In a randomized multicenter study, a strategy based on sentinel node biopsy (SNB) was equivalent to elective neck dissection (END) in the management of T1-T2N0 oral and oropharyngeal squamous cell carcinomas, with comparable 2-year neck recurrence-free survival (RFS) and lower morbidity in year 1 after surgery (Abstract 6501). Renaud Garrel, MD, of CHU Montpellier, France, presented the results during the ASCO20 Virtual Scientific Program.
This phase III trial provides a high level of evidence of similarity for SNB and END, Dr. Garrel asserted, with no significant differences in neck RFS and overall survival (OS) in comparable groups in a representative population.
The study was designed to demonstrate equivalence of these two approaches in the management of T1-T2N0 oral and oropharyngeal squamous cell carcinomas. The primary outcome was 2-year neck RFS, and secondary outcomes included 2- and 5-year locoregional RFS, disease-specific survival, and OS. Morbidity, as assessed by hospital stay, a neck and shoulder impairment questionnaire/objective arm abduction test, and the amount of physiotherapy prescribed during follow-up, were other secondary endpoints.
In the randomized trial, patients in the standard treatment arm underwent surgery for the primary tumor and systematic END; patients in the experimental arm underwent SNB and then had surgery only of the primary tumor if they were SNB-negative, or END if they were SNB-positive. Secondary END was performed if further tissue analysis detected a false SNB-negative. The sample size was determined on the basis of a hypothesis of equivalence of 2-year neck RFS, with an alpha-risk of 5% and a power of 90%, requiring a total of 310 patients.
Over a period of 5 years, 307 patients were randomly assigned to one of the treatment arms. After exclusions, the researchers analyzed 139 patients in the END arm and 140 in the SNB arm. Mean follow-up was 4.95 years.
In the primary outcome, neck RFS at 2 years was 89.6% in the END arm and 90.7% in the SNB arm, a difference of 1.1%, which was “far less than the 10% hypothesis, confirming the equivalence with p = 0.008,” Dr. Garrel noted. At 5 years, neck RFS was 89.6% in the END arm and 89.4% in the SNB arm. Survival curves were not statistically significantly different at 2- and 5-year analysis of locoregional RFS, disease-specific survival, nor OS, respectively.
At 2-, 4-, and 6-month postoperative morbidity evaluations, several functional outcomes assessed by the questionnaire were statistically worse in the END arm than in the SNB arm. By month 12, only being bothered by the appearance of the neck was worse in the END arm. The length of hospital stay was shorter (median 7 vs. 8 days, p = 0.001), the results of the arm abduction test were better, and the rate of physical therapy prescription was lower in the SNB arm than in the END arm.
Dr. Garrel acknowledged that the study did not meet its accrual goal, but he noted that it nonetheless achieved statistical significance in the primary endpoint. He also acknowledged that the study did not include an estimate of costs.
“This establishes SNB as the standard of care for the treatment of T1-T2N0 squamous cell carcinoma of the oral cavity and oropharynx,” Dr. Garrel said.
“This establishes SNB as the standard of care for the treatment of T1-T2N0 squamous cell carcinoma of the oral cavity and oropharynx,” Dr. Garrel said.
Discussant Hisham Mehanna, PhD, of the University of Birmingham, United Kingdom, had a slightly different assessment. “SNB should be considered astandard of care,” he said, emphasizing the indefinite article. “It should be offered as an option alongside or instead of END.”
“Make no mistake,” Dr. Mehanna said, “this is a significant achievement, to do this trial. We’ve been talking about it for a long time. … But really data on cost effectiveness would be important if this strategy is going to be adopted widely because SNB is resource intensive. If [SNB] is more expensive, this will remain an issue.”
— Tim Donald, ELS
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