Management of neck metastases of unknown primary origin united in two European centers

Radiotherapy to the neck after neck dissection for head and neck squamous cell carcinoma from an unknown primary: A narrative review

PURPOSE

To conduct a comprehensive narrative review of the evidence for radiotherapy target volumes to the neck, after neck dissection, for head and neck squamous cell carcinoma from an unknown primary (HNSCCUP). Inclusion or exclusion of mucosal irradiation is not the focus of interest for this review article.

MATERIALS AND METHODS

Literature (PubMed-Medline, EMBASE database and Cochrane library) was searched using the relevant keywords. The search results were limited to the studies published in year 2000 or after.

RESULTS

Eight studies met the inclusion criteria. All studies were retrospective in nature. The incidence of contralateral recurrence rates in the untreated neck when the involved neck only is treated remains very low (0%-10%). Survival has improved over the past two decades, most likely due to improved diagnostic techniques and the increase in incidence of HPV-related disease.

CONCLUSION

Given the rarity of disease, level one evidence from randomised controlled trials is lacking. Available data are retrospective but support unilateral post-operative radiotherapy as a treatment option in selected cases.

Predictors for Survival of Patients with Squamous Cell Carcinoma of Unknown Primary in the Head and Neck Region

Background: Human papillomavirus (HPV) status is the most important predictor of survival in oropharyngeal squamous cell carcinoma (OPSCC). In patients with cervical lymph node metastases of squamous cell carcinoma of unknown origin (CUPHNSCC), much less is known. Methods: We assessed a consecutive cohort of CUPHNSCC diagnosed from 2000–2018 for HPV DNA, mRNA, p16INK4a (p16) expression, and risk factors to identify prognostic classification markers. Results: In 32/103 (31%) CUPHNSCC, p16 was overexpressed, and high-risk HPV DNA was detected in 18/32 (56.3%). This was mostly consistent with mRNA detection. In recursive partitioning analysis, CUPHNSCC patients were classified into three risk groups according to performance status (ECOG) and p16. Principal component analysis suggests a negative correlation of p16, HPV DNA, and gender in relation to ECOG, as well as a correlation between N stage, extranodal extension, and tobacco/alcohol consumption. Conclusions: Despite obvious differences, CUPHNSCC shares similarities in risk profile with OPSCC. However, the detection of p16 alone appears to be more suitable for the classification of CUPHNSCC than for OPSCC and, in combination with ECOG, allows stratification into three risk groups. In the future, additional factors besides p16 and ECOG may become important in larger studies or cases with special risk profiles.

Cervical squamous cell carcinoma of unknown primary: Oncological outcomes and prognostic factors

BACKGROUND/OBJECTIVES

Cervical squamous cell carcinoma of unknown primary (SCCUP) is a rare entity within head and neck cancer and both treatment regimens as well as identified potential predictors for oncological outcomes vary between published series. In this study, we evaluated oncological outcomes and identified potential prognostic factors for outcome.

PATIENTS AND METHODS

This retrospective monocentric cohort study includes 82 SCCUP patients diagnosed and treated between January 2000 and June 2021. Overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS) and locoregional recurrence-free survival (LRFS) were evaluated. The Cox proportional hazards model was used to analyze the prognostic effect of patient and tumor characteristics on oncological outcomes.

RESULTS

Five year OS, DSS, DFS and LRFS were respectively 53.9%, 72.2%, 68.9% and 67.3%. The p16 status was evaluated in 55 patients with 40% being p16 positive. On univariable analysis, p16 negative SCCUPs had significantly worse survival and recurrence rates in the presence of clinical extranodal extension (cENE) (OS: p=0.0013, DSS: p=0.0099, DFS: p=0.0164, LRFS: p=0.0099) and radiological extranodal extension (rENE) (OS: p=0.0034, DSS: p=0.0137, DFS: p=0.0167, LRFS: p=0.0100). In p16 positive SCCUP patients, rENE had a significantly negative prognostic effect on DFS (p=0.0345) and LRFS (p=0.0367). Total group multivariate analysis identified rENE as an independent negative predictor for all oncological outcomes. The "number of positive lymph nodes" was a second independent predictor for DSS (p=0.0257) and DFS (p=0.0435).

