From the Guidelines
The adequate number of lymph nodes to harvest for accurate staging varies by organ, with a minimum of 16 lymph nodes recommended for gastric cancer, as stated in the most recent and highest quality study 1. For other organs, the following minimum lymph node harvests are recommended:
- Colon cancer: at least 12 lymph nodes 1
- Rectal cancer: at least 12 nodes
- Breast cancer: at least 10 axillary lymph nodes
- Lung cancer: a minimum of 10 mediastinal lymph nodes from at least three stations
- Pancreatic cancer: at least 12-15 lymph nodes These recommendations ensure adequate sampling to detect potential metastases, as insufficient lymph node evaluation can lead to understaging and inappropriate treatment decisions. The number of positive nodes relative to the total examined is crucial for accurate staging and prognosis determination. Surgeons and pathologists should collaborate to ensure adequate lymph node harvesting during resections, as proper nodal staging directly impacts treatment planning and patient outcomes. In gastric cancer, the Chinese Society of Clinical Oncology guidelines recommend that ≥ 16 lymph nodes should be pathologically evaluated, and for a more accurate evaluation, the preferred number of lymph nodes should be > 30 1. Similarly, for esophageal and esophagogastric junction cancers, at least 15 lymph nodes should be removed for adequate nodal staging 1. It is essential to note that the specific number of lymph nodes required may vary depending on the organ and the individual patient's situation, and the most recent and highest quality study should be consulted for the most up-to-date recommendations.
From the Research
Adequate Lymph Nodes to Harvest per Organ
The adequate number of lymph nodes to harvest for accurate staging varies per organ.
- For colon cancer, the minimum number of lymph nodes required for accurate staging is still a topic of debate.
- A study published in the Journal of hematology & oncology 2 found that examination of at least 12 lymph nodes is recommended, but the examination of ≥20 lymph nodes was associated with a reduced risk of recurrence and mortality for Stage II patients.
- Another study published in Revista espanola de enfermedades digestivas 3 found that harvesting a larger number of lymph nodes is related to improved rates of 5-years survival for patients with colon cancer staged as pN0, and it seems reasonable to recommend obtaining as many lymph nodes as possible.
- A study published in Colorectal disease 4 found that the retrieval of at least 12 lymph nodes is crucial for accurate staging of colorectal cancer, and survival in patients with Dukes' A and B cancers was significantly reduced if <12 nodes were sampled.
- A study published in Hepato-gastroenterology 5 found that the determination of the minimum number of lymph nodes required for accurate nodal staging of patients with colorectal cancer needs to be individualized, and several recommendations have been published for the minimum number of lymphatic nodes that need to be harvested, ranging from 6 to 17 lymph nodes.
- A study published in the Journal of gastrointestinal surgery 6 found that harvesting and examining a minimum of 18 lymph nodes per surgical specimen might be taken into consideration for more reliable staging of lymph node-negative colorectal carcinoma.
Factors Influencing Lymph Node Harvest
Several factors can influence the number of lymph nodes harvested, including:
- Preoperative chemo-radiotherapy 4
- Operation type 4
- Specimen length 4
- Patient age 4
- Male gender 5
- Better tumor differentiation 5
- Greater tumor size 5
- Presence of acute inflammation 5
Organ-Specific Recommendations
Based on the available evidence, the following organ-specific recommendations can be made: