Tumor control of cervical lymph node metastases of unknown primary origin: the impact of the radiotherapy target volume.

PURPOSE: Debate on the extent of treatment of neck metastasis of cancer of unknown primary tumors (CUPs) is still ongoing. In two Dutch tertiary referral centers, the post-surgical radiation target volume changed from the bilateral neck including the pharyngeal axis to the unilateral neck only, in the course of the last decade. This study aims to investigate the outcome of patients with CUP before and after de-escalation of post-surgical radiotherapy. METHODS: Data of two Dutch tertiary referral centers were merged. Disease-free survival (DFS), overall survival (OS), and regional control rate (RCR) of 80 patients diagnosed with CUP (squamous cell and undifferentiated carcinomas) between 1990 and 2009 were retrospectively analyzed. RESULTS: Thirty patients received bilateral neck and pharyngeal axis radiotherapy and 42 patients ipsilateral radiotherapy only. In another eight patients, the postsurgical radiation target volume was expanded to the contralateral neck or to the pharyngeal axis, due to suspicious lesions on imaging. The 5-year DFS, OS and RCR were 60%, 51.2%, and 80%, respectively, in the total patient population. RCR did not differ in patients treated with ipsilateral as compared to bilateral radiotherapy nor did 5-year OS and DFS. No tumors occurred in the pharyngeal axis. CONCLUSION: In this study, omitting elective treatment of the contralateral neck and pharyngeal axis did not lead to a decrease in locoregional control or survival rates when treating patients with CUP.

An expression profile for diagnosis of lymph node metastases from primary head and neck squamous cell carcinomas.

Metastasis is the process by which cancers spread to distinct sites in the body. It is the principal cause of death in individuals suffering from cancer. For some types of cancer, early detection of metastasis at lymph nodes close to the site of the primary tumor is pivotal for appropriate treatment. Because it can be difficult to detect lymph node metastases reliably, many individuals currently receive inappropriate treatment. We show here that DNA microarray gene-expression profiling can detect lymph node metastases for primary head and neck squamous cell carcinomas that arise in the oral cavity and oropharynx. The predictor, established with an 82-tumor training set, outperforms current clinical diagnosis when independently validated. The 102 predictor genes offer unique insights into the processes underlying metastasis. The results show that the metastatic state can be deciphered from the primary tumor gene-expression pattern and that treatment can be substantially improved.

Pathology-based validation of FDG PET segmentation tools for volume assessment of lymph node metastases from head and neck cancer.

PURPOSE: FDG PET is increasingly incorporated into radiation treatment planning of head and neck cancer. However, there are only limited data on the accuracy of radiotherapy target volume delineation by FDG PET. The purpose of this study was to validate FDG PET segmentation tools for volume assessment of lymph node metastases from head and neck cancer against the pathological method as the standard. METHODS: Twelve patients with head and neck cancer and 28 metastatic lymph nodes eligible for therapeutic neck dissection underwent preoperative FDG PET/CT. The metastatic lymph nodes were delineated on CT (NodeCT) and ten PET segmentation tools were used to assess FDG PET-based nodal volumes: interpreting FDG PET visually (PETVIS), applying an isocontour at a standardized uptake value (SUV) of 2.5 (PETSUV), two segmentation tools with a fixed threshold of 40% and 50%, and two adaptive threshold based methods. The latter four tools were applied with the primary tumour as reference and also with the lymph node itself as reference. Nodal volumes were compared with the true volume as determined by pathological examination. RESULTS: Both NodeCT and PETVIS showed good correlations with the pathological volume. PET segmentation tools using the metastatic node as reference all performed well but not better than PETVIS. The tools using the primary tumour as reference correlated poorly with pathology. PETSUV was unsatisfactory in 35% of the patients due to merging of the contours of adjacent nodes. CONCLUSION: FDG PET accurately estimates metastatic lymph node volume, but beyond the detection of lymph node metastases (staging), it has no added value over CT alone for the delineation of routine radiotherapy target volumes. If FDG PET is used in radiotherapy planning, treatment adaptation or response assessment, we recommend an automated segmentation method for purposes of reproducibility and interinstitutional comparison.

Novel diagnostic modalities for assessment of the clinically node-negative neck in oral squamous-cell carcinoma.

