Micrometastases and isolated tumour cells in sentinel lymph nodes in oral and oropharyngeal squamous cell carcinoma

Prognostic role of lymph node micrometastasis in oral and oropharyngeal cancer: A systematic review

BACKGROUND

An estimated 20% of patients with oral and oropharyngeal squamous cell carcinoma (OOSCC) have micrometastases (Mi) or isolated tumor cells (ITC) in the cervical lymph nodes that evade detection by standard histological evaluation of lymph node sections. Lymph node Mi and ITC could be one reason for regional recurrence after neck dissection. The aim of this study was to review the existing data regarding the impact of Mi on the survival of patients with OOSCC.

METHODS

PubMed and the Cochrane Library were searched for articles reporting the impact of Mi and ITC on patient survival. Two authors independently assessed the methodological quality of retrieved studies using the Downs and Black index. Data were also extracted on study type, number of included patients, mode of histological analysis, statistical analysis, and prognostic impact.

RESULTS

Sixteen articles with a total of 2064 patients were included in the review. Among the 16 included studies, eight revealed a statistically significant impact of Mi on at least one endpoint in the Kaplan-Meier and/or multivariate analysis. Three studies regarded Mi as Ma, while five studies found no impact of Mi on survival. Only one study demonstrated an impact of ITC on patient's prognosis in the univariate but not in the multivariate analysis.

CONCLUSION

The majority of cases included in the review were patients with oral cancer. The findings provide low-certainty evidence that Mi negatively impacts survival. Data on ITC were scarcer, so no conclusions can be drawn about their effect on survival. The lower threshold to discriminate between Mi and ITC should be defined for OOSCC since the existing thresholds are based on data from different tumors. The histological, immunohistological, and anatomical characteristics of Mi and ITC in OOSCC as well as the effect of radiotherapy on Mi should be further investigated separately for oral and oropharyngeal carcinomas.

Oral Cavity Cancer Surgical and Nodal Management: A Review From the American Head and Neck Society

Importance

Lymph node metastases from oral cavity cancers are seen frequently, and there is still inconsistency, and occasional controversies, regarding the surgical management of the neck in patients with oral cancer. This review is intended to offer a surgically focused discussion of the current recommendations regarding management of the neck, focusing on the indications and extent of dissection required in patients with oral cavity squamous cell carcinoma while balancing surgical risk and oncologic outcome.

Observations

The surgical management of the neck for oral cavity cancer has been robustly studied, as evidenced by substantial existing literature surrounding the topic. Prior published investigations have provided a sound foundation on which data-driven treatment algorithms can generally be recommended.

Conclusions

Existing literature suggests that patients with oral cavity cancer should be fully staged preoperatively, and most patients should receive a neck dissection even when clinically N0. Quality standards supported by the literature include separation of each level during specimen handling and lymph node yield of 18 or more nodes. Sentinel lymph node biopsy can be considered in select tumors and within a well-trained multidisciplinary team.

A Systematic Review of Oral Biopsies, Sample Types, and Detection Techniques Applied in Relation to Oral Cancer Detection

Background: Early identification of the stage of oral cancer development can lead to better treatment outcomes and avoid malignant transformation. Therefore, this review aims to provide a comprehensive overview that describes the development of standardized procedures for oral sample collection, characterization, and molecular risk assessment. This can help investigators to choose the appropriate sampling method and downstream analyses for different purposes. Methods: This systematic review was conducted according to the PRISMA guidelines. Using both PubMed and Web of Science databases, four independent authors conducted a literature search between 15 and 21 June 2021. We used key search terms to broaden the search for studies. Non-conforming articles were removed using an EndNote-based and manual approach. Reviewers used a designed form to extract data. Results: This review included a total of 3574 records, after eliminating duplicate articles and excluding papers that did not meet the inclusion criteria. Finally, 202 articles were included in this review. We summarized the sampling methods, biopsy samples, and downstream analysis. The biopsy techniques were classified into tissue and liquid biopsy. The common sequential analysis of tissue biopsy includes histopathological examination such as H&E or IHC to identify various pathogenic features. Meanwhile, liquid samples such as saliva, blood, and urine are analyzed for the purpose of screening to detect mutations in cancer. Commonly used technologies are PCR, RT-PCR, high-throughput sequencing, and metabolomic analysis. Conclusions: Currently, tissue biopsies provide increased diagnostic value compared to liquid biopsy. However, the minimal invasiveness and convenience of liquid biopsy make it a suitable method for mass screening and eventual clinical adoption. The analysis of samples includes histological and molecular analysis. Metabolite analysis is rising but remains scarce.

