Lymph node revealing solutions in colorectal cancer: should they be used routinely?

Abstract

The Royal College of Pathologists (RCPath) and College of American Pathologists recommend that at least 12 lymph nodes should be harvested for adequate staging of colorectal carcinoma. Just one nodal tumour deposit upstages the malignancy from pN0 to pN1. This is critically important as node-positive patients (pN1) are considered for adjuvant chemotherapy whereas node-negative patients (pN0) may not be. It is not always easy to harvest the required number, especially in patients with rectal carcinoma who may have received neoadjuvant therapy—an increasingly common treatment. The use of neoadjuvant therapy is known to further decrease the number and size of identifiable lymph nodes within specimens, meaning that the lymph node harvest often fails to reach RCPath guidelines. Lymph node revealing solutions consisting of either single chemicals such as alcohol or acetone or compounds have been investigated to help improve the lymph node harvest in difficult specimens, for example, those received following neoadjuvant therapy. Published research evidence reviewed here suggests that lymph node revealing solutions significantly improve lymph node harvesting, and that glacial acetic acid, ethanol, water and formalin is advantageous in comparison with other revealing solutions in that it is safe, cheap, easy to use and relatively quick. However, the quantity of good evidence is limited and the clinical implications of improving lymph node harvesting require further research.

Acetone clearance of mesocolic or mesorectal fat increases lymph node yield and may improve detection of high‐risk Stage II colorectal cancer patients

“…An increase in the total number of LNs per specimen has been reported with the use of a number of fat clearing techniques, including acetone [14,15,[18][19][20][21][22]. All these studies reported changes in the lymph node status (pN).…”

Fat-suppressed gadolinium-enhanced isotropic high-resolution 3D-GRE-T1WI for predicting small node metastases in patients with rectal cancer

“…High-resolution pelvic MRI is widely considered the optimal imaging method for rectal cancer [ 3 ], and it enables precise identification of high-risk factors, such as the extent of tumor invasion, extramural vascular invasion (EMVI) and the potential circumferential resection margin (CRM) [ 18 ]; however, the prediction of regional node metastases remains a challenge. Size is the usual criterion for metastatic nodes using MRI; however, the considerable size overlap between benign and malignant nodes affects the overall predictive value [ 19 ]. We found similar results in this study.…”

Rectal cancer: a methodological approach to matching PET/MRI to histopathology

“…After the cut-out, the slices were packaged in gauze in numerical order from the aboral to the oral end. The packages were, subsequently, placed in a GEWF solution (Glacial acetic acid, Ethanol, distilled Water, and Formaldehyde) for at least 48 h to optimize the lymph node yield [ 23 ].…”