Constraining the brachial plexus does not compromise regional control in oropharyngeal carcinoma

BACKGROUND Accumulating evidence suggests that brachial plexopathy following head and neck cancer radiotherapy may be underreported and that this toxicity is associated with a dose-response. Our purpose was to determine whether the dose to the brachial plexus (BP) can be constrained, without compromising regional control. METHODS The radiation plans of 324 patients with oropharyngeal carcinoma (OPC) treated with intensity-modulated radiation therapy (IMRT) were reviewed. We identified 42 patients (13%) with gross nodal disease <1 cm from the BP. Normal tissue constraints included a maximum dose of 66 Gy and a D05 of 60 Gy for the BP. These criteria took precedence over planning target volume (PTV) coverage of nodal disease near the BP. RESULTS There was only one regional failure in the vicinity of the BP, salvaged with neck dissection (ND) and regional re-irradiation. There have been no reported episodes of brachial plexopathy to date. CONCLUSIONS In combined-modality therapy, including ND as salvage, regional control did not appear to be compromised by constraining the dose to the BP. This approach may improve the therapeutic ratio by reducing the long-term risk of brachial plexopathy.