Conserved stromal-immune cell circuits secure B cell homeostasis and function.

B cell zone reticular cells (BRCs) form stable microenvironments that direct efficient humoral immunity with B cell priming and memory maintenance being orchestrated across lymphoid organs. However, a comprehensive understanding of systemic humoral immunity is hampered by the lack of knowledge of global BRC sustenance, function and major pathways controlling BRC-immune cell interactions. Here we dissected the BRC landscape and immune cell interactome in human and murine lymphoid organs. In addition to the major BRC subsets underpinning the follicle, including follicular dendritic cells, PI16+ RCs were present across organs and species. As well as BRC-produced niche factors, immune cell-driven BRC differentiation and activation programs governed the convergence of shared BRC subsets, overwriting tissue-specific gene signatures. Our data reveal that a canonical set of immune cell-provided cues enforce bidirectional signaling programs that sustain functional BRC niches across lymphoid organs and species, thereby securing efficient humoral immunity.

PI16+ reticular cells in human palatine tonsils govern T cell activity in distinct subepithelial niches.

Fibroblastic reticular cells (FRCs) direct the interaction and activation of immune cells in discrete microenvironments of lymphoid organs. Despite their important role in steering innate and adaptive immunity, the age- and inflammation-associated changes in the molecular identity and functional properties of human FRCs have remained largely unknown. Here, we show that human tonsillar FRCs undergo dynamic reprogramming during life and respond vigorously to inflammatory perturbation in comparison to other stromal cell types. The peptidase inhibitor 16 (PI16)-expressing reticular cell (PI16+ RC) subset of adult tonsils exhibited the strongest inflammation-associated structural remodeling. Interactome analysis combined with ex vivo and in vitro validation revealed that T cell activity within subepithelial niches is controlled by distinct molecular pathways during PI16+ RC-lymphocyte interaction. In sum, the topological and molecular definition of the human tonsillar stromal cell landscape reveals PI16+ RCs as a specialized FRC niche at the core of mucosal immune responses in the oropharynx.

Prediction of extranodal extension in oropharyngeal cancer patients and carcinoma of unknown primary: value of metabolic tumor imaging with hybrid PET compared with MRI and CT.

OBJECTIVES: The aim of this study was to investigate the value of metabolic tumor imaging using hybrid PET for the preoperative detection of extranodal extension (ENE) in lymph node metastases of oropharyngeal squamous cell carcinoma (OPSCC). METHODS: We performed a retrospective analysis of a consecutive cohort of patients with OPSCC treated with primary surgery with or without adjuvant (chemo-) radiotherapy at the Kantonsspital Sankt-Gallen and the University Hospital Zurich, Switzerland, from 2010 until 2019. Hybrid PET was compared to conventional cross-sectional imaging with MRI and CT. Histopathological presence of ENE of neck dissection specimen served as gold standard. RESULTS: A total number of 234 patients were included in the study, 95 (40.6%) of which had pathological ENE (pENE). CT has a good specificity with 93.7%; meanwhile, MRI was the most sensitive diagnostic method (72.0%). The nodal metabolic tumor parameters (SUVmax, TLG, MTV) were significantly higher in patients with positive ENE (p < 0.001 for all three parameters) than in patients with negative ENE (p < 0.001, for all three parameters). CONCLUSIONS: CT achieved the best specificity, while MRI had the best sensitivity to detect ENE. Nodal metabolic tumor parameters differed significantly between ENE-positive/negative and p16-positive/negative patients. Hence, quantitative data obtained by metabolic imaging might predict presence of ENE and, therefore, could be helpful in customizing therapy management.

Zenker's diverticulum: outcome of endoscopic surgery is dependent on the intraoperative exposure.

