Extracellular Vesicle and Particle Biomarkers Define Multiple Human Cancers.

There is an unmet clinical need for improved tissue and liquid biopsy tools for cancer detection. We investigated the proteomic profile of extracellular vesicles and particles (EVPs) in 426 human samples from tissue explants (TEs), plasma, and other bodily fluids. Among traditional exosome markers, CD9, HSPA8, ALIX, and HSP90AB1 represent pan-EVP markers, while ACTB, MSN, and RAP1B are novel pan-EVP markers. To confirm that EVPs are ideal diagnostic tools, we analyzed proteomes of TE- (n = 151) and plasma-derived (n = 120) EVPs. Comparison of TE EVPs identified proteins (e.g., VCAN, TNC, and THBS2) that distinguish tumors from normal tissues with 90% sensitivity/94% specificity. Machine-learning classification of plasma-derived EVP cargo, including immunoglobulins, revealed 95% sensitivity/90% specificity in detecting cancer. Finally, we defined a panel of tumor-type-specific EVP proteins in TEs and plasma, which can classify tumors of unknown primary origin. Thus, EVP proteins can serve as reliable biomarkers for cancer detection and determining cancer type.

New techniques to identify the tissue of origin for cancer of unknown primary in the era of precision medicine: progress and challenges.

Despite a standardized diagnostic examination, cancer of unknown primary (CUP) is a rare metastatic malignancy with an unidentified tissue of origin (TOO). Patients diagnosed with CUP are typically treated with empiric chemotherapy, although their prognosis is worse than those with metastatic cancer of a known origin. TOO identification of CUP has been employed in precision medicine, and subsequent site-specific therapy is clinically helpful. For example, molecular profiling, including genomic profiling, gene expression profiling, epigenetics and proteins, has facilitated TOO identification. Moreover, machine learning has improved identification accuracy, and non-invasive methods, such as liquid biopsy and image omics, are gaining momentum. However, the heterogeneity in prediction accuracy, sample requirements and technical fundamentals among the various techniques is noteworthy. Accordingly, we systematically reviewed the development and limitations of novel TOO identification methods, compared their pros and cons and assessed their potential clinical usefulness. Our study may help patients shift from empirical to customized care and improve their prognoses.

A Fast, Affordable, and Minimally Invasive Diagnostic Test for Cancer of Unknown Primary Using DNA Methylation Profiling.

Currently, we cannot provide a conclusive diagnosis for 3% to 5% of people who are confronted with cancer. These patients have cancer of unknown primary (CUP), ie, a metastasized cancer for which the tissue of origin cannot be determined. Studies have shown that the DNA methylation profile is a unique "fingerprint" that can be used to classify tumors. Here we used cell-free reduced representation bisulfite sequencing (cfRRBS), a technique that allows us to identify the methylation profile starting from minimal amounts of highly fragmented DNA, for CUP diagnosis on formalin-fixed paraffin-embedded (FFPE) tissue and liquid biopsies. We collected 80 primary tumor FFPE samples covering 16 tumor entities together with 15 healthy plasma samples to use as a custom cfRRBS reference data set. Entity-specific methylation regions are defined for each entity to build a classifier based on nonnegative least squares deconvolution. This classification framework was tested on 30 FFPE, 19 plasma, and 40 pleural and peritoneal effusion samples of both known metastatic tumors and clinical CUPs for which pathological investigation finally resulted in a cancer diagnosis. Using this framework, 27 of 30 FFPE (all CUPs) and 16 of 19 plasma samples (10/13 CUPs) obtained an accurate diagnosis, with a minimal DNA input of 400 pg. Diagnosis of the 40 pleural and peritoneal effusion samples is possible in 9 of 27 samples with negative/inconclusive cytology (6/13 CUPs), showing that cell-free DNA (cfDNA) methylation profiling could complement routine cytologic analysis. However, a low "cfDNA - high-molecular weight DNA ratio" has a considerable impact on the prediction accuracy. Moreover, the accuracy improves significantly if the predicted tumor percentage is >7%. This proof-of-concept study shows the feasibility of using DNA methylation profiling on FFPE and liquid biopsy samples such as blood, ascites, and pleural effusions in a fast and affordable way. Our novel RRBS-based technique requires minimal DNA input, can be performed in

N-cadherin: A diagnostic marker to help discriminate primary liver carcinomas from extrahepatic carcinomas.