Thorny ground, rocky soil: Tissue-specific mechanisms of tumor dormancy and relapse

Disseminated tumor cells (DTCs) spread systemically yet distinct patterns of metastasis indicate a range of tissue susceptibility to metastatic colonization. Distinctions between permissive and suppressive tissues are still being elucidated at cellular and molecular levels. Although there is a growing appreciation for the role of the microenvironment in regulating metastatic success, we have a limited understanding of how diverse tissues regulate DTC dormancy, the state of reversible quiescence and subsequent awakening thought to contribute to delayed relapse. Several themes of microenvironmental regulation of dormancy are beginning to emerge, including vascular association, co-option of pre-existing niches, metabolic adaptation, and immune evasion, with tissue-specific nuances. Conversely, DTC awakening is often associated with injury or inflammation-induced activation of the stroma, promoting a proliferative environment with DTCs following suit. We review what is known about tissue-specific regulation of tumor dormancy on a tissue-by-tissue basis, profiling major metastatic organs including the bone, lung, brain, liver, and lymph node. An aerial view of the barriers to metastatic growth may reveal common targets and dependencies to inform the therapeutic prevention of relapse.

Systematic review and meta-analysis of randomized controlled trials comparing elective neck dissection versus sentinel lymph node biopsy in early-stage clinically node-negative oral and/or oropharyngeal squamous cell carcinoma: Evidence-base for practice and implications for research

PURPOSE

Management of clinically node-negative (N0) neck in early-stage (T1-T2) oral and/or oropharyngeal squamous cell carcinoma (OOSCC) has been controversial. The purpose of this systematic review and meta-analysis was to compare sentinel lymph node biopsy (SLNB) with elective neck dissection (END) in early-stage OOSCC.

METHODS

Studies comparing SLNB versus END in early-stage clinically node-negative OOSCC were identified using validated search strategy. To be considered eligible, trials had to include patients with early-stage, clinically node-negative OOSCC who had been randomly assigned to either SLNB or END. Primary outcome of interest was overall survival (OS), while secondary outcomes included isolated neck nodal recurrence (NNR), loco-regional recurrence (LRR), and neck-shoulder function. Outcome data was pooled using random-effects model and reported as hazard ratio (HR) or risk ratio (RR) with 95% confidence interval (CI). Any p-value < 0.05 was considered statistically significant.

RESULTS

A total of 608 patients from three trials comparing SLNB versus END in early-stage clinically node-negative OOSCC were included. The pooled HR of death for SLNB versus END was 1.18 (95% CI: 0.79-1.78, p = 0.41) which was not statistically significant. The rates of isolated NNR (pooled RR = 1.11, 95% CI: 0.69-1.80, p = 0.66) and LRR (pooled RR = 1.18, 95% CI: 0.81-1.72, p = 0.39) were also similar. Pooled analysis of the neck-shoulder function significantly favoured SLNB arm (pooled RR = 1.21, 95% CI: 1.12-1.32, p < 0.00001).

CONCLUSION

There is low-certainty evidence that SLNB is oncologically non-inferior to END and is associated with potentially lesser functional morbidity making it an emerging alternative standard of care in patients with early-stage clinically node-negative OOSCC.

