Comment on: Hospital volume matters: a meta-analysis of mortality after colorectal cancer surgery

Dear Editor, We read with great interest the recent meta-analysis by Guo et al examining the association between hospital surgical volume and postoperative mortality after colorectal cancer surgery1. By pooling data from 45 studies and more than 2 million patients, the authors provide robust and contemporary evidence that higher hospital volume is associated with a significant reduction in postoperative mortality for both colon and rectal cancer surgery. Importantly, this work quantifies the magnitude of the volume–outcome relationship, demonstrating a 27% reduction in postoperative mortality after colon resection and a 25% reduction after rectal resection in higher-volume hospitals. The identification of a volume threshold of approximately 30 rectal resections per year, beyond which mortality appears to plateau, is particularly relevant for health policy makers seeking to define evidence-based criteria for referral and organization of care. These findings are consistent with a substantial body of prior literature demonstrating strong volume–outcome and structure–outcome relationships in complex surgery2. At the same time, as the authors appropriately acknowledge, hospital volume alone is an imperfect surrogate for quality. The observed benefits of high-volume care likely reflect the broader characteristics of specialized centers, including multidisciplinary decision-making, subspecialized surgical teams, standardized perioperative pathways, and effective systems for complication management and rescue. In this context, the present meta-analysis reinforces the notion that centralization is necessary but not sufficient. Procedural concentration must be embedded within formal quality frameworks to ensure that increased volume translates into sustained improvements in outcomes. Certification systems and external quality assurance mechanisms therefore represent essential complements to volume-based centralization3. Previous studies have shown that audit-based certification of cancer centers is associated with improved guideline adherence and, in some settings, superior survival outcomes4,5. Crucially, external audit and certification frameworks ensure that minimum case-load requirements apply not only at the institutional level, but also at the level of individual surgeons, preventing dilution of experience within high-volume centers and aligning procedural volume with true operator expertise. Effective centralization strategies should thus incorporate: (1) clearly defined minimum case-load thresholds informed by outcome data, such as those proposed by Guo et al; (2) mandatory participation in national or international outcome registries; (3) regular external audits focusing on risk-adjusted outcomes rather than structural criteria alone; and (4) time-limited accreditation with periodic reassessment. The Swiss framework of Highly Specialized Medicine6 exemplifies such an integrated approach, linking authorization for complex procedures to volume requirements, institutional resources, and recurrent evaluation. Similarly, certified European Cancer Centers7 embed multidisciplinary care, guideline adherence, and continuous quality monitoring into formal accreditation processes. In conclusion, the meta-analysis by Guo et al provides strong contemporary evidence supporting selective centralization of colorectal cancer surgery to higher-volume hospitals, particularly for rectal cancer. Crucially, it also highlights the need to move beyond volume alone and to integrate certification, external auditing, and continuous quality assessment into centralized care models. Future efforts should focus not only on where colorectal cancer surgery is performed, but on how quality is measured, validated, and maintained over time.