Gamma Probe Accuracy in Detecting the Sentinel Lymph Node in Clinically No Squamous Cell Carcinoma of the Head and Neck

The sentinel node, which is not always located at the first-echelon nodal area close to the primary tumor, is the initial recipient of possible metastasis. In order to verify the usefulness of the sentinel lymph node technique in the staging of head and neck cancers, we studied 31 untreated patients with squamous cell carcinoma of the upper airways by injecting them around the primary tumor with technetium 99m albumin microcolloid (99mTc) and submitting them to selective neck dissection with en bloc tumor removal. The nodes were examined after γ-probe identification of the sentinel node(s). No patients were found to have microscopic tumor spread outside the level(s) containing the γ-probe-identified sentinel node(s). In only 1 case was the metastatic node not the γ-probe-posi-tive one, but an adjacent one. Lymphoscintigraphy with 99mTc seems reliable in identifying the sentinel node(s) and might contribute to the reduction of surgical morbidity by reserving therapeutic neck dissection for cases with histologically confirmed nodal metastasis.

Reappraisal of metastatic lymph node topography in head and neck squamous cell carcinomas

Objective

To analyze the lymphatic distribution of metastatic carcinomatous cells in cervical lymph nodes in head and neck squamous cell carcinoma (HNSCC).

Study Design and Setting

We retrospectively reviewed 119 patients treated in our hospital for HNSCC (1999-2004). Topography of the neck dissection specimens was prospectively classified according to the classification of Robbins. The 4000 lymph nodes were analyzed by optical microscopy using hematoxylin-eosin-safran (HES) staining. In cases of negative results in level II, cytokeratin (AE1/AE3) immunodetection was performed.

Results

Metastases were visualized using HES in 6.4% of lymph nodes for oral cavity, and 4.7% of oropharyngeal, 4.4% of hypopharyngeal, and 1.3% of endolaryngeal cancers. The highest incidence of nodal metastasis was observed in level IIa ( P < 0.01). In eight patients (6.7%) with lymph node metastases, level II was spared. In these patients, all 134 nodes histologically negative on HES were confirmed to be negative by IHC.

Conclusions

Level IIa is the main level involved in regional metastases of HNSCC, regardless of the primary site of cancer. However, in eight (6.7%) patients, level II was spared, as confirmed by IHC. In these cases, level II did not represent the first step of drainage from the tumor. The sentinel lymph node technique in HNSCC is discussed in light of these results.

Sentinel lymph node biopsy for oral cancer: supporting evidence and recent novel developments

Occult spread to regional lymphatics occurs in a significant percentage of patients with early-stage oral cavity cancer. While elective neck dissection continues to be the gold standard for assessing for the presence of occult regional disease, the optimal management strategy continues to evolve. Increasingly, sentinel lymph node biopsy is being recognized as a viable alternative to elective neck dissection for staging the neck in early-stage oral cavity cancer. In this article, we examine the evidence supporting sentinel lymph node biopsy for early-stage oral cancer and provide an update on some of the novel developments in this field.

The first and second echelon sentinel lymph node evaluation in oral cancer

Sentinel lymph node biopsy shows promise as a minimally invasive technique that samples the first echelon (station) of nodes to predict the need for more extensive neck dissection. This paper discusses the accuracy and feasibility of sentinel node and "station II node" biopsy for predicting the status of neck in 20 patients of oral cancer. We identified sentinel node in these patients. The next higher-order nodes, that is, second echelon of nodes known as "station II nodes" were delineated by further injecting 0.1 ml of isosulfan blue dye in sentinel lymph node. Identification rate for station I nodes was 95 %. Station II nodes were identified in 84 % of patients. One patient had false negative station I node. Station II node status was false negative in two patients. "Station I and station II concept" is feasible in early-stage tumors of oral cavity.

