OGC SO33 - Resection Margins in Gastrectomy Patients – Are Current Guidelines Fit for Purpose? An Observational Study from a Tertiary Centre

Abstract Background Positive resection margins in cancer surgery are associated with higher likelihood of locoregional recurrence and poor outcomes. The Association of Upper GI Surgeons (AUGIS) outlined a target of less than 5% margin positivity for gastric resections, a goal not met in repeated national audits (NOGCA). Our study aimed to evaluate the positive resection margin rate after a gastrectomy in a tertiary centre and identify associated factors to assess the current guideline's suitability. Our hypothesis is that positive longitudinal margins are more related to tumour factors, such as proximity to the intended margin, rather than poor surgical technique. Method All records of patients who underwent gastrectomy from June 2015 to September 2021 were retrospectively reviewed. Data collection included demographic details, type of gastrectomy, exposure to neoadjuvant chemotherapy, and post operative histopathological information such as tumour differentiation, presence of signet ring (SR) morphology and linitis-plastica (LP), and resection margin(RM) status. Chi square tests of association were utilised to determine associations between the resection margin status and the potential determinant factors. Results Our study included 144 subjects (100 males, mean age 66, range 27-87). Types of gastrectomy were subtotal (38.9%), proximal (4.2%), total (29.2%), extended total (ETG) (27.8%). Positive RMs were found in 13.2%, with 8.3% having positive longitudinal margins and 6.3% positive circumferential margins. Neoadjuvant-chemotherapy was completed by 73% of subjects. Poor tumour differentiation was seen in 59.7%, SR presence in 12.5%, and LP in 3.5%. Significant associations were noted between positive margins and LP (80%, p<0.001) and age (<65: 15%, >=65: 4%, p=0.028). ETGs had double the rate of positive margins (12.5%) than that of other gastrectomies (6.7%,p=0.314). Conclusion The overall positive longitudinal margin rate was higher than the national guideline, replicating NOGCA audits. Our hypothesis was not proved: although the longitudinal positive margin rate in ETGs was almost double that of other gastrectomies, this did not reach statistical significance. Positive margin rates were higher in younger patients, and those with LP. Further large-scale audit is urgently required to determine if the recommended margin rate is appropriate or whether it should be adjusted for factors such as tumour location, presence of LP and age when the risk of a positive margin is higher.