Sentinel lymph node biopsy for oral squamous cell carcinoma. Where are we now?

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.

Evaluation of micrometastasis and isolated tumor cells in node-negative early-stage oral tongue squamous cell carcinoma: a cross-sectional study in tertiary-level hospitals in eastern India

OBJECTIVE

The present study aimed to investigate the incidence of micrometastasis (MMs) and isolated tumor cells (ITCs) in node-negative early-stage oral tongue squamous cell carcinoma (T1-T2 N0). The secondary objective was to correlate the incidence with the clinicopathologic parameters of age, sex, depth of invasion, pattern of invasion, host lymphocytic response, and size and grade of primary tumor.

STUDY DESIGN

Micrometastasis and ITCs in cervical nodes of 30 patients with early-stage oral tongue squamous cell carcinoma were detected and compared using 3 methods: routine hematoxylin and eosin staining, serial-sectioning at intervals of 150 microns employing hematoxylin and eosin, and serial sectioning pan-cytokeratin immunostaining. Associations with clinicopathological variables were analyzed.

RESULTS

Metastatic tumor cells were detected in the cervical nodes of 2 patients using serial sectioning and immunohistochemistry, resulting in upstaging of 6.6% of all cases. Level I and II lymph nodes were primarily involved.

CONCLUSIONS

Early-stage oral tongue squamous cell carcinoma has a significant potential for MMs that frequently go undetected in routine histopathologic examination. However, laborious and technique-sensitive, serial sectioning in combination with pan-cytokeratin staining (AE1/AE3) may aid in detecting MMs and ITCs in patients with early-stage OTSCC.

Management of clinically node-negative early-stage oral cancer: network meta-analysis of randomized clinical trials

The best treatments for the clinically node-negative (cN0) neck in early-stage oral squamous cell carcinoma (OSCC) patients are a subject of ongoing debate and there is no consensus. A network meta-analysis (NMA) of randomized clinical trials (RCTs) was conducted to determine the most effective treatment and to rank treatments based on their effectiveness. A systematic search was performed in accordance with the PRISMA guidelines to retrieve RCTs that compared therapeutic neck dissection (TND), sentinel lymph node biopsy (SLNB), and elective neck dissection (END). The outcomes analysed were overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), and nodal recurrence. Hazard ratios and risk ratios were calculated by direct meta-analysis and NMA. Ten RCTs with a total of 1858 patients were eligible for inclusion. Direct meta-analysis showed END to be superior to TND and comparable to SLNB. The NMA revealed no statistically significant difference between END and SLNB (very low quality evidence) regarding OS, DSS, DFS, and nodal recurrence. However, END was found to significantly improve OS and DFS, and reduce nodal recurrence when compared to TND (moderate quality evidence). END ranked as probably the top treatment option for maximizing OS and DSS, and reducing nodal recurrence in early-stage OSCC, followed by SLNB and TND. There was very low quality evidence supporting SLNB as non-inferior to END for patients with early-stage OSCC. This NMA yielded favourable results for the use of END (with moderate quality evidence) in early-stage OSCC patients, although excellent results have also been obtained with SLNB. However, data in the literature for SLNB are scarce, as this technique has not yet been formalized in many countries. There is a need to further explore SLNB for early-stage OSCC patients, as well as its value in detecting occult lymph node metastases on the contralateral side. More studies comparing morbidity, quality of life, and costs between the different management strategies for the clinically negative neck in early-stage OSCC patients are needed.

The potential of the Crystal Cam handheld gamma-camera for preoperative and intraoperative sentinel lymph node localization in early-stage oral cancer

PURPOSE

Evaluating the Crystal Cam handheld gamma-camera for preoperative and intraoperative sentinel lymph node (SLN) localization in early-stage oral cancer.

METHODS

The handheld gamma-camera was used complementary to conventional gamma-probe guidance for intraoperative SLN localization in 53 early-stage oral cancer patients undergoing SLN biopsy. In 36 of these patients, a blinded comparison was made between preoperative handheld gamma-camera and lymphoscintigraphy outcomes. Of those, the reliability for marking the SLN's location using both handheld gamma-camera and a 57Co-penpoint marker was evaluated in 15 patients.

RESULTS

In the entire cohort, the handheld gamma-camera preoperatively detected 116/122 (95%) of SLNs identified by lymphoscintigraphy. In those patients where the observer was blinded for lymphoscintigraphy (n = 36), 71/77 (92%) SLNs were correctly identified by handheld gamma-camera. Overlooked SLNs by handheld gamma-camera were mainly located near the injection site. The SLN's marked location by handheld gamma-camera and 57Co-penpoint marker was considered accurate in 42/43 (98%) SLNs. The intraoperative use of the handheld gamma-camera led to the extirpation of 16 additional 'hot' lymph nodes in 14 patients, 4 of which harbored metastases, and prevented 2 patients (4%) from being erroneously staged negative for nodal metastasis. In those with follow-up ≥ 24 months or false-negative outcomes < 24 months following SLNB, a sensitivity of 82% and negative predictive value of 93% was obtained.

CONCLUSION

The Crystal Cam handheld gamma-camera offers reliable preoperative and intraoperative SLN localization and might reduce the risk of missing a malignant SLN during surgery. Detecting SLNs near the injection site by handheld gamma-camera remains challenging.

Health-related quality of life, functional outcomes, and complications after sentinel lymph node biopsy and elective neck dissection in early oral cancer: A systematic review

BACKGROUND

Elective neck dissection improves survival in early oral cancer. Sentinel lymph node biopsy may also do this with less morbidity. This systematic review compared health-related quality of life, functional outcomes, and complications after sentinel lymph node biopsy and elective neck dissection in early oral cancer.

METHODS

PRISMA guidelines were followed. Thirteen studies met inclusion criteria.

RESULTS

Results favoring sentinel lymph node biopsy were found in complications, scar length and appearance, length of hospital stay, time to drain removal, and objective shoulder measures at timepoints up to 12 months. Where differences in health-related quality of life were found, methodological issues make their clinical significance questionable.

CONCLUSIONS

Sentinel lymph node biopsy was associated with fewer complications and statistically better outcomes in a number of physical measures. There is as yet no strong evidence to suggest it is associated with better health-related quality of life outcomes. While a number of health-related quality of life outcome measures show promise, their interpretation is hampered by methodological concerns. Further rigorous research is required to address this.