The purpose of the present study is to evaluate long-term outcome and patients' satisfaction after endoscopic therapy of Zenker's diverticulum (ZD) and to analyze the results of the stapler technique in comparison with the application of the carbon dioxide (CO2) laser. A retrospective cohort study with outcome analysis of patients undergoing endoscopic cricopharyngeal myotomy with either stapler or CO2 laser between October 2000 and December 2010 by a single surgeon was performed. Patient's medical charts were reviewed with respect to symptoms before intervention, intra and post operative complications, reasons for the choice of endoscopic technique, and postoperative relief of symptoms. Long-term follow-up was acquired by a standardized self-assessment questionnaire. Seventy-four patients (51 men, 23 women) with a median age at operation of 74 years (range 45-93 years) were enrolled in this study. Forty-five patients underwent endoscopic repair of a ZD with stapler, 29 patients with CO2 laser. The mean follow-up was 4.7 years. We did not observe significant differences for intra and post operative complications, hospital stay, time until normal oral food intake, need for revision, and long-term subjective symptom relief between the two groups. Overall complication (12 %) and recurrence rate (11 %) for the endoscopic techniques were low. Endoscopic surgery had also a high success rate in recurrence cases (87.5 %). According to our study, the most important factor for the success rate of endoscopic treatment was the intraoperative exposure of the ZD. The endoscopic minimally invasive approach is a safe and effective treatment modality and can be considered as the treatment of choice for primary and recurrent ZD. The intraoperative exposure is decisive for the technique applied and the long-term success.

Human papilloma virus and survival of oropharyngeal cancer patients treated with surgery and adjuvant radiotherapy.

Impact of p16 protein, a surrogate marker for human papilloma virus induced cancer, p53 and EGFR as well as clinical factors on survival in a patient cohort with oropharyngeal squamous cell carcinoma (OPSCC) treated by surgical resection and adjuvant radiotherapy (RT) ± concomitant chemotherapy (CT). This is a retrospective analysis of patient's charts and tumor tissue. 57 patients were consecutively included and their tumor tissue assembled on a tissue microarray following immunohistochemical analysis. Survival times were estimated by means of Kaplan-Meier analysis. The importance of clinical and immunohistochemical factors for outcome was estimated by cox proportional hazard models. With 88% 5-year overall survival, 91% 5-year disease-specific survival and 91% 5-year disease-free survival, respectively, we found excellent survival rates in this surgically treated patient cohort of mainly advanced OPSCC (93% AJCC stage III or IV). The only factors positively influencing survival were p16 overexpression as well as p53 negativity and even more pronounced the combination of those biomarkers. Survival analysis of patients classified into three risk categories according to an algorithm based on p16, smoking, T- and N-category revealed a low, intermediate and high-risk group with significant survival differences between the low and the high-risk group. Patients with OPSCC can be successfully treated by surgery and adjuvant RT ± CT with a clear survival benefit of p16 positive, p53 negative patients. We recommend considering a combination of immunohistochemical (p16, p53) and clinical factors (smoking, T- and N-category) for risk stratification.

The role of sentinel lymph node biopsy for thin cutaneous melanomas of the head and neck.

From 18% to 35% of cutaneous melanomas are located in the head and neck, and nearly 70% are thin (Breslow thickness ≤ 1 mm). Sentinel lymph node biopsy (SLNB) has an established role in staging of intermediate-thickness melanomas, however its use in thin melanomas remains controversial. In this article, we review the literature regarding risk factors for occult nodal metastasis in thin cutaneous melanoma of the head and neck (CMHN). Based on the current literature, we recommend SLNB for all lesions with Breslow thickness ≥ 0.75 mm, particularly when accompanied by adverse features including mitotic rate ≥ 1 per mm(2), ulceration, and extensive regression. SLNB should also be strongly considered in younger patients (e.g. < 40 years old), especially in the presence of additional adverse features. All patients who do not proceed with sentinel lymph node biopsy must be carefully followed to monitor for regional relapse.

Validity of frozen section in sentinel lymph node biopsy for the staging in oral and oropharyngeal squamous cell carcinoma.