Oral squamous-cell carcinomas arise in mucosal linings of the oral cavity and frequently metastasise to regional lymph nodes in the neck. The presence of nodal metastases is a determinant of prognosis and clinical management. The neck is staged by palpation and imaging, but accuracy of these techniques to detect small metastases is low. In general, 30-40% of patients will have occult nodal disease and will develop clinically detectable lymph-node metastases when the neck is left untreated. The choice at present is either elective treatment or careful observation followed by treatment of the neck in patients who develop manifest metastases. These unsatisfying therapeutic options have been the subject of debate for decades. Recent developments in staging of the neck, including expression profiling and sentinel lymph-node biopsy, will allow more personalised management of the neck.

Interobserver variability of laryngeal mucosal premalignant lesions: a histopathological evaluation.

The objective of this study is to measure interobserver variability in the classification of laryngeal mucosal premalignant lesions by reassessing the histopathology of previously diagnosed cases and to determine the possible therapeutic consequences of disagreement among observers. Histopathological assessment of 110 laryngeal mucosal premalignant lesions was done by three pathologists. Each slide had to be classified according to the World Health Organization, Squamous Intraepithelial Neoplasia, and the Ljubljana Squamous Intraepithelial Lesions systems. After the independent assessment, a joint meeting took place. To assess the relation between histopathological grading and subsequent clinical management, we created a two- and a three-grade system besides one comprising all options. For all analyses, the SAS/STAT statistical software was used. The highest unweighted κ-values concerning the all-options system are observed for the Squamous Intraepithelial Neoplasia classification (0.28, 95% confidence interval 0.23-0.33), followed by the World Health Organization and Ljubljana classifications. For the two-grade system the Ljubljana classification shows the highest unweighted κ-values (0.50, 95%, 0.39-0.61), followed by the World Health Organization and Squamous Intraepithelial Neoplasia classifications. For the three-grade system, the unweighted κ-values are similar. The implementation of weighted κ-values led to higher scores within all three classification systems, although these did not exceed 0.55 (moderate agreement). Given the high level of consensus, simultaneous pathological assessment may be said to provide added value in comparison with independent assessment. In the current study, no clear tendency is observed in favor of any one classification system. The proposed three-grade system could be an improved histopathological tool because it is easier to correlate with clinical decision making and because it yields better unweighted κ-values and proportions of concordance than the all-options system. Furthermore, clinical management could benefit from assessment by more than one pathologist in suspected cases of dysplasia or carcinoma.

ß-TCP versus autologous bone for repair of alveolar clefts in a goat model.

OBJECTIVE: The aim of this study in goats was to test the hypothesis that a novel synthetic bone substitute beta tricalcium phosphate (ß-TCP) can work as well as autologous bone harvested from the iliac crest for grafting and repair of alveolar clefts. DESIGN: Ten adult Dutch milk goats (Capra hircus) were used in a split-mouth study design. MAIN OUTCOME MEASURES: Volumetric histologic assessment of new bone formation and radiographic measurement of orthodontic movement of teeth in a formerly created alveolar cleft. CONCLUSIONS: The synthetic bone substitute ß-TCP was shown to result in bone healing similar to that of iliac crest bone. The surgical, orthodontic, and histologic results now warrant the testing of ß-TCP in the human cleft situation.

Unilateral condylar hyperactivity: a histopathologic analysis of 47 patients.

PURPOSE: To perform a histopathologic analysis of condyles that were resected because of unilateral condylar hyperactivity and compare the results of the bone scan with the histopathologic findings. PATIENTS AND METHODS: A total of 47 resected condyles were histopathologically examined. In 29 cases, a single photon emission computed tomography (SPECT) bone scan was available. For all condylar specimens, a standardized histologic scoring system was used to assess the number of cartilage islands and the thickness of the cartilage layer. The SPECT scans were analyzed by calculating the difference in bone activity between the hyperactive and contralateral condyles. RESULTS: The number of cartilage islands was highly variable, ranging from almost absent in 37% of the patients to abundant in 35%. Furthermore, the relative thickness of the cartilage layer exhibited considerable variation, from less than one quarter of the total thickness of the condylar articular layer in 22% of the patients to one half of the total thickness in 35%. We found no significant relationship between the number of cartilage islands and bone activity using SPECT (P = .11) or between the relative thickness of the cartilage layer and bone activity using SPECT (P = .82). CONCLUSIONS: Unilateral condylar bone growth can occur without large numbers of cartilage islands and without abundant cartilage formation. The bone activity measured by bone scintigraphy was not related to the histologic results. The histopathologic findings of resected condyles in unilateral condylar hyperactivity cannot, therefore, be used as a reference standard. Nevertheless, histopathologic examination should always be performed to rule out other diseases.