Interventions for the treatment of oral cavity and oropharyngeal cancers: surgical treatment

BACKGROUND

Surgery is a common treatment option in oral cavity cancer (and less frequently in oropharyngeal cancer) to remove the primary tumour and sometimes neck lymph nodes. People with early-stage disease may undergo surgery alone or surgery plus radiotherapy, chemotherapy, immunotherapy/biotherapy, or a combination of these. Timing and extent of surgery varies. This is the third update of a review originally published in 2007.

OBJECTIVES

To evaluate the relative benefits and harms of different surgical treatment modalities for oral cavity and oropharyngeal cancers.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 9 February 2022.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared two or more surgical treatment modalities, or surgery versus other treatment modalities, for primary tumours of the oral cavity or oropharynx.

DATA COLLECTION AND ANALYSIS

Our primary outcomes were overall survival, disease-free survival, locoregional recurrence, and recurrence; and our secondary outcomes were adverse effects of treatment, quality of life, direct and indirect costs to patients and health services, and participant satisfaction. We used standard Cochrane methods. We reported survival data as hazard ratios (HRs). For overall survival, we reported the HR of mortality, and for disease-free survival, we reported the combined HR of new disease, progression, and mortality; therefore, HRs below 1 indicated improvement in these outcomes. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We identified four new trials, bringing the total number of included trials to 15 (2820 participants randomised, 2583 participants analysed). For objective outcomes, we assessed four trials at high risk of bias, three at low risk, and eight at unclear risk. The trials evaluated nine comparisons; none compared different surgical approaches for excision of the primary tumour. Five trials evaluated elective neck dissection (ND) versus therapeutic (delayed) ND in people with oral cavity cancer and clinically negative neck nodes. Elective ND compared with therapeutic ND probably improves overall survival (HR 0.64, 95% confidence interval (CI) 0.50 to 0.83; I2 = 0%; 4 trials, 883 participants; moderate certainty) and disease-free survival (HR 0.56, 95% CI 0.45 to 0.70; I2 = 12%; 5 trials, 954 participants; moderate certainty), and probably reduces locoregional recurrence (HR 0.58, 95% CI 0.43 to 0.78; I2 = 0%; 4 trials, 458 participants; moderate certainty) and recurrence (RR 0.58, 95% CI 0.48 to 0.70; I2 = 0%; 3 trials, 633 participants; moderate certainty). Elective ND is probably associated with more adverse events (risk ratio (RR) 1.31, 95% CI 1.11 to 1.54; I2 = 0%; 2 trials, 746 participants; moderate certainty). Two trials evaluated elective radical ND versus elective selective ND in people with oral cavity cancer, but we were unable to pool the data as the trials used different surgical procedures. Neither study found evidence of a difference in overall survival (pooled measure not estimable; very low certainty). We are unsure if there is a difference in effect on disease-free survival (HR 0.57, 95% CI 0.29 to 1.11; 1 trial, 104 participants; very low certainty) or recurrence (RR 1.21, 95% CI 0.63 to 2.33; 1 trial, 143 participants; very low certainty). There may be no difference between the interventions in terms of adverse events (1 trial, 148 participants; low certainty). Two trials evaluated superselective ND versus selective ND, but we were unable to use the data. One trial evaluated supraomohyoid ND versus modified radical ND in 332 participants. We were unable to use any of the primary outcome data. The evidence on adverse events was very uncertain, with more complications, pain, and poorer shoulder function in the modified radical ND group. One trial evaluated sentinel node biopsy versus elective ND in 279 participants. There may be little or no difference between the interventions in overall survival (HR 1.00, 95% CI 0.90 to 1.11; low certainty), disease-free survival (HR 0.98, 95% CI 0.90 to 1.07; low certainty), or locoregional recurrence (HR 1.04, 95% CI 0.91 to 1.19; low certainty). The trial provided no usable data for recurrence, and reported no adverse events (very low certainty). One trial evaluated positron emission tomography-computed tomography (PET-CT) following chemoradiotherapy (with ND only if no or incomplete response) versus planned ND (before or after chemoradiotherapy) in 564 participants. There is probably no difference between the interventions in overall survival (HR 0.92, 95% CI 0.65 to 1.31; moderate certainty) or locoregional recurrence (HR 1.00, 95% CI 0.94 to 1.06; moderate certainty). One trial evaluated surgery plus radiotherapy versus radiotherapy alone and provided very low-certainty evidence of better overall survival in the surgery plus radiotherapy group (HR 0.24, 95% CI 0.10 to 0.59; 35 participants). The data were unreliable because the trial stopped early and had multiple protocol violations. In terms of adverse events, subcutaneous fibrosis was more frequent in the surgery plus radiotherapy group, but there were no differences in other adverse events (very low certainty). One trial evaluated surgery versus radiotherapy alone for oropharyngeal cancer in 68 participants. There may be little or no difference between the interventions for overall survival (HR 0.83, 95% CI 0.09 to 7.46; low certainty) or disease-free survival (HR 1.07, 95% CI 0.27 to 4.22; low certainty). For adverse events, there were too many outcomes to draw reliable conclusions. One trial evaluated surgery plus adjuvant radiotherapy versus chemotherapy. We were unable to use the data for any of the outcomes reported (very low certainty).

AUTHORS' CONCLUSIONS

We found moderate-certainty evidence based on five trials that elective neck dissection of clinically negative neck nodes at the time of removal of the primary oral cavity tumour is superior to therapeutic neck dissection, with increased survival and disease-free survival, and reduced locoregional recurrence. There was moderate-certainty evidence from one trial of no difference between positron emission tomography (PET-CT) following chemoradiotherapy versus planned neck dissection in terms of overall survival or locoregional recurrence. The evidence for each of the other seven comparisons came from only one or two studies and was assessed as low or very low-certainty.

Centralised pathology service for sentinel node biopsy in oral cavity cancer: The Southeast England Consortium experience

BACKGROUND

Sentinel lymph node biopsy is an increasingly recognised option for accurate staging and subsequent management of the clinically negative neck in early stage oral cavity squamous cell carcinoma. However, the technique is currently underused due to several logistic constraints including increased burden on pathology services. Here, we describe the feasibility of an outsourced centralised pathology processing and reporting service for sentinel lymph node biopsies in oral cavity squamous cell carcinoma.

PATIENTS AND METHODS

The Southeast England Consortium comprises four surgical centres utilising a central pathology service. Consecutive cases between January 2016 and February 2020 were retrospectively evaluated for survival outcomes and laboratory turnaround times.