BACKGROUND AND OBJECTIVES: The potential of avoiding a secondary surgery for therapeutic neck dissection (TND) by sentinel node (SN) positivity makes the intraoperative evaluation of SNs an attractive option. The aim of this study was to analyze accuracy of intraoperative frozen section (FS) for detection of occult metastases in a large single institutional patient cohort undergoing SN-biopsy. METHODS: Between 2000 and 2010, 92 consecutive patients with early stage oropharyngeal squamous cell carcinoma (OSCC) (cT1/cT2/cN0) were prospectively enrolled. Detection rate of occult metastases by monoslice FS was compared with the definitive histopathologic work up by step serial sectioning (SSS) and immunohistochemistry (IHC). In case of SN-positivity on FS TND was performed in the same narcosis. RESULTS: 15/92 patients revealed positive SNs by FS compared to 34/92 after SSS and IHC. Sensitivity, NPV and FNR for the detection of all sizes of metastases by FS was 47, 77, and 52%, for isolated tumor cells (ITC) 8, 86, 92%, for micrometastases 43, 90, 57%, and for macrometastases 93, 98, 7%. CONCLUSION: Sensitivity of FS by the monoslice depends on the metastases size and allows a single-stage procedure in half of the SN-positive patients. To improve sensitivity for small tumor deposits either a multislice-technique or molecular methods are needed.

Thyroid incidentalomas in FDG-PET/CT: prevalence and clinical impact.

To evaluate the prevalence of thyroid FDG-PET/CT incidentalomas and the risk of malignancy in focal findings. A retrospective study of 3,062 PET scans was performed between 05/2006 and 09/2009. Prevalence of thyroid incidentalomas, risk of malignancy and correlation between standard uptake value (SUV) and cancer risk were analysed. The overall prevalence of thyroid incidentalomas was 2.4%. 71% showed a focal and 29% a diffuse uptake. In the focal uptake group, the diagnosis was clarified in 79% with cytology/histology. In 23.8% of the patients with a focal uptake, a malignant lesion was found. Diffuse uptake was predominantly associated with autoimmune thyroiditis. There was no statistically significant difference in the SUVmax between benign and malignant focal lesions (p = 0.0982). Patients with incidental focal uptake in the thyroid during FDG-PET/CT bear a considerable risk of malignancy and should undergo cytologic clarification of the diagnosis.

Prevalence of Transcriptionally Active HPV Infection in Tumor-Free Oropharyngeal Tissue of OPSCC-Patients.

Objectives: The natural history of HPV-related oropharyngeal squamous cell carcinoma (OPSCC) is still largely unknown. Since reports of second primary tumors (SPTs) in patients with HPV-related OPSCCs are increasing, a multifocal HPV infection, hinting a «virus-induced field effect¼, has been hypothesized. This study aimed to investigate the HPV-prevalence in normal appearing oropharyngeal tissue in patients with OPSCCs. Materials and Methods: 49 OPSCC patients undergoing panendoscopy were prospectively enrolled. Tumor specimens and biopsies of normal appearing oropharyngeal tissue adjacent to and distant from the index OPSCC underwent histopathological examination, p16INK4A immunohistochemical staining, HPV DNA and mRNA-detection. Patient characteristics and follow-up data on SPTs were obtained. Results: 26 of 49 (53%) OPSCC were positive for HPV DNA and p16INK4A. HPV mRNA was detected in 23 of 26 (88%) of these tumor samples. HPV DNA was detected in 36% adjacent mucosa and in 17% distant mucosa samples and only in patients with an HPV-related index OPSCC. HPV mRNA could not be detected in tumor-free distant and adjacent mucosa samples. No evidence of association between HPV detection in normal appearing mucosa and development of second primary tumors was found. Conclusions: HPV was detectable but not transcriptionally active in adjacent/distant tumor-free oropharyngeal tissue. This suggests that a multifocal HPV infection, hinting a «virus-induced fielcd cancerization¼, may not be pertaining to HPV-related OPSCC.

Podoplanin expression correlates with sentinel lymph node metastasis in early squamous cell carcinomas of the oral cavity and oropharynx.

