Pathologic analysis of sentinel lymph nodes

Abstract

The sentinel lymph node (SLN) procedure enables selective targeting of the first draining lymph node, where the initial metastases will form. A negative SLN predicts the absence of tumor metastases in the other regional lymph nodes with a high degree of accuracy. This means that in case of a negative SLN, regional lymph node dissection is no longer necessary. Besides saving patients the significant morbidity associated with lymph node dissection, it will also save costs. Crucial for the success of the SLN procedure is the screening of the SLN for metastases by the pathologist. To this end, several techniques are available such as standard histo- and cytopathological techniques, immunohistochemistry, flow cytometry, and molecular biological techniques. In this paper, the value of these methods for detecting SLN metastases is discussed. Some of these techniques have also appeared to be quite useful for intraoperative evaluation of SLNs. The standard protocol for detection of SLN metastases consists of extensive histopathological investigation including stepped sections stained with hematoxylin and eosin (HE) and immunohistochemistry. Intraoperative frozen section analysis and imprint cytology of SLNs have been shown to be reasonably reliable for detecting breast cancer metastases in SLNs. Further studies are necessary to establish the role of multiparameter flow cytometry and sophisticated molecular biological techniques such as reverse transcription polymerase chain reaction (RT-PCR) in detecting SLN metastases.

Sentinel node staging for breast cancer: intraoperative molecular pathology overcomes conventional histologic sampling errors

“…Accurate intraoperative molecular analysis of all or part of the SLN offers the potential to significantly reduce false-negative findings that necessarily occur with the limited tissue sampling of conventional histologic methods [3], [4], [5], [6] and [7]. Although a molecular assay can overcome the errors resulting from limited tissue sampling associated with traditional histologic evaluation, several new challenges arise.…”

Pemphigus vulgaris antigen mRNA quantification for the staging of sentinel lymph nodes in head and neck cancer

“…Semi-serial sectioning, associated with IHC, has a higher detection rate of MI than examination of only a few sections, and can reach the sensitivity of intra-operative fine-sectioned frozen sectioning of 93% (Tschopp et al, 2005). However, this approach is very time consuming and the inevitable loss of material can lead to some MIs being missed (van Diest et al, 2001). Furthermore, as the results reported are partly due to a high degree of attention and skill being provided by pathologists during clinical studies, such results are not likely to be achievable in a routine clinical setting (van Diest et al, 2001).…”

“…However, this approach is very time consuming and the inevitable loss of material can lead to some MIs being missed (van Diest et al, 2001). Furthermore, as the results reported are partly due to a high degree of attention and skill being provided by pathologists during clinical studies, such results are not likely to be achievable in a routine clinical setting (van Diest et al, 2001). Molecular diagnosis with QRT-PCR may be a substitute for histopathology for intra-operative SN analysis.…”

“…However, the main pitfall of this strategy is that histopathological diagnosis based on serial sections with immunohistochemistry (SS-IHC) is far too time consuming to be made use of during surgery in routine practice (van Diest et al, 2001). A delayed pN diagnosis compels pN þ patients (up to 40% of cases) to undergo further additional surgery with an increased risk of post-operative complications and a damaged functional outcome (Kuntz and Weymuller, 1999;Schiefke et al, 2009).…”

The value of intraoperative imprint cytology in the assessment of lymph node status in gastric cancer surgery

“…It takes about 2 min to prepare a harvested lymph node and make an imprint slide, and about 4 min for the staining. Currently available techniques for intraoperative diagnosis, apart from frozen section and imprint cytology, are rapid immunohistochemistry and other nonmorphologic methods, such as flow cytometry and molecular analysis [7]. To date, there is no single ideal method for the intraoperative diagnosis of lymph node status.…”