Clinical significance of cytokeratin in the cervical lymph nodes of patients with mandibular gingival squamous cell carcinoma

The present study aims to analyze the expression of broad spectrum cytokeratin in the cervical lymph nodes of patients with mandibular gingival squamous cell carcinoma and explore the metastasis of mandibular gingival squamous cell carcinoma in cervical lymph nodes. This study included 42 patients with mandibular gingival squamous cell carcinoma, which was staged according to the clinical staging criteria by International Union Against Cancer 2002 (UICC) and the Level staging method of cervical lymph node by American Academy of Otolaryngology-Head and Neck Surgery 1991. Monoclonal mouse anti-human cytokeratin (AE1/AE3) antibody was used in immunohistochemical examination and hematoxylin and eosin (H&E) staining. All positive sections by H&E staining were also positive by immunohistochemistry (IHC). The positive rate of routine H&E staining and serial-section H&E staining was 8.03 and 9.57%, respectively, the positive rate of IHC was 12.82%. The positive rate of IHC was significantly different with that of routine H&E staining (χ²=7.17, P<0.01), yet not significantly different with that of serial-section H&E staining (χ²=3.10, P>0.05). Lymph node metastasis was mainly in Level I, II and III, both serial-section H&E staining and IHC showed lymph node metastasis in Level IV for advanced patients. IHC showed 19 lymph node micrometastasis in 12 patients, while neither serial-section nor routine H&E staining showed micrometastasis. Lymph node dissection of hyoid bone (mainly in Level I, II and III) could be used for early patients, and the dissection could be expanded to Level IV for advanced patients.

Sentinel lymph node biopsy for early oral cancers: Westmead Hospital experience

BACKGROUND

Sentinel lymph node biopsy (SLNB) has become an alternative option to elective neck dissection (END) for early oral cavity squamous cell carcinoma (OCSCC) outside of Australia. We sought to assess the technical feasibility of SLNB and validate its accuracy against that of END in an Australian setting.

METHODS

We performed a prospective cohort study consisting of 30 consecutive patients with cT_1-2 N₀ OCSCC referred to the Head and Neck Cancer Service, Westmead Hospital, Sydney, between 2011 and 2014. All patients underwent SLNB followed by immediate selective neck dissection (levels I-III).

RESULTS

A total of 30 patients were diagnosed with an early clinically node-negative OCSCC (seven cT1 and 23 cT2), with the majority located on the oral tongue. A median of three (range: 1-14) sentinel nodes were identified on lymphoscintigraphy, and all sentinel nodes were successfully retrieved, with 50% having a pathologically positive sentinel node. No false-negative sentinel nodes were identified using selective neck dissection as the gold standard. The negative predictive value (NPV) of SLNB was 100%, with 40% having a sentinel node identified outside the field of planned neck dissection on lymphoscintigraphy. Of these, one patient had a positive sentinel node outside of the ipsilateral supraomohyoid neck dissection template.

CONCLUSION

SLNB for early OCSCC is technically feasible in an Australian setting. It has a high NPV and can potentially identify at-risk lymphatic basins outside the traditional selective neck dissection levels even in well-lateralized lesions.

Additional non-sentinel lymph node metastases in early oral cancer patients with positive sentinel lymph nodes

To determine risk factors for additional non-sentinel lymph node metastases in neck dissection specimens of patients with early stage oral cancer and a positive sentinel lymph node biopsy (SLNB). A retrospective analysis of 36 previously untreated SLNB positive patients in our institution and investigation of currently available literature of positive SLNB patients in early stage oral cancer was done. Degree of metastatic involvement [classified as isolated tumor cells (ITC), micro- and macrometastasis] of the sentinel lymph node (SLN), the status of other SLNs, and additional non-SLN metastases in neck dissection specimens were analyzed. Of 27 studies, comprising 511 patients with positive SLNs, the pooled prevalence of non-SLN metastasis in patients with positive SLNs was 31 %. Non-SLN metastases were detected (available from 9 studies) in 13, 20, and 40 % of patients with ITC, micro-, and macrometastasis in the SLN, respectively. The probability of non-SLN metastasis seems to be higher in the case of more than one positive SLN (29 vs. 24 %), the absence of negative SLNs (40 vs. 19 %), and a positive SLN ratio of more than 50 % (38 vs. 19 %). Additional non-SLN metastases were found in 31 % of neck dissections following positive SLNB. The presence of multiple positive SLNs, the absence of negative SLNs, and a positive SLN ratio of more than 50 % may be predictive factors for non-SLN metastases. Classification of SLNs into ITC, micro-, and macrometastasis in the future SLNB studies is important to answer the question if treatment of the neck is always needed after positive SLNB.