In patients with early head and neck squamous cell carcinoma (HNSCC), occult lymph node metastasis is difficult to predict by clinical or pathological parameters. However, such parameters are necessary to select patients either for elective neck dissection or the sentinel lymph node (SLN) procedure. The membrane glycoprotein podoplanin is normally expressed in lymphatic endothelial cells. Recently, expression of podoplanin by cancer cells was demonstrated to promote tumor cell motility and tumor lymphangiogenesis in vitro. The value of cancer cell-expressed podoplanin was to be determined as a predictive marker for SLN metastasis in early HNSCC of the oral cavity and oropharynx. One hundred twenty patients with HNSCC of the oral cavity and oropharynx undergoing a SLN biopsy were enrolled in this prospective clinical trial of SLN biopsy. Cancer cell-expressed podoplanin was determined by immunohistochemistry using tissue microarrays. Podoplanin expression was quantified by the intensity reactivity score and categorized into expression and nonexpression. SLN examination revealed occult metastasis in 45 patients (37.5%). Twenty-nine of 120 (24.2%) primary HNSCC showed podoplanin expression. Podoplanin expression correlated significantly with SLN metastasis (p = 0.029) and remained a significant predictor for lymph node status even after controlling for tumor stage (p = 0.028). As a predictive marker for SLN metastasis, however, podoplanin expression reached a sensitivity of a mere 36% and a specificity of 83%. Podoplanin expression is associated with metastasis to lymph nodes in vivo. Podoplanin immunohistochemistry in early HNSCC of the oral cavity and oropharynx may help to select patients for the SLN procedure and to identify patients with increased risk for presence of occult lymph node metastasis in the neck.

Long-term experience in sentinel node biopsy for early oral and oropharyngeal squamous cell carcinoma.

OBJECTIVE: Long-term results of sentinel node biopsy (SNB) in early (T1/T2) oral and oropharyngeal squamous cell carcinoma (OSCC) in a single-institution experience. METHODS: Prospective consecutive cohort analysis of 79 patients (67% male, median age 60 years, age range 34-87 years) included between 2000 and 2006. Lymphatic mapping consisted of preoperative lymphoscintigraphy, single photon emission computed tomography (SPECT/CT), and intraoperative use of a handheld gamma probe. Endpoints of the study were neck control rate, overall (OS), disease-specific (DSS), and disease-free survival (DFS). RESULTS: Twenty-nine of 79 patients (37%) had positive sentinel nodes (SN). Six of 29 (21%) patients showed isolated tumor cells, 14/29 (48%) micrometastases, and 9/29 (31%) macrometastases. OS, DFS, and DSS at 5 years for the entire cohort were 80, 85, and 87%, for SN-negative patients were 88, 96, and 96%, and for SN-positive patients were 74, 73, and 77%, respectively. Only the difference in DSS achieved statistical significance. The neck control rate after 5 years was 96% in SN-negative and 74% in SN-positive patients. This difference was statistically significant. CONCLUSIONS: SNB is a safe and accurate staging modality to select patients with clinically stage I/II OSCC with occult lymph node disease for elective neck dissection (END). The promising reported short-term results have been sustained by long-term follow-up. Patients with negative SN and no END achieve an excellent neck control rate which compares favorably with reports on primary END. The neck control rate in SN-negative patients is superior to that in SN-positive patients, which is reflected in superior DSS.

Down regulation of E-Cadherin (ECAD) - a predictor for occult metastatic disease in sentinel node biopsy of early squamous cell carcinomas of the oral cavity and oropharynx.

BACKGROUND: Prognostic factors in predicting occult lymph node metastasis in patients with head and neck squamous-cell carcinoma (HNSCC) are necessary to improve the results of the sentinel lymph node procedure in this tumour type. The E-Cadherin glycoprotein is an intercellular adhesion molecule in epithelial cells, which plays an important role in establishing and maintaining intercellular connections. OBJECTIVES: To determine the value of the molecular marker E-Cadherin in predicting regional metastatic disease. METHODS: E-Cadherin expression in tumour tissue of 120 patients with HNSCC of the oral cavity and oropharynx were evaluated using the tissue microarray technique. 110 tumours were located in the oral cavity (91.7%; mostly tongue), 10 tumours in the oropharynx (8.3%). Intensity of E-Cadherin expression was quantified by the Intensity Reactivity Score (IRS). These results were correlated with the lymph node status of biopsied sentinel lymph nodes. Univariate and multivariate analysis was used to determine statistical significance. RESULTS: pT-stage, gender, tumour side and location did not correlate with lymph node metastasis. Differentiation grade (p = 0.018) and down regulation of E-Cadherin expression significantly correlate with positive lymph node status (p = 0.005) in univariate and multivariate analysis. CONCLUSION: These data suggest that loss of E-cadherin expression is associated with increased lymhogeneous metastasis of HNSCC. E-cadherin immunohistochemistry may be used as a predictor for lymph node metastasis in squamous cell carcinoma of the oral cavity and oropharynx. LEVEL OF EVIDENCE: 2b.

