Clinicopathological Factors Affecting Lymph Node Yield and Positivity in Left-Sided Colon and Rectal Cancers.

Background Colorectal cancer (CRC) is a significant cause of cancer-related deaths worldwide and is the third most common cause of cancer deaths in the UK. The status of lymph node metastasis is a key factor for predicting the prognosis of a patient's CRC. Aims This study aimed to analyze the demographics of left-sided colonic and rectal cancers at a single institution. We looked closely at the correlation between patient age and various histological factors. We tried to find any significant difference in lymph node yield (LNY) between laparoscopic surgery (LS) and open surgery (OS). We aimed to identify any statistical correlation between LNY and lymph node positivity (LNP) with other patient, surgical and histopathological features. Methodology This is a retrospective, non-interventional review of consecutive patients who underwent left-sided colonic and rectal cancer resections over a three-year period between 01 April 2018 and 31 March 2021. Descriptive and inferential statistical analyses were used. Chi-squared / Fisher exact test was used on a categorical scale between two or more groups and non-parametric setting for qualitative data analysis. Results A total of 102 patients were included in the study. No statistical correlation was found between the age of the patient with the LNY, LNP, location of the tumor, type, and urgency of the operation. LNY ranged between one and 43 nodes (median (interquartile range (IQR)) 17, 8). There was no statistically significant difference in LNY between laparoscopic surgery (LS) and open surgery (OS) (p=0.1449). Significant statistical correlation was identified between LNP and completeness of resection (CoR) (p=0.039), vascular invasion (VI) (p<0.001), perineural invasion (PI) (p<0.001), and circumferential resectional margin involvement (CRMI) (p=0.039). Discussion LNY and LNP are important prognostic indices in colorectal cancer. Patient age, tumor location, the urgency of surgery, and consultant experience did not significantly impact the LNY. Our study showed a positive correlation between LNP and CRMI, VI and PI comparable to literature. Contrary to other studies, we found no statistical significance between LS vs. OS and LNY. Whether 12 nodes per patient is an appropriate level remains controversial.