Distinguishing primary liver cancer (PLC), namely hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA), from liver metastases is of crucial clinical importance. Histopathology remains the gold standard, but differential diagnosis may be challenging. While absent in most epithelial, the expression of the adherens junction glycoprotein N-cadherin is commonly restricted to neural and mesenchymal cells, or carcinoma cells that undergo the phenomenon of epithelial-to-mesenchymal transition (EMT). However, we recently established N- and E-cadherin expression as hallmarks of normal hepatocytes and cholangiocytes, which are also preserved in HCC and iCCA. Therefore, we hypothesized that E- and/or N-cadherin may distinguish between carcinoma derived from the liver vs carcinoma of other origins. We comprehensively evaluated E- and N-cadherin in 3359 different tumors in a multicenter study using immunohistochemistry and compared our results with previously published 882 cases of PLC, including 570 HCC and 312 iCCA. Most carcinomas showed strong positivity for E-cadherin. Strong N-cadherin positivity was present in HCC and iCCA. However, except for clear cell renal cell carcinoma (23.6% of cases) and thyroid cancer (29.2%), N-cadherin was only in some instances faintly expressed in adenocarcinomas of the gastrointestinal tract (0%-0.5%), lung (7.1%), pancreas (3.9%), gynecological organs (0%-7.4%), breast (2.2%) as well as in urothelial (9.4%) and squamous cell carcinoma (0%-5.6%). As expected, N-cadherin was detected in neuroendocrine tumors (25%-75%), malignant melanoma (46.2%) and malignant mesothelioma (41%). In conclusion, N-cadherin is a useful marker for the distinction of PLC vs liver metastases of extrahepatic carcinomas (P < .01).

Carcinoma of unknown primary (CUP): an update for histopathologists.

Carcinoma of unknown primary (CUP) is a heterogeneous group of metastatic cancers in which the site of origin is not identifiable. These carcinomas have a poor outcome due to their late presentation with metastatic disease, difficulty in identifying the origin and delay in treatment. The aim of the pathologist is to broadly classify and subtype the cancer and, where possible, to confirm the likely primary site as this information best predicts patient outcome and guides treatment. In this review, we provide histopathologists with diagnostic practice points which contribute to identifying the primary origin in such cases. We present the current clinical evaluation and management from the point of view of the oncologist. We discuss the role of the pathologist in the diagnostic pathway including the control of pre-analytical conditions, assessment of sample adequacy, diagnosis of cancer including diagnostic pitfalls, and evaluation of prognostic and predictive markers. An integrated diagnostic report is ideal in cases of CUP, with results discussed at a forum such as a molecular tumour board and matched with targeted treatment. This highly specialized evolving area ultimately leads to personalized oncology and potentially improved outcomes for patients.

Cancers of Unknown Primary Origin: Real-World Clinical Outcomes and Genomic Analysis at the European Institute of Oncology.

BACKGROUND: Cancer of unknown primary origin (CUP) poses a significant challenge due to poor clinical outcomes and limited treatment options. As such, further definition of clinicopathological factors and genomic profile to better adapt treatment strategies is required. METHODS: Medical records were interrogated to retrospectively include CUP with available clinical and genomics data at the European Institute of Oncology. Next-generation sequencing (NGS) included targeted panels. Statistical analyses were conducted with R Software 4.2.2. RESULTS: A total of 44 patients were included. With a median follow-up of 39.46 months (interquartile range [IQR] 35.98-47.41 months), median PFS (mPFS) to first-line regimen was 3.98 months (95% CI 3.22-5.98), with a clinical benefit rate of 26% (95% CI 14%-49%), and disease control rate (DCR) limited to 48.28%. Most patients (26 of 31, 83.87%) received platinum-doublet chemotherapy, with no statistically significant difference between first-line treatment regimens. Median OS (mOS) was 18.8 months (95% CI 12.3-39.9), with a 12-month OS rate of 66% (95% CI 50%-85%). All patients received comprehensive genomic profiling (CGP). For 11 patients, NGS was unsuccessful due to low sample quantity and/or quality. For the remaining, TP53 (n = 16, 48%) and KRAS (n = 10, 30%) represented the most altered (alt) genes. No microsatellite instability was observed (0 of 28), while 6 of 28 (21.43%) tumors carried high TMB (≥10 mutation per megabase). Eight of 33 tumors (24.2%) displayed at least one actionable alteration with potential clinical benefit according to ESCAT. Only 2 of them received targeted therapy matched to genomic alterations, with a combined mPFS of 2.63 months (95% CI 1.84-not evaluable) as third-line regimens. Six patients received anti-PD1/PD-L1 therapy, showing a meaningful mPFS of 13 months (95% CI 2.04-not evaluable). CONCLUSION: CUP exhibits poor prognosis with limited benefits from standard treatment regimens. A significant proportion of CUPs carry actionable alterations, underscoring the importance of genomic profiling to gather additional treatment opportunities. In addition, immunotherapy might represent a valuable treatment option for a subset of CUP. Finally, accurate definition of sequencing methods and platforms is crucial to overcome NGS failures.