Minimally invasive techniques for head and neck malignancies: current indications, outcomes and future directions.

The trend toward minimally invasive surgery, appropriately applied, has evolved over the past three decades to encompass all fields of surgery, including curative intent cancer surgery of the head and neck. Proper patient and tumor selection are fundamental to optimizing oncological and functional outcomes in such a personalized approach to cancer treatment. Training, experience, and appropriate technological equipment are prerequisites for any type of minimally invasive surgery. The aim of this review was to provide an overview of currently available techniques and the evidence justifying their use. Much evidence is in favor of routine use of transoral laser resection, transoral robot-assisted surgery, transnasal endoscopic resection, sentinel node biopsy, and endoscopic neck surgery for selected malignant tumors, by experienced surgical teams. Technological advances will enhance the scope of this type of surgery in the future and physicians need to be aware of the current applications and trends.

Impact of the new TNM Staging System (8th edition) on oral tongue cancers.

AIM OF THE STUDY: For tumours of the oral tongue, the most recent 8th edition of the AJCC/UICC staging system has introduced depth of infiltration (DOI) as a novel parameter. With this study we wanted to investigate its impact regarding this risk stratification compared with the preceding 7th edition. METHODS: Between 2008 and 2017, 161 patients of two tertiary referral centres in Switzerland (Kantonsspital St. Gallen and University Hospital Zurich) with T1 N0 or T2 N0 tongue cancers were enrolled in this study. The primary tumours were restaged according to the 8th edition of the TNM classification. Kaplan-Meier curves for overall and disease-specific survival were calculated. RESULTS: According to the 7th edition, of the 161 patients, 102 were staged after surgery as pT1 (stage I) and 59 as pT2 (stage II). According to the 8th edition, 36 patients (22.4%) were re-staged to a higher stage. Of these 36 patients, 8 (22.2%) experienced a recurrence, and 9 (25%) died. In the remaining, not re-staged group, 20 patients (16.0%) experienced a recurrence (p = 0.55) and 14 (11.2%) died (p = 0.025*). The 7th edition showed a statistically significant difference between pT1 and pT2 tumours for overall survival (p = 0.025), but not for disease-specific survival (p = 0.091), whereas the 8th edition was able to well discriminate between pT1, pT2 and pT3 for both overall (pT1 vs pT2, p = 0.016*; pT2 vs pT3, p = 0.031*) and disease-specific survival (pT1 vs pT2, p = 0.037*; pT2 vs pT3, p = 0.023*). CONCLUSION: The recent TNM 8th edition provides a more accurate prediction of overall and disease-specific survival for this subgroup of patients. Hence, a more aggressive treatment should be considered for patients re-staged to pT3 due to depth of infiltration.

Distinct microbial communities colonize tonsillar squamous cell carcinoma.

