18 F-FDG PET/CT vs. human papillomavirus, p16 and Epstein-Barr virus detection in cervical metastatic lymph nodes for identifying primary tumors

Challenges and Considerations in Diagnosing and Managing p16+-Related Oropharyngeal Squamous Cell Carcinoma (OPSCC) with Neck Metastasis: Implications of p16 Positivity, Tobacco Exposure, and De-Escalation Strategies

BACKGROUND

The incidence of patients showing neck metastasis and no obvious primary tumor at the initial diagnostic evaluation or neck cancer of unknown primary (NCUP) is rising. It is estimated that a relevant part of these tumors arises in the tonsillar crypts or base of the tongue and are p16+-related. However, today, the detection rate of the primary tumor is suboptimal. Identifying the primary tumor and its biomolecular characterization is essential since it influences the treatment administered, possibly reducing radiation fields and providing de-escalation to primary surgical management. However, p16 IHC (immunohistochemistry) might not be sufficient to diagnose HPV-related OPSCC. The other subset of patients discussed are the HPV-positive patients who have a history of tobacco exposure and/or p53 mutations. Possible factors that could negatively influence the outcomes of these patients are investigated and discussed below. So, this paper aims to analyze the diagnostic, bio-molecular, clinico-radiological, morphological, prognostic and therapeutical aspects of p16-positive OPSCC, highlighting the possible bias that can occur during the diagnostic and prognostic process.

METHODS

A narrative review was conducted to investigate the biases in the diagnostic and therapeutic process of two groups of patients: those who are p16-positive but HPV-negative patients, and those who are p16-positive and HPV-positive with exposure to traditional risk factors and/or p53 mutations. The keywords used for the literature research included the following: NCUP, OPSCC, p16IHC, HPV testing, p16 positive HPV negative OPSCC, p16 positive HPV positive OPSCC, tonsillectomy, tobacco exposure, p53 mutations, cystic neck metastasis, extranodal extension (ENE), radiotherapy, de-escalation and neck neck dissection.

RESULTS

HPV-positive OPSCC has specific clinico-radiological features. Bilateral tonsillectomy should be considered for the identification of the primary tumor. P16 IHC alone is not sufficient for diagnosing HPV-related OPSCC; additional detection methods are required. The role of tobacco exposure and p53 mutations should be investigated especially in cases of HPV-positive tumors. Extranodal extension (ENE) must be taken into consideration in the prognostic staging of HPV-positive tumors. Surgical primary treatment involving neck dissection (ND) and bilateral tonsillectomy followed by adjuvant radiation may represent the most appropriate approach for N3 cases. Diagnosis, prognosis and therapeutical implications must be addressed considering clinical, biomolecular and morphological aspects. At least today, the numerous biases that are still present influencing the diagnostic and prognostic process do not permit considering de-escalation protocols.

CONCLUSIONS

A precise and accurate diagnosis is required in order to adequately stage and manage p16+ OPSCC, particularly with neck metastasis. The role of tobacco exposure and/or p53 mutations must be considered not only in p16+ OPSCC but especially in HPV-positive OPSCC. Until a more accurate diagnosis is possible, ENE should be considered even in p16+HPV+ OPSCC. Primary surgery with unilateral ND and bilateral tonsillectomy might be the treatment of choice given the numerous diagnostic and prognostic pitfalls. Therefore, it is inappropriate and risky to propose de-escalation protocols in routine clinical practice due to the risk of undertreatment.

Head and neck squamous cell carcinomas of unknown primary: Can ancillary studies help identify more primary tumor sites?

