18F-fluorodeoxyglucose positron emission tomography to evaluate cervical node metastases in patients with head and neck squamous cell carcinoma: a meta-analysis

Diagnostic Performance of 18F-FDG PET/CT According to Delay After Treatment to Detect Subclinical Recurrence of Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) remains a malignancy with high rates of locoregional recurrence and poor prognosis for recurrent cases. Early detection of subclinical lesions is challenging but critical for effective patient management. Imaging surveillance after treatment, particularly 18F-FDG PET/CT, has shown promise in the diagnosis of HNSCC recurrence. The aim was to evaluate the diagnostic performance of 18F-FDG PET/CT according to delay after treatment in detecting subclinical recurrence (SCR) in HNSCC patients. Methods: In this retrospective study, all 18F-FDG PET/CT scans were performed at a single center. All adults with histologically proven HNSCC who were treated with curative intent between January 1, 2006, and December 31, 2021, were included. They had a normal clinical examination before each scan. Patients who underwent an intensive follow-up strategy after treatment had 18F-FDG PET/CT with an intravenous contrast agent at 3-6 mo and annually thereafter for 5 y. The primary endpoint was diagnostic performance (positive and negative predictive values, sensitivity, specificity, and accuracy). Results: In total, 2,566 18F-FDG PET/CT scans were performed among 852 patients, with an average of 3 scans per patient. The overall diagnostic performance measures were as follows: positive predictive value (88%), negative predictive value (98%), sensitivity (98%), specificity (89%), and accuracy (93%). There were no significant differences in diagnostic performance over time. The scans detected 126 cases of SCR (14.8%) and 118 cases of metachronous cancer (13.8%). The incidence of SCR decreased over time, with the highest detection rate in the first 2 y after treatment. Positive predictive value improved over time, reaching 90% for the digital Vision 600 system (third period) compared with 76% for the analog Gemini GXLi system (first period, P < 0.001). Multivariate analysis identified advanced stage, high body mass index, and initial PET/CT upstaging as predictive factors for detection of SCR. Conclusion: Our study demonstrates that 18F-FDG PET/CT has high diagnostic performance in detecting SCR during follow-up after treatment of HNSCC, especially in the first 2 y. Advanced tumor stage, initial PET/CT upstaging, and high body mass index were associated with a higher likelihood of SCR detection. The routine use of 18F-FDG PET/CT during follow-up seems justified for patients with HNSCC.

Modelling the lymphatic metastatic progression pathways of OPSCC from multi-institutional datasets

The elective clinical target volume (CTV-N) in oropharyngeal squamous cell carcinoma (OPSCC) is currently based mostly on the prevalence of lymph node metastases in different lymph node levels (LNLs) for a given primary tumor location. We present a probabilistic model for ipsilateral lymphatic spread that can quantify the microscopic nodal involvement risk based on an individual patient's T-category and clinical involvement of LNLs at diagnosis. We extend a previously published hidden Markov model (HMM), which models the LNLs (I, II, III, IV, V, and VII) as hidden binary random variables (RVs). Each represents a patient's true state of lymphatic involvement. Clinical involvement at diagnosis represents the observed binary RVs linked to the true state via sensitivity and specificity. The primary tumor and the hidden RVs are connected in a graph. Each edge represents the conditional probability of metastatic spread per abstract time-step, given disease at the edge's starting node. To learn these probabilities, we draw Markov chain Monte Carlo samples from the likelihood of a dataset (686 OPSCC patients) from three institutions. We compute the model evidence using thermodynamic integration for different graphs to determine which describes the data best.The graph maximizing the model evidence connects the tumor to each LNL and the LNLs I through V in order. It predicts the risk of occult disease in level IV is below 5% if level III is clinically negative, and that the risk of occult disease in level V is below 5% except for advanced T-category (T3 and T4) patients with clinical involvement of levels II, III, and IV. The provided statistical model of nodal involvement in OPSCC patients trained on multi-institutional data may guide the design of clinical trials on volume-deescalated treatment of OPSCC and contribute to more personal guidelines on elective nodal treatment.

N0 neck trial: Does intensification of follow-up (Ultrasound + Physical Examination) influence outcomes in early-stage oral cancer?

AIM OF THE STUDY

We previously reported a survival benefit of elective neck dissection (END) over therapeutic neck dissection (TND) in patients with clinically node-negative early-stage oral cancer. We now report the results of the second question in the same study addressing the impact of adding neck ultrasound to physical examination during follow-up on outcomes.

METHODS

Patients with lateralized T1/T2 oral squamous cell carcinoma (SCC) were randomized to END or TND and to follow-up with physical-examination plus neck ultrasound (PE+US) versus physical-examination (PE). The primary endpoint was overall survival (OS).

RESULTS

Between January 2004 and June 2014, 596 patients were enrolled. This is an intention to treat analysis of 592 analysable patients, of whom 295 were allocated to PE+US and 297 to PE with a median follow-up of 77.47 months (interquartile range (IQR) 54.51-126.48). There was no significant difference (unadjusted hazard ratio [HR], 0.92, 95% CI, 0.71-1.20, p = 0.54) in 5-year OS between PE+US (70.8%, 95% CI, 65.51-76.09) and PE (67.3%, 95% CI, 61.81-72.79). Among 131 patients with neck node relapse as the first event, the median time to relapse detection was 4.85 (IQR 2.33-9.60) and 7.62 (IQR 3.22-9.86) months in PE+US and PE arms, respectively. The N stage in the PE+US arm was N1 33.8%, N2a 7.4%, N2b/c 44.1% and N3 14.7% while in PE was N1 28.6%, N2a 9.5%, N2b/c 39.7%, N3 20.6% and unknown 1.6%.

