Does surgeon specialization add value to surgeon volume in gastric cancer surgery?

BACKGROUND:This study aimed to assess the combined impact of surgeon specialization and surgeon volume on both short- and long-term outcomes in patients underwent curative gastrectomy for gastric cancer. METHODS:Patients with cStage1-3 gastric adenocarcinoma who underwent curative-intent surgery between January 2010 and December 2020 were evaluated. The impact of surgeon specialization and surgeon volume on clinical outcomes was scrutinized, both individually and in combination. For the purpose of assessing the combined effect, surgeons were classified into three groups: Non-specialized low-volume (NS-low), non-specialized high-volume (NS-high), and specialized high-volume (S-high). Postoperative outcomes and survival were evaluated. The adjusted effect sizes were expressed as odds ratio (OR) or hazard ratio (HR) with the corresponding 95% confidence interval. RESULTS:Total of 537 patients operated by twelve surgeons were included in the analysis. For all cohort, the 30d-, in-hospital and 90d-mortality were 3.5%, 3%, and 6.3%, respectively. High surgeon volume alone had a significant impact (OR: 0.31 [0.10-0.82, p = 0.023]) on 30-day mortality. However, upon evaluating the combined effects of the parameters, while the most favorable 30-day mortality rate was observed in the S-high group, neither the NS-low group (OR: 3.82 [1.10-18.17, p = 0.054]) nor the NS-high group (OR: 1.37 [0.23-8.37, p = 0.724]) demonstrated a statistically significant difference when compared to the S-high group. The NS-low group showed poor results for several types of postoperative outcomes. In terms of overall survival, the S-high group outperformed, while the NS-low and NS-high groups presented with notably worse outcomes (HRs: 2.04 [1.51-2.75, p < 0.001], and 1.75 [1.25-2.44, p = 0.001], respectively). CONCLUSION:The primary factor influencing short-term outcomes for patients who underwent gastric cancer surgery was found to be surgeon volume, while specialization provided a limited additional value. However, specialization emerges as an independent factor with a greater contribution to long-term survival than the impact attributed to high-volume.