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Head and neck cancer patients undergoing definitive radiotherapy can experience severe toxicities requiring enteral feeding to optimise their nutrition. There is a paucity of data on which paediatric and TYA patients would benefit from prophylactic RIG placement versus reactive tube feeding. This study aimed to identify the risk factors for enteral feeding in paediatric and TYA head and neck (HN) cancer patients treated with proton beam therapy (PBT).

The records of HN cancer patients aged ≤25 years old who completed PBT at our single institution from 1 January 2019 to 31 December 2020 were retrospectively reviewed (n=56). Paediatric patients were defined as patients <16 years old at the commencement of treatment. Patients requiring enteral feeding at the commencement of PBT were excluded (n=12). The patient, tumour and treatment details were collected from the electronic records. Feeding tube status had been prospectively recorded during treatment reviews and at each follow-up. Exploratory analyses were conducted alongside t-tests and univariate logistic regression models, with significance assessed at the 5% level, and risk thresholds found using ROC analyses.

25 paediatric patients and 19 TYA patients met the inclusion criteria (Table 1). Of the 44 patients, 12/44 (27%) had a prophylactic RIG placed and 1/44 patients required NGT insertion during PBT. 9/12 (75%) patients used their prophylactic RIG during PBT. At 6 weeks post-PBT, 2 patients remained on enteral feeds. All patients with 12 months follow-up (46%) no longer needed enteral feeding.

The oral cavity mean dose and V30Gy were significantly associated with increased risk of enteral feeding. No patients with an oral cavity mean dose <28.4Gy(RBE=1.1) required enteral feeds. There was also a higher risk in patients with oral cavity V30Gy 45%, stage T4 tumours,  and tumour at diagnosis >76cc (Figure 1 and 2). Other statistically significant risk factors for enteral feeding were increased parotids mean dose (p=0.029) and CTV_Low volume (p=0.002). There was also a higher risk in patients with primary midline tumours (p=0.097).

Table 1: Patient Characteristics

Risk factors such as large tumour at diagnosis, midline tumours, mean dose and V30Gy to the oral cavity and parotids mean dose increases the likelihood of needing enteral feeding during PBT. Therefore patients with these risk factors should be considered for prophylactic RIG placement. Further work is being carried out to explore other dosimetric parameters and risk thresholds, with multivariate analysis ongoing.