Head and Neck Squamous Cell Carcinoma of Unknown Primary: A Diagnostic Work-Up.

The current work-up of the primary tumor site of a head and neck squamous cell carcinoma of unknown primary is not standardized and results in several time-consuming procedures that delay treatment initiation. This article seeks to consolidate contemporary strategies used to identify the primary tumor site of an unknown primary head and neck squamous cell carcinoma and offer recommendations based on current literature review.

Refinement of computational identification of somatic copy number alterations using DNA methylation microarrays illustrated in cancers of unknown primary.

High-throughput genomic technologies are increasingly used in personalized cancer medicine. However, computational tools to maximize the use of scarce tissues combining distinct molecular layers are needed. Here we present a refined strategy, based on the R-package 'conumee', to better predict somatic copy number alterations (SCNA) from deoxyribonucleic acid (DNA) methylation arrays. Our approach, termed hereafter as 'conumee-KCN', improves SCNA prediction by incorporating tumor purity and dynamic thresholding. We trained our algorithm using paired DNA methylation and SNP Array 6.0 data from The Cancer Genome Atlas samples and confirmed its performance in cancer cell lines. Most importantly, the application of our approach in cancers of unknown primary identified amplified potentially actionable targets that were experimentally validated by Fluorescence in situ hybridization and immunostaining, reaching 100% specificity and 93.3% sensitivity.

Primary Tumour Detection in Carcinoma of Unknown Primary with Transoral Robotic Surgery (TORS) Tongue Base Mucosectomy: A Meta-analysis.

BACKGROUND: Head and neck carcinoma of unknown primary (CUP) represents a challenging diagnostic process when standard work-up fails to identify the primary tumour site. The aim of this systematic review and meta-analysis was to evaluate the diagnostic utility and complication profile of transoral robotic surgery (TORS) tongue base mucosectomy (TBM) in the management of CUP. PATIENTS AND METHODS: An electronic database search was performed in the EMBASE, MEDLINE, PubMed and Cochrane databases. A meta-analysis of proportions was performed to obtain an estimate of the overall proportion for the detection and complication rates. RESULTS: Nine studies representing 235 patients with CUP who had TORS TBM were included in the final analysis. The overall pooled tumour detection rate was 66.2% [95% confidence interval (CI) 56.1-75.8]. The incidence of tumour detection in human papilloma virus (HPV)-positive cases (81.5%, 95% CI 60.8-96.4) was significantly higher than HPV-negative cases (2.3%, 95% CI 0.00-45.7). Weighted overall complication rate was 11.4% (95% CI 7.2-16.2). The majority were grade I or II (80%) according to the Clavien-Dindo classification. CONCLUSIONS: This meta-analysis suggests TORS to be safe and effective in localising the primary tumour site in patients with CUP. While the current data supports the use of TORS in patients who are HPV positive, larger numbers of HPV-negative cases are required to determine the true diagnostic effect with TORS before any valid conclusions can be inferred in this particular subgroup. Further research should focus on high quality prospective trials with stringent methodological work-up to minimise heterogeneity and allow for more accurate statistical analysis.

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.

A comparison of DNA sequencing and gene expression profiling to assist tissue of origin diagnosis in cancer of unknown primary.

