive optimal radiation dose emerged for either postoperative or primary RT in the era of modern techniques.

Conclusions:

• The current evidence is insufficient to define a universally optimal radiation dose for thymic epithelial tumors using modern RT techniques.
• Further high-quality research is necessary to establish evidence-based RT dose recommendations for different TETs subtypes and stages.
• This review underscores the need for new evidence to guide optimal radiation dosing for TETs patients treated with advanced radiotherapy modalities.