Retrospective observational cohort study investigating Single modality Trans Oral Robotic surgery for primary oropharyngeal cancer: exploring the impact of surgical Margins on local disease recurrence.

The STORM study will examine transoral surgery performed before 31st July 2019. STORM is a retrospective observational cohort study, involving international centres performing TORS for primary OPSCC.

The main aim of this study is to explore the impact of surgical margins on local disease recurrence in primary oropharyngeal squamous cell carci-noma treated with transoral robotic surgery (TORS) without adjuvant therapy.

The primary objective is to report local recurrence-free survival. The primary endpoint will be Local recurrence-free survival time.

The secondary objectives are to report overall survival, disease-specific survival and disease-free survival, and to report post-operative haemor-rhage rates. The secondary endpoints include Overall survival time, Dis-ease-specific survival time, Disease-free survival time, Post-operative haemorrhage time.

Exploratory objective to identify a clinically relevant cut-off for surgical margins as a predictor of local disease recurrence.

Inclusion Criteria:

• 18 years and older.
• Primary OPSCC.
• Index cancer treated with TORS without adjuvant therapy.
• Any post-operative TNM classification.
• TORS performed on or before 31st July 2019.

Exclusion Criteria:

• TORS preformed for diagnostic or palliative intentions.
• Known distant metastasis at time of TORS.
• Nasopharyngeal and thyroid cancers.
• Patients undergoing neoadjuvant or adjuvant chemotherapy, biotherapy, immunotherapy or radiotherapy to either the neck or primary site.

Patients with a diagnosis of Primary OPSCC with Index cancer treated with TORS, without adjuvant therapy, on or before 31st July 2019.