A subset of head and neck squamous cell carcinomas present solely as metastatic disease in the neck and are of unknown primary origin (SCCUP). Most primary tumors will ultimately be identified, usually in the oropharynx. In a minority of cases, the primary site remains elusive. Here, we examine the role of ancillary testing, including mutational signature analysis (MSA), to help identify likely primary sites in such cases. Twenty-two cases of SCCUP in the neck, collected over a 10-year period, were classified by morphology and viral status; including human papillomavirus (HPV) testing by p16 immunohistochemistry (IHC) and RT-qPCR, as well as Epstein-Barr virus (EBV) testing by EBER-ISH. CD5 and c-KIT (CD117) IHC was done to evaluate for possible thymic origin in all virus-negative cases. Whole exome sequencing, followed by MSA, was used to identify UV signature mutations indicative of cutaneous origin. HPV was identified in 12 of 22 tumors (54.5%), favoring an oropharyngeal origin, and closely associated with nonkeratinizing tumor morphology (Fisher's exact test; p = 0.0002). One tumor with indeterminant morphology had discordant HPV and p16 status (p16+/HPV-). All tumors were EBV-negative. Diffuse expression of CD5 and c-KIT was identified in 1 of 10 virus-negative SCCUPs (10%), suggesting a possible ectopic thymic origin rather than a metastasis. A UV mutational signature, indicating cutaneous origin, was identified in 1 of 10 (10%) virus-negative SCCUPs. A cutaneous auricular primary emerged 3 months after treatment in this patient. Primary tumors became clinically apparent in 2 others (1 hypopharynx, 1 hypopharynx/larynx). Thus, after follow-up, 6 tumors remained unclassifiable as to the possible site of origin (27%). Most SCCUPs of the neck in our series were HPV-associated and thus likely of oropharyngeal origin. UV signature mutation analysis and additional IHC for CD5 and c-KIT for possible thymic origin may aid in further classifying virus-negative unknown primaries. Close clinical inspection of hypopharyngeal mucosa may also be helpful, as a subset of primary tumors later emerged at this site.

The radiological unknown primary of the head and neck: Recommendations for imaging strategies based on a systematic review

OBJECTIVES

To develop recommendations for the radiological investigation of clinically occult primary cancer in the head and neck.

DESIGN AND SETTING

In accordance with PRISMA guidelines, a search was performed on Medline, Embase and Cochrane library databases to investigate the efficacy of ultrasound guided Fine Needle Aspiration (US FNAC), contrast enhanced CT (CECT), magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose PET-CT (18F-FDG PET-CT) in the investigation of head and neck squamous cell carcinoma from an unknown primary (HNSCCUP) presenting with a metastatic cervical lymph node (s). The Quality Assessment of Diagnostic Accuracy Studies Version 2 tool and SIGN 50 guidelines were used to assess the risk of bias and quality of the included studies.

PARTICIPANTS

Adult patients presenting with metastatic cervical lymph nodes from a HNSCCUP.

MAIN OUTCOME MEASURES

Utility of different imaging modalities (PET-CT, MRI, CE CT and US FNAC in the management of HNSCCUP).

RESULTS

Twenty-eight studies met inclusion criteria; these were meta-analyses, systematic reviews, prospective and retrospective studies.

CONCLUSIONS

The optimal imaging strategy involves utilisation of various imaging modalities. US FNAC can provide the initial diagnosis and HPV status of the occult primary tumour. CECT and MRI detect up to 44% of occult tumours and guide management. FDG PET-CT is the most sensitive imaging modality for the detection of CUP and should be performed prior to panendoscopy.

Challenges of Pharyngeal Cancer Screening in Lower-Income Countries during Economic and Social Transitions: A Population-Based Analysis

Background and Objectives: The rate of head and neck cancer (HNC) is expected to increase by 30% by 2030. However, there are many similarities between the symptomatology of a benign and a malign diagnosis; thus, a protocol for conducting a full head and neck examination is of high importance since the absence of adenopathy does not exclude a malignant diagnosis and also a favorable prognosis. Material and methods: The current study presents a retrospective study on 515 adult patients who underwent a biopsy for possible head and neck tumor pathology. Results: The patients identified with cancer were older than the rest of the group, with a higher developing trend in men than in women. However, the top 10 symptomatology patterns were identical in the malign and benign groups, meaning that new HNC may be missed due to the common symptomatology between benign and malign outcomes. Conclusions: The importance of a full ear, nose, and throat (ENT) examination may be of significant relevance for a proper diagnosis that can improve the overall prognosis of a patient with cancer. The absence of routine screening tests and screening guidelines for oral and pharyngeal cancers represents a significant barrier to secondary HNC prevention.

