BACKGROUND/OBJECTIVES: Since 2007, our institution has used validated guidelines for the insertion of proactive gastrostomy feeding tubes in patients with head and neck cancer. Helical intensity-modulated radiotherapy (H-IMRT) delivered by Tomotherapy, is an advanced radiotherapy technique introduced at our centre in 2010. This form of therapy reduces long-term treatment-related toxicity to normal tissues. The aim of this study is to compare weight change and need for tube feeding following H-IMRT (n=53) with patients that would have previously been treated with three-dimensional conformal radiotherapy (n=134). SUBJECTS/METHODS: Patients with head and neck cancer assessed as high nutritional risk with recommendation for proactive gastrostomy were identified from cohorts from 2007 to 2008 and 2010 to 2011. Retrospective data were collected on clinical factors, weight change from baseline to completion of treatment, incidence of severe weight loss (⩾ 10%) and tube feeding. Statistical analyses to compare outcomes between the two treatments included χ(2)-test, Fisher's exact and two-sample Wilcoxon tests (P<0.05). RESULTS: The H-IMRT cohort had higher proportions of patients with definitive chemoradiotherapy (P=0.032) and more advanced N stage (P<0.001). Nutrition outcomes were not significantly different between H-IMRT and conformal radiotherapy, respectively: need for proactive gastrostomy (n=49, 92% versus n=115, 86%, P=0.213), median percentage weight change (-7.2% versus -7.3%, P=0.573) and severe weight loss incidence (28% versus 27%, P=0.843). CONCLUSIONS: Both groups had median weight loss >5% and high incidences of tube feeding and severe weight loss. Nutrition intervention remains critical in this patient population, despite advances in radiotherapy techniques, and no changes to current management are recommended.