The American College of Surgeons’ (ACS) Cancer Research Program developed the Operative Standards for Cancer Surgery manuals to present recommendations for surgical procedures critical to the technical conduct of cancer operations. These evidence-based recommendations are organized by disease site and are the foundation for the ACS Commission on Cancer (CoC) Operative Standards.1,2,3 The standards describe critical elements of cancer operations or subsequent pathologic review as well as the associated documentation necessary to satisfy the standard. Underlying these standards are data-driven recommendations associated with improvements in patient outcomes.1,2 The goal of adoption and implementation of these standards is to provide high-level care to all cancer patients across the United States.

The following editorial will review and summarize CoC Operative Standard 5.6, which describes the technical and documentation components for colectomy performed for colon cancer. Furthermore, it will discuss the rationale, timeline for implementation, and best practices to support compliance.

CoC Standard 5.6

Like all of the CoC Operative Standards, the operative standard for colon cancer resection contains two key components: a technical standard and documentation of the standard. All resections performed with curative intent for patients with colon cancer should include resection of the anatomic segment of colon harboring the primary tumor, as well as vascular ligation of that segment’s blood supply at its origin. By doing so, the length of the associated mesentery, and in turn the completeness of the lymphadenectomy, is maximized. For those areas that lie in a watershed area, or between pedicles, the surgeon should consider ligation of both pedicles with a more extensive resection. Operative reports should contain the following elements within a synoptic format: whether the operation was done with curative intent, tumor location, extent of the colon resection, and extent of the associated vascular ligation. Documentation for CoC Standard 5.6 provides flexibility to describe any reason why proximal ligation of the vascular pedicle cannot be performed. Furthermore, it allows for documentation for resection of multiple segments of colon by listing all that apply. The same principle applies to documentation for proximal vascular ligation. A full listing of the synoptic elements to be included in the operative notes are provided in the CoC Optimal Resources for Cancer Care manual and the Cancer Surgery Standards Program (CSSP) Operative Standards Toolkit online1.

Rationale

In 2023, there were 150,000 new cases of colon cancer diagnosed in the United States with a mortality of approximately 50,000 persons per year, making it the second most-common cause of cancer deaths in the United States.4 During the past 20 years, the incidence of colorectal cancer within the 20–49-year-old age group has increased, leading to the widely supported recommendation that routine screening begin at age 45 years.5,6 Treatment for colon cancer is multidisciplinary; however, surgical resection remains a mainstay of treatment in localized disease. Tenets for colon cancer surgery include complete resection of the involved segment of colon, proximal ligation of its vascular supply at the origin to optimize lymphadenectomy, and removal of any involved adjacent structures en bloc with the specimen. Although there are a variety of primary tumor locations within the colon, the oncologic principles for resection remain similar despite anatomical location.

The importance of adequate lymphadenectomy was identified almost two decades ago in a secondary analysis of the Intergroup 0089 trial.7 In that analysis, the number of lymph nodes pathologically assessed after colectomy for colon cancer was compared with patient survival. After controlling for the number of lymph nodes involved, survival increased as more nodes were analyzed. Even when no lymph nodes were pathologically involved, overall survival and cause-specific survival improved with an increasing volume of nodes assessed. This analysis informed the minimum examined lymph node standard of 12 nodes for colon cancer ascribed to by the National Comprehensive Cancer Network.7,8,9 The number of lymph nodes removed with the specimen not only reflects the completeness of the lymphadenectomy but ensures proper staging of the patient, which has implications for systemic therapy. Since the early 2000s, lymphadenectomy has improved significantly in response to the Intergroup data, but modern rates of adherence remains around 80% for lymph node yields ≥ 12 with colon cancer specimens.9

While a specific number of nodes analyzed can be a surrogate for adequate lymphadenectomy, and the improvements in adequacy of lymphadenectomy are laudable, this endpoint can be falsely reassuring at times. The new standard focuses instead on proper surgical technique with high ligation of the feeding vessel and en bloc resection of all draining lymph nodes. High ligation of the main colonic vascular pedicles optimizes lymph node yield by maximizing the length of associated mesentery extirpated en bloc with the specimen.

