Postoperative complications following salvage neck dissection after (chemo)radiotherapy for head and neck squamous cell carcinoma: which patients are at high risk?

Background Salvage neck dissection (ND) is the treatment of choice for residual neck disease after (chemo)radiotherapy for head-and-neck squamous cell carcinoma (HNSCC). Although ND is a relatively safe surgical procedure, several studies have shown that salvage ND will increase the morbidity of (chemo)radiotherapy with possible increase in acute and late toxicity and deterioration of quality-of-life. Therefore, unnecessary salvage ND need to be avoided. However, the available literature could not identify potential groups at higher risk of post-operative complications because of the missing demographic information and the heterogeneity in studies and outcome data. We aim to report on the types, rates, and severity of postoperative complications and to identify groups of patients at high risk of these complications. Methods Of 908 patients with node-positive HNSCC primarily treated with (chemo)radiotherapy between 2008 and 2022, 130 (14%) underwent salvage ND. Endpoints of the study are the incidence of G ≥ 2 and G3 postoperative complications, identification of risk factors for these complications and the oncologic outcomes. Results Only 41% of patient who underwent salvage ND still had vital tumor in ND-specimen (pN+). No G4-5 complications were reported. The incidence of G3 and G ≥ 2(CTCAE.v5) postoperative complications were 18% and 52%, respectively. Events reported as G3 complications were wound infection/dehiscence (n = 9), fistula (n = 4), bleeding (n = 4), tracheotomy (n = 6), dysphagia (n = 4), severe pneumonia and septicemia (n = 2), and frozen shoulder (n = 1). Seven patients had more than one type of G3 complications. Logistic regression showed that extent of salvage ND, size of the largest node and HPV-negative disease were independent predictors for G ≥ 2 complications. Multivariable analysis showed that G ≥ 2 complications was not associated with worse OS while HPV-negative and N3-disease were independent predictors for worse survival. Conclusions Only 41% of patients who underwent salvage ND still had residual neck disease while 52% developed G ≥ 2 and 18% G3 complications. Although OS was not worse in these patients, accurate detection of residual neck disease is essential to spare considerable number of patients from unnecessary salvage ND with its possible complications. Patients with lymph nodes larger than 3 cm, HPV-negative disease and those treated by (modified)radical ND were at high risk of G ≥ 2 complications.