CONCLUSIONS

We report favorable oncological outcomes, comparable to previously published results. Although the presence of rENE seems associated with poor oncological outcomes, the differential effect of clinical, radiological and pathological ENE in both p16 positive and negative subgroups remain to be elucidated by further prospective research.

Sparing the Larynx and Hypopharynx With Radiation Therapy for Squamous Cell Carcinoma of Unknown Primary Site and Predominant Adenopathy in Level IIA

PURPOSE

There is controversy about the need to target the mucosa of the larynx and hypopharynx during radiation therapy (RT) for squamous cell carcinoma of an unknown primary site (SCCA-UP). By 1997, the policy in our department was to target only the oropharynx and nasopharynx in patients with SCCA-UP metastatic to the level II cervical nodes. The purpose of this study was to report the rate of cancer recurrence in the larynx or hypopharynx using an approach that excluded these areas from the RT target volumes.

METHODS AND MATERIALS

The inclusion criteria for this study were RT in our department for SCCA-UP between January 1, 1997, and December 31, 2019; no history of surgery that could disrupt the cervical lymphatics; predominant adenopathy in level IIA; and neck stage N1-2c. We excluded N3 because the incidental dose to the larynx and hypopharynx is usually high in patients with a >6-cm nodal conglomerate.

RESULTS

The study population was comprised of 50 patients with a median follow-up after RT of 7.1 years. No patient developed recurrent cancer in a mucosal site (0/50), 2% (1/50) developed a neck recurrence in a high-dose area with synchronous distant metastases, and 2% (1/50) developed distant metastases with no evidence of local or regional recurrence.

CONCLUSIONS

When delivering RT for SCCA-UP metastatic predominantly to level IIA, it is not necessary to target the mucosa of the larynx or hypopharynx. The extent to which the incidental RT dose to these areas contributes to cancer control is not evaluated in this study.

Influence of postoperative radiotherapy target volumes in unilateral head and neck carcinoma of unknown primary: A multicentric study using propensity score

OBJECTIVE

To compare the impact of two radiation modalities on loco-regional control, survival and tumour emergence, after node dissection for an unilateral head and neck carcinoma of unknown primary (HNCUP).

MATERIALS AND METHODS

This is a multicentric retrospective study of 138 patients with unilateral HNCUP treated between 2002 and 2017. The absence of primary tumour was assessed by a systematic panendoscopy and positron emission tomography. Neck dissection was initially performed for all patients. Radiation Therapy was delivered on ipsilateral lymph node areas in 62 cases (44%: UL-RT group) and on bilateral lymph node areas and the entire pharyngeal mucosa in 77 cases (56%: COMP-RT group). Impact of radiation modalities on locoregional control and overall survival was assessed using propensity score matching method in order to balance baseline characteristics between the two groups.

RESULTS

The population included 80.4% men, 80.4% smokers, 32.6% P16 positive tumours and 71.0% extracapsular extension. After a median follow-up of 5 years, the locoregional control rate was 80.3% in the UL-RT group and 75.3% in the COMP-RT group (p = 0.688). The corresponding rate of contralateral lymph node recurrence was 0% versus 2.6% (p = 0.503) and the rate of tumour emergence was 11.5% versus 9.1% (p = 0.778). No significant difference was observed between the UL-RT and the COMP-RT groups for overall survival (p = 0.9516), specific survival (p = 0.4837) or tumour emergence (p = 0.9034).

CONCLUSION

UL-RT seems to provide similar outcomes as COMP-RT in unilateral HNCUP post-operative management.

Metastatic Squamous Cell Carcinoma to the Cervical Lymph Nodes From an Unknown Primary Cancer: Management in the HPV Era

Background

Patients with metastases in the lymph nodes of the neck and no obvious primary tumor, neck cancer with unknown primary (NCUP), represent a management challenge. A majority of patients have metastatic squamous cell carcinoma (SCC), although other histologies do occur.