Use of a novel receptor-targeted (CD206) radiotracer, 99mTc-tilmanocept, and SPECT/CT for sentinel lymph node detection in oral cavity squamous cell carcinoma: initial institutional report in an ongoing phase 3 study

IMPORTANCE

Sentinel lymph node biopsy has been proposed as an alternative to up-front elective neck dissection (END) for determination of pathologic nodal status in patients undergoing surgical treatment for oral cavity squamous cell carcinoma (OSCC) with clinically negative neck (cN0). Sentinel lymph node biopsy using current standard tracer agents and imaging adjuncts such as radiolabeled sulfur-colloid and planar lymphoscintigraphy (LS), however, is associated with several drawbacks.

OBJECTIVE

To assess the preliminary utility of technetium Tc 99m (99mTc)-tilmanocept, a novel molecular imaging agent for sentinel lymph node (SLN) mapping, in OSCC.

DESIGN, SETTING, AND PARTICIPANTS

Prospective, nonrandomized, single-arm, part of an ongoing phase 3 clinical trial. Patients had previously untreated, clinically and radiographically node-negative OSCC (T1-4aN0M0) at an academic tertiary referral center.

INTERVENTIONS

Patients received a single dose of 50 µg 99mTc-tilmanocept injected peritumorally followed by dynamic planar LS and fused single-photon emission computed tomography/computed tomography (SPECT/CT) prior to surgery. Surgical intervention consisted of excision of the primary tumor and radioguided SLN dissection followed by planned END. The excised lymph nodes (SLNs and non-SLNs) underwent histopathologic evaluation for presence of metastatic disease.

MAIN OUTCOMES AND MEASURES

False-negative rate and negative predictive value of SLNB using 99mTc-tilmanocept and comparison of planar LS with SPECT/CT in SLN localization.

RESULTS

Twelve of 20 patients (60%) had metastatic neck disease on pathologic examination. All 12 had at least 1 SLN positive for metastases. No patients had a positive END node who did not have at least 1 positive SLN. These data yield a false-negative rate of 0% and negative predictive value of 100% using 99mTc-tilmanocept in this setting. Dynamic planar LS and SPECT/CT revealed a mean (range) number of hot spots per patient of 2.9 (1-7) and 3.7 (1-12), respectively. Compared with planar LS, SPECT/CT identified additional putative SLNs in 11 of 20 cases (55%).

CONCLUSIONS AND RELEVANCE

The high negative predictive value and low false-negative rate in identification of occult metastases shows 99mTc-tilmanocept to be a promising agent in SLN identification in patients with OSCC. Use of SPECT/CT improves preoperative SLN localization including delineation of SLN locations near the primary tumor when compared with planar LS imaging.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00911326.

Prognostic biological features in neck dissection specimens

The superior prognostic value offered by routine histopathological staging of neck dissections, as compared to clinical staging using palpation and modern imaging techniques, is well established in the literature concerning the management of squamous cell carcinoma of the head and neck. In this review, we discuss the definitions and criteria used in standardised routine histopathological reporting and explore additional potential nodal prognostic features. In addition, we critically appraise the value of immunohistochemistry, histochemistry, molecular and other non-morphological techniques and suggest tumour and host features that merit further investigations.