Trends in incidence and mortality of thyroid carcinoma in The Netherlands between 1989 and 2003: correlation with thyroid fine-needle aspiration cytology and thyroid surgery.

A persistent increase in incidence of thyroid carcinoma (TC) has been reported worldwide. The aim of our study was to assess trends in incidence and mortality of TC in The Netherlands between 1989 and 2003 and to examine whether these trends correlate with changes in diagnostic practices such as changes in the number of fine needle aspiration biopsies (FNAB) and/or thyroid surgeries. Population-based incidence and mortality data were retrieved from the Netherlands Cancer Registry. Data concerning FNAB and thyroid surgeries were obtained through the nationwide network and registry of histo- and cytopathology in The Netherlands (PALGA). Overall, the incidence of TC remained unchanged. However, there was a slight increase in incidence of papillary TC of 2.1% per year (p < 0.001) particularly in stage I tumors, possibly, in part, because of a marked increase in use of FNAB. Appropriate iodine intake, reduced radiation exposure and a more conservative diagnostic approach toward asymptomatic thyroid nodules may explain why this increase is less pronounced compared to other countries. Incidence of other subtypes of TC decreased (follicular TC, 1.3% per year, p = 0.02 and anaplastic TC, 7.1% per year, p = 0.006) or remained unchanged (medullary TC). The number of FNABs per year progressively increased from 1,093 in 1989 to 4,123 in 2003, whereas the number of thyroid surgeries decreased from 3,419 in 1989 to 2,825 in 2003. The mortality rates decreased by 2.3% per year (p = 0.01). The decrease in incidence of both follicular and anaplastic TC is assumed to be largely responsible for the decrease in TC mortality rates.

Multiple robust signatures for detecting lymph node metastasis in head and neck cancer.

Genome-wide mRNA expression measurements can identify molecular signatures of cancer and are anticipated to improve patient management. Such expression profiles are currently being critically evaluated based on an apparent instability in gene composition and the limited overlap between signatures from different studies. We have recently identified a primary tumor signature for detection of lymph node metastasis in head and neck squamous cell carcinomas. Before starting a large multicenter prospective validation, we have thoroughly evaluated the composition of this signature. A multiple training approach was used for validating the original set of predictive genes. Based on different combinations of training samples, multiple signatures were assessed for predictive accuracy and gene composition. The initial set of predictive genes is a subset of a larger group of 825 genes with predictive power. Many of the predictive genes are interchangeable because of a similar expression pattern across the tumor samples. The head and neck metastasis signature has a more stable gene composition than previous predictors. Exclusion of the strongest predictive genes could be compensated by raising the number of genes included in the signature. Multiple accurate predictive signatures can be designed using various subsets of predictive genes. The absence of genes with strong predictive power can be compensated by including more genes with lower predictive power. Lack of overlap between predictive signatures from different studies with the same goal may be explained by the fact that there are more predictive genes than required to design an accurate predictor.

Maintenance of head and neck tumor gene expression profiles upon lymph node metastasis.

Spread of cancer and development of solid metastases at distant sites is the main cause of cancer-related deaths. To understand and treat metastases, it is important to determine at which stages the most pivotal steps for development of metastases occur. In head and neck squamous cell carcinoma (HNSCC), metastasis nearly always occurs first in local lymph nodes before development of distant metastasis. Here, we have investigated gene expression patterns in HNSCC lymph node metastases using DNA microarrays. Several types of analyses show that the gene expression patterns in lymph node metastases are most similar to the corresponding primary tumors from which they arose, as long as samples contain sufficient proportions of tumor cells. Strikingly, gene expression patterns of metastatic primary HNSCC are largely maintained upon spread to the lymph node. Only a single gene, metastasis-associated gene 1 (MTA1), was found to show consistently changed expression between a large number of matched primary tumor-lymph node metastasis pairs. The maintained expression pattern includes the predictive signature for HNSCC lymph node metastasis. These results underscore the importance of the primary tumor gene expression profile for development and treatment of metastasis. The findings also agree with the concept that disseminated cancer cells alter the surrounding tissue into a metastatic environment that resembles the primary tumor microenvironment.