A Systematic Review of Diagnostic and Prognostic Biomarkers for Head and Neck Cancer of Unknown Primary: An Unmet Clinical Need

Head and neck cancer of unknown primary (HNCUP) is defined as cervical lymph node metastases without a detectable primary tumor. The management of these patients presents a challenge to clinicians since guidelines in the diagnosis and treatment of HNCUP remain controversial. An accurate diagnostic workup is fundamental for the search for the hidden primary tumor to allow the best adequate treatment strategy. The purpose of this systematic review is to present the currently available data about the diagnostic and prognostic molecular biomarkers for HNCUP. Systematic research in an electronic database was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol and identified 704 articles, of which 23 studies were selected and included in the analysis. Fourteen studies investigated HNCUP diagnostic biomarkers and focused on the human papilloma virus (HPV) and the Epstein-Barr virus (EBV) due to the strong associations with oropharyngeal cancer and nasopharyngeal cancer, respectively. HPV status was shown to possess prognostic value, correlating with longer disease-free survival and overall survival. HPV and EBV are the only available HNCUP biomarkers, and they are already used in clinical practice. A better characterization of the molecular profiling and the development of tissue-of-origin classifiers are necessary to improve the diagnosis, staging, and therapeutic management of patients with HNCUP.

Performance of oral HPV DNA, oral HPV mRNA and circulating tumor HPV DNA in the detection of HPV-related oropharyngeal cancer and cancer of unknown primary

A biomarker that is useful for the detection of human papillomavirus (HPV)‐related oropharyngeal cancer (OPC) and cancer of unknown primary (CUP) is indispensable. We evaluated the diagnostic performance of HPV DNA and mRNA in oral gargle samples and circulating tumor HPV16 DNA (ctHPV16DNA) in blood samples. Oral HPV DNA and mRNA were analyzed using commercially available HPV assays of the GENOSEARCH HPV31 and Aptima, respectively. ctHPV16DNA was analyzed using in‐house droplet digital polymerase chain reaction. Seventy‐four patients with OPC and eight patients with CUP were included. The sensitivity and specificity of oral HPV DNA, oral HPV mRNA, and ctHPV16DNA were 82% (95% confidence interval [CI] = 66‐92) and 100% (95% CI = 88‐100), 85% (95% CI = 69‐94) and 94% (95% CI = 73‐100), and 93% (95% CI = 81‐99) and 97% (95% CI = 84‐100), respectively, for HPV16‐related OPC, while those were 20% (95% CI = 1‐72) and 100% (95% CI = 3‐100), 0% (95% CI = 0‐52) and 100% (95% CI = 3‐100), and 100% (95% CI = 54‐100) and 100% (95% CI = 16‐100), respectively, for HPV16‐related CUP. The sensitivity of ctHPV16DNA for HPV16‐related OPC was higher than that of oral biomarkers, though the difference was not statistically significant. ctHPV16DNA remarkably correlated with the anatomic extent of disease, total metabolic tumor volume and HPV16 copy number per tumor genome in patients with HPV16‐related OPC/CUP, whereas oral biomarkers did not. In conclusion, ctHPV16DNA is a potentially promising biomarker for HPV16‐related OPC, while further studies are required for HPV16‐related CUP.

What's new?

A minimally‐invasive biomarker that allows the detection of human papillomavirus (HPV)‐related oropharyngeal cancer and cancer of unknown primary is indispensable. Here, the authors show that circulating tumour HPV DNA (ctHPVDNA) correlates with the tumour burden and HPV copy number per tumour genome in HPV‐related oropharyngeal cancer and cancer of unknown primary. Neither oral HPV DNA nor mRNA exhibits such a correlation. ctHPVDNA outperforms oral HPV DNA and mRNA in detecting HPV‐related oropharyngeal cancer and in distinguishing HPV‐related cancer of unknown primary from HPV‐unrelated cancers. ctHPVDNA emerges as a potentially useful biomarker for HPV‐related oropharyngeal cancer and cancer of unknown primary.

PET Imaging for Head and Neck Cancers

Head and neck cancers are commonly encountered cancers in clinical practice in the United States. Fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET/CT has been clinically applied in staging, occult primary tumor detection, treatment planning, response assessment, follow-up, recurrent disease detection, and prognosis prediction in these patients. Alternative PET tracers remain investigational and can provide additional valuable information such as radioresistant tumor hypoxia. The recent introduction of ¹⁸F-FDG PET/MR imaging has provided the advantage of combining the superior soft tissue resolution of MR imaging with the functional information provided by ¹⁸F-FDG PET. This article is a concise review of recent advances in PET imaging in head and neck cancer.

