Trismus following radiotherapy to the head and neck is likely to have distinct genotype dependent cause

After radiotherapy or chemo-radiotherapy the reduction in mouth opening was shown to be significantly related to the presence of the T allele (p < 0.001), with patients homozygous the most likely to be severely affected. No other patient, tumour or treatment factors were significant. Hence the TGF β1 genotype is likely to be an important predictor of the degree of post radiotherapy or chemo-radiotherapy trismus.