Prognostic significance of matrix metalloproteinase-2, -8, -9, and -13 in oral tongue cancer

BACKGROUND

Oral tongue squamous cell carcinoma (OTSCC) often metastasizes to cervical lymph nodes. Mechanisms of this disease progression are not fully known. We aimed at finding new predictive markers for diagnosis and disease monitoring.

METHODS

Seventy-three consecutive T1N0M0 and T2N0M0 OTSCC patients treated at Helsinki University Central Hospital, Helsinki, Finland, in 1992-2002 were included. Tissue array blocks were prepared from primary tumors and immunostained. Immunoexpression of matrix metalloproteinase (MMP)-2, -8, -9, and -13 was compared with patient characteristics and outcome.

RESULTS

Nuclear expression of MMP-13, but not cytoplasmic expression of MMP-2, -8, and -9, was associated with invasion depth (P = 0.017) and tumor size (P = 0.008). Furthermore, high nuclear MMP-13 expression was predictive of poor outcome (P = 0.042).

CONCLUSION

Our results suggest that especially MMP-13 may be regarded as a prognostic biomarker in OTSCC.

Long-term experience in sentinel node biopsy for early oral and oropharyngeal squamous cell carcinoma

OBJECTIVE

Long-term results of sentinel node biopsy (SNB) in early (T1/T2) oral and oropharyngeal squamous cell carcinoma (OSCC) in a single-institution experience.

METHODS

Prospective consecutive cohort analysis of 79 patients (67% male, median age 60 years, age range 34-87 years) included between 2000 and 2006. Lymphatic mapping consisted of preoperative lymphoscintigraphy, single photon emission computed tomography (SPECT/CT), and intraoperative use of a handheld gamma probe. Endpoints of the study were neck control rate, overall (OS), disease-specific (DSS), and disease-free survival (DFS).

RESULTS

Twenty-nine of 79 patients (37%) had positive sentinel nodes (SN). Six of 29 (21%) patients showed isolated tumor cells, 14/29 (48%) micrometastases, and 9/29 (31%) macrometastases. OS, DFS, and DSS at 5 years for the entire cohort were 80, 85, and 87%, for SN-negative patients were 88, 96, and 96%, and for SN-positive patients were 74, 73, and 77%, respectively. Only the difference in DSS achieved statistical significance. The neck control rate after 5 years was 96% in SN-negative and 74% in SN-positive patients. This difference was statistically significant.

CONCLUSIONS

SNB is a safe and accurate staging modality to select patients with clinically stage I/II OSCC with occult lymph node disease for elective neck dissection (END). The promising reported short-term results have been sustained by long-term follow-up. Patients with negative SN and no END achieve an excellent neck control rate which compares favorably with reports on primary END. The neck control rate in SN-negative patients is superior to that in SN-positive patients, which is reflected in superior DSS.

Future of the TNM classification and staging system in head and neck cancer

Staging systems for cancer, including the most universally used TNM classification system, have been based almost exclusively on anatomic information. However, the question arises whether staging systems should be based on this information alone. Other parameters have been identified that should be considered for inclusion in classification systems like the TNM. This is all the more important, as a shift toward nonsurgical treatments for head and neck cancer has been made over the years. For these treatment modalities tumor/biologic characteristics next to anatomic information may be particularly important for treatment choice and outcome. The shortcomings of the current TNM classification system will be discussed, along with suggestions for improvement and expansion of the TNM system based on tumor, patient, and environment-related factors. Further improvement of the TNM classification is expected to result in better treatment choices, outcome and prognostication of patients with head and neck cancer.

The prevalence of occult metastases in nonsentinel lymph nodes after step-serial sectioning and immunohistochemistry in cN0 oral squamous cell carcinoma

OBJECTIVES

To examine the prevalence of isolated tumor cells (ITC) and micrometastases (MM) in nonsentinel lymph nodes (NSN) using additional step-serial sectioning and immunohistochemistry (IHC) as for sentinel lymph nodes (SN).

STUDY DESIGN

Prospective, consecutive, and clinically controlled trial.

