Does the Use of Volumetric Modulated Arc Therapy Reduce Gastrointestinal Symptoms after Pelvic Radiotherapy?

Abstract

Aims: Growing numbers of patients with cancer are surviving after treatment with pelvic radiotherapy. We evaluated the technique of volumetric modulated arc therapy (VMAT), which delivers a decreased dose to the organs at risk. We aimed to determine outcomes of this technique in terms of patient-reported acute toxicity and late effects and correlate the frequency of gastrointestinal symptoms with the volume of bowel receiving radiation dose.

Materials and methods: Patients who were to receive VMAT for gynaecological malignancy completed patient-reported outcomes at baseline, the end of treatment, 8 weeks and 1 year. The rates of patient-reported toxicity were correlated with the volume of bowel irradiated.

Results: The frequencies of patient-reported gastrointestinal symptoms increased in the acute toxicity phase and tended to improve at 1 year, with the exception of faecal incontinence and rectal bleeding (P < 0.05). There was not a strong association between the volume of small bowel that was irradiated (P > 0.05 at all dose levels) and reported toxicity, suggesting that other factors are involved in the development of toxicity.

Conclusion: Although VMAT decreases the dose delivered to the small bowel, this does not translate into a reduction in patient-reported toxicity.

Keywords: Gastrointestinal; VMAT; gynaecological malignancy; toxicity.