Squamous cell carcinoma of the tonsil is one of the most frequent cancers of the oropharynx. The escalating rate of tonsil cancer during the last decades is associated with the increase of high risk-human papilloma virus (HR-HPV) infections. While the microbiome in oropharyngeal malignant diseases has been characterized to some extent, the microbial colonization of HR-HPV-associated tonsil cancer remains largely unknown. Using 16S rRNA gene amplicon sequencing, we have characterized the microbiome of human palatine tonsil crypts in patients suffering from HR-HPV-associated tonsil cancer in comparison to a control cohort of adult sleep apnea patients. We found an increased abundance of the phyla Firmicutes and Actinobacteria in tumor patients, whereas the abundance of Spirochetes and Synergistetes was significantly higher in the control cohort. Furthermore, the accumulation of several genera such as Veillonella, Streptococcus and Prevotella_7 in tonsillar crypts was associated with tonsil cancer. In contrast, Fusobacterium, Prevotella and Treponema_2 were enriched in sleep apnea patients. Machine learning-based bacterial species analysis indicated that a particular bacterial composition in tonsillar crypts is tumor-predictive. Species-specific PCR-based validation in extended patient cohorts confirmed that differential abundance of Filifactor alocis and Prevotella melaninogenica is a distinct trait of tonsil cancer. This study shows that tonsil cancer patients harbor a characteristic microbiome in the crypt environment that differs from the microbiome of sleep apnea patients on all phylogenetic levels. Moreover, our analysis indicates that profiling of microbial communities in distinct tonsillar niches provides microbiome-based avenues for the diagnosis of tonsil cancer.

Lysyl oxidase expression is an independent marker of prognosis and a predictor of lymph node metastasis in oral and oropharyngeal squamous cell carcinoma (OSCC).

Proteins of the lysyl oxidase (LOX) family are important modulators of the extracellular matrix. However, they have an important role in the tumour development as well as in tumour progression. To evaluate the diagnostic and prognostic value of the LOX protein in oral and oropharyngeal squamous cell carcinoma (OSCC) we performed QRT-PCR and immunohistochemical analysis on two tissue microarrays (622 tissue samples in total). Significantly higher LOX expression was detected in high grade dysplastic oral mucosa as well as in OSCC when compared to normal oral mucosa (P < 0.001). High LOX expression was correlated with clinical TNM stage (P = 0.020), lymph node metastases for the entire cohort (P < 0.001), as well as in the subgroup of small primary tumours (T1/T2, P < 0.001). Moreover, high LOX expression was correlated with poor overall survival (P = 0.004) and disease specific survival (P = 0.037). In a multivariate analysis, high LOX expression was an independent prognostic factor, predicting unfavourable overall survival. In summary, LOX expression is an independent prognostic biomarker and a predictor of lymph node metastasis in OSCC. Moreover, LOX overexpression may be an early phenomenon in the pathogenesis of OSCC and thus an attractive novel target for chemopreventive and therapeutic strategies.

Evaluation of clinical and histomorphological parameters as potential predictors of occult metastases in sentinel lymph nodes of early squamous cell carcinoma of the oral cavity.

BACKGROUND: Sentinel node biopsy (SNB) for cN0 early squamous cell carcinoma (SCC) of the oral cavity has been validated by numerous studies. Around 30% of SNB will detect occult disease. Several clinical and morphological features of the primary tumor have been claimed to be predictive for occult metastasis in elective neck dissections. The aim of this study was to assess these factors in the context of SNB. METHODS: Seventy-eight patients undergoing SNB for T(1/2) oral SCC from the years 2000 to 2007 were prospectively included. Primary tumors were reviewed for the following morphological and clinical parameters: grade of differentiation, tumor depth, tumor thickness, perineural invasion, lymphatic invasion, vascular invasion, muscle invasion, lymphoplasmacytic infiltration, and mode of invasion, age, gender, primary tumor site, tumor side, and cT category. RESULTS: Statistical analysis revealed significance to predict occult metastasis in the SNB for grade of differentiation (P = 0.002), lymphatic invasion (P < 0.001), and mode of invasion (P < 0.001). None of the other factors reached significance. The mean tumor depth was 6.45 mm (range 0.72-15.15 mm) and the mean tumor thickness was 7.2 mm (range 0.72-15.15 mm). None of the cutoff values reached significance for predicting occult disease. CONCLUSIONS: Tumor depth and tumor thickness failed to achieve statistical significance for prediction of occult metastases in the context of SNB. Patients with cN0 early squamous cell carcinoma of the oral cavity should be offered SNB regardless of their tumor depth and thickness. Poorly differentiated carcinomas, carcinomas with lymphangiosis, and carcinomas with a dissolute mode of invasion show a high probability of positive SNB.

