Early versus delayed postoperative radiotherapy for treatment of low‐grade gliomas
Plain language summary
Are there any differences in survival between people with low-grade glioma having early compared with delayed radiotherapy at the time of progression?
Low-grade gliomas (LGG) are brain tumours that predominantly affect young adults. They grow at slower rates and are typically associated with a favourable prognosis compared with high-grade gliomas. One of the most common presenting symptoms of people with LGG are seizures. Although, there are no definitive guidelines on the management of LGGs, most people with LGGs are treated with a combination of surgery followed by radiotherapy. However, it is unclear whether to use radiotherapy in the early postoperative period, or to delay until the disease progresses.
Aim of the review:
We aimed to compare the timing of radiotherapy from early (the postoperative period) or whether it should be delayed until the disease (tumour) re-occurs.
What are the main findings?
From the literature search in September 2014, we included one randomised controlled trial, involving 311 participants, that looked at early or delayed radiotherapy given at the time of disease progression in people with LGG. This study was well-designed and reported useful data on survival, but did not include other clinically important information, such as functional independent survival (functional, or neurological impairment, or both) and quality of life. Therefore, we felt that the trial was of unclear quality. People who received early (soon after surgery) radiotherapy had a longer time until their disease progressed than people who only had radiotherapy once the disease had progressed. However, the people that were initially observed had similar survival to the people who had early radiotherapy. Quality of life measures such as memory, executive function, and cognitive deterioration differences were not evaluated in either group. The findings did not suggest that people who received early radiotherapy lived longer than those had delayed radiotherapy. However, people who had early radiotherapy had better control over their seizures than those who had delayed radiotherapy. The toxic effects of radiotherapy were rated as minimal in both groups using a grading system which measured severity and included skin reactions, ear inflammation, mild headache, nausea, and vomiting.
Update searches in November 2019 found no new articles which met the inclusion criteria. No articles were considered eligible for inclusion in this review update.
What are the conclusions?
Based on the current evidence, the results should be interpreted with caution. It is unclear whether or not early radiotherapy is better than delayed radiotherapy because survival was the same in both groups. People who had early radiotherapy experienced longer periods of tumour remission compared with patients who had delayed radiotherapy. However, it is unclear if these people suffered increased rates of cognitive impairment, neuroendocrine dysfunction, or radiation necrosis compared with people who had delayed radiotherapy. Toxic effects of radiation were minimal in both groups and there were no cases of second malignancies.