Methods

We comprehensively reviewed the literature, compared available guidelines, and conferred with an international team of experts.

Results

Positron emission tomography-computed tomography (PET-CT) and fine needle aspiration (FNA) under ultrasound guidance increase accuracy of diagnosis. Immunohistochemistry (IHC), determination of human papilloma virus (HPV) status, by p16 staining or by in situ hybridization (ISH), and next-generation gene sequencing can guide us regarding probable primary sites and tumor biology. Narrow Band Imaging (NBI) has been introduced for the early detection of subtle mucosal lesions. Direct laryngoscopy (DL) and tonsillectomy have long been procedures used in the search for a primary site. More recently, TransOral Robotic Surgery (TORS) or Transoral LASER Microsurgery (TLM) have been introduced for lingual tonsillectomy.

Conclusions

New technologies have been developed which can better detect, diagnose, and treat occult primary tumors. Decisions regarding therapy are based on the primary tumor site (if discovered) and N stage. Options include neck dissection with or without postoperative adjuvant therapy, primary irradiation, or combined chemotherapy with irradiation. The preferred treatment of patients whose primary remains unidentified is controversial.

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.

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.

Significance of the Neutrophil-to-Lymphocyte Ratio in p16-Negative Squamous Cell Carcinoma of Unknown Primary in Head and Neck

Objective: The neutrophil-to-lymphocyte ratio (NLR) has been reported to be associated with survival in solid malignancies. The main goal was to evaluate the prognostic significance of the NLR in patients with p16-negative squamous cell carcinoma of unknown primary (SCCUP) in head and neck.

Methods: The association between the NLR and clinical pathologic variables was evaluated by the chi-square test. The primary endpoint of interest was disease-specific survival (DSS). Univariate and Coxmodel analyses were used to evaluate prognostic factors.

Results: A total of 153 patients were included in the analysis. Cancer cachexia was noted in 10 patients. The mean NLR value was 3.9 (range: 1.4–8.3). A high NLR was significantly associated with cancer cachexia development. The 5-year DSS rate was 58%. In patients with NLRs varying from 1.4 to 3.7, the 5-year DSS rate was 71%; in patients with NLRs varying from 3.7 to 6.0, the 5-year DSS rate was 57%; in patients with NLRs varying from 6.0 to 8.3, the 5-year DSS rate was 39%, and the difference was significant (p = 0.001). Further Cox model analysis confirmed the independence of the NLR in predicting survival.

Conclusions: In patients with p16-negative SCCUP, an NLR ≥ 6.0 is significantly associated with worse prognosis.

Human papillomavirus and p16 immunostaining, prevalence and prognosis of squamous carcinoma of unknown primary in the head and neck region

The prevalence of human papillomavirus (HPV) in squamous cell carcinoma of unknown primary in the head and neck (SCCUPHN), and prognosis by HPV status of SCCUPHN patients has been difficult to estimate because of the rarity of this subtype. In MEDLINE, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, EMBASE, Cochrane library and Web of Science searches, observational studies and clinical trials that reported survival rates of patients with SCCUPHN by HPV status were identified. Meta-analysis estimated the prevalence and prognosis (overall survival, OS; progression-free survival, PFS) of SCCUPHN by HPV status, and compared them to studies of oropharyngeal squamous cell carcinoma (OPSCC) from the same institutions and across continents. In 17 SCCUPHN studies (n = 1,149) and 17 institution-matched OPSCC studies (n = 6,522), the pooled HPV prevalence of SCCUPHN was 49%, which was only 10% (95%CI: 1-19%) lower than OPSCC prevalence in the underlying population. Estimated 5-year OS for HPV-negative SCCUPHN was 44% (95%CI: 36-51%) vs. HPV-positive SCCUPHN of 91% (95%CI: 86-96%); hazard ratio (HR) for OS was 3.25 (95%CI: 2.45-4.31) and PFS was 4.49 (95%CI: 2.88-7.02). HRs by HPV status for OPSCC were similar to that in SCCUPHN. While North American SCCUPHNs had higher HPV prevalence than European SCCUPHNs (OR = 2.68 (95%CI: 1.3-5.6)), HR of OS for HPV-negative vs. HPV-positive patients were similar in both continents (HRs of 3.78-4.09). Prevalence of HPV among SCCUPHN patients were lower than in OPSCC. The survival benefit conferred by being HPV-positive was similar in SCCUPHN as in OPSCCs, independent of continent.

