OP066: Is there a need for elective contralateral neck irradiation in all locally advanced gingivobuccal squamous cell carcinomas?

Abstract

Purpose To evaluate outcomes in resectable gingivobuccal SCC patients treated with adjuvant radiotherapy and assess the impact of unilateral irradiation on nodal failure. Methods We retrospectively reviewed 129 patients of newly diagnosed resectable gingivobuccal SCC who underwent radical surgery and postoperative radiotherapy between April 2005 and March 2009. 123 patients (95%) were pathological AJCC stage IV. 20 patients (15.5%) had bilateral neck nodal dissection. All patients received postoperative radiation using 60 Cobalt with shrinking fields to a median dose of 60 Gy/30 fractions. 86.8% (112/129) patients received unilateral irradiation with anterolateral fields. The remaining 17 patients received bilateral nodal irradiation in view of disease involving midline, multiple ipsilateral or bilateral nodal metastases. About 187.6% patients completed planned radiotherapy. Concurrent weekly cisplatin (30 mg/m 2 ) was offered to 34 patients with multiple nodal metastases, extracapsular extension and/or inadequate cut margins. Results With median follow up of 16 months, 2 year local control, locoregional control (LRC) and disease free survival were 83.6%, 70% and 61% respectively. The 2 year LRC for pN0-N1 and pN2 was 78.8% and 56.3% respectively ( p = 0.008). The 2 year LRC with N0, 1, 2–3 and ⩾4 metastatic neck nodes was 80.3%, 69.1%, 64.3% and 43.2% respectively ( p = 0.02). Among node positive patients with and without extracapsular extension, the 2 year LRC was 52.9% vs. 100% respectively ( p = 0.01). The incidence of contralateral nodal failure was 8.5% (11/23). 9 of these 11 patients had received unilateral neck irradiation. These had a combination of deep infiltrating tumours, nodal metastases at multiple levels and/ or extracapsular extension. Conclusions Risk of contralateral nodal failure is high in patients with lateralised gingivobuccal SCC having multiple high risk factors. They should be offered elective bilateral nodal irradiation. In patients without high risk features, unilateral nodal irradiation may allow acceptable outcomes with the potential for reduced late toxicity.