Radiotherapy versus radiotherapy combined with temozolomide in high-risk low-grade gliomas after surgery: study protocol for a randomized controlled clinical trial

BACKGROUND: It has been reported that radiation therapy (RT) followed by procarbazine, lomustine, and vincristine (PCV) chemotherapy could improve progression-free survival (PFS) and overall survival (OS) in patients with high-risk World Health Organization (WHO) grade 2 gliomas after surgery. However, procarbazine is not available in China. In clinical practice, Chinese doctors often use radiotherapy combined with temozolomide (TMZ) to treat these patients, although large-scale prospective studies are lacking. This trial aims to confirm whether RT combined with temozolomide can improve PFS and OS in high-risk patients with low-grade gliomas (LGGs). METHODS/DESIGN: This is a two-group, randomized controlled trial (RCT) enrolling patients who have LGGs (WHO grade 2) and are aged 40 years or older without regard to the extent of resection or are aged younger than 40 years old with subtotal resection or biopsy. An estimated 250 patients will be enrolled. Eligible participants will be randomly assigned to receive RT alone or RT plus TMZ chemotherapy in a 1:1 ratio. The same RT will be given to all eligible participants regardless of whether they are randomly assigned to the RT group or the chemoradiotherapy (CRT) group. While in the CRT group, patients will receive adjuvant TMZ with or without concurrent radiochemotherapy. The primary outcome of this trial is PFS, and it will be analyzed by the intention-to-treat approach. Secondary outcomes include OS, adverse events, and cognitive function. DISCUSSION: The objective of our research is to assess the effect of radiotherapy coupled with TMZ in high-risk patients with LGGs after surgery, compared with RT alone. Different histological types and molecular subtypes will be examined, and a corresponding subgroup analysis will be conducted. Our data can provide evidence for postoperative adjuvant therapy in patients with high-risk LGGs in China. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800015199. Registered on 13 March 2018.