METHODS

Fifty-one patients with oral cavity squamous cell carcinoma (OSCC) T1-T2 and clinically N0 neck underwent surgical treatment including sentinel-node biopsy (SNB) assisted selective neck dissection (SND). The location of the SN was determined using dynamic and planar lymphoscintigraphy and SPECT-CT. The harvested NSN from the neck dissections underwent the same histopathologic examinations as the SN using step-serial sectioning (SSS) at 150-micron intervals. Two sections from each level were stained with hematoxylin-eosin (H&E) and cytokeratin antibodies (AE1/AE3) and examined for tumor deposits. Results were compared with the previous routine examination of the NSN.

RESULTS

A total of 403 NSN were examined with a median of 8 per patient. A total of 1/51 patients (2%) had involvement of an additional NSN not found on routine examination. This was the only lymph node with involvement not detected previously. However, this patient had metastases in SN and in another NSN detected on routine examination. The overall incidence of occult metastasis (SN + NSN) was 21.6% (11/51) as previously reported.

CONCLUSIONS

The incidence of occult metastases in NSN after additional SSS and IHC was 2%. The risk of NSN involvement would seem to be extremely low in patients with early OSCC and negative SN. This study further validates SNB as an accurate staging tool for cN0 early OSCC.

Evaluation of Immunohistochemical Fine Sectioning for Sentinel Lymph Node Biopsy in Oral Squamous Cell Carcinoma

Objective. To determine the level of sentinel lymph node sectioning necessary to accurately detect nodal micrometastasis.

Study Design. Cross-sectional.

Setting. Tertiary care university medical center.

Subjects and Methods. Fine sections of oral squamous cell carcinoma sentinel lymph nodes previously sectioned at 2-mm intervals in a prospective clinical trial were reexamined. The results yielded from prior hematoxylin and eosin and immunohistochemical staining were compared with results following exhaustive serial sectioning at 150-µm intervals using identical staining methods. These experimental findings were compared with pathologic results of immediate completion selective neck dissection, previously recorded prospectively.

Results. Reexamination of 35 sentinel nodes at 150-µm intervals has not revealed any missed micrometastatic disease at 2-mm intervals used initially. Both comparisons of 150-µm sectioning analysis to the original 2-mm section samples and to the neck dissection pathology reports demonstrate a 100% negative predictive value.

Conclusion. These data suggest that sentinel lymph node sectioning at 2-mm intervals for oral carcinoma using hematoxylin and eosin staining and then immunohistochemical analysis maximizes efficiency, accuracy, and expenditure for the detection of micrometastasis.

Oral cavity squamous cell carcinoma and the clinically n0 neck: the past, present, and future of sentinel lymph node biopsy

Oral cavity squamous cell carcinoma (OCSCC) has a yearly incidence of 274,000 patients. Twenty percent to 30% of patients will harbor occult regional metastases, an important feature that correlates with worse outcomes. Supraomohyoid neck dissection (SND) is the gold standard treatment, but because of recent successes of sentinel lymph node (SLN) biopsy in the management of breast cancer and melanoma, many have begun evaluating its use in head and neck mucosal cancers. SLN biopsy offers patients decreased morbidity compared with SND, and has shown reproducibly low false-negative rates, high-negative predictive values, and high sensitivities. Limitations with floor-of-mouth primaries and delayed secondary SNDs have been described, but a new agent designed to address these shortcomings, Lymphoseek (Neoprobe Corp.; Dublin, OH), is currently under investigation. This article reviews the current literature on SLN biopsy and introduces a phase 3 study evaluating the efficacy of Lymphoseek in SLN biopsy of OCSCCs.

Sentinel node biopsy in head and neck squamous cell cancer: 5-year follow-up of a European multicenter trial

BACKGROUND

Sentinel node biopsy (SNB) may represent an alternative to elective neck dissection for the staging of patients with early head and neck squamous cell carcinoma (HNSCC). To date, the technique has been successfully described in a number of small single-institution studies. This report describes the long-term follow-up of a large European multicenter trial evaluating the accuracy of the technique.