RESULTS

Twenty-eight per cent from a cohort of 139 patients had positive sentinel nodes. There was a trend towards greater overall, disease-free and disease-specific survival (OS, DFS and DSS, respectively) in sentinel node negative compared to sentinel node positive patients, but these differences were not statistically significant. The sensitivity, negative predictive value and false negative rate were 92.8%, 97.0% and 6.8%, respectively. The mean and mode laboratory TAT were 5 and 4 working days, respectively.

CONCLUSION

An outsourced centralised pathology service is a feasible option to widen the availability of sentinel node biopsy in oral cavity squamous cell carcinoma.

Synchronous oral squamous cell carcinoma and a lymphoproliferative disorder in an adult: a challenge in diagnosis and management

Synchronous primary malignancies present challenges in diagnosis, treatment sequencing and management. We present a rare case of a synchronous oral cavity and lymphoproliferative malignancy in a middle-age man. Our patient presented with a primary oral cavity squamous cell carcinoma and was subsequently found to have a secondary lymphoproliferative malignancy (chronic lymphocytic leukaemia/small lymphocytic lymphoma). The challenge of staging and sequencing of treatment is discussed. In addition, this case highlights the importance of multidisciplinary consultation, designing a personalised treatment plan that is coincident with the standard of care for each malignancy, and close follow-up.

Practical aspects of sentinel node biopsy in oral cavity cancer: all nodes that emit a signal are important

BACKGROUND AND OBJECTIVES

Sentinel node biopsy (SNB) is a safe and effective way to examine an N0 neck in early-stage oral cavity cancer (OCC). In this study, we evaluated the variables of SNB detection, surgery, and outcome.

MATERIAL AND METHODS

Ninety-two patients with N0 OCC examined with SNB were included. Number and brightness of nodes detected on preoperative imaging and during surgery were analyzed and compared with histological findings. Patients with recurrent disease were evaluated separately and the effect of smoking and alcohol consumption was analyzed.

RESULTS

Eighteen patients had at least malignant cells in the sentinel lymph node (SLN); 18 patients had recurrent disease and nine patients died from the cancer. The negative predictive value of SNB was 95%. Six patients did not have metastases in the node with the strongest signal, but metastases were found in an SLN with a weaker signal. Smoking and alcohol consumption did not affect disease-specific or overall survival.

CONCLUSION AND SIGNIFICANCE

SNB has been confirmed to be safe and effective in early stage N0 OCC. However, it is important to carefully harvest up to four hottest SLNs that emit a signal. Treatment of patients with only isolated tumor cells (ITC) in the SLN appears to be necessary.

Sentinel lymph node biopsy versus elective neck dissection in squamous cell carcinoma of the oral cavity with a clinically N0 neck: Systematic review and meta-analysis of prospective studies

Sentinel lymph node biopsy (SLNB) is an emerging strategy for managing early-stage oral squamous cell carcinoma (SCC) with a clinically N0 (cN0) neck. However, the role of SLNB in this scenario is debatable. Herein, relevant literature was systematically reviewed, and a meta-analysis was performed to evaluate the potential dividends of SLNB compared to elective neck dissection (END) for these patients. The meta-analysis, including six prospective studies, showed comparable results of the two management strategies in terms of regional recurrence (risk ratio [RR] = 0.99; 95% confidence interval [CI], 0.58-1.70), 5-year disease-free survival (RR = 0.99; 95% CI, 0.87-1.11), and 5-year overall survival (RR = 1.01; 95% CI, 0.90-1.13). Fewer adverse events occurred in the SLNB arm than in the END arm (RR = 0.12; 95% CI, 0.02-0.70). Overall, SLNB results in as favorable an oncologic prognosis for patients with cN0 oral SCC as END, while significantly lessening side effects and unnecessary surgeries.

Sentinel Lymph Node Biopsy in Early Stages of Oral Squamous Cell Carcinoma Using the Receptor-Targeted Radiotracer 99mTc-Tilmanocept

Neck management in patients with early-stage, clinically node-negative oral squamous cell carcinoma (OSCC) remains a matter of discussion. Sentinel lymph node biopsy (SLNB) represents a treatment alternative to avoid elective neck dissection (END) in this cohort and different protocols and tracers exist. Here we present the clinical outcome of SLNB using ^99mTc-tilmanocept in a two-day protocol in patients suffering from early-stage OSCC. A total of 13 patients (males: 6; females: 7; mean age: 65.7 years, ranging from 47 to 89 years) were included in this study. Most of the patients suffered from an OSCC of the floor of mouth (n = 6), followed by tongue (n = 5) and upper alveolar crest/hard palate (n = 2). Sentinel lymph nodes (SLNs) were successfully identified in all cases (range: 1–7). The average length of hospital stay was 4.7 days (range: 3–8 days) and mean duration of surgical intervention was 121 min (range: 74–233 min). One patient who suffered from an OSCC of the tongue was sentinel lymph node positive (SLN+). The mean follow-up for all sentinel lymph node negative (SLN-) patients (n = 12) was 20.3 months (range: 10–28 months). No local or nodal recurrences were observed within the observation period. In our patient cohort, SLNB using ^99mTc-tilmanocept in a two-day protocol proved to be a reliable and safe staging method for patients suffering from early-stage, clinically node-negative OSCC. These results and their possible superiority to colloid tracers have to be confirmed in a prospective randomized controlled study.

[Near-infrared sentinel diagnostics in head and neck squamous cell carcinoma: a systematic review]

BACKGROUND

 Near-infrared fluorescence (NIR) imaging is a new technique for intraoperative identification of sentinel lymph nodes (SLN). It has shown promising results in several surgical specialties. This article reviews the current study situation of NIR SLN diagnosis of head and neck malignancy.

MATERIAL AND METHODS

 systematic literature search in the following online databases: PubMed, MEDLINE, Thompson Reuters Web of Science, SPIE for the search terms: sentinel node, sentinel node biopsy, head and neck squamous cell carcinoma, near-infrared imaging, indocyanine green, icg. Evaluation of scientific relevance of papers according to established criteria.

RESULTS

 Studies were analyzed in terms of clinical application, clinical reporting, identification rate, and false-negative rate. The identification rate of SLN is 97-100 %, with an average of 1.2-3.4 fluorescence positive lymph nodes per examination. The overall false-negative rate varies between 0 and 20 %.

CONCLUSIONS

 In the synopsis of the currently published results, NIR imaging promises the great potential to improve the diagnosis of SLN in carcinomas of the oral cavity and pharynx. A simple and fast procedure with high spatial resolution and without radiation exposure is beneficial.

