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Study Shows Equivalence of Sentinel Node Biopsy vs Neck Node Dissection in Operable Oral or Oropharyngeal Cancer


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Renaud Garrel, MD, PhD

Renaud Garrel, MD, PhD

In the French phase III Senti-MERORL trial reported in the Journal of Clinical Oncology, Renaud Garrel, MD, PhD, of the University Hospital Center of Montpellier, France, and colleagues, found that sentinel node biopsy was equivalent to neck lymph node dissection in 2-year neck node recurrence-free survival in patients with operable cT1-T2N0 oral or oropharyngeal cancer.1

Study Details

In the multicenter equivalence trial, 279 eligible patients were randomly assigned to undergo node dissection (n = 139) or sentinel node biopsy (n = 140). Biopsy alone was performed if the result was negative or followed by node dissection if the result was positive during primary tumor surgery. The primary outcome was neck node recurrence-free survival at 2 years.

For the node dissection vs sentinel node groups, N pathologic stage was not invaded in 79.0% vs 75.0%, invaded without extranodal extension in 14.5% vs 17.1%, and invaded with extranodal extension in 6.5% vs 7.9% (overall P = .73). First-line treatment was surgery alone in 105 patients (75.5%) in the node dissection group vs 107 patients (76.4%) in the sentinel node group; adjuvant treatments consisted of radiotherapy alone in 17.3% vs 12.1%, chemoradiotherapy in 4.3% vs 7.1%, and brachytherapy in 2.9% vs 4.3% (overall P = .46)

Neck Node Recurrence-Free Survival

Mean follow-up was 4.95 years in the node dissection group and 4.74 years in the sentinel node group. The mean number of dissected nodes per patient was 29.09 in the node dissection group and 2.93 in the sentinel node group. In the sentinel node group, 29 patients underwent neck node dissection during primary tumor surgery, 8 due to sentinel node biopsy technical failure that precluded node localization and surgical excision, and 21 due to detection of at least one invaded sentinel node in intraoperative histopathologic analysis. Node dissection was performed during a second surgical intervention in 12 patients in the sentinel node group with negative intraoperative histologic analysis.

During follow-up, neck node recurrence without relapse of the primary tumor or development of a second primary head and neck tumor occurred in 14 patients (10.1%) in the node dissection group vs 13 patients (9.3%) in the sentinel node group. Neck node recurrence-free survival at 2 years was 89.6% in the node dissection group vs 90.7% in the sentinel node group; the difference between groups was 1.1%, which was lower than the 10% hypothesis, confirming equivalence (P for equivalence < .01). Neck node recurrence-free survival at 5 years was 88.6% vs 93.0%. No significant difference was observed between the node dissection group and the sentinel node group (P = .92).

Among the patients with clinical neck relapse without relapse of the primary tumor or development of a second primary head and neck tumor, 11 patients in the node dissection group were initially classified as pN0 (10.1% of the 109 patients with pN0) and 8 in the sentinel node group were initially classified as pSN0 (8.1% of the 99 patients with pSN0; P = .61).

In the node dissection group, 18 patients (12.9%) developed a second head and neck primary tumor, and 20 (14.4%) had local relapse (associated with node recurrence in 1 patient). Progression to metastatic disease occurred in two patients, and four patients developed another cancer type. In the sentinel node group, 14 patients (10.0%) developed a second head and neck tumor, and 19 (13.6%) had local relapse (associated with node recurrence in 3 patients). Progression to metastatic disease occurred in one patient, and six patients developed another cancer type.

Secondary Endpoints

Locoregional recurrence–free survival was 83.1% in the node dissection group vs 81.8% in the sentinel node group at 2 years and 73.6% vs 76.3% at 5 years (P = .83). Disease-specific survival was 95.5% vs 93.0% at 2 years and 88.6% vs 87.1% at 5 years (P = .68). Overall survival was 92.6% vs 88.7% at 2 years and 81.8% vs 82.2% at 5 years (P = .42).

The median hospital stay was 8 days (range = 2–94 days) in the node dissection group vs 7 days (range = 3–30 days) in the sentinel node group (P < .01). The mean stay was 10.4 days vs 8.09 days (P = .01).

KEY POINTS

  • The equivalence of sentinel node biopsy vs neck lymph node dissection was demonstrated for 2-year neck node recurrence-free survival.
  • No significant differences were observed in neck node recurrence-free survival, locoregional recurrence-free survival, disease-specific survival, or overall survival.

Functional outcomes were significantly worse in the node dissection group until 6 months after surgery. For example, for self-reported neck-shoulder impairment, shoulder stiffness and limitation in leisure activities were significantly worse in the node dissection group at 2, 4, and 6 months. In the arm abduction test, the exercise could be achieved without pain or effort by 51% vs 71% of patients at 2 months, 58% vs 74% at 4 months, and 60% vs 76% at 6 months (all P < .05), with no differences observed at 12 or 24 months. Physiotherapy prescription rates were 33% vs 10%, 38% vs 18%, and 32% vs 18% at 2, 4, and 6 months (all P < .05), with no differences observed at 12 or 24 months.

The investigators concluded: “This study demonstrated the oncologic equivalence of the sentinel node and node dissection approaches, with lower morbidity in the sentinel node arm during the first 6 months after surgery, thus establishing sentinel node as the standard of care in [oral/oropharyngeal cancer].” 

DISCLOSURE: The study was supported by the French National Institute of Cancer. Dr. Garrel and coauthors reported no conflicts of interest.

REFERENCE

1. Garrel R, Poissonnet G, Plana AM, et al: Equivalence randomized trial to compare treatment on the basis of sentinel node biopsy versus neck node dissection in operable T1-T2N0 oral and oropharyngeal cancer. J Clin Oncol. October 14, 2020 (early release online).


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