Multi-institutional insight into the prognostic significance of lymph node yield and lymph node ratio in clinically node negative early oral cavity squamous cell carcinoma.

Presentation: AHNS22
Topic: Oral Cavity
Type: Oral
Date: Wednesday, April 27, 2022
Session: 4:15 PM – 5:00 PM Oral Larynx
Authors: Nathan Farrokhian, BS, BA1; Andrew Holcomb, MD2; Erin Dimon1; Omar Karadaghy, MD1; Christina Ward1; Erin Whiteford, MS2; Claire Tolan, BA2; Elyse K Hanly, MD, PhD3; Marisa R Buchakjian, MD, PhD3; Brette Harding, MD4; Laura Dooley, MD4; Justin Shinn, MD5; C Burton Wood, MD5; Sarah Rohde, MD5; Sobia Khaja, MD6; Anuraag S Parikh, MD7; Mustafa G Bulbul, MD7; Mark Varvares, MD7; Joseph Penn1; Sarah Goodwin1; Andres M Bur, MD1
Institution(s): 1Department of Otolaryngology - Head and Neck Surgery, University of Kansas Medical Center; 2Department of Otolaryngology, Nebraska Methodist Health System; 3Department of Otolaryngology - Head and Neck Surgery, University of Iowa; 4Department of Otolaryngology - Head and Neck Surgery, University of Missouri; 5Department of Otolaryngology - Head and Neck Surgery, Vanderbilt University; 6Department of Otolaryngology - Head and Neck Surgery, University of Minnesota; 7Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear Infirmary


Importance:

In early stage (cT1-2N0) oral cavity squamous cell carcinoma (OCSCC), regional lymph node metastasis is known to portend a poor prognosis. Given the high propensity of sub-clinical nodal disease in these patients, upfront elective neck dissections (END) for clinically node negative patients are common and associated with better outcomes. Unfortunately, even with this risk adverse treatment paradigm, regional recurrence still occurs and our understanding of factors that modulate this risk and alter survival have yet to be fully elucidated.


Objective:

Investigate the prognostic significance of lymph node yield (LNY) and lymph node ratio (LNR) in patients with cT1-2N0 OCSCC.

Design, Setting, and Participants: Data was collected retrospectively from seven tertiary care academic medical centers. cT1-2N0 OCSCC patients that underwent elective neck dissections concurrent with primary tumor surgical extirpation were identified. The cohort was further divided into patients that were pathologically node negative and those with identified pathologic nodal disease.

Exposure: For the cohort of patients that were pathologically node negative, the number of lymph nodes recovered (LNY) was evaluated. For patients with pathologic nodal disease, the ratio of positive nodes against total lymph nodes recovered after elective neck dissection (LNR) was calculated.

Outcome(s) and Measure(s): The incidence of regional recurrence and mortality were evaluated using non-parametric Kaplan Meier survival curves and semi-parametric Cox proportional hazard regressions.

Results: Of the 502 patients that underwent neck dissection in our cohort, 394 patients were pathologically node negative and 108 patients had confirmed pathologic nodal disease. For pathologically node negative patients, five year predicted regional recurrence-free survival in patients with a LNY greater than 18 was 81.74% (95% CI, % 75.66% - 86.43%) compared to 68.22% (95% CI, 59.28% - 75.60%) in patients with a LNY less than or equal to 18 (log-rank p = 0.030). Amongst patients with pathological nodal disease identified after elective neck dissection, those with a LNR less than or equal to the cohort median (0.05556) had a predicted five-year regional recurrence-free survival of 59.94% (95% CI, 44.65% - 72.25%) compared to 44.85% (95% CI, 30.50% - 58.18%) in patients with a LNR greater than the cohort median (log-rank p = 0.033). Cox proportional hazard regression revealed that even when controlling for pathologic tumor stage, age, and adjuvant radiation therapy, patients in the low LNR group had a lower risk of regional recurrence or mortality when compared to the high LNR group (HR 0.56; 95% CI, 0.32 - 0.97; p = 0.040).

Conclusions and Relevance: Our data suggest that a high LNY in pathologically node negative early OCSCC patients is associated with an overall higher rate of regional recurrence-free survival. Additionally, lower LNR in early OCSCC patients with identified nodal disease is also associated with higher rates of regional recurrence-free survival. Interestingly, this association remains significant even after controlling for adjuvant radiation, pathologic tumor stage, and age. As such, quality of neck dissections, as assessed by LNY, and regional disease burden, as assessed by LNR, can be utilized as valuable risk stratification tools in patients with early OCSCC.