Molecular Staging of Cervical Lymph Nodes in Squamous Cell Carcinoma of the Head and Neck

Clinical staging of cervical lymph nodes from patients with squamous cell carcinoma of the head and neck (SCCHN) has only 50% accuracy compared with definitive pathologic assessment. Consequently, both clinically positive and clinically negative patients frequently undergo neck dissections that may not be necessary. To address this potential overtreatment, sentinel lymph node (SLN) biopsy is currently being evaluated to provide better staging of the neck. However, to fully realize the potential improvement in patient care afforded by the SLN procedure, a rapid and accurate SLN analysis is necessary. We used quantitative reverse transcription-PCR (QRT-PCR) to screen 40 potential markers for their ability to detect SCCHN metastases to cervical lymph nodes. Seven markers were identified with good characteristics for identifying metastatic disease, and these were validated using a set of 26 primary tumors, 19 histologically positive lymph nodes, and 21 benign nodes from patients without cancer. Four markers discriminated between positive and benign nodes with accuracy >97% but only one marker, pemphigus vulgaris antigen (PVA), discriminated with 100% accuracy in both the observed data and a statistical bootstrap analysis. A rapid QRT-PCR assay for PVA was then developed and incorporated into a prototype instrument capable of performing fully automated RNA isolation and QRT-PCR. The automated analysis with PVA provided perfect discrimination between histologically positive and benign lymph nodes and correctly identified two lymph nodes with micrometastatic tumor deposits. These assays were completed (from tissue to result) in approximately 30 minutes, thus demonstrating the feasibility of intraoperative staging of SCCHN SLNs by QRT-PCR.

The ability of lymphoscintigraphy to direct sentinel node biopsy in the clinically N0 neck for patients with head and neck squamous cell carcinoma

This study aimed to evaluate the ability of lymphoscintigraphy (LSG) to direct sentinel node biopsy (SNB) in the identification of occult metastases in the clinically N0 neck for patients with head and neck squamous cell carcinoma (HNSCC). 57 clinically N0 neck sides in 48 patients were assessed using the triple diagnostic approach of pre-operative LSG, intra-operative use of a gamma probe and blue dye. SNB was performed after radiocolloid and blue dye injection. Pre-operative LSG and the intra-operative use of a gamma probe identified radioactive sentinel nodes, and visualization of blue stained lymphatics identified blue sentinel nodes. 104 sentinel nodes were harvested from 43 patients. The identification rate was 90% (43 of 48). Of the 104 nodes harvested, 17 of 62 (27%) nodes identified as both radioactive and blue were positive for occult metastases compared with 5 of 42 (12%) nodes identified as hot or blue only (p<0.05). Sentinel nodes were identified in 39 of 48 (81%) patients using LSG. Of 39 patients in whom sentinel nodes were identified using LSG, 37 of 39 (95%) had radioactive sentinel nodes harvested intra-operatively. In patients who had no sentinel nodes identified on LSG, 4 of 9 (44%) had radioactive sentinel nodes harvested intra-operatively. This difference was statistically significant using the t-test (p<0.05). LSG directs SNB and is essential in the identification of occult metastases within the clinically N0 neck for patients with HNSCC.

Sentinel Lymph Node Biopsy in SCC of the Head and Neck: A Major Advance in Staging the NO Neck

The management of the NO neck in patients with head and neck cancer is controversial. Neck dissection provides important staging information that guides patient treatment. We examined the feasibility of using a dye technique for staging patients by sentinel lymph node biopsy (SLNBX). We studied seven patients with previously untreated early-stage squamous cell carcinoma of the oral cavity and NO necks. Each patient underwent SLNBX guided by an intraoperative injection of 1% isosulfan blue dye. An open biopsy of the sentinel node was followed by neck dissection. We identified the sentinel node in four of the seven patients (57%). The sentinel node accurately predicted the pathologic status of the neck in three of these four patients (75%). In one of the three patients, the sentinel node was one of four histopathologically positive nodes, whereas in two others, the neck was free of disease. One patient had a histopathologically negative sentinel node and tumor metastasis present in the neck. Of the four patients in whom a sentinel node was identified, the negative predictive value for the absence of cervical metastases was 67%. Based on our findings and those of other authors, we conclude that the use of blue dye in lymphatic mapping for SLNBX in head and neck cancer patients is technically feasible but of limited clinical utility. Our literature review also suggests that performing SLNBX with a radiotracer technique or a combination of a radiotracer and blue dye is a promising method of staging the NO neck in head and neck cancer patients and warrants further clinical study.