Abstract 881P
Background
To assess the efficacy in terms of neck failure of an initial neck dissection (ND) before definitive chemo-radiotherapy (CRT) in N2-3 oropharyngeal squamous-cell carcinomas (SCC), as well as the dosimetric impact and the acute and delayed morbidity of this approach.
Methods
All patients consecutively treated between 2009 and 2018 with definitive CRT using intensity-modulated conformal radiotherapy (IMRT) for a histologically proven N2-3 oropharyngeal SCC were retrospectively included. The therapeutic approach consisted of induction chemotherapy, followed by cisplatine-based CRT preceded or not by ND. IMRT using a simultaneous-integrated boost delivered 70 Gy in 35 fractions on macroscopic tumor volumes, 63 Gy on intermediate-risk levels or extra-nodal extension and 54 Gy on prophylactic lymph node areas.
Results
Two groups were constituted: 47 (62.7%) patients without an initial ND, and 28 (37.3%) patients with a ND prior to definitive CRT. Initial patient characteristics were not statistically different between the two groups. The median follow-up was 60.1 [3.2-119] months. Incidence of neck failure was higher in patients without ND (p=0.015). The neck failure rate at 5 years was 19.8% (95%CI [7.4-30.6], p=0.015) without ND versus 0% following ND. All lymph node failures occurred in the planned target volume at 70 Gy. Upfront ND reduced the mean dose to the homolateral parotid gland (p=0.01), mandible (p=0.02) and thyroid gland (p=0.02). Acute toxicity of CRT was lower after ND in terms of grade ≥ 3 adverse events (p=0.04), early discontinuation of concomitant chemotherapy (p=0.009), interruption of radiotherapy ≥ 4 days (p=0.06) and feeding tube-dependence (p=0.008). During follow-up, there were no differences between the two groups in terms of xerostomia, dysgeusia, dysphagia or feeding tube-dependence.
Conclusions
ND prior to definitive CRT in N2-3 oropharyngeal SCC resulted in improved neck control without additional mid and long-term morbidity.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
G. Klausner.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.