Contemporary management of cancer of the oral cavity.

Oral cancer represents a common entity comprising a third of all head and neck malignant tumors. The options for curative treatment of oral cavity cancer have not changed significantly in the last three decades; however, the work up, the approach to surveillance, and the options for reconstruction have evolved significantly. Because of the profound functional and cosmetic importance of the oral cavity, management of oral cavity cancers requires a thorough understanding of disease progression, approaches to management and options for reconstruction. The purpose of this review is to discuss the most current management options for oral cavity cancers.

Is there an additional value of SPECT/CT over planar lymphoscintigraphy for sentinel node mapping in oral/oropharyngeal squamous cell carcinoma?

BACKGROUND: Lymphatic mapping for sentinel node biopsy (SNB) has been shown to be crucial for detection of sentinel lymph nodes (SLN). Previous reports suggested a benefit of single photon emission computed tomography with CT (SPECT/CT) over dynamic planar lymphoscintigraphy (LS) alone. The aim was to assess whether there is an additional value of SPECT/CT over LS alone for lymphatic mapping of SLNs in oral/oropharyngeal SCC. METHODS: A consecutive cohort of 58 patients was evaluated using SNB with additional SPECT/CT to preoperative LS. RESULTS: In the entire cohort of 58 patients undergoing LS and SPECT/CT, hot spots could be revealed in all but 4 cases. The guidance of the handheld gamma probe was able to reveal 9 additional SLNs within 3 patients not detected by either modality. Lymphoscintigraphy showed full concordance with SPECT/CT in 81% of the cases. SPECT/CT was able to detect additional HS in 11 patients, in 1 case even with additional metastatic disease. The false negative rate for SNB was 6%, and the negative predictive value 98%. CONCLUSIONS: SPECT/CT has the potential to detect more SLNs, which might harbor occult disease, than LS alone. With regard to the excellent results achieved with LS and the intraoperative use of the gamma probe, SPECT/CT is not indispensable for successful SNB. Both imaging modalities have difficulties in detecting level I sentinel nodes close to the injection site.

Head and neck squamous cell carcinoma (HNSCC)--detection of synchronous primaries with (18)F-FDG-PET/CT.

PURPOSE: The aim of the study was to evaluate (18)F-FDG-PET/CT for the detection of synchronous primaries at initial staging of patients with head and neck squamous cell carcinoma (HNSCC). METHODS: FDG-PET/CT images acquired between March 2001 and October 2007 in 589 consecutive patients (147 women, 442 men; mean age 61.5 years, age range 32-97 years) with proven HNSCC were reviewed for the presence of synchronous primaries. Cytology, histology and/or clinical and imaging follow-up served as reference standard. RESULTS: FDG-PET/CT showed 69 suspected synchronous primaries in 62 patients of which 56 were finally confirmed in 44 patients. Of the 56 second cancers, 46 (82%) were found in the aerodigestive tract in the following locations: lung (26, 46%), head and neck (15, 17%), oesophagus (5, 9%). Ten second cancers (18%) were located outside the aerodigestive tract (colon, five; stomach, lymphoma, breast, thymus and kidney, one each). Six patients had three synchronous primaries and three patients had four synchronous cancers. Nine synchronous cancers were not detected by PET/CT (four head and neck, two lung, two oesophageal, one gastric). False-positive PET/CT findings were mainly related to benign FDG uptake in the intestine due to benign or precancerous polyps or physiological FDG uptake in other head and neck regions. Overall the prevalence of synchronous second primaries according to the reference standard was 9.5%, of which 84% were detected with FDG-PET/CT. In 80% of the patients, therapy was changed because of the detection of a synchronous primary. CONCLUSION: FDG-PET/CT detects a considerable number of synchronous primaries (8.0% prevalence) at initial staging of patients with HNSCC. Synchronous cancers were predominantly located in the aerodigestive tract, primarily in the lung, head and neck and oesophagus. Detection of second primaries has an important impact on therapy. PET/CT should be performed before panendoscopy.