Cancer of unknown primary (CUP) is a syndrome defined by clinical absence of a primary cancer after standardised investigations. Gene expression profiling (GEP) and DNA sequencing have been used to predict primary tissue of origin (TOO) in CUP and find molecularly guided treatments; however, a detailed comparison of the diagnostic yield from these two tests has not been described. Here, we compared the diagnostic utility of RNA and DNA tests in 215 CUP patients (82% received both tests) in a prospective Australian study. Based on retrospective assessment of clinicopathological data, 77% (166/215) of CUPs had insufficient evidence to support TOO diagnosis (clinicopathology unresolved). The remainder had either a latent primary diagnosis (10%) or clinicopathological evidence to support a likely TOO diagnosis (13%) (clinicopathology resolved). We applied a microarray (CUPGuide) or custom NanoString 18-class GEP test to 191 CUPs with an accuracy of 91.5% in known metastatic cancers for high-medium confidence predictions. Classification performance was similar in clinicopathology-resolved CUPs - 80% had high-medium predictions and 94% were concordant with pathology. Notably, only 56% of the clinicopathology-unresolved CUPs had high-medium confidence GEP predictions. Diagnostic DNA features were interrogated in 201 CUP tumours guided by the cancer type specificity of mutations observed across 22 cancer types from the AACR Project GENIE database (77,058 tumours) as well as mutational signatures (e.g. smoking). Among the clinicopathology-unresolved CUPs, mutations and mutational signatures provided additional diagnostic evidence in 31% of cases. GEP classification was useful in only 13% of cases and oncoviral detection in 4%. Among CUPs where genomics informed TOO, lung and biliary cancers were the most frequently identified types, while kidney tumours were another identifiable subset. In conclusion, DNA and RNA profiling supported an unconfirmed TOO diagnosis in one-third of CUPs otherwise unresolved by clinicopathology assessment alone. DNA mutation profiling was the more diagnostically informative assay. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Liver transplant for primary biliary tract neuroendocrine tumor in a nine-year-old girl.

BACKGROUND: Neuroendocrine tumors (NETs) are rare epithelial neoplasms that arise most commonly from the gastrointestinal tract. In pediatrics, the most common site of origin is in the appendix, with the liver being the most common site of metastasis. Neuroendocrine tumors arising from the biliary tract are extremely rare. METHODS: We describe a case of a nine-year-old girl who presented with obstructive cholestasis and was found to have multiple liver masses identified on biopsy as well-differentiated neuroendocrine tumor with an unknown primary tumor site. RESULT: The patient underwent extensive investigation to identify a primary tumor site, including endoscopy, endoscopic ultrasound, and capsule endoscopy. The patient ultimately underwent definitive management with liver transplant, and on explant was discovered to have multiple well-differentiated neuroendocrine tumors, WHO Grade 1, with extensive infiltration into the submucosa of bile duct, consistent with primary biliary tract neuroendocrine tumor. CONCLUSION: Identifying the site of the primary tumor in NETs found within the liver can be challenging. To determine if an extrahepatic primary tumor exists, workup should include endoscopy, EUS, and capsule endoscopy. Children with well-differentiated hepatic NETs, with no identifiable primary tumor, and an unresectable tumor, are considered favorable candidates for liver transplantation.

PD-L1 expression and microsatellite instability (MSI) in cancer of unknown primary site.

BACKGROUND: Cancer of unknown primary site (CUP) is a heterogeneous group of tumors for which the origin remains unknown. Clinical outcomes might be influenced by regulatory processes in its microenvironment. Microsatellite instability (MSI) is a predictive biomarker for cancer immunotherapy and its status, as well as co-occurrence with PD-L1 expression, is poorly evaluated. We aim to evaluate the expression of PD-L1 and the status of MSI in CUP and their possible associations with clinical-pathological features. METHODS: The combined positive score (CPS) PD-L1 expression was evaluated by immunohistochemistry. MSI status was assessed using a hexa-plex marker panel by polymerase chain reaction followed by fragment analysis. RESULTS: Among the 166 cases, MSI analysis was conclusive in 120, with two cases being MSI positive (1.6%). PD-L1 expression was positive in 18.3% of 109 feasible cases. PD-L1 expression was significantly associated with non-visceral metastasis and a dominance of nodal metastasis. The median overall survival (mOS) was 3.7 (95% CI 1.6-5.8) months and patients who expressed PD-L1 achieved a better mOS compared to those who did not express PD-L1 (18.7 versus 3.0 months, p-value: < .001). ECOG-PS equal to or more than two and PD-L1 expression were independent prognostic factors in multivariate analysis (2.37 and 0.42, respectively). CONCLUSION: PD-L1 is expressed in a subset (1/5) of patients with CUP and associated with improved overall survival, while MSI is a rare event. There is a need to explore better the tumor microenvironment as well as the role of immunotherapy to change such a bad clinical outcome.

