Main outcome measures, variables, and data sources
Anonymised data was collected from patients’ electronic clinic letters and operation notes for age, histological diagnosis, site of the tumour, date of operation, details of surgical management, postoperative complications, need for revision surgery and outcome at five years post-operatively (or most recent follow up if less than five years).
Surgical procedures were classified as primary if surgery was conducted at our centre for the first time and secondary if a prior attempted resection had been undertaken elsewhere.
Statistical analysis was done using a Chi-squared calculation with the significance level of p<0.05.