Late Breaking Abstract – ASCO 2015 Elective Neck Dissection Improves Overall Survival and Disease Free Survival in Early Oral Cavity Cancers

SUMMARY: The American Cancer Society estimates that approximately 39,500 individuals will be diagnosed with oral cavity and oropharyngeal cancer in the United States in 2015 and about 7,500 will die of the disease. These cancers are more than twice as common in men as in women and tobacco and alcohol use are among the strongest risk factors. Routinely screening for oral mucosal lesions can improve survival in this patient group. The primary treatment of oral cavity squamous cell carcinoma is complete surgical resection with tumor free margins. Surgical management of the neck in patients with early stage oral cancers has remained unclear, with regards to the benefit of ipsilateral Elective Neck Dissection (END) at the time of primary surgery following diagnosis versus Therapeutic Neck Dissection (TND) after nodal relapse in the neck. To address this question, the authors conducted a prospective, randomized, controlled trial between 2004 and 2014, in which 596 treatment naïve patients with invasive squamous cell carcinoma of the oral cavity (tongue-85%, buccal mucosa-14%, floor of the mouth-1%) were enrolled and randomized to 1:1 to Elective Neck Dissection (END) or Therapeutic Neck Dissection (TND) following primary oral surgery. Patients had T1 (2 cm or less) or T2 (more than 2 cm and less than 4 cm) tumors that was lateralized to one side of the midline and were amenable to oral excision with adequate margins. Elective Neck Dissection (END) consisted of removal of submandibular (level 1), upper jugular (level 2)and midjugular (level 3) lymph nodes, with lower jugular (level 4) and posterior triangle (level 5) lymph nodes removed only if any of the lymph nodes in the first three levels showed intraoperative metastatic disease. Therapeutic Neck Dissection (TND) consisted of modified neck dissection (level 1-5) at the time of nodal relapse. All patients with high risk disease received adjuvant radiotherapy. The Primary end point was Overall Survival and Secondary end point was Disease Free Survival.

This publication summarizes the outcomes for the first 500 patients (245 in the END group and 255 in the TND group), following a median follow-up of 39 months. The 3 year Overall Survival was significantly higher in the Elective Neck Dissection group compared with the Therapeutic Neck Dissection group (80.0% vs. 67.5%, HR=0.63; P=0.01). The three year Disease Free Survival was also significantly higher in the END arm compared with TND (69.5% vs 45.9%, HR=0.45; P<0.001). The authors concluded that Elective Neck Dissection in patients with early stage oral squamous cell carcinoma resulted in 37% reduction in mortality risk as well as significantly high Disease Free Survival rates with a 55% reduction in the risk of disease recurrence. END should therefore be considered a standard treatment option. Elective versus Therapeutic Neck Dissection in Node-Negative Oral Cancer. D’Cruz AK, Vaish R, Kapre N, et al. N Engl J Med 2015; 373:521-529