METHODS

A total of 227 SNB procedures were carried out across 6 centers, of which 134 were performed in clinically T1/2 N0 patients. All patients underwent SNB with preoperative lymphoscintigraphy, intraoperative blue dye, and handheld gamma probe. Sentinel nodes were evaluated with hematoxylin and eosin (H&E) staining, step-serial sectioning (SSS), and immunohistochemistry (IHC). There were 79 patients who underwent SNB as the sole staging tool, while 55 patients underwent SNB-assisted elective neck dissection.

RESULTS

Sentinel nodes were successfully identified in 125 of 134 patients (93%), with a lower success rate observed for floor-of-mouth tumors (FoM; 88% vs. 96%, P = 0.138). Also, 42 patients were upstaged (34%); of these, 10 patients harbored only micrometastatic disease. At a minimum follow-up of 5 years, the overall sensitivity of SNB was 91%. The sensitivity and negative predictive values (NPV) were lower for patients with FoM tumors compared with other sites (80% vs. 97% and 88% vs. 98%, respectively, P = 0.034).

CONCLUSIONS

Sentinel node biopsy is a reliable and reproducible means of staging the clinically N0 neck for patients with cT1/T2 HNSCC. It can be used as the sole staging tool for the majority of these patients, but cannot currently be recommended for patients with tumors in the floor of the mouth.

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

Background:

Molecular diagnosis has been proposed to enhance the intra-operative diagnosis of sentinel lymph node (SLN) invasion in head and neck squamous cell carcinoma (HNSCC). Although cytokeratin (CK) mRNA quantification with real-time reverse transcriptase-PCR (QRT–PCR) has produced encouraging results, the more discriminating markers remain to be identified.

Methods:

Pemphigus vulgaris antigen (PVA), squamous cell carcinoma antigen (SCCA), and CK17 mRNA were quantified using QRT–PCR, and the results were compared with an extensive histopathological examination of the entire SLNs on 78 SLNs harvested from 22 patients with HNSCC.

Results:

SCCA and CK17 quantification showed significantly higher mRNA values for macrometastases (MAs) than for either negative or isolated tumour cell (ITC) SLNs (P<0.01). Pemphigus vulgaris antigen allowed the discrimination of all MAs and micrometastases from both negative and ITC SLNs (P<0.001). For the neck staging of patients, considering metastatic vs non-metastatic status, receiver-operating characteristic curve analysis found areas under the curve of 93.8, 97.9, and 100% for CK17, SCCA, and PVA, respectively. With PVA, a cutoff value of 562 copies per 100 ng of cDNA permitted the correct distinction between patients with positive as opposed to negative neck nodes in all cases.

Conclusion:

PVA seems to be a highly promising marker for accurate intra-operative SLN staging in HNSCC by QRT–PCR.

Head and neck sentinel lymph node biopsy: current state of the art

Sentinel node biopsy is an alternative to elective neck dissection for the management of T1/T2 oral and oro-pharyngeal squamous cell carcinomas and is also finding application to head and neck cancer at other sites. The main clinical aim of sentinel node biopsy is to achieve better staging and there is now evidence that the procedure reduces morbidity. Reported detection rates for sentinel neck nodes are greater than 95% and there is also a negative predictive value of 95% for negative sentinel nodes. Current histopathological protocols have been developed for use in the research setting and are designed to identify all micrometastatic disease. However the use of step serial sectioning at 150 micron intervals with pan-cytokeratin immunohistochemistry is currently advised and appears to upstage nodes by approximately 20% over the initial single routine stained section. Adoption of the UICC/TNM definitions is recommended for future sentinel node studies, but further refinements and descriptions are required. The SENT trial has recruited over 300 cases from 10 European centres and a quality control study of the pathological material is in progress. At the first consensus meeting of the SENT pathology group there were excellent levels of agreement on the diagnosis of positive and negative nodes, and a number of potential pitfalls such as non-malignant inclusions and staining artefacts were identified.