S121 Resection margins and patterns of recurrence following surgical resection of non-small cell lung cancer

Background Failure to gain complete microscopic resection (R0) for Non-Small Cell Lung Cancer (NSCLC) affects prognosis and guides further treatment. There is a lack of data regarding the impact of pattern of disease recurrence and the proposed uncertain resection margin status (R(Un)). Methods A single institute retrospective analysis of patients undergoing resection of NSCLC between 01/04/2008 and 30/3/2017. Data was retrieved from case and histopathology records. The certainty of resection margin (R0 vs R(Un)) was derived. The pattern of first recurrence (PoR, defined as locoregional or distant) was determined from digitally held radiology records. Correlations were assessed between continuous and categorical variables, using standard statistical methods. Survival and recurrence-free survival differences were assessed using univariate and multivariate analysis models. Results After the exclusion of non-anatomic resections, second primary NSCLCs or new non-pulmonary cancers within the follow-up period, 1503 patients remained within the study. After a minimum follow up period of 38 months, 514 (34.1%) had tumour recurrence and 691 (46.0%) were alive. There were correlations between PoR and grade of tumour differentiation (p=0.002), T-Stage (p Conclusion The correlations with PoR were as expected. However, whilst R(Un) has previously been shown to have a worse prognosis than R0, R(Un) was not associated with increased locoregional recurrence or a reduced time to recurrence. A distant PoR at first recurrence was strongly negatively prognostic compared to other patterns of recurrence.