Lymphatic mapping in second primary or recurrent oral cavity cancer with prior neck treatment: A case series and scoping review

Objectives: Lymphatic mapping is an established technique to map drainage patterns in oral cancer. Its utility in patients who have undergone prior radiation or neck dissection is not well studied.3 Methods: Patients presenting to a single tertiary cancer center between 2021-2023 for a recurrent/second oral cancer that underwent lymphatic mapping were considered. All patients had a history of a head and neck cancer treated with either radiation or neck dissection. We further conducted a scoping review in MEDLINE, Embase, and Web of Science of lymphatic mapping in oral cancer patients with previous neck treatment. Results: In our single center review, a total of 11 patients were included. 73 % received prior radiotherapy and 55 % underwent prior neck dissections for a head and neck cancer. Lymphoscintigraphy-directed neck dissections identified sentinel nodes in 9/11 patients, with only one patient who had positive sentinel node disease. There were no reports of regional recurrence at a median of 10 months follow-up. Our scoping review of 980 studies identified 151 additional patients who underwent sentinel node biopsy for a second oral cancer after previous neck treatment. Overall, the negative predictive value of lymphatic mapping in all studies was 96.7 %. Conclusion: Lymphatic mapping is feasible in secondary or recurrent oral cavity cancers even in patients with prior radiation or surgical management of the neck. The literature to date demonstrates a negative predictive value of similar to 97 % for sentinel node mapping and warrants further consideration in the management of salvage oral cancer.