Sinonasal cancer in The Netherlands: Follow-up of a population-based study 1989-2014 and incidence of occupation-related adenocarcinoma.

BACKGROUND: Long-term trends of sinonasal cancer in The Netherlands have been investigated with particular attention on adenocarcinoma for which wood or leather dust is a well-known risk factor. METHODS: All 4345 patients (1989-2014) registered in the Netherlands Cancer Registry were included. Standardized 3-year moving incidence rates per 1 000 000/person-years, and estimated annual percentage change (EAPC) were calculated. RESULTS: Forty-seven percent of the patients had squamous cell carcinoma (SCC), 12% had lymphoma, and 12% had adenocarcinoma. Sixty-one percent of the tumors were located in the nasal cavity, 22% in the maxillary, and 11% in the ethmoidal sinus. Male incidence decreased to 11.5/1 000 000 due to less SCC (EAPC -0.9%; 95% confidence interval [CI] -1.6 to 0.3) and adenocarcinoma (EAPC -4.3%; 95% CI -5.5 to 3.1). Female incidence increased to 7/1 000 000 (EAPC +2.0%; 95% CI +1.1 to +3.0) due to more SCC (EAPC +2.2%; 95% CI +1.0 to +3.5), whereas adenocarcinoma remained stable (0.6/1 000 000; EAPC +1.1%; 95% CI -6.0 to +8.7). Tumors of the nasal cavity increased in women (EAPC +3.3%; 95% CI +2.0 to 4.7). CONCLUSION: The decrease of male sinonasal adenocarcinoma may be the result of preventive measures combined with less workers in high-risk occupations.

Digital Video Laryngoscopy and Flexible Endoscopic Biopsies as an Alternative Diagnostic Workup in Laryngopharyngeal Cancer: A Prospective Clinical Study.

OBJECTIVES: An office-based workup strategy for patients with laryngopharyngeal lesions suspicious for carcinoma is analyzed. The feasibility of office-based transnasal flexible endoscopic biopsies under local anesthesia and the impact on the diagnostic workup are evaluated. METHODS: This study is a prospective analysis of patients with laryngeal, oropharyngeal, and hypopharyngeal lesions suspicious for carcinoma. One hundred eighty-eight participants were divided into 2 groups. The first group underwent an office-based biopsy procedure under local anesthesia using a flexible digital video laryngoscope with instrument channel (n = 53), and the second group underwent a biopsy procedure under general anesthesia using rigid laryngopharyngoscopy (n = 135). RESULTS: Office-based flexible endoscopic biopsies were tolerated well, and there were no complications. These biopsies were 92.5% successful in acquiring a definitive diagnosis. Costs were reduced. Diagnostic workup time and time until start of therapy were reduced to 2 days and 27 days, respectively. CONCLUSION: Office-based biopsy under local anesthesia using flexible digital video laryngoscopy is safe, cost-effective, and successful in providing a histopathological diagnosis. It reduces the diagnostic workup time significantly in patients with laryngeal, oropharyngeal, and hypopharyngeal cancer, while also reducing the necessity to subsequently perform a rigid laryngopharyngoscopy under general anesthesia.

18F-FLT PET does not discriminate between reactive and metastatic lymph nodes in primary head and neck cancer patients.

UNLABELLED: Repopulation of clonogenic tumor cells is inversely correlated with radiation treatment outcome in head and neck squamous cell carcinomas. A functional imaging tool to assess the proliferative activity of tumors could improve patient selection for treatment modifications and could be used for evaluation of early treatment response. The PET tracer 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) can image tumor cell proliferation before and during radiotherapy, and it may provide biologic tumor information useful in radiotherapy planning. In the present study, the value of (18)F-FLT PET in determining the lymph node status in squamous cell carcinoma of the head and neck was assessed, with pathology as the gold standard. METHODS: Ten patients with newly diagnosed stage II-IV squamous cell carcinoma of the head and neck underwent (18)F-FLT PET before surgical tumor resection with lymph node dissection. Emission (18)F-FLT PET and CT images of the head and neck were recorded and fused, and standardized uptake values (SUVs) were calculated. From all 18 (18)F-FLT PET-positive lymph node levels and from 8 (18)F-FLT PET-negative controls, paraffin-embedded lymph node sections were stained and analyzed for the endogenous proliferation marker Ki-67 and for the preoperatively administered proliferation marker iododeoxyuridine. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for (18)F-FLT PET. RESULTS: Primary tumor sites were oral cavity (n=7), larynx (n=2), and maxillary sinus (n=1). Nine of the 10 patients examined had (18)F-FLT PET-positive lymph nodes (SUV(mean): median, 1.2; range, 0.8-2.9), but only 3 of these patients had histologically proven metastases. All metastatic lymph nodes showed Ki-67 and iododeoxyuridine staining in tumor cells. In the remaining 7 patients, there was abundant Ki-67 and iododeoxyuridine staining of B-lymphocytes in germinal centers in PET-positive lymph nodes, explaining the high rate of false-positive findings. The sensitivity, specificity, positive predictive value, and negative predictive value of (18)F-FLT PET were 100%, 16.7%, 37.5%, and 100%, respectively. CONCLUSION: In head and neck cancer patients, (18)F-FLT PET showed uptake in metastatic as well as in nonmetastatic reactive lymph nodes, the latter due to reactive B-lymphocyte proliferation. Because of the low specificity, (18)F-FLT PET is not suitable for assessment of pretreatment lymph node status. This observation may also negatively influence the utility of (18)F-FLT PET for early treatment response evaluation of small metastatic nodes.

