Lymph node pooling: a feasible and efficient method of lymph node molecular staging in colorectal carcinoma

Area of Science:

• Oncology
• Molecular Pathology
• Cancer Diagnostics

Background:

• Traditional lymph node (LN) staging in colon cancer (CC) is becoming insufficient in the molecular era.
• High costs and time demands limit the use of sensitive molecular analysis for nodal staging.
• A feasible and efficient molecular method is needed for routine CC LN pathology diagnosis.

Purpose of the Study:

• To develop and evaluate a cost-effective molecular method for colon cancer lymph node staging using RT-LAMP.
• To assess the feasibility of pooling lymph nodes for molecular analysis to reduce costs and time.
• To improve the accuracy of lymph node pathological staging in colon cancer.

Main Methods:

• Reverse transcription loop-mediated isothermal amplification (RT-LAMP) was used to detect cytokeratin 19 (CK19) mRNA in colon cancer lymph nodes.
• Two cohorts were analyzed: individual LN analysis (1449 LNs, 102 patients) and pooled LN analysis (1757 LNs, 86 patients).
• The pooling method significantly reduced the number of molecular assays performed per patient.

Main Results:

• The pooling method analyzed a median of 2 LNs per patient, compared to 13 in the individual method, saving a median of 16 assays per patient.
• Sensitivity and specificity for LN involvement using the pooling method were 88.9% and 79.2%, respectively.
• Total tumor load (TTL) was similar between the individual and pooling cohorts, indicating comparable detection of tumor burden.

Conclusions:

• LN pooling with RT-LAMP enables analysis of numerous LNs from colectomies using fewer molecular tests per patient.
• This approach provides a feasible way to integrate molecular analysis into routine colon cancer pathology diagnosis.
• The method offers more accurate LN pathological staging with potential prognostic implications.