Roles of Ki-67 and p16 as biomarkers for unknown primary head and neck squamous cell carcinoma

PURPOSE

Treatment guidelines have not been established for unknown primary head and neck squamous cell carcinoma (SCC). For these patients, chemoradiotherapy (CRT) can provide a better prognosis than that for patients with other head and neck cancers. The presence of HPV in the tumor is associated with a better outcome. However, not all patients with HPV-positive unknown primary head and neck SCC experience good treatment outcomes in actual clinical settings.

METHODS

We thus retrospectively determined the Ki-67 proliferation index and p16 expression status to assess the associations of these parameters with treatment outcomes of patients with unknown primary head and neck SCC.

RESULTS

The subjects were 13 patients who underwent CRT after surgery or excision biopsy between 1999 and 2016. The 2- and 5-year overall survival (OS) rate was 76.9% and 68.4%, respectively. The prognostic factor was age. There was no significant difference in survival between patients with a high Ki-67 vs. low Ki-67 or between patients with p16-positive vs. p16-negative metastases OS. However, all p16-positive patients with low Ki-67 showed good locoregional control.

CONCLUSIONS

The combination of ki67 expression and p16 expression status may allow prediction of local control more accurately than p16 expression status alone.

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.

Unknown primary squamous cell carcinoma of the head and neck: retrospective analysis of 80 cases

OBJECTIVES

The management of patients with cervical metastasis in head and neck cancer of unknown primary (HNCUP) remains controversial. This current multicenter retrospective study investigated the treatment outcomes of patients with HNCUP.

METHODS

The study included patients who were treated curatively at 12 institutions in Japan from January 2006 to December 2015.

RESULTS

Eighty patients with HNCUP were included. The median follow-up period was 34 months. The three-year overall survival (OS), disease-specific survival (DSS), regional relapse-free survival (RRFS), local progression-free survival (LPFS), and distant metastasis-free survival (DMFS) rates were 72.5%, 80.3%, 74.0%, 89.7%, and 86.9%, respectively. Nodal status was a significant factor for OS, DSS, RRFS, and DMFS; and extracapsular extension (ECE) was significant for OS and DSS. There was a distinct difference between the survival rates of patients with N1-2a and N2b-3 disease. RT was a significant positive factor for LPFS (3-year LPFS, RT 93.0% vs. no RT 83.0%, p = .043).

CONCLUSIONS

For N2a as well as N1 disease without ECE, a single treatment modality, including ND or RT alone is acceptable. When ND alone is performed, thorough monitoring should be continued during follow-up to identify the emergence of the primary lesion.

Unilateral radiotherapy treatment for p16/human papillomavirus-positive squamous cell carcinoma of unknown primary in the head and neck

OBJECTIVES/HYPOTHESIS

The outcomes of unilateral radiotherapy treatment for patients with p16/HPV-positive squamous cell carcinomas of unknown primary (SCCUP) affecting cervical lymph nodes are under-reported. Compared to radiating large volumes of the pharyngeal axis (the more common approach), this is potentially a much less toxic treatment for a good prognosis group.

STUDY DESIGN

Retrospective cohort study.

METHODS

We identified patients with SCCUP who were treated radically at our center and did not have parotid or isolated level IV or V nodal involvement. Failure-free and overall survivals were calculated using Kaplan-Meier methods.

