Role of one-step nucleic acid amplification in colorectal cancer lymph node metastases detection

Abstract

Current histopathological staging procedures in colorectal cancer (CRC) depend on midline division of the lymph nodes (LNs) with one section of hematoxylin and eosin staining. Cancer cells outside this transection line may be missed, which could lead to understaging of Union for International Cancer Control Stage II high-risk patients. The one-step nucleic acid amplification (OSNA) assay has emerged as a rapid molecular diagnostic tool for LN metastases detection. It is a molecular technique that can analyze the entire LN tissue using a reverse-transcriptase loop-mediated isothermal amplification reaction to detect tumor-specific cytokeratin 19 mRNA. Our findings suggest that the OSNA assay has a high diagnostic accuracy in detecting metastatic LNs in CRC and a high negative predictive value. OSNA is a standardized, observer-independent technique, which may lead to more accurate staging. It has been suggested that in stage II CRC, the upstaging can reach 25% and these patients can access postoperative adjuvant chemotherapy. Moreover, intraoperative OSNA sentinel node evaluation may allow early CRC to be treated with organ-preserving surgery, while in more advanced-stage disease, a tailored lymphadenectomy can be performed considering the presence of aberrant lymphatic drainage and skip metastases.

Lymph Node Molecular Analysis with OSNA Enables the Identification of pT1 CRC Patients at Risk of Recurrence: A Multicentre Study

“…We had 1.1% false negatives, but this rate has been reported up to 15.4% in other series [61]. Despite this limitation, almost all published studies have shown good performance of this technique, showing a high sensitivity (90.4%), specificity (96.8%), concordance (96.0%), positive predictive value (79.8%), and negative predictive value (98.6%) [28,65]. In this regard, OSNA LN staging can be improved and achieve its full clinical significance and impact in early-stage CRC only through a complete analysis of the LN tissue.…”

“…This could be solved by submitting the whole LN for molecular analysis, as carried out in LNs from breast carcinoma [13,28]. In fact, all the OSNA studies on CRC to date have used similar methodologies, with part of the LN used for H&E and part used for OSNA, which may be the reason for the false negativities and the limiting of its applicability in general practice [65]. We had 1.1% false negatives, but this rate has been reported up to 15.4% in other series [61].…”

Non-exposed endoscopic wall-inversion surgery with one-step nucleic acid amplification for early gastrointestinal tumors: Personal experience and literature review

“…These studies pave the way for a new molecular staging using OSNA based on the amount of CK19mRNA rather than the number of LN metastases. Furthermore, TTL has been suggested to be related to a poor prognosis, worse disease-free survival, and other CRC risk factors[ 45 , 93 , 94 ], such as pN, pT, tumor grade, male sex, tumor size, and lymph vascular invasion.…”

“…Individual imaging modalities face specific intrinsic limitations, which negatively impact detection and it does not allow a correct evaluation of important lymph node (LN) details. Therefore we only have the size criterion available to determine lymphadenopathies[ 45 ]. A new semi-automated diagnostic method called one-step nucleic acid amplification (OSNA) has been developed to detect LN metastases.…”

Nonexposed endoscopic wall inversion surgery with sentinel node mapping for a high risk gastric lesion

“…This nonexposed approach prevents possible peritoneal spillage and at the same time allows for full-thickness resection. Compared with laparoscopic wedge resection, NEWS enables minimal tissue resection, especially in difficult positions [4]. Early data on NEWS and sentinel node mapping have demonstrated their safety and efficacy [4,5].…”