What is the Most Common Lymph Node Yield for Colorectal Cancer Cases? The results may scare you.

July 1, 2023

Lymph nodes act as channels for cancers to spread and are used as an integral part of cancer staging. Identifying whether cancer cells have spread from the primary tumor site to the regional lymph nodes is one of the most important tasks in TNM staging.

Decades of clinical publications have shown that the number of lymph nodes retrieved is correlated with the survival rate of cancer patients. According to the official cancer staging manual, American Joint Cancer Committee (AJCC) Cancer Staging Manual 8th edition, “The number of nodes removed and retrieved from an operative specimen has been reported to correlate with improved survival, possibly because of increased accuracy in staging.”[1]

Because of this clear correlation between lymph node count and patient survival rate, all grossing protocols require Pathologists’ Assistants, residents, and pathologists to find “all the lymph nodes,”[2] or “as many lymph nodes as possible.”[3] Lymph node yield is also being used as a quality metric. Every colorectal cancer case must examine at least 12 lymph nodes. This is a standard stipulated by many medical authorities, including AJCC, CAP, and NCCN.

    Now the question is – when protocols ask clinicians to find all the lymph nodes and the authorities are requiring at least 12 lymph nodes, what are the lymph node yields that are currently being reported?

         The answer is 13-15, barely over the required minimum, based on the latest data published by Surveillance, Epidemiology, and End ResultsProgram (SEER) from the National Cancer Institute. [4]

Figure 1: Lymph node yield for colon cancer cases in the SEER database in the year of 2016 (original research)

This answer can be disturbing because the correlation between the number of lymph nodes and survival rate does not suggest any clinically significant value for the previously established number 12. In fact, based on data in the AJCC staging manual 8th edition, there is clear correlation between lymph node yield and patient survival beyond a count of more than 25 lymph nodes.

Figure 2. Correlation between lymph node yield and colon cancer survival rate. (Green: N0, Red: N1a; Orange N1b; Light Blue: N2a; Blue: N2b)

The unfortunate truth is that the reason behind why 13-15 is the most common lymph node yield is because lymph nodes are extremely difficult to find given the current retrieval techniques. The current standard of care is manual palpation and it can take an extensive amount of time for clinicians to identify 12 lymph nodes, especially for cancer cases treated with neoadjuvant therapy. While all clinicians have the best interest of their patients in mind, it becomes practically impossible to find far more than 12 lymph nodes without prolonging the workflow to an unsustainable extent. The anatomical pathology community is in need of an innovation to resolve this issue.

We are Cision Vision, and we help PAs, residents, and pathologists find lymph nodes more quickly and accurately by displaying them as the opposite color when compared to the surrounding fat. This is done in real-time without radiation or injection. Learn more about how Cision Vision can help you improve clinical workflow and patient care at your institution at cisionvision.com or email us at info@cisionvision.com.

[1] Amin, Mahul B.; Gress, Donna M.; Meyer Vega, Laura R.; Edge, Stephen B.. AJCC Cancer Staging Manual, Eighth Edition (p. 279). American College of Surgeons. 

[2] Colleges of American Pathologists, “Protocol for the Examination of Specimens From Patients With Primary Carcinoma of the Colon and Rectum” , June 2017 https://documents.cap.org/protocols/cp-gilower-colonrectum-17protocol-4010.pdf

 [3] National Comprehensive Cancer Network, “Protocol for the Examination of Specimens From Patients With Primary Carcinoma of the Colon and Rectum” March 13, 2017, https://www2.tri-kobe.org/nccn/guideline/colorectal/english/colon.pdf

 [4] Original data compiled by author based on the cancer surveillance data published by Surveillance, Epidemiology, and End Results (SEER) Program – National Cancer Institute.