RESULTS

From 2004 to 2012, there were 49 radically treated patients with SCCUP. Fourteen patients had bilateral neck treatment (they had bilateral nodal disease or suspected lesions in the base of tongue, though not proven with biopsy), two had surgery alone, whereas 33 had unilateral radiotherapy (after neck dissection, excisional biopsy, or definitively with concurrent chemotherapy). Of the 33 patients, 21 tested positive to p16/HPV and had median follow-up of 57 months. In this group, no isolated contralateral neck failures or putative primaries emerged. There was 1/21 (4.3%) ipsilateral neck failure, 1/21 (4.3%) concurrent contralateral neck and distant failure, and 1/21 (4.3%) patient with distant failure. The 5-year freedom from failure was 78% (95% confidence interval [CI]: 56%-100%) and overall survival was 90% (95% CI: 79%-100%).

CONCLUSIONS

With no emergence of putative primaries and no isolated contralateral neck failures, this single-institution experience in p16/HPV-positive SCCUP patients suggests that unilateral radiotherapy may be an underutilized management strategy.

LEVELS OF EVIDENCE

4 Laryngoscope, 128:2076-2083, 2018.

Optimization of radiotherapy for neck carcinoma metastasis from unknown primary sites: a meta-analysis

This meta-analysis was designed to evaluate radiotherapy (RT) options preferable for neck cancer metastases from unknown primary sites (NCUP). Relevant articles published up through September 2015 were selected from EMBASE, Cochrane, PubMed and Web of Science. Thirty-three articles were identified, and relative risks (RRs) and 95% CIs for all pre-specified endpoints were calculated. Surgery plus RT showed an advantage for 5-year overall survival (OS) (RR 0.66, 95% CI 0.52-0.83, p = 0.0004) and neck recurrence (NR) (RR = 0.74, 95% CI 0.59-0.92, p = 0.008) compared to RT alone. The RRs for NR, primary tumor emergence (PTE), and 5-year disease free survival (DFS) for bilateral neck compared to ipsilateral neck irradiation were 0.61 (95% CI 0.41-0.91, p = 0.01), 0.44(95% CI 0.26-0.77, p = 0.004), and 0.81 (95% CI 0.64-1.03, p = 0.09), respectively. Irradiation of the neck plus potential primary tumor sites (PPTS) showed a benefit for 5-year DFS (RR 0.75, 95% CI 0.61-0.92, p = 0.005), NR (RR = 0.72, 95% CI 0.56-0.92, p = 0.009), and PTE (RR = 0.23, 95% CI 0.12-0.45, p < 0.0001) compared to neck-only irradiation. Adverse events occurred more frequently with bilateral neck plus PPTS irradiation. For NCUP, surgery plus RT of the bilateral neck and PPTS was associated with greater improvement of clinical outcomes.

[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.

Diagnostic and treatment modalities for patients with cervical lymph node metastases of unknown primary site - current status and challenges

Background and Purpose

This review aims to provide a comprehensive overview of the literature and elucidate open questions for future clinical trials concerning diagnostics and treatment modalities for cervical cancer of unknown primary (CUP).

Methods

A literature search for head and neck CUP was performed with focus on diagnostics and therapies as well as molecular markers.

Results

High level evidence on CUP is limited. However, it seems that a consensus exists regarding the optimal diagnostic procedures. The correct implementation of biomarkers for patient stratification and treatment remains unclear. An even greater dispute dominates about the ideal treatment with publications ranging from sole surgery to surgery with postoperative bilateral radiotherapy with inclusion of the mucosa and concomitant chemotherapy.

Conclusions

Cervical CUP represents a very heterogeneous malignant disease. On this account many aspects concerning treatment optimization remain unclear, despite a considerable number of publications in the past. Future research in form of prospective randomized trials is needed in order to better define patient stratification criteria and enable tailored treatment.

Unknown primary head and neck squamous cell carcinoma in the era of fluorodeoxyglucose-positron emission tomography/CT and intensity-modulated radiotherapy

BACKGROUND

The diagnosis and treatment of head and neck carcinoma of unknown primary (CUP) have changed with the introduction of fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT and intensity-modulated radiotherapy (IMRT), with potential implications for outcome.