Swallowing outcomes after transoral robotic surgery and adjuvant treatment in unknown primary.

OBJECTIVES: Robotic transoral mucosectomy of the base of tongue was introduced as a diagnostic procedure in patients treated for head and neck cancer with unknown primary (CUP), increasing the identification rate of the primary tumour. For the treatment of CUP, a considerable percentage of patients require adjuvant (chemo)radiation. The aim of this study was to investigate swallowing outcomes among CUP patients after TORS and adjuvant treatment. SUBJECTS AND METHODS: A systematic review was carried out on studies investigating the impact of TORS and adjuvant treatment on swallowing-related outcomes among CUP patients In addition, a cross-sectional study was carried out on swallowing problems (measured using the SWAL-QOL questionnaire) among CUP patients in routine care who visited the outpatient clinic 1-5 years after TORS and adjuvant treatment. RESULTS: The systematic review (6 studies; n = 98) showed that most patients returned to a full oral diet. The cross-sectional study (n = 12) showed that all patients were able to return to a full oral diet, nevertheless, 50% reported swallowing problems in daily life (SWAL-QOL total score ≥14). CONCLUSION: Although after TORS and adjuvant treatment for CUP a full oral diet can be resumed, patients still experience problems with eating and drinking in daily life.

Transoral robotic surgery in HPV+ oropharyngeal cancer of unknown primary.

PURPOSE: This study was designed to assess trends in and outcomes associated with TORS-treated HNCUP using a large national database. MATERIALS AND METHODS: HPV+ oropharyngeal HNCUPs were isolated from the 2004-2017 National Cancer Database. Overall survival (OS) was assessed, with patients stratified by 1) use of TORS and 2) whether the occult tumor was ultimately located. Demographic and oncologic predictors of survival were evaluated on regression. RESULTS: The cohort contained 284,734 cases, of which 8336 were HNCUPs. HNCUPs represented 2.49 % of all HNSCC in 2010 versus 3.13 % in 2017. 3897 (46.7 %) of these unknown primaries were ultimately identified. The proportion of cases treated with TORS increased from 6.9 % in 2010 to 18.1 % in 2017 (p < 0.001). Kaplan-Meier analysis of 2991 HPV+ oropharyngeal HNCUPs demonstrated higher 5-year overall survival (OS) for patients treated with robotic surgery versus no robotic surgery (95.4 % ± 1.7 % standard error [SE] versus 84.0 % ± 0.9 % SE; p < 0.001). Patients with primary tumors identified during treatment had improved OS compared to those whose tumors were not located (5-year OS was 90.5 % ± 0.9 % SE and 77.3 % ± 1.5 % SE, respectively; p < 0.001). For patients in which the primary tumor was found, those who received robotic surgery survived longer than those who did not (96.5 % ± 1.4 % SE versus 89.1 % ± 1.0 % SE 5-year OS; p < 0.001). The relationship between TORS and OS remained significant on Cox regression controlling for confounders. CONCLUSIONS: Use of TORS in the workup for HPV+ HNCUP is associated with higher rates of tumor identification and improved OS.

The role of non-oropharyngeal biopsies in head and neck squamous cell carcinoma of unknown primary: A systematic review.