Human monoclonal antibodies as a tool for the detection of HLA class I allele-specific expression loss in head-and-neck squamous cell carcinoma and corresponding lymph node metastases.

Human leukocyte antigen (HLA) expression is important for the elimination of tumor cells by the immune system and immunotherapy. Activated T cells directed against tumor-associated antigens are fully capable of recognizing and eradicating neoplastic cells. Therefore, HLA expression loss is considered to be a main factor in tumor development. We report for the first time HLA-A and HLA-B allele-specific expression analysis by immunohistochemical staining of fresh tumor tissue and 9 lymph node metastases of 15 patients with head-and-neck squamous cell carcinoma. Heterogeneous HLA expression and HLA expression loss was detected in 13 tumor patients. Approximately 50% of the tumors had allele-specific expression loss, which would have remained undetected using HLA monomorphic and locus-specific antibodies. In the majority of the patients with head-and-neck squamous cell carcinoma, HLA allele-specific expression loss differed between primary lesions and metastases. This is important for the efficacy of immunotherapy in these patients. It can be concluded that it is crucial to study HLA expression at the allele-specific level of primary lesions and metastases. It increases and refines our knowledge of HLA expression loss in tumorgenesis, which will improve the development of specific immunotherapy.

Spontaneous oesophageal rupture: a diagnostic challenge in resource-limited setting.

Spontaneous oesophageal rupture after swallowing a bolus of food is a very rare condition. In resource-limited settings, it is very challenging to diagnose this condition especially when its presentation is atypical. Its prognosis is very poor when diagnosis is delayed due to risk of mediastinitis. We report a case of 37-year-old man who was admitted to our hospital complaining of sudden onset of chest tightness and pain after a meal 8 h prior to admission. Urgent chest radiograph revealed right hydropneumothorax with collapsed lung. Water-seal drainage was established gushing 1200 ml of food materials. Definitive diagnosis of oesophageal rupture was reached after post-mortem.

The role of systemic therapy in the management of sinonasal cancer: A critical review.

PURPOSE: Due to the rarity and the variety of histological types of sinonasal cancers, there is a paucity of data regarding strategy for their optimal treatment. Generally, outcomes of advanced and higher grade tumors remain unsatisfactory, despite the employment of sophisticated surgical approaches, technical advances in radiation techniques and the use of heavy ion particles. In this context, we critically evaluated the role of systemic therapy as part of a multidisciplinary approach to locally advanced disease. RESULTS: Induction chemotherapy has shown encouraging activity and could have a role in the multimodal treatment of patients with advanced sinonasal tumors. For epithelial tumors, the most frequently employed chemotherapy is cisplatin, in combination with either 5-fluorouracil, taxane, ifosfamide, or vincristine. Only limited experiences with concurrent chemoradiation exist with sinonasal cancer. The role of systemic treatment for each histological type (intestinal-type adenocarcinoma, sinonasal undifferentiated carcinoma, sinonasal neuroendocrine carcinoma, olfactory neuroblastoma, sinonasal primary mucosal melanoma, sarcoma) is discussed. CONCLUSIONS: The treatment of SNC requires a multimodal approach. Employment of systemic therapy for locally advanced disease could result in better outcomes, and optimize the therapeutic armamentarium. Further studies are needed to precisely define the role of systemic therapy and identify the optimal sequencing for its administration in relation to local therapies.

