Role of “Second Look” Lymph Node Search in Harvesting Optimal Number of Lymph Nodes for Staging of Colorectal Carcinoma

Abstract

As with other malignancies, lymph node metastasis is an important staging element and prognostic factor in colorectal carcinomas. The number of involved lymph nodes is directly related to decreased 5-year overall survival for all pT stages according to United States Surveillance, Epidemiology, and End Results (SEER) cancer registry database. The National Quality Forum specifies that the presence of at least 12 lymph nodes in a surgical resection is one of the key quality measures for the evaluation of colorectal cancer. Therefore, the harvesting of a minimum of twelve lymph nodes is the most widely accepted standard for evaluating colorectal cancer. Since this is an accepted quality standard, a second attempt at lymph node dissection in the gross specimen is often performed when the initial lymph node count is less than 12, incurring a delay in reporting and additional expense. However, this is an arbitrary number and not based on any hard scientific evidence. We decided to investigate whether the additional effort and expense of submitting additional lymph nodes had any effect on pathologic lymph node staging (pN). We identified a total of 99 colectomies for colorectal cancer in which the prosector subsequently submitted additional lymph nodes following initial review. The mean lymph node count increased from 8.3 ± 7.5 on initial search to 14.6 ± 8.0 following submission of additional sections. The number of cases meeting the target of 12 lymph nodes increased from 14 to 69. Examination of the additional lymph nodes resulted in pathologic upstaging (pN) of five cases. Gross reexamination and submission of additional lymph nodes may provide more accurate staging in a limited number of cases. Whether exhaustive submission of mesenteric fat or fat-clearing methods is justified will need to be further investigated.

Evaluating the impact of lymph node resampling on colorectal cancer nodal stage

“…This is the largest study to evaluate the effectiveness of lymph node resampling in CRC, and the first study to use a cohort exclusively comprising cases with initial yields of <12. Two previous studies assessed lymph node resampling; however, the samples included specimens that required additional sections for any indication, or cases for which resampling was performed even with initial yields of ≥12 41,42 . Because of the application of stricter criteria, the findings of the present study better reflect the utility of lymph node resampling when it is performed in accordance with the recommended guidelines.…”

Influence of colonic mesenteric area on the number of lymph node retrieval for colon cancer: a prospective cohort study

“…All these parameters, separately or in combination, have been evaluated considering their impacts on the LN yield. Quality of the pathological examination is another essential parameter that has an impact on the number of retrieved LNs [19][20][21]. In the presence of adequate proximal and distal borders, a detailed and careful pathological examination may lead to an increased yield.…”

“…In the presence of adequate proximal and distal borders, a detailed and careful pathological examination may lead to an increased yield. Although the second-look LN search caused considerable increases in the LN counts and number of cases with at least 12 LNs, its benefit on the accurate staging was limited [20]. Becerra et al [19] reported a large variation particularly between pathologists in suboptimal LN examination following colectomy.…”

“…In the light of these explanations, we think that there is a difficulty in the standardization of the pathological examination techniques. Future studies are needed to investigate the impact of several approaches including the second-look LN search, exhaustive submission of mesenteric fat, or fat-clearing methods [20].…”

“…Besides, there is a lack of data regarding improved survival secondary to the higher yield of total LNs in association with the mere elongation of the bowel resected [3]. Some studies also failed to show any improvement in the staging in association with an increased LN count [5,20]. So, evidences that an adequate number of nodes will alter the staging and improve outcomes should be provided by future studies.…”