Elective neck dissection improves survival in early-stage oral cancer
CHICAGO – The prophylactic removal of lymph nodes during primary surgery improves survival and reduces the rate of recurrence in early-stage oral cancer compared with dissection at the time of nodal occurrence, according to phase 3 study results presented at the plenary session during the ASCO Annual Meeting.
Although early oral cancer is frequently cured with surgery to remove the tumor, it can recur and spread to the lymph nodes in the neck, according to study background. Elective neck dissection (END) of the lymph nodes is conducted at the time of the primary oral cancer surgery whereas therapeutic neck dissection is performed once a patient relapses.
“END should be the standard of care for early total node-negative squamous cell cancers based on the findings of our study,” Anil D’Cruz, MBBS, MS, FRCS, professor and chief of the department of head and neck surgery at Tata Memorial Centre in Mumbai, India said during a press briefing. “For every eight patients who undergo an END, one death is prevented. For every four patients who undergo an END, one recurrence is prevented.”
D’Cruz and colleagues conducted this prospective, phase 3 trial to compare END compared with therapeutic neck dissection in patients with lateralized T1 or T2 squamous carcinoma of the oral cavity that is amenable to peroral excision.
OS served as the study’s primary endpoint and PFS served as the secondary endpoint.
Researchers designed the trial to demonstrate a 10% superiority of OS for END compared with therapeutic dissection under the assumption that 60% of patients in the therapeutic dissection arm would achieve 5-year OS.
The planned sample size was 710 patients; however, the trial was terminated after researchers enrolled 596 patients randomly assigned them to one of the two treatment arms between January 2004 and June 2014.
Researchers conducted interim analyses from the initial 500 patients (therapeutic dissection, n = 255; END, n = 245) after a minimum follow-up of 9 months. The researchers identified 427 tongue tumors, 68 buccal mucosa tumors and five floor of mouth tumors. Further, 221 tumors were T1 and the remaining 279 were T2.
After a median follow-up of 39 months, there were 146 disease recurrences in the therapeutic dissection arm compared with 81 recurrences in the END arm.
Eighty percent of patients in the END cohort achieved 3-year OS compared with 67.5% of patients in the therapeutic dissection cohort. These data equated to a 37% reduction in the risk for death with END (HR = 0.63; 95% CI, 0.44-0.89).
The 3-year rate for DFS was 69.5% in the END group and 45.9% in the therapeutic dissection arm for a 56% reduction in the risk for relapse or death with END (HR = 0.44; 95% CI, 0.34-0.58).
Although the researchers concluded that END should be the new standard of care for patients with early-stage oral cancer, they noted neck dissection increases the risk for shoulder dysfunction in some patients (range, 5% to 40%) because the nerve that supplies the muscles responsible for shoulder movement runs through the field where surgical dissection takes place.
“Our study is the first to conclusively prove that more lives can be saved with elective neck dissection,” D’Cruz said in a press release. “Armed with the results of this study, doctors will be able to confidently counsel patients that adding neck surgery to their initial treatment is worthwhile.” – by Anthony SanFilippo
D’Cruz A, et al. Abstract LBA3. Presented at: ASCO Annual Meeting; May 29-June 2, 2015; Chicago.
Disclosure: This study was funded by the Tata Memorial Centre. D’Cruz reports a speakers bureau role with Merck Serono and research funding from GlaxoSmithKline.