Cortactin expression assessment improves patient selection for a watchful waiting strategy in pT1cN0-staged oral squamous cell carcinomas with a tumor infiltration depth below 4 mm

BACKGROUND

In this feasibility study we aimed to evaluate the value of previously reported molecular tumor biomarkers associated with lymph node metastasis in oral squamous cell carcinoma (OSCC) to optimize neck strategy selection criteria.

METHODS

The association between expression of cortactin, cyclin D1, FADD, RAB25, and S100A9 and sentinel lymph node status was evaluated in a series of 87 (cT1-2N0) patients with OSCC treated with primary resection and SLNB procedure.

RESULTS

Tumor infiltration depth and tumor pattern of invasion were independent prognostic markers for SLN status, while none of the tumor makers showed a better prognostic value to replace SLNB as neck staging technique in the total cohort. However, in the subgroup of patients with pT1N0 OSCC, cortactin expression (OR 16.0, 95%CI 2.0-127.9) was associated with SLN classification.

CONCLUSIONS

Expression of cortactin is a promising immunohistochemical tumor marker to identify patients at low risk that may not benefit from SLNB or END.

Contralateral Regional Recurrence in Lateralized or Paramedian Early-Stage Oral Cancer Undergoing Sentinel Lymph Node Biopsy-Comparison to a Historic Elective Neck Dissection Cohort

Introduction: Nowadays, two strategies are available for the management of the clinically negative neck in early-stage (cT1-2N0) oral squamous cell carcinoma (OSCC): elective neck dissection (END) and sentinel lymph node biopsy (SLNB). SLNB stages both the ipsilateral and the contralateral neck in early-stage OSCC patients, whereas the contralateral neck is generally not addressed by END in early-stage OSCC not involving the midline. This study compares both incidence and hazard of contralateral regional recurrences (CRR) in those patients who underwent END or SLNB.

Materials and Methods: A retrospective multicenter cohort study, including 816 lateralized or paramedian early-stage OSCC patients, staged by either unilateral or bilateral END (n = 365) or SLNB (n = 451).

Results: The overall rate of occult contralateral nodal metastasis was 3.7% (30/816); the incidence of CRR was 2.5% (20/816). Patients who underwent END developed CRR during follow-up more often than those who underwent SLNB (3.8 vs. 1.3%; p = 0.018). Moreover, END patients had a higher hazard for developing CRR than SLNB patients (HR = 2.585; p = 0.030). In addition, tumor depth of invasion was predictive for developing CRR (HR = 1.922; p = 0.009). Five-year disease-specific survival in patients with CRR was poor (42%) compared to patients in whom occult contralateral nodal metastases were detected by SLNB or bilateral END (88%), although not statistically different (p = 0.066).

Conclusion: Our data suggest that SLNB allows for better control of the contralateral clinically negative neck in patients with lateralized or paramedian early-stage OSCC, compared to END as performed in a clinical setting. The prognosis of those in whom occult contralateral nodal metastases are detected at an earlier stage may be favorable compared to those who eventually develop CRR, which highlights the importance of adequate staging of the contralateral clinically negative neck.

[Expression of cyclophilin A in oral squamous cell carcinoma and its effect on cell proliferation and invasion]

OBJECTIVES

To investigate the expression of cyclophilin A (CyPA) in oral squamous cell carcinoma (OSCC) and explore the effect of downregulating the expression of CyPA gene on the proliferation and invasion of SCC-25 cells.

METHODS

A total of 77 cases of patients with OSCC were selected. The expression levels of CyPA proteins in OSCC and adjacent normal tissues were evaluated. SCC-25 cells were cultured and divided into the CyPA interference sequence group, negative control group, and blank group. The expression levels of CyPA mRNA and protein in cells were detected by using real-time fluorescent quantitative polymerase chain reaction and Western blot, respectively. Cell proliferation was detected by using methyl thiazolyl tetrazolium and plate colony formation assays. Cell invasion was detected by using Transwell assay.

RESULTS

The positive expression rate of CyPA protein in OSCC tissues was 76.62%, which was higher than that in adjacent tissues (P<0.05). The positive expression rate of CyPA protein in TNM stage T₃+T₄, clinical stage Ⅲ+Ⅳ, moderately or poorly differentiated lymph node metastasis was increased (P<0.05). Compared with the negative control and blank groups, the CyPA interference sequence group had decreased relative expression levels of CyPA mRNA and protein (P<0.05); optical density va-lues of cells at 24, 48, 72, and 96 h (P<0.05); and number of cell colonies and invasive cells (P<0.05).

CONCLUSIONS

The CyPA protein is highly expressed in OSCC tissues, and the downregulation of CyPA gene expression in SCC-25 cells can reduce cell proliferation and inhibit cell invasion.

Sentinel lymph node biopsy versus elective neck dissection: long-term oncologic outcomes in clinically node-negative tongue cancer

Objectives

The aim of this study was to compare the long-term oncologic outcomes of sentinel lymph node biopsy (SLNB) versus elective neck dissection (END) in clinically node-negative (cN0) tongue cancer.

Methods

This was a retrospective cohort study of patients with cN0 tongue cancer from a single institution, including 91 patients in the SLNB group and 120 patients in the END group.

Results

The overall recurrence rate showed no significant difference between the two groups. The regional control rate was also comparable between the two groups (P=0.490). The 5-year recurrence-free survival (RFS) was slightly better in the SLNB group than in the END group (P=0.427). The 5-year overall survival (OS) rate was 89.9% in the SLNB group versus 91.9% in the END group (P=0.737). In a propensity-matched subgroup analysis, the type of neck management did not affect RFS or OS.

Conclusion

SLNB showed non-inferior oncologic outcomes compared to END in patients with cN0 tongue squamous cell carcinoma.

Novel Diagnostic Approaches for Assessment of the Clinically Negative Neck in Head and Neck Cancer Patients

In head and neck cancer, the presence of nodal disease is a strong determinant of prognosis and treatment. Despite the use of modern multimodality diagnostic imaging, the prevalence of occult nodal metastases is relatively high. This is why in clinically node negative head and neck cancer the lymphatics are treated “electively” to eradicate subclinical tumor deposits. As a consequence, many true node negative patients undergo surgery or irradiation of the neck and suffer from the associated and unnecessary early and long-term morbidity. Safely tailoring head and neck cancer treatment to individual patients requires a more accurate pre-treatment assessment of nodal status. In this review, we discuss the potential of several innovative diagnostic approaches to guide customized management of the clinically negative neck in head and neck cancer patients.

