Brachial Plexus Dose Tolerance in Head-and-Neck Cancer Patients Treated With Sequential Intensity Modulated Radiation Therapy

Abstract

Purpose: We aimed to study the radiation induced brachial plexopathy in patients with head and neck squamous cell carcinoma (HNSCC) treated with Sequential Intensity Modulated Radiation Therapy (S-IMRT). Methods and materials: This IRB approved study included 68 patients with HNSCC treated consecutively. Detailed dose volume histogram data was generated for ipsilateral and contralateral brachial plexus (BP) volumes receiving a specified dose (Vds) i.e. V50-V75 and dose in Gray covering specified percent of BP volume (Dvs) i.e. D5-D30 and maximum point doses (Dmax). To assess BP injury all patients' charts were reviewed in detail for sign and symptoms of BP damage. Post-hoc comparisons were done using Tukey-Kramer method to account for multiple significance testing.Results: The mean and maximum doses to BP were significantly different (p < .05) based on tumor site, nodal status and tumor stage. The mean volume to the ipsilateral BP for V50, V60, V70, and V75 were 7.01 cc, 4.37 cc, 1.47 cc and 0.24 cc, respectively. The mean dose delivered to ≤5% of ipsilateral BP was 68.70 Gy (median 69.5Gy). None of the patients had acute or late brachial plexopathy or any other significant neurological complications, with a minimum follow up of two years (mean 54 months). Conclusions:In this study cohort, at a minimum of two-years follow up, the mean dose of 68.7Gy, a median dose to 69.5Gy to ≤5% of ipsilateral BP, and a median Dmax of 72.96Gy did not result in BP injury when patients were treated with S-IMRT technique. However, longer follow up is needed. Keywords: Brachial plexus, Radiation, Tolerance SummaryRadiation therapy may induce brachial plexopathy. Current Radiation Therapy Oncology Group (RTOG) guidelines suggest dose constraints ranging from 60-66Gy. We found that over a minimum follow-up of two years (mean 54 months) none of our patients developed acute or late brachial plexopathy with a mean, and median dose of 68.7Gy, and 69.5Gy delivered to less than 5% of ipsilateral BP and a median maximum point dose of 72.96 Gy to the ipsilateral BP although longer follow-up is necessary.