Operative Technique

Fulfilling the technical component of Standard 5.6 requires ligation of the proper vascular pedicle corresponding to the involved segment of colon at its origin, as well as en bloc removal of the specimen with its mesentery.3 Dissection through the colonic mesentery to skeletonize and properly identify the origin of the correct vascular pedicle is critical to proper performance of this operative standard. Ligation of the vessel closer to the colon may result in a harvest of 12 lymph nodes but leave a significant portion of the associated mesentery and, thus, the draining lymph nodes in situ. Figure 1A outlines the vascular pedicles, which require proximal ligation based on the primary tumor location within the colon.

Fig. 1
figure 1

A Diagram of specific colon resections and associated vascular pedicles for proximal ligation. B Timeline for the implementation and assessment of Operative Standard 5.6

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As previously mentioned, ligation of the vascular pedicle at its origin maximizes the associated length of mesentery removed with the specimen and optimizes the number of lymph nodes retrieved. The reason increased lymph node yield portends improved survival is debated; however, there are two important theories: stage migration and immune response.10 Stage migration, or false-negative nodal staging due to low lymph node yield, links survival to understaging and misguided selection of adjuvant therapies. The immune response theory posits that higher lymph node yield reflects the inherent immunogenicity of the tumor and the subsequent response with the immune system is the cause for improved survival. The interplay of these two contribute to survival and reflect the importance of the operative standard for proximal ligation. It is important to note that areas of obvious tumor invasion or surrounding inflammatory reaction with adjacent intra-abdominal structures should be included in the en bloc resection of the specimen.3 The operative approach is left to the discretion of the surgeon as long as they can meet the technical standard as outlined above.

Measure of Compliance and Timeline

Starting in January 2023, all colon resections performed with curative intent for patients with cancer should fulfill the technical standard and associated synoptic documentation within the operative report. Starting in 2024, compliance with CoC Standard 5.6 will be assessed, evaluating cases that occurred in 2023. During 2024, site visits will include an assessment of compliance based on charts from 2023 to 2024. In 2025 and thereafter, assessment will be based on the previous 3 years. In 2024, there will be an expectation of 70% compliance. In 2025 and going forward, the expectation will be 80% overall compliance. Site reviewers will audit randomly selected charts from up to 3 years before ascertain whether the standard was met. Figure 1B reviews all relevant timeline benchmarks since introduction of the operative standards.

Best Practices for Compliance

Compliance with CoC Standard 5.6 requires completion of critical steps intraoperatively and documentation of these steps within the operative report in synoptic format. While the CoC does not require a program that uses a specific operative report, the synoptic elements must be included in the operative report for cases intending curative resection, as outlined in Fig. 2. The CSSP Operative Standards Toolkit can be utilized as a resource for assistance with implementation of the Operative Standards. Internal auditing can be helpful to inform programs about compliance with the CoC Operative Standards before official site review and help to identify any concerns with adherence to the 70% requirement, which began in January 2023. Additional information about the technical aspects of meeting CoC Standard 5.6 can be found within the Operative Standards Toolkit and Operative Standards for Cancer Surgery Volume 1.2

Fig. 2
figure 2

Critical elements and responses for CoC Standard 5.6

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Conclusions

CoC Operative Standard 5.6 for colon cancer resection is an evidence-based standard comprising both technical and documentation components. It describes proximal ligation of vascular pedicles during colectomy, which has been associated with optimized lymphadenectomy and improved patient survival. Compliance to the technical and documentation requirements of CoC Standard 5.6 began January 1, 2023. Beginning in January 2024, site visits will commence with expected 70% compliance to these standards. Furthermore, subsequent years will require 80% compliance to these standards. Sites should strive to implement and maintain compliance to the CoC Operative Standard 5.6. A timeline for site visits and compliance is outlined in Fig. 1B.