New Developments in Imaging for Sentinel Lymph Node Biopsy in Early-Stage Oral Cavity Squamous Cell Carcinoma

Sentinel lymph node biopsy (SLNB) is a diagnostic staging procedure that aims to identify the first draining lymph node(s) from the primary tumor, the sentinel lymph nodes (SLN), as their histopathological status reflects the histopathological status of the rest of the nodal basin. The routine SLNB procedure consists of peritumoral injections with a technetium-99m [^99mTc]-labelled radiotracer followed by lymphoscintigraphy and SPECT-CT imaging. Based on these imaging results, the identified SLNs are marked for surgical extirpation and are subjected to histopathological assessment. The routine SLNB procedure has proven to reliably stage the clinically negative neck in early-stage oral squamous cell carcinoma (OSCC). However, an infamous limitation arises in situations where SLNs are located in close vicinity of the tracer injection site. In these cases, the hotspot of the injection site can hide adjacent SLNs and hamper the discrimination between tracer injection site and SLNs (shine-through phenomenon). Therefore, technical developments are needed to bring the diagnostic accuracy of SLNB for early-stage OSCC to a higher level. This review evaluates novel SLNB imaging techniques for early-stage OSCC: MR lymphography, CT lymphography, PET lymphoscintigraphy and contrast-enhanced lymphosonography. Furthermore, their reported diagnostic accuracy is described and their relative merits, disadvantages and potential applications are outlined.

Sentinel lymph node mapping using ICG fluorescence and cone beam CT - a feasibility study in a rabbit model of oral cancer

BACKGROUND

Current sentinel lymph node biopsy (SLNB) techniques, including use of radioisotopes, have disadvantages including the use of a radioactive tracer. Indocyanine green (ICG) based near-infrared (NIR) fluorescence imaging and cone beam CT (CBCT) have advantages for intraoperative use. However, limited literature exists regarding their use in head and neck cancer SLNB.

METHODS

This was a prospective, non-randomized study using a rabbit oral cavity VX2 squamous cell carcinoma model (n = 10) which develops lymph node metastasis. Pre-operatively, images were acquired by MicroCT. During surgery, CBCT and NIR fluorescence imaging of ICG was used to map and guide the SLNB resection.

RESULTS

Intraoperative use of ICG to guide fluorescence resection resulted in identification of all lymph nodes identified by pre-operative CT. CBCT was useful for near real time intraoperative imaging and 3D reconstruction.

CONCLUSIONS

This pre-clinical study further demonstrates the technical feasibility, limitations and advantages of intraoperative NIR-guided ICG imaging for SLN identification as a complementary method during head and neck surgery.

Challenges and outcomes in establishing a sentinel lymph node biopsy service for oral squamous cell carcinoma in a regional district specialist hospital

UK national guidelines in 2016 recommended that sentinel lymph node biopsy (SLNB) should be offered to patients with early oral squamous cell carcinoma (OSCC). We review the establishment of an OSCC SLNB service with specific consideration to resources, service implications and patient outcomes. A review of processes was performed to identify key stages in establishing the service, and subsequently a retrospective cohort study consisting of 46 consecutive patients with T1/T2 N0 OSCC was undertaken. The key stages identified were: coordinating a nuclear medicine pathway and reliable cost-appropriate pathology service, constructing a Trust business case, and gaining approval of a new interventional service policy. A median (range) of 3.3 (1-8) sentinel nodes (SLN) were removed, with 17 patients having a positive SLN. The negative predictive value of SLNB was 100%, with 12 having a SLN outside the field if elective neck dissection (END) was planned. There was a significantly increased risk of a positive SLN with increasing depth of invasion (DOI) (p=0.007) and increased diameter (p=0.036). We also identified a longer-than-ideal time to completion neck dissection and inadequate ultrasound follow up of negative SLNB patients. Establishment of a service requires careful planning. Our results were in keeping with those reported in the literature, and showed that SLNB for OSCC has a high negative predictive value and can identify at-risk SLN outside the traditional END levels, even in well-lateralised tumours. Our findings show that DOI and size of SLN were significantly associated with a positive SLN, and also identified areas requiring improvement.

Head and neck robotic surgery combined with sentinel lymph node biopsy. Fascinating, but feasible?

Robotic approaches and sentinel lymph node (SLN) biopsy are both strategies that evolved driven by the need to reduce impact of head and neck oncological surgery in terms of operative timing, morbidity, hospitalization time, and aesthetic results. A comprehensive review of the scientific literature was performed on PubMed, Embase, ResearchGate, Cochrane, and CENTRAL electronic databases with the aim to discuss the role that these two approaches can play together in the management of head and neck cancers (HNCs) of various sites. Dedicated publications on the combined robotics and SLN biopsy approaches resulted, up to now very limited, while their separated application in non-shared fields is gaining strength. However, the possibility to implement and combine technologies to minimize sequelae of head and neck surgery is an interesting and evolving topic.

Prediction of cervical metastasis and survival in cN0 oral cavity cancer using tumour 18F-FDG PET/CT functional parameters

PURPOSE

Oral cavity squamous cell carcinoma (OCC) can spread to the neck without apparent lymphadenopathy. Pretreatment detection or prediction of occult metastasis might contribute to proper management of clinically node-negative (cN0) OCC. We examined the role of tumour quantitative 18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) measurements for predicting OCC occult metastasis and survival.

METHODS

This study included 130 cN0 OCC patients who underwent ¹⁸F-FDG PET/CT scanning and subsequent curative surgery and neck dissection. Maximum, peak, and mean standardized uptake value (SUV_max, SUV_peak, and SUV_mean), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) were measured on pretreatment ¹⁸F-FDG PET/CT. Binary logistic regression was used to identify factors predicting occult cervical metastasis. Univariate and multivariate Cox proportional hazard regression were used to find factors associated with overall survival (OS).

RESULTS

Pathological cervical metastasis (pN +) was found in 29 (22.3%) patients. Age, tumour differentiation, lymphovascular invasion, and T classification were significantly associated with pN + (all P < 0.05). After adjustment for these factors, MTV and TLG independently predicted pN + (P < 0.05). Invasion depth, lymphovascular invasion, T and N classifications, and overall TNM stage were significantly associated with OS. After adjustment for these factors, SUV_max and TLG independently predicted OS (all P < 0.05). Patients with TLG > 9.3 g had a 5.7-fold increased risk of overall mortality.

CONCLUSIONS

Tumour ¹⁸F-FDG PET/CT parameters might predict occult metastasis and survival in cN0 OCC patients.

