# A National Analysis of Microscopic Positive Margins in Oropharyngeal Cancer Patients Undergoing Transoral Robotic Surgery

## TL;DR

This study analyzed factors linked to positive surgical margins in oropharyngeal cancer patients and how adjuvant treatments affect survival.

## Contribution

Identified clinical variables associated with positive margins and compared the effectiveness of adjuvant therapies in a national cohort.

## Key findings

- 16.6% of patients had microscopic positive margins after surgery.
- HPV-negative cancer, tumor size, and treatment at low-volume hospitals were linked to positive margins.
- Adjuvant radiation or chemoradiotherapy improved survival for patients with positive margins but no extranodal extension.

## Abstract

The objective was to identify clinical variables associated with microscopic positive margins (PMs) during transoral robotic surgery (TORS) for oropharyngeal cancer (OPC) resection, and to explore the association of the receipt of adjuvant treatment with overall survival (OS) in this population.

Retrospective cohort analysis.

2019 Patient User File of the National Cancer Database.

Patients >18 years of age with OPC were stratified based on margin status. Multivariable logistic regression was used to identify clinical variables associated with PM. Survival analyses were performed using multivariable Cox proportional hazards models. Adjusted odds ratios (aORs) and hazard ratios (aHRs) with associated 95% confidence intervals (CIs) were generated.

In total, 4294 patients met the criteria. The PM rate was 16.6%. Human papillomavirus (HPV)‐negative squamous cell carcinoma (SCCa), salivary gland carcinoma, clinical T category, base of tongue primary site, and treatment at low‐volume, nonacademic institutions were independently associated with PM. PMs were associated with increased mortality (aHR 1.67, 95% CI: 1.40‐1.99). In patients with PM, but without extranodal extension (ENE), adjuvant radiation therapy (aRT) (aHR 0.29, 95% CI: 0.19‐0.45) and adjuvant chemoradiotherapy (aCRT) (aHR 0.31, 95% CI: 0.21‐0.45) were associated with an improvement in OS versus surgery alone; however, OS between aRT and aCRT was similar for both HPV‐positive and HPV‐negative SCCa.

Histologic type, clinical T category, tumor subsite, and treatment at low‐volume, nonacademic institutions were independently associated with TORS PM. aCRT did not confer a survival benefit over aRT in the overall cohort, or in subgroups of HPV‐associated or HPV‐negative SCCa patients with PM without ENE.