High level of aneuploidy of chromosome 6 by FISH analysis of head and neck squamous cell carcinoma: limited applicability of LOH analysis to define HLA loss.

Human Leukocyte Antigen (HLA) class I molecules are essential for tumor cell recognition by cytotoxic T cells of the adaptive immune system. Loss of HLA expression provides tumor cells with an escape mechanism to evade the immune system and thus immune therapy. Therefore, HLA loss, and in particular loss of heterozygosity (LOH), is frequently studied in tumors using microsatellite marker LOH analysis. Because LOH analysis detects any allelic imbalance and not just allelic loss, we evaluated the LOH analysis in nine head and neck squamous cell carcinomas (HNSCCs) using fluorescence in situ hybridization (FISH). These tumors were selected from 53 HNSCCs based upon the HLA class I immunohistochemical staining and LOH data. FISH analysis showed that only two tumors with LOH and one without LOH indeed had loss and a normal chromosome 6 copy number, respectively. Strikingly, for the remaining six tumors, LOH analysis did not reflect the genome HLA copy number. We demonstrated that LOH analysis cannot distinguish loss from gain and that the HLA region is not homogeneously affected within a tumor. Tumor heterogeneity and complex aneuploidy in tumors hinder a straightforward interpretation of microsatellite marker analysis. For immune therapy strategies in cancer patients, knowledge of the HLA expression on tumor cells is essential, to which LOH analysis has a limited contribution.

Aggressive fibromatosis in the head and neck region: Benign tumor with often mutilating effects.

BACKGROUND: Aggressive fibromatosis (AF) or desmoid tumor of the head and neck region is a rare, usually unresectable, benign soft tissue tumor with locally aggressive behavior. METHODS AND RESULTS: A 31-year-old woman presented with a progressive trismus, a swelling in the retromandibular area, as well as loss of sensibility of the maxillary and mandibular branch of the trigeminal nerve. MRI of the head and neck revealed an infiltrative mass involving the masticator, parapharyngeal, and prevertebral and paravertebral space on the left with intracranial extension through the orbital fissure. After the fifth biopsy, 15 months after presentation, the diagnosis of AF was made. The tumor was unresectable, so intensity-modulated radiotherapy was given with curative intent using a total dose of 60 Gy in 30 fractions of 2 Gy. After 16 months, she showed progressive disease, for which tamoxifen 40 mg twice daily was started with a good response for 2 years. After that, she started with sorafinib, on which she has stable disease now. CONCLUSION: The often long delay in proper diagnosis and the treatment challenges of a desmoid tumor are illustrated in this case. Furthermore, this article reviews the literature concerning AF, especially of the head and neck region.

Validation of a gene expression signature for assessment of lymph node metastasis in oral squamous cell carcinoma.

PURPOSE: Current assessment of lymph node metastasis in patients with head and neck squamous cell carcinoma is not accurate enough to prevent overtreatment. The aim of this study was validation of a gene expression signature for distinguishing metastasizing (N+) from nonmetastasizing (N0) squamous cell carcinoma of the oral cavity (OSCC) and oropharynx (OPSCC) in a large multicenter cohort, using a diagnostic DNA microarray in a Clinical Laboratory Improvement Amendments/International Organization for Standardization-approved laboratory. METHODS: A multigene signature, previously reported as predictive for the presence of lymph node metastases in OSCC and OPSCC, was first re-evaluated and trained on 94 samples using generic, whole-genome, DNA microarrays. Signature genes were then transferred to a dedicated diagnostic microarray using the same technology platform. Additional samples (n=222) were collected from all head and neck oncologic centers in the Netherlands and analyzed with the diagnostic microarray. Human papillomavirus status was determined by real-time quantitative polymerase chain reaction. RESULTS: The negative predictive value (NPV) of the diagnostic signature on the entire validation cohort (n=222) was 72%. The signature performed well on the most relevant subset of early-stage (cT1-T2N0) OSCC (n=101), with an NPV of 89%. CONCLUSION: Combining current clinical assessment with the expression signature would decrease the rate of undetected nodal metastases from 28% to 11% in early-stage OSCC. This should be sufficient to enable clinicians to refrain from elective neck treatment. A new clinical decision model that incorporates the expression signature is therefore proposed for testing in a prospective study, which could substantially improve treatment for this group of patients.