Elective Neck Dissection in T1N0M0 Oral Squamous Cell Carcinoma: When Is It Necessary?

PURPOSE

Elective neck dissection (END) versus observation remains controversial for cT1N0M0 oral cavity squamous cell carcinoma (OSCC). The aim of this study was to determine whether neck dissection is indicated for cT1N0M0 OSCC versus observation when considering oral cavity subsites and depth of invasion (DOI) as predictors.

PATIENTS AND METHODS

A multicenter, ambispective cohort study of patients with cT1N0M0 OSCC treated at the University of Michigan and Beijing Stomatological Hospital from August 1998 to July 2017 with a follow-up end date of July 2019 was performed. Patients were excluded if follow-up was less than 2 years and no neck disease had occurred or if the final pathologic analysis resulted in upstaging to T2 using American Joint Committee on Cancer criteria, eighth edition. A total of 283 patients met the criteria. The main outcome parameter was the 2-year neck metastatic rate.

RESULTS

The total 2-year lymph node metastatic rate was 11.3%. Overall neck metastatic rates escalated consistently according to DOI: less than 2 mm, 2.1%; 2 to 3 mm, 9.4%; 3 to 4 mm, 15.2%; and 4 to 5 mm, 24.6%. On univariate Cox regression analysis, DOI greater than 3 mm, tumor grade, and perineural invasion were statistically significant indicators of 2-year neck metastasis. On multivariate analysis, only DOI and tumor grade remained. On multivariate analysis of 2-year survival, no factors were independent predictors. Our proposed treatment strategy for END based both on statistically significant results for DOI and on review of the raw data using a 20% cutoff analysis showed cutoffs of 2 mm for the tongue (18.2%), 3 mm for the floor of the mouth (40.0%) and upper gingiva (20%), and 4 mm for the lower gingiva (33.3%) and no cutoff for the hard palate (0.0%).

CONCLUSIONS

The watch-and-wait approach remains a reasonable approach in selected patients with cT1N0M0 OSCC. Decision making for END in T1N0M0 patients should minimally consider tumor grade, DOI, and oral cavity subsite.

Elective Neck Dissection or Sentinel Lymph Node Biopsy in Early Stage Oral Cavity Cancer Patients: The Dutch Experience

Background: Sentinel lymph node biopsy (SLNB) has been introduced as a diagnostic staging modality for detection of occult metastases in patients with early stage oral cancer. Comparisons regarding accuracy to the routinely used elective neck dissection (END) are lacking in literature. Methods: A retrospective, multicenter cohort study included 390 patients staged by END and 488 by SLNB. Results: The overall sensitivity (84% vs. 81%, p = 0.612) and negative predictive value (NPV) (93%, p = 1.000) were comparable between END and SLNB patients. The END cohort contained more pT2 tumours (51%) compared to the SLNB cohort (23%) (p < 0.001). No differences were found for sensitivity and NPV between SLNB and END divided by pT stage. In floor-of-mouth (FOM) tumours, SLNB had a lower sensitivity (63% vs. 92%, p = 0.006) and NPV (90% vs. 97%, p = 0.057) compared to END. Higher disease-specific survival (DSS) rates were found for pT1 SLNB patients compared to pT1 END patients (96% vs. 90%, p = 0.048). Conclusion: In the absence of randomized clinical trials, this study provides the highest available evidence that, in oral cancer, SLNB is as accurate as END in detecting occult lymph node metastases, except for floor-of-mouth tumours.

Comparison Between PET-CT-Guided Neck Dissection and Elective Neck Dissection in cT1-2N0 Tongue Squamous Cell Carcinoma

Objective: Neck management in cT1-2N0 tongue squamous cell carcinoma (SCC) remains controversial. Our goal was to compare the survival difference between PET-CT–guided neck dissection and elective neck dissection (END) for the treatment of cT1-2 tongue SCC.

Methods: Patients with surgically treated cT1-2N0 tongue SCC were retrospectively enrolled. These patients were divided into two groups. Group A: The decision of whether to perform neck dissection was mainly based on the results of preoperative PET-CT examinations. Group B: Patients received END treatment without preoperative PET-CT examinations. The study endpoints were regional control (RC) and disease-specific survival (DSS). The Kaplan–Meier method was used to calculate the survival rates.

Results: Group A consisted of 66 patients, and 16 patients underwent neck dissection owing to positive PET-CT results. Group B consisted of 169 patients. The 5-year RC rates in group A and group B were 86 and 87%, respectively, and the difference was not significant (p = 0.731). The 5-year DSS rates in group A and group B were 93 and 90%, respectively, and the difference was not significant (p = 0.583).

Conclusions: Neck dissection can be safely avoided when the PET-CT scan reveals no neck lymph node involvement.

Extent of neck dissection for patients with clinical N1 oral cancer

BACKGROUND

No clear consensus has been reached on the indication of supraomohyoid neck dissection (SOHND) for clinically positive lymph-node metastasis.

PATIENTS

Consecutive 100 patients with previously untreated oral cancer treated at Kobe University Hospital were included in this study. All patients were clinically staged as anyTN1M0 and underwent radical dissection of the primary site and level I-V neck dissection as the initial treatment.

RESULTS

None of the 100 patients had pathological lymph-node metastasis (pLN) to level V. pLN to level IV was observed in two patients with tongue cancer in whom clinical lymph-node metastasis was preoperatively observed at level II.

CONCLUSIONS

Level V may be excluded in the neck dissection for patients with N1 oral cancers. Level IV dissection should be considered in the patient with tongue cancer and clinical lymph-node metastasis at level II.

Effectiveness of sentinel lymph node scintigraphy and intraoperative gamma probing with gold standard elective neck dissection in patients with N0 oral squamous cell cancers

OBJECTIVE

Oral cancer ranks in the top three of all cancers in India, accounting for over 30% of all cancers reported. Elective neck dissection (END) is the mainstay of treatment in early disease. Performing ENDs for node negative (N0) patients can result in significant morbidity with questionable benefit and impair the patients' quality of life. Sentinel Lymph Node Biopsy (SLNB), is an emerging investigation helping in risk stratification of patients with early oral cancer and node negative disease. SLNB is a simple, easy to perform investigation with a high sensitivity and plays a major role in avoiding neck dissection. Studies have compared SLNB-based neck dissection with END in early oral cancers, and also on survival benefit with prophylactic neck dissection at the time of primary surgery as compared to watchful waiting followed by therapeutic neck dissection for nodal relapse, in patients with clinical N0 (cN0) oral squamous cell carcinoma (OSCC) on literature search.

