Study Outlines Factors Linked With IMA Lymph Node Metastases in Rectal Cancer

In patients with rectal cancer, there was an association between inferior mesenteric artery (IMA) lymph node metastases and tumor location, tumor size, T stage, and pre-surgery levels of carcinoembryonic antigen (CEA), according to a review published in World Journal of Gastrointestinal Oncology.¹

Colorectal cancer (CRC) is the third most common and second deadliest type of cancer worldwide.² IMA lymph node metastasis indicates a worse prognosis in patients with the condition, as it can lead to local recurrence or distant organ metastasis.¹ However, doing a resection for IMA lymph node metastasis is debatable, as some doctors believe that the rate of the disease is low and the risks of the surgery are high.

The new review aimed to study the clinical and pathological features of IMA root lymph node metastasis in rectal cancer to help determine optimal treatment for patients.

Rectal cancer is associated with lymph node metastases | Image credit: SewcreamStudio - stock.adobe.com

PubMed and Google Scholar were used to search for studies for this review. Studies that reported on risk factors, both clinical and pathological, for IMA root lymph node metastasis from the inception of the database through December 31, 2023, were eligible for the study. Studies were included if CRC was established through a colonoscopy or postoperative pathology, the research purposes and statistical methods were similar between all literature, and if the included study was the first published literature on the risk factors of IMA root lymph node metastasis. If papers appeared to have the same author, only 1 was chosen.

Studies were excluded if they were comprehensive analyses, reviews, case reports, or conference reports; had incomplete data; or if the full text of the article could not be obtained. All studies had their data extracted for the review, and all studies underwent a quality evaluation. There were 7 studies included in the meta-analysis overall.

A total of 6 studies included sex as a risk factor of IMA root lymph node metastasis (total OR, 0.89; 95% CI, 0.69-1.16). A total of 6 studies also found that age was a risk factor for IMA root lymph node metastasis (total OR, 1.21; 95% CI, 0.93-1.57). There were 3 studies that reported on preoperative CEA, which all found that it was a risk factor for IMA root lymph node metastasis (total OR, 0.32; 95% CI, 0.18-0.55). The test for overall effect was found to be 4.06, indicating statistical significance.

Tumor location was evaluated in 4 of the studies, where a significant association was found (total OR, 3.10; 95% CI, 1.78-5.42). A tumor location above the peritoneal recurrence was a significant risk factor. Tumor size was evaluated in 5 studies, which found that a tumor size of 5 cm or more was a risk factor, as the Z score was 4.33. Pathological type was evaluated in 4 studies, which found that mucinous adenocarcinoma and signet ring cell carcinoma were a risk factor, as the Z score was 5.11. Low tumor differentiation was found to be a risk factor due to a Z score of 14.47. Lastly, T-stages T3 and T4 were risk factors due to the Z score of the pooled 6 studies being 4.91.

There were some limitations to this study. The number of studies used was small, and the studies were primarily retrospective analyses. Some of the studies were also of low quality. However, the researchers expect to conduct further multi-center studies with larger sample sizes to expand on the evidence related to IMA root lymph node dissection in the future.

The researchers concluded that preoperative levels of CEA, the tumor location and size, the tumor pathological type, and T stage were all associated with a positive rate of IMA root lymph node metastasis in patients with rectal cancer.

"The results of this study reflect some of the clinicopathological features that may lead to IMA root lymph node metastasis in rectal cancer, and provide evidence-based medical evidence for the selection of surgical procedures for IMA root lymph node dissection in rectal cancer," the authors concluded.

References

1. Wang Q, Zhu FX, Shi M. Clinical and pathological features of advanced rectal cancer with submesenteric root lymph node metastasis: meta-analysis. World J Gastrointest Oncol. 2024;16(7):3299-3307. doi:10.4251/wjgo.v16.i7.3299
2. Colorectal cancer. World Health Organization. July 11, 2023. Accessed August 1, 2024. https://www.who.int/news-room/fact-sheets/detail/colorectal-cancer