Increased Lymph Node Yield in Colorectal Cancer Is Not Necessarily Associated with a Greater Number of Lymph Node Positive Cancers

Abstract

The presence of lymph node metastasis is a key prognostic factor in colorectal cancer and lymph node yield is an important parameter in assessing the quality of histopathology reporting of colorectal cancer excision specimens. This study assesses the trend in lymph node evaluation over time in a single institution and the relationship with the identification of lymph node positive tumours. It compares the lymph node yield of a contemporary dataset compiled from the histopathology reports of 2178 patients who underwent surgery for primary colorectal cancer between 2005 and 2012 with that of a historic dataset compiled from the histopathology reports of 1038 patients who underwent surgery for colorectal cancer at 5 yearly intervals from 1975 to 2000. The mean lymph node yield was 14.91 in 2005 rising to 21.38 in 2012. In 2012 92.9% of all cases had at least 12 lymph nodes examined. Comparison of the mean lymph node yield and proportion of Dukes C cases shows a significant increase (Pearson correlation = 0.927, p = 0.001) in lymph node yield while there is no corresponding significant trend in the proportion of Dukes C cases (Pearson correlation = −0.138, p = 0.745). This study shows that there is increasing yield of lymph nodes from colorectal cancer excision specimens. However, this is not necessarily associated with an increase number of lymph node positive cancers. Further risk stratifying of colorectal cancer requires consideration of other pathological parameters especially the presence of extramural venous invasion and relevant biomarkers.

The Evaluation of More Lymph Nodes in Colon Cancer Is Associated with Improved Survival in Patients of All Ages

“…Though the removal of less than 12 lymph nodes is not uncommon [ 13 , 19 , 20 ]. In accordance with our results, multiple studies show that there is an increase over time in the number of lymph nodes removed, whereas the number of patients diagnosed with lymph nodal metastases remains the same [ 21 – 24 ]. Currently the percentage of patients with 10 or more lymph nodes removed and 12 or more lymph nodes removed in the Netherlands is approximately 83% and 73% respectively, and thereby stable over the last years.…”

Prognostic value of lymph node ratio and extramural vascular invasion on survival for patients undergoing curative colon cancer resection

“…A number of observational studies have suggested different cutoffs for total number of lymph nodes to be harvested ( Cianchi et al , 2002 ; Bui et al , 2006 ; Chen and Bilchik, 2006 ; Choi et al , 2010 ). O'Shea et al (2014) compared total lymph node yield of 3216 patients undergoing surgery for colorectal cancer. The authors demonstrated an increasing lymph node yield over time (14.91 in 2005 rising to 21.38 in 2012), but this was not associated with increased number of lymph node-positive cancers.…”

Lymph node hypoplasia is associated with adverse outcomes in node-negative colon cancer using advanced lymph node dissection methods

“…These false-negative cases would affect the results of stage-specific survival analyses. However, improvements in lymph node yield have failed to influence the lymph node positivity rates in colon cancers [20,23,24]. In a recently published study, we were able to show the superiority of methylene blue-assisted lymph node harvesting over conventional technique (mean lymph node count 34 ± 17 vs. 13 ± 5; P < 0.001), with rates of sufficient staging of 98 versus 62 % (P < 0.001), respectively.…”