AIM

Our primary aim was to determine the effectiveness of lymphoscintigraphy in OSCC in clinically neck node negative (cN0) patients in comparison to gold standard END for nodal metastases identification and secondly to assess the utility of gamma probe in guiding SLNB in this group of patients.

MATERIALS AND METHODS

Fifty-eight patients (M:F = 42:16) with histologically confirmed OSCC of T1-3 stage with cN0 and planned for curative intent primary surgical treatment were divided into two arms. All patients underwent sentinel lymph node (SLN) imaging and biopsy. Arm 1 underwent nodal dissection based on SLNB positivity, while all patients in arm 2 had wide neck dissection irrespective of SLNB findings.

RESULTS

SLN was detected in all 58 patients, 96.4% patients showed SLN immediately postinjection. More than one SLN was found in 94.3% patients and 6.8% patients showed contralateral SLN also. Higher proportion of nodal metastasis were observed in tongue cancers than in remaining floor of mouth and buccal mucosa cancers (38% vs 12%, P< 0.01). We also found significant association between T size and nodal metastasis in our series. Sensitivity of SLNB was 88.23% with a specificity of 100%, both for SLN imaging and gamma probing localization reflecting the reliability of this technique. Serial step sectioning at 150 micrometre is recommended. SLNB showed positive nodes in 29.3 % patients with cN0 neck. We found that the association between the outcome in both arms was not statistically significant. On follow-up, three patients with T3N0 OSCC of arm 2 had nodal recurrence/lung metastases. One patient of arm 1 had nodal recurrence. Two patients expired within one year. As high as 73% patients (22 negative necks out of 30) had unwarranted neck dissection in arm 2.

CONCLUSION

SLNB is an effective method to circumvent unwarranted neck dissection in early OSCC and prevent complications. Gamma probing is a robust and easy tool to identify SLN in T1-3 stages with N0 necks clinically. A positive SLNB is found to be reliable in guiding neck dissection in this small study. Larger studies are warranted to establish its recommendation in routine clinical practice.

A Review of Controversial Issues in the Management of Head and Neck Cancer: A Swiss Multidisciplinary and Multi-Institutional Patterns of Care Study-Part 1 (Head and Neck Surgery)

Background: The Head and Neck Cancer Working Group of Swiss Group for Clinical Cancer Research (SAKK) has investigated the level of consensus (LOC) and discrepancy in everyday practice of diagnosis and treatment in head and neck cancer.

Materials and Methods: An online survey was iteratively generated with 10 Swiss university and teaching hospitals. LOC below 50% was defined as no agreement, while higher LOC were arbitrarily categorized as low (51–74%), moderate (75–84%), and high (≥85%).

Results: Any LOC was achieved in 62% of topics (n = 60). High, moderate and low LOC were found in 18, 20, and 23%, respectively. Regarding Head and Neck Surgery, Radiation Oncology, Medical Oncology, and biomarkers, LOC was achieved in 50, 57, 83, and 43%, respectively.

Conclusions: Consensus on clinical topics is rather low for surgeons and radiation oncologists. The questions discussed might highlight discrepancies, stimulate standardization of practice, and prioritize topics for future clinical research.

Surgical consensus guidelines on sentinel node biopsy (SNB) in patients with oral cancer

BACKGROUND

The eighth international symposium for sentinel node biopsy (SNB) in head and neck cancer was held in 2018. This consensus conference aimed to deliver current multidisciplinary guidelines. This document focuses on the surgical aspects of SNB for oral cancer.

METHOD

Invited expert faculty selected topics requiring guidelines. Topics were reviewed and evidence evaluated where available. Data were presented at the consensus meeting, with live debate from panels comprising expert, nonexpert, and patient representatives followed by voting to assess the level of support for proposed recommendations. Evidence review, debate, and voting results were all considered in constructing these guidelines.

RESULTS/CONCLUSION

A range of topics were considered, from patient selection to surgical technique and follow-up schedule. Consensus was not achieved in all areas, highlighting potential issues that would benefit from prospective studies. Nevertheless these guidelines represent an up-to-date pragmatic recommendation based on current evidence and expert opinion.

Multicenter Trial of [18F]fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Staging of Head and Neck Cancer and Negative Predictive Value and Surgical Impact in the N0 Neck: Results From ACRIN 6685

PURPOSE

The objective of this study was to determine the negative predictive value (NPV) of positron emission tomography (PET)/computed tomography (CT) for the clinically N0 neck on the basis of neck dissection.

METHODS

Participants with newly diagnosed, first-time, head and neck squamous cell carcinoma (HNSCC) and at least one clinically N0 neck side for which dissection was planned were included. A total of 287 participants were prospectively enrolled from 23 American College of Radiology Imaging Network-qualified institutions. PET/CT was compared with findings at neck dissection.

RESULTS

PET/CT scans and pathology findings were available for 270 N0 neck sides from 212 participants. For visual assessment, the NPV specific to the clinical-N0 sides was 0.868 (95% CI, 0.803 to 0.925). For dichotomized maximum standardized uptake value, the NPVs specific to the nodal basins were 0.940 (95% CI, 0.928 to 0.952) and 0.937 (95% CI, 0.925 to 0.949) at prespecified cutoffs of 2.5 and 3.5, respectively. The optimal cutoff maximum standardized uptake value was determined to be 1.8, with an NPV of 0.942 (95% CI, 0.930 to 0.953). The PET/CT-informed surgical treatment plan was changed in 51 of 237 participants (22%) compared with the PET/CT-blinded surgical plan. In 34 participants (14%), this led to planned dissection of additional nodal levels. In 12 participants (5%), this led to fewer planned dissected nodal levels. Negative PET/CT scans in N0 necks was true negative in 87% and false negative in 13%.

CONCLUSION

[¹⁸F]fluorodeoxyglucose-PET/CT has high NPV for the N0 neck in T2 to T4 HNSCC. The surgical treatment plans on the basis of PET/CT findings may be changed in approximately 22% of this group. These findings suggest that [¹⁸F]fluorodeoxyglucose-PET/CT may assist the clinician in deciding on the best therapy for the clinically N0 neck in HNSCC. Well-designed clinical trials should be performed to test the outcome of omitting neck dissection by using PET/CT.

Management of clinically N0 neck in oropharyngeal carcinoma

Purpose

Only a minority of patients with oropharyngeal squamous cell carcinoma (OPSCC) are diagnosed without regional metastasis (cN0). Studies focusing on the management of cN0 neck in OPSCC are scarce.