INTRODUCTION: This systematic review aims to evaluate the role of biopsies in non-oropharyngeal subsites in patients with cervical metastasis from head and neck squamous cell carcinoma of unknown primary (HNSCCUP). METHODS: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Articles that encompassed non-oropharyngeal biopsies in HNSCCUP as part of the diagnostic work-up were selected and analysed. RESULTS: A comprehensive search strategy was used to search relevant literature in PubMed from inception to October 2021. Eleven articles out of 860 were included, comprising 990 patients. There are no randomised control trials comparing the outcomes of survival and or locoregional control between patients who have or have not undergone non-targeted biopsies of non-oropharyngeal sub-sites for HNSCCUP. Several retrospective studies which showed an extremely low yield from random biopsies (range of yield, 0%-9%) of non-oropharyngeal subsites. Even targeted biopsies showed a low yield (range of yield, 0.6%-16.6%) from non-oropharyngeal subsites. The primary site identified for Epstein-Barr virus (EBV) positive cervical lymph nodes with an unknown primary is mainly the nasopharynx (51.7%). Narrow band imaging (NBI) (sensitivity range, 64%-91%) helps in the detection of primaries to target biopsies in non-oropharyngeal subsites. CONCLUSIONS: On the basis of this systematic review, it is not appropriate to offer biopsies of clinically and radiologically normal upper aerodigestive tract mucosa at non-oropharyngeal sites. Offer nasopharyngeal biopsies when the cervical node sampling reveals EBV-positive metastasis. Where available, NBI should be used to help detect and target biopsies in non-oropharyngeal subsites.

Indications for oropharyngeal biopsy in head and neck squamous cell carcinoma of unknown primary: A systematic review (HNSCCUP).

INTRODUCTION: Patients presenting with head and neck squamous cell carcinoma of unknown primary (HNSCCUP) remain challenging clinical scenarios as large variation exists in practices used to locate the primary. OBJECTIVE: The objective of this systematic review is to review of the literature and offer recommendations for oropharyngeal biopsies in HNSCCUP. METHOD: Pubmed, Medline and Embase were searched to identify studies from inception to October 2021. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. RESULTS: A total of 483 articles were included and screened, 41 studies met the inclusion criteria, including over 3400 patients from the original articles (122 of these patients were reported on in two sequential articles by a single author - table 1) and 4 large metaanalyses including 1852 patients. The primary site identification rate following random biopsies or deep tissue biopsies is less than 5% in most studies. The mean detection rate following ipsilateral tonsillectomy is 34%; two pooled analyses indicate that the mean detection rate following tongue base mucosectomy is 64%, with this figure rising when the tonsils are negative. CONCLUSIONS: High level evidence is lacking, with heterogeneity in the reported studies. Published meta-analyses are based on retrospective data. There is little evidence supporting the practice of random/non-directed oropharyngeal biopsies. Available evidence supports palatine tonsillectomy and tongue base mucosectomy compared to deep tissue biopsies.

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.

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.

Survival outcomes in head and neck squamous cell carcinoma of unknown primary: A national cohort study.

INTRODUCTION: To investigate factors influencing survival in head and neck squamous cell carcinoma of unknown primary (HNSCCUP). METHODS: A retrospective observational cohort study was conducted, over 5 years from January 2015, in UK Head and Neck centres, of consecutive adults undergoing 18F-Fluorodeoxyglucose-PET-CT within 3 months of diagnosis with metastatic cervical squamous cell carcinoma. Patients treated as HNSCCUP underwent survival analysis, stratified by neck dissection and/or radiotherapy to the ipsilateral neck, and by HPV status. RESULTS: Data were received from 57 centres for 965 patients, of whom 482 started treatment for HNSCCUP (65.7% HPV-positive, n = 282/429). Five-year overall survival (OS) for HPV-positive patients was 85.0% (95% CI 78.4-92.3) and 43.5% (95% CI 32.9-57.5) for HPV-negative. HPV-negative status was associated with worse OS, disease-free (DFS), and disease-specific (DSS) survival (all p < .0001 on log-rank test) but not local control (LC) (p = .16). Unilateral HPV-positive disease treated with surgery alone was associated with significantly worse DFS (p < .0001) and LC (p < .0001) compared to radiotherapy alone or combined modalities (5-year DFS: 24.9%, 82.3% and 94.3%; 5-year LC: 41.8%, 98.8% and 98.6%). OS was not significantly different (p = .16). Unilateral HPV-negative disease treated with surgery alone was associated with significantly worse LC (p = .017) (5-year LC: estimate unavailable, 93.3% and 96.6%, respectively). Small numbers with bilateral disease precluded meaningful sub-group analysis. CONCLUSIONS: HPV status is associated with variable management and outcomes in HNSCCUP. Unilateral neck disease is treated variably and associated with poorer outcomes when managed with surgery alone. The impact of diagnostic oropharyngeal surgery on primary site emergence, survival and functional outcomes is unestablished.