Management of the neck after definitive chemoradiation in patients with HPV-associated oropharyngeal cancer: An institutional experience

Purpose: To investigate the multidisciplinary management of patients with Human Papilloma Virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) and an incomplete nodal response on restaging PET/CT after definitive chemoradiation (CRT). Materials and methods: A retrospective chart review was performed of patients diagnosed with node-positive HPV-associated OPSCC from 2012 to 2017, who underwent definitive upfront CRT, and had an incomplete response on post-therapy PET/CT according to NCCN criteria. Post-CRT PET/CT results, management decisions, and clinical outcomes were recorded. Results: Seventy-four patients with node-positive HPV-associated OPSCC were identified; 20 patients with incomplete neck response on PET/CT according to NCCN criteria were included in the final case series. Median follow-up time was 33 months. Patients were managed as follows: 8 underwent observation and surveillance imaging, 6 underwent ultrasound-guided fine needle aspiration (FNA), and 6 had immediate neck dissection. All the observed patients were disease-free at most recent follow-up. None of the patients who underwent immediate neck dissection had residual neck disease on pathological examination; two patients in this group ultimately developed metastatic disease. Among the 6 who underwent FNA, 1 individual had positive pathology, along with residual primary disease, for which the patient underwent salvage surgery. The 5 remaining individuals had negative FNA results, were subsequently observed, and remained free of disease. Conclusions: This institutional experience supports the notion of a high threshold for neck dissection in this low-risk population; only 1 of 20 patients with suspicious PET/CT findings had residual disease in the neck. Moreover, these patients should be managed by a multidisciplinary tumor board (MTB) since current algorithms do not universally include HPV status. Finally, the use of restaging PET/CT to guide management of the neck can be improved with changes in terminology and consideration of FDG-avidity at the primary site and on pre-therapy scans.