Lymphatic mapping Of Oropharyngeal Cancer (LOOC): protocol for a phase II surgical imaging trial to evaluate contralateral drainage and occult metastasis in oropharyngeal cancer.

introductionTreatment of the node negative contralateral neck in oropharyngeal cancer (OPC) remains debated, with no clear consensus. Prophylactic contralateral neck treatment (either surgically or via irradiation) is generally recommended when the estimated risk of occult nodal metastasis is >20%. Unfortunately, patients undergoing bilateral neck treatment often require long-term supportive care for swallowing dysfunction. Reducing the impact of treatment on long-term quality of life is key in patients with OPC who have a good prognosis and tend to be young and fit at presentation. Lymphatic mapping and the use of free-hand single photon emission CT (fhSPECT) combined with sentinel lymph node biopsy is a novel approach to address this clinical need. The Lymphatic mapping Of Oropharyngeal Cancer trial aims to (a) validate a lymphatic mapping protocol in OPC using new technology (fhSPECT) with radiotracers and (b) establish lymphatic drainage patterns and the occult metastatic rate in the contralateral neck in OPC. METHODS AND ANALYSIS: The design is a prospective multicentre cohort trial to understand the lymphatic drainage pattern in 150 patients with OPC and unilateral neck metastases. The trial has two phases: (1) ETHICS AND DISSEMINATION: The outcome of this trial will provide a validated protocol and evidence to inform the design of future research in which management of the contralateral neck is based on surgical staging. Ethical approval was granted by the Yorkshire & The Humber-South Yorkshire Research Ethics Committee (REC ref: 20/YH/0111). Results from the trial will be presented to the scientific community at appropriate meetings and international journals. Patients and the public will be informed via patient groups, cancer charities and social media/press releases. TRIAL REGISTRATION NUMBER: NCT04498221.