METHODS

We conducted a retrospective analysis of 80 patients with head and neck CUP who were PET-staged and treated with curative intention using IMRT between 2006 and 2016 in the Netherlands Cancer Institute. Patient, tumor, and treatment demographics were recorded and oncologic outcomes were analyzed.

RESULTS

Local control was 100% in mucosal irradiated patients. Regional control was 90%. Ten patients developed distant metastases, which were associated with N3, extracapsular extension (ECE) and lower neck positive lymph nodes. Overall survival (OS) at 5 years was 62% and disease-specific survival was 78%. ECE, N3 neck, multiple levels of positive lymph nodes, and positive lymph nodes in the lower neck were associated with worse prognosis.

CONCLUSION

Locoregional outcome of head and neck CUP managed with modern techniques is good. Future research needs to focus on reducing toxicity and patients prone for distant metastasis.

The prevalence of human papillomavirus in squamous cell carcinoma of unknown primary site metastatic to neck lymph nodes: a systematic review

A subset of head and neck squamous cell carcinoma, which mainly arise from the crypt epithelium of the palatine and lingual tonsils, may be caused by high-risk human papillomavirus (HPV) infections. This topographical restriction together with other overlapping clinical features have led investigators to suspect that HPV plays a role in squamous cell carcinoma of unknown primary (SCCUP) site metastatic to neck lymph nodes. We performed a systematic review of articles listed in PubMed to identify studies testing HPV and/or p16(INK4a) status (p16) in tissue samples from initial and definitive SCCUP. The prevalence of HPV-related (HPV DNA-positive and/or p16 positive) SCCUP was calculated for all the SCCUP, initial SCCUP, suspected definitive SCCUP, and true definitive SCCUP whenever a minimum of 10 cases of each category was identified. In addition, data concerning patients' diagnostic work-up, the HPV detection methods, and the correlations between HPV-status, the localization of the occult primary tumor, and the clinical outcome were also extracted. Eighteen retrospective cohort studies, assessing a total of 659 patients, met the inclusion criteria. The overall median prevalences of HPV-DNA(pos), of p16(pos), and of positivity for both HPV markers were, respectively, 37.0, 48.5, and 36.0 %. Patients with diagnosis of initial SCCUP had overall median prevalences of HPV-DNA(pos), of p16(pos), and of positivity for both HPV markers, respectively, of 81.8, 86.2, and 80.8 %. The data uncovered by this systematic review confirm that SCCUP is frequently causally associated to HPV-driven oropharyngeal squamous cell carcinomas. This finding supports the view that HPV-status could be routinely assessed in SCCUP patients as it may lead to identifying the primary tumor and the decision to de-escalate treatment.

Transoral robotic surgery for the management of head and neck squamous cell carcinoma of unknown primary

CONCLUSION

The addition of transoral robotic surgery (TORS) in the diagnostic management of patients classified with head and neck squamous cell carcinoma of unknown primary (SCCUP) is promising and appears to improve detection rates of the primary tumour. The approach presented in this first Scandinavian study could potentially minimize the radiation field to the pharyngeal axis in patients with identified primary tumours.

OBJECTIVES

The aim of the study was to investigate whether bilateral lingual tonsillectomy performed with TORS is feasible, and whether it could improve the detection rates of primary tumours in patients diagnosed and classified as having SCCUP.

METHODS

The study was retrospective and included 13 patients with SCCUP who were referred to TORS between October 2013 and January 2015. All 13 patients had previously undergone a full investigation programme following the national guidelines including whole-body PET/CT, examination in general anaesthesia, including random biopsies of the base of the tongue and bilateral palatine tonsillectomy without identification of the primary tumour.

RESULTS

The primary tumour was identified by TORS in seven of the 13 patients (54%) at the lingual tonsils. Human papillomavirus DNA and p16 were positive in all identified primary tumour specimens and in the corresponding lymph node metastases.