Methods

We reviewed all OPSCC patients treated at our institution with cN0 neck between 2000 and 2009. The treatment of neck and pattern of regional control was analyzed. Median follow-up was 5 years (range 3.5–9.0) or until death.

Results

Of the total 313 OPSCC patients treated within the period, 56 (18%) presented with cN0 neck. Of them, 51 (91%) received completed treatment with curative intent: 46 (90%) underwent elective neck treatment with either neck dissection ± (chemo)radiotherapy (C)RT (n = 23) or (C)RT (n = 23). A regional recurrence occurred in three patients (6%) and they all had a p16-negative soft palate midline primary tumor. Two of these patients had received RT on the neck.

Conclusions

While the overall prognosis of OPSCC is generally favorable and regional recurrences are infrequent, soft palate tumors, that are usually p16 negative, may form an subgroup warranting more aggressive treatment despite the clinical appearance of early stage.

Interventions for the treatment of oral and oropharyngeal cancers: surgical treatment

BACKGROUND

Surgery is an important part of the management of oral cavity cancer with regard to both the removal of the primary tumour and removal of lymph nodes in the neck. Surgery is less frequently used in oropharyngeal cancer. Surgery alone may be treatment for early-stage disease or surgery may be used in combination with radiotherapy, chemotherapy and immunotherapy/biotherapy. There is variation in the recommended timing and extent of surgery in the overall treatment regimens of people with these cancers. This is an update of a review originally published in 2007 and first updated in 2011.

OBJECTIVES

To determine which surgical treatment modalities for oral and oropharyngeal cancers result in increased overall survival, disease-free survival and locoregional control and reduced recurrence. To determine the implication of treatment modalities in terms of morbidity, quality of life, costs, hospital days of treatment, complications and harms.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 20 December 2017), the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 11), MEDLINE Ovid (1946 to 20 December 2017) and Embase Ovid (1980 to 20 December 2017). We searched the US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. There were no restrictions on the language or date of publication.

SELECTION CRITERIA

Randomised controlled trials where more than 50% of participants had primary tumours of the oral cavity or oropharynx, or where separate data could be extracted for these participants, and that compared two or more surgical treatment modalities, or surgery versus other treatment modalities.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently extracted data and assessed risk of bias. We contacted study authors for additional information as required. We collected adverse events data from included studies.

MAIN RESULTS

We identified five new trials in this update, bringing the total number of included trials to 12 (2300 participants; 2148 with cancers of the oral cavity). We assessed four trials at high risk of bias, and eight at unclear. None of the included trials compared different surgical approaches for the excision of the primary tumour. We grouped the trials into seven main comparisons.Future research may change the findings as there is only very low-certainty evidence available for all results.Five trials compared elective neck dissection (ND) with therapeutic (delayed) ND in participants with oral cavity cancer and clinically negative neck nodes, but differences in type of surgery and duration of follow-up made meta-analysis inappropriate in most cases. Four of these trials reported overall and disease-free survival. The meta-analyses of two trials found no evidence of either intervention leading to greater overall survival (hazard ratio (HR) 0.84, 95% confidence interval (CI) 0.41 to 1.72; 571 participants), or disease-free survival (HR 0.73, 95% CI 0.25 to 2.11; 571 participants), but one trial found a benefit for elective supraomohyoid ND compared to therapeutic ND in overall survival (RR 0.40, 95% CI 0.19 to 0.84; 67 participants) and disease-free survival (HR 0.32, 95% CI 0.12 to 0.84; 67 participants). Four individual trials assessed locoregional recurrence, but could not be meta-analysed; one trial favoured elective ND over therapeutic delayed ND, while the others were inconclusive.Two trials compared elective radical ND with elective selective ND, but we were unable to pool the data for two outcomes. Neither study found evidence of a difference in overall survival or disease-free survival. A single trial found no evidence of a difference in recurrence.One trial compared surgery plus radiotherapy with radiotherapy alone, but data were unreliable because the trial stopped early and there were multiple protocol violations.One trial comparing positron-emission tomography-computed tomography (PET-CT) following chemoradiotherapy (with ND only if no or incomplete response) versus planned ND (either before or after chemoradiotherapy), showed no evidence of a difference in mortality (HR 0.92, 95% CI 0.65 to 1.31; 564 participants). The trial did not provide usable data for the other outcomes.Three single trials compared: surgery plus adjunctive radiotherapy versus chemoradiotherapy; supraomohyoid ND versus modified radical ND; and super selective ND versus selective ND. There were no useable data from these trials.The reporting of adverse events was poor. Four trials measured adverse events. Only one of the trials reported quality of life as an outcome.

AUTHORS' CONCLUSIONS

Twelve randomised controlled trials evaluated ND surgery in people with oral cavity cancers; however, the evidence available for all comparisons and outcomes is very low certainty, therefore we cannot rely on the findings. The evidence is insufficient to draw conclusions about elective ND of clinically negative neck nodes at the time of removal of the primary tumour compared to therapeutic (delayed) ND. Two trials combined in meta-analysis suggested there is no difference between these interventions, while one trial (which evaluated elective supraomohyoid ND) found that it may be associated with increased overall and disease-free survival. One trial found elective ND reduced locoregional recurrence, while three were inconclusive. There is no evidence that radical ND increases overall or disease-free survival compared to more conservative ND surgery, or that there is a difference in mortality between PET-CT surveillance following chemoradiotherapy versus planned ND (before or after chemoradiotherapy). Reporting of adverse events in all trials was poor and it was not possible to compare the quality of life of people undergoing different surgical treatments.

Biomarkers: paving stones on the road towards the personalized precision medicine for oral squamous cell carcinoma

Traditional therapeutics have encountered a bottleneck caused by diagnosis delay and subjective and unreliable assessment. Biomarkers can overcome this bottleneck and guide us toward personalized precision medicine for oral squamous cell carcinoma. To achieve this, it is important to efficiently and accurately screen out specific biomarkers from among the huge number of molecules. Progress in omics-based high-throughput technology has laid a solid foundation for biomarker discovery. With credible and systemic biomarker models, more precise and personalized diagnosis and assessment would be achieved and patients would be more likely to be cured and have a higher quality of life. However, this is not straightforward owing to the complexity of molecules involved in tumorigenesis. In this context, there is a need to focus on tumor heterogeneity and homogeneity, which are discussed in detail. In this review, we aim to provide an understanding of biomarker discovery and application for precision medicine of oral squamous cell carcinoma, and have a strong belief that biomarker will pave the road toward future precision medicine.