The prognostic role of radiotherapy and radiotherapy target in cervical lymph node metastatic squamous cell carcinoma with unknown primary: a retrospective study

OBJECTIVES

Aim to analyze the effect of radiotherapy for cervical lymph node metastatic carcinoma with unknown primary (CCUP) and compare the survival benefits between Comprehensive radiotherapy and Involved Field radiotherapy.

MATERIALS AND METHODS

The patients diagnosed with CCUP between 2009 and 2019 in our institution were analyzed retrospectively. The categorical variables were tested by χ² test. Kaplan-Meier method was used for survival analysis. Log-rank test and Cox proportional hazards regression were performed with overall survival (OS) and disease-free survival (DFS) as the primary outcome variables.

RESULTS

Of 139 patients, 64.7% (90/139) of them received radiotherapy. Of the 90 patients who underwent radiotherapy, 45.6% (41/90) received Involved Field radiotherapy and the rest 49 patients received Comprehensive radiotherapy. The median follow-up of 139 patients is 69 months. The 1-year, 3-year, and 5-year OS rates are 87%, 62%, and 39%, respectively, and the DFS rates are 73%, 45%, and 29%, respectively. Multivariate analysis of 139 patients with CCUP shows that differentiation grade, N stage, radiotherapy, and the length of the largest lymph node (D_maxLN) are the independent prognostic factors for both OS and DFS. Subgroup analysis of 90 patients who received radiotherapy shows that the Comprehensive radiotherapy group has a better OS (P < 0.001) and DFS (P < 0.001) compared with Involved Field radiotherapy.

CONCLUSION

Radiotherapy is the independent prognostic factor for CCUP. Comprehensive radiotherapy may be superior to Involved Field radiotherapy in survival benefits.

Diagnostic performance of 18F-FDG PET/CT for the detection of occult primary tumors in squamous cell carcinoma of unknown primary in the head and neck: a single-center retrospective study

OBJECTIVE

To investigate the diagnostic performance of 18F-FDG PET/computed tomography (CT) for the detection of occult primary tumors in patients with squamous cell carcinoma of unknown primary (SCCUP) in the head and neck.

PATIENTS

From March 2016 to January 2020, 37 patients diagnosed as SCCUP before PET/CT were retrospectively reviewed. The diagnosis of SCCUP was made when an overt primary tumor location could not be found for histologically proven squamous cell cervical lymphadenopathy after a complete diagnostic workup which includes full medical history, physical examinations, flexible rhinolaryngoscopy and CT or MRI. The PET/CT images were visually assessed by two nuclear medicine radiologists. Histopathological investigations after the PET scan served as the reference standard.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PET/CT for SCCUP were 71.4, 43.8, 62.5, 53.9 and 59.5%, respectively. PET/CT allowed identification of previously undetected lesions in 40.5% of the SCCUP patients. A total of 24 PET/CT scans indicated a positive result. Among them, nine were categorized into false-positive because of negative results from subsequent targeted and random biopsies. There were 13 PET/CT scans with a negative result, six of which, however, were revealed to have a primary site by subsequent random biopsies.

CONCLUSION

18F-FDG PET/CT was shown to be useful in detecting a primary tumor for SCCUP, but had limitations in terms of both false-positive cases and false-negative cases. Therefore, histopathological investigations such as targeted and random biopsy should be viewed as necessary practice irrespective of PET/CT results.

Carcinoma of Unknown Primary and the 8th Edition TNM Classification for Head and Neck Cancer

OBJECTIVE

In the 8th Edition TNM Classification for Head and Neck Cancer, the classification for carcinoma of unknown primary (CUP) changed in addition to oropharyngeal carcinomas. The current classification considers extranodal extension (ENE), determination of p16 (surrogate marker for human papillomavirus), and detection of Epstein-Barr virus (EBV). The aim of this study was to investigate the influence of the new classification on the prognosis of p16-positive and p16-negative CUP and the impact of EBV proof.

