Radiotherapy is often used to treat head and neck cancers. The dosage of radiation is measured in Gray (Gy). When radiotherapy is given alone, the most commonly used schedule is 2 Gy in a single fraction per day, five days a week, for seven weeks. However, alternative radiotherapy regimens to reduce the total treatment time for head and neck cancers have been assessed. 'Acceleration' of the treatment (delivering the same total dose in a shorter time) should reduce the regrowth of the tumour between sessions, resulting in improved local control of the disease. In 'hyperfractionated' regimens, two to three fractions are delivered each day, with a reduced dose per fraction equal to 1.1 to 1.2 Gy. The reduction of the dose per fraction may reduce the risk of late toxicity, despite an increased total dose. Acceleration and hyperfractionation can be combined, in particular for regimens in which overall treatment time is reduced.
This Cochrane Review is an individual patient data based meta-analysis and the aim was to assess whether this type of radiotherapy could improve survival. We identified randomised trials comparing conventional radiotherapy with hyperfractionated or accelerated radiotherapy, or both, in patients with non-metastatic head and neck cancers and grouped trials into three pre-specified categories: hyperfractionated, accelerated without total dose reduction and accelerated with total dose reduction. The results of this meta-analysis suggest that altered fractionation radiotherapy improves survival in patients with head and neck cancer. Comparison of the different types of altered fractionation radiotherapy suggests that hyperfractionation provides the greatest benefit.
Individual patient data meta-analysis is a long process and this review included all eligible trials which had completed recruiting patients by 1998. A major update of the analysis, including data from more recent trials, is currently underway.