METHODS

Clinical and pathological data from patients with CUP of the head and neck between 2009 and 2018 were evaluated. The 7th (UICC7) and 8th (UICC8) edition of the Union for International Cancer Control staging system were applied and compared.

RESULTS

There were 97 patients treated, 26.8% women and 73.2% men. The average age at initial diagnosis was 64.6 years. Of which, 58.8% had a documented history of smoking, 37.1% were positive for p16, 4.1% were positive for EBV, and 66% had ENE. Most of the patients were at stage III/IVa (78.4% according to UICC7). According to UICC8, p16+ patients were mainly at stage I (86.1%), and p16- at stage IVb (56.1%). P16 status (P = .002), ENE (P = .001), nodal category (TNM7, P < .001), UICC stage (TNM7, P < .001) and UICC stage (TNM8, P < .001) had a significant impact on survival in the univariate analysis. The 8th TNM classification resulted in a downstaging of p16-positive CUP syndromes and an upstaging of p16-negative syndromes.

CONCLUSION

The 8th TNM classification shows the lower UICC stage in p16-positive CUP syndromes. The prognostic significance for survival has improved from the 7th to the 8th TNM classification. LEVEL OF EVIDENCE USING THE 2011 OCEBM: Level 3. Laryngoscope, 131:E2534-E2542, 2021.

[18F]PARPi Imaging Is Not Affected by HPV Status In Vitro

Background

Human papillomavirus- (HPV-) associated oropharyngeal squamous cell carcinomas (OPSCCs) are clinically and pathologically distinct from HPV-negative tumors. Here, we explore whether HPV affects functional biomarkers, including γH2AX, RAD51, and PARP1. Moreover, the role of [18F]PARPi as a broadly applicable imaging tool for head and neck carcinomas is investigated.

Methods

HPV-positive and HPV-negative cell lines were used to evaluate the γH2AX, RAD51, and PARP1 expression with immunoblotting and immunofluorescence. Effects of external beam ionizing radiation were investigated in vitro, and survival was investigated via colony-formation assay. [18F]PARPi uptake experiments were performed on HPV-negative and HPV-positive cell lines to quantify PARP1 expression. PARP1 IHC and γH2AX foci were quantified using patient-derived oropharyngeal tumor specimens.

Results

Differences in DNA repair were detected, showing higher RAD51 and γH2AX expression in HPV-positive cell lines. Clonogenic assays confirm HPV-positive cell lines to be significantly more radiosensitive. PARP1 expression levels were similar, irrespective of HPV status. Consequently, [18F]PARPi uptake assays demonstrated that this tracer is internalized in cell lines independently from their HPV status.

Conclusion

The HPV status, often used clinically to stratify patients, did not affect PARP1 levels, suggesting that PARP imaging can be performed in both HPV-positive and HPV-negative patients. This study confirms that the PET imaging agent [18F]PARPi could serve as a general clinical tool for oropharyngeal cancer patients.

Diagnosis and Management of Squamous Cell Carcinoma of Unknown Primary in the Head and Neck: ASCO Guideline

PURPOSE

To provide evidence-based recommendations to practicing physicians and other health care providers on the diagnosis and management of squamous cell carcinoma of unknown primary in the head and neck (SCCUP).

METHODS

The American Society of Clinical Oncology convened an Expert Panel of medical oncology, surgery, radiation oncology, radiology, pathology, and advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 2008 through 2019. Outcomes of interest included survival, local and regional disease control, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 100 relevant studies to inform the evidence base for this guideline. Four main clinical questions were addressed, which included subquestions on preoperative evaluations, surgical diagnostic and therapeutic procedures, appropriate pathology techniques, and adjuvant therapy.

RECOMMENDATIONS

Evidence-based recommendations were developed to address preoperative evaluation for patients with a neck mass, surgical diagnostic and therapeutic procedures, appropriate treatment options in unilateral versus bilateral SCCUP.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

Update 2018: 18F-FDG PET/CT and PET/MRI in Head and Neck Cancer

There are recent advances, namely, a standardized method for reporting therapy response (Hopkins criteria), a multicenter prospective cohort study with excellent negative predictive value of F-FDG PET/CT for N0 clinical neck, a phase III multicenter randomized controlled study establishing the value of a negative posttherapy F-FDG PET/CT for patient management, a phase II randomized controlled study demonstrating radiation dose reduction strategies for human papilloma virus-related disease, and Food and Drug Administration approval of nivolumab for treatment of recurrent head and neck squamous cell carcinoma.

GEORCC recommendations on target volumes in radiotherapy for Head Neck Cancer of Unkown Primary

Head Neck Cancer of Unknown Primary (HNCUP) is a rare condition, representing approximately 5-10% of all head neck cancers. Radiotherapy, adjuvant or radical, is usually employed in the treatment of those patients. To date, no specific guidelines for the optimal definition of the target volume to be irradiated have been published. In recent years, there have been advances in the knowledge of the molecular biology of HNCUP, its diagnostic imaging and the implementation of sophisticated radiotherapy techniques with enhanced precision in target localization and treatment delivery. These progresses have provided valuable information about the natural history of HNCUP that will allow for establishment of the best treatment for each patient, including standardized, consistent and reproducible target volumes definitions. Several recommendations regarding how to choose volumes when contouring HNCUP in clinical practice are reported, in order to achieve a high rate of loco-regional control while avoiding unnecessary toxicity.

Effectiveness of primary surgery versus primary radiotherapy on unknown primary head and neck squamous cell carcinoma: a systematic review protocol

REVIEW QUESTION

The review question is: what is the effectiveness of primary surgery versus primary radiotherapy on disease-free survival and quality of life in adults with an unknown primary, head and neck squamous cell carcinoma?

[Advances in the management of cervical lymphadenopathies of unknown primary: advances in diagnostic imaging and surgical modalities and new international staging system]

INTRODUCTION

Cervical lymphadenopathies of unknown primary represent 3 % of head and neck cancers. Their diagnostic work up has largely changed in recent years. This review provides an update on diagnostic developments and their potential therapeutic impact.

MATERIALS AND METHODS

This is a systematic review of the literature.

RESULTS

In recent years, changes in epidemiology-based prognostic factors such as human papilloma virus (HPV) cancers, advances in imaging and minimally invasive surgery have been integrated in the management of cervical lymphadenopathies of unknown primary. In particular, systematic use of PET scanner and increasing practice of robotic or laser surgery have contributed to increasing detection rate of primary cancers. These allow more adapted and personalized treatments. The impact of changes in the eighth TNM staging system is discussed.

CONCLUSION

The management of cervical lymphadenopathies of unknown primary cancer has changed significantly in the last 10 years. On the other hand, practice changes will have to be assessed.

Correlation between HPV status at T and N sites of oropharyngeal squamous cell carcinomas

OBJECTIVES

Human papilloma virus (HPV) is known to be associated with oropharyngeal squamous cell carcinomas (OPSCC) and may potentially play a vital role in tumor metastasis. The purpose of this study was to correlate HPV status of cervical lymph node metastases with their respective primary OPSCC tumor.

METHODS

Formalin-fixed, paraffin-embedded (FFPE) tissue samples obtained from 34 patients with cervical lymph node metastases were analyzed with HPV 16 DNA polymerase chain reaction (PCR), p16 immunohistochemistry and HPV typing. The results were correlated with the HPV status and type found in the primary tumors of OPSCC.

RESULTS

Comparing HPV DNA status with p16 we found that 21 primary tumors and lymph node metastases were HPV positive (61.8%) and seven primary tumors and lymph node metastases were HPV negative (20.6%). Six patient samples differed when correlating the primary tumor and lymph node metastasis (17.6%).

CONCLUSIONS

In this study, HPV status in OPSCCs and their cervical lymph node metastases correlated in the vast majority of cases. However, HPV detection methods may have certain limitations resulting in varying degree of non-correlation. This should be taken into account when stratifying treatment in regard to HPV status.

Computed Tomography Versus Magnetic Resonance in Head and Neck Cancer: When to Use What and Image Optimization Strategies

This article provides a practical overview of head and neck cancers, outlining an approach to evaluating these lesions and optimizing imaging strategies. Recognition of key anatomic landmarks as suggested by American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) criteria is emphasized. Further, the recently updated eighth edition of the AJCC staging manual has introduced some modifications that influence the TNM staging. These modifications are discussed throughout the article to provide an updated review on head and neck cancer.