CONCLUSION

Adding neck ultrasound to physical examination during follow-up detects nodal relapses earlier but does not improve overall survival.

Role of 18F-FDG PET/CT in Head and Neck Squamous Cell Carcinoma: Current Evidence and Innovative Applications

This article provides an overview of the use of 18F-FDG PET/CT in various clinical scenarios of head-neck squamous cell carcinoma, ranging from initial staging to treatment-response assessment, and post-therapy follow-up, with a focus on the current evidence, debated issues, and innovative applications. Methodological aspects and the most frequent pitfalls in head-neck imaging interpretation are described. In the initial work-up, 18F-FDG PET/CT is recommended in patients with metastatic cervical lymphadenectomy and occult primary tumor; moreover, it is a well-established imaging tool for detecting cervical nodal involvement, distant metastases, and synchronous primary tumors. Various 18F-FDG pre-treatment parameters show prognostic value in terms of disease progression and overall survival. In this scenario, an emerging role is played by radiomics and machine learning. For radiation-treatment planning, 18F-FDG PET/CT provides an accurate delineation of target volumes and treatment adaptation. Due to its high negative predictive value, 18F-FDG PET/CT, performed at least 12 weeks after the completion of chemoradiotherapy, can prevent unnecessary neck dissections. In addition to radiomics and machine learning, emerging applications include PET/MRI, which combines the high soft-tissue contrast of MRI with the metabolic information of PET, and the use of PET radiopharmaceuticals other than 18F-FDG, which can answer specific clinical needs.

Elective Neck Dissection in Patients Undergoing Salvage Laryngectomy: Outcomes, Complications, and Considerations

Objective In this study, we sought to identify the predictors for occult nodal disease (OND) and compare oncologic outcomes in patients undergoing elective neck dissection (END) at the time of salvage laryngectomy (SLE) versus the observation group. Methods A retrospective chart review was conducted involving all patients with clinically node-negative (cN0) necks who underwent SLE at a tertiary academic center over 12 years. A total of 58 patients met the inclusion criteria and were divided into two groups: END (n=39) and observation (n=19). Primary endpoints were OND, regional recurrence-free survival (RRFS), and disease-specific survival (DSS). Univariate analysis was performed to establish the association between variables with Fisher's exact test and Mann-Whitney U test. Survival analysis was performed with the log-rank test. Results The cohort comprised 46 (79.3%) males and 12 (20.7%) females, with a mean age of 60 years. Pathological nodal disease was identified in five of 71 (7%) examined neck dissection specimens, with positive nodes found in levels II through IV. The only statistically significant predictor of OND was the rT3/rT4 stage (p=0.017). There were no differences in perioperative complications, RRFS (p=0.216), or DSS (p=0.298) between the END and observation groups. Conclusions In cN0 necks, the advanced recurrent T-stage (rT3-rT4) is a predictor for OND. As OND was found involving levels II, III, and IV in this study's specimens, formal lateral neck dissection should be the procedure of choice if END is to be performed alongside SLE. While END did not show a significantly higher morbidity profile versus conservative management in this cohort, the procedure did not improve loco-regional control or survival, even when stratifying by tumor stage.

Comprehensive literature review of oral and intravenous contrast-enhanced PET/CT: a step forward?

The integration of diagnostic CT scans into PET/CT facilitates a comprehensive single examination, presenting potential advantages for patients seeking a thorough one-shot check-up. The introduction of iodinated contrast media during PET scanning raises theoretical concerns about potential interference with uptake quantification, due to the modification of tissue density on CT. Nevertheless, this impact appears generally insignificant for clinical use, compared to the intrinsic variability of standardized uptake values. On the other hand, with the growing indications of PET, especially 18F-FDG PET, contrast enhancement increases the diagnostic performances of the exam, and provides additional information. This improvement in performance achieved through contrast-enhanced PET/CT must be carefully evaluated considering the associated risks and side-effects stemming from the administration of iodinated contrast media. Within this article, we present a comprehensive literature review of contrast enhanced PET/CT, examining the potential impact of iodinated contrast media on quantification, additional side-effects and the pivotal clinically demonstrated benefits of an all-encompassing examination for patients. In conclusion, the clinical benefits of iodinated contrast media are mainly validated by the large diffusion in PET protocols. Contrary to positive oral contrast, which does not appear to offer any major advantage in patient management, intravenous iodine contrast media provides clinical benefits without significant artifact on images or quantification. However, studies on the benefit-risk balance for patients are still lacking.

Oral Cavity Cancer Surgical and Nodal Management: A Review From the American Head and Neck Society

Importance

Lymph node metastases from oral cavity cancers are seen frequently, and there is still inconsistency, and occasional controversies, regarding the surgical management of the neck in patients with oral cancer. This review is intended to offer a surgically focused discussion of the current recommendations regarding management of the neck, focusing on the indications and extent of dissection required in patients with oral cavity squamous cell carcinoma while balancing surgical risk and oncologic outcome.

Observations

The surgical management of the neck for oral cavity cancer has been robustly studied, as evidenced by substantial existing literature surrounding the topic. Prior published investigations have provided a sound foundation on which data-driven treatment algorithms can generally be recommended.

Conclusions

Existing literature suggests that patients with oral cavity cancer should be fully staged preoperatively, and most patients should receive a neck dissection even when clinically N0. Quality standards supported by the literature include separation of each level during specimen handling and lymph node yield of 18 or more nodes. Sentinel lymph node biopsy can be considered in select tumors and within a well-trained multidisciplinary team.

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.

MRI and PET/CT in the assessment of lymph node metastases in head and neck cancer

The aim of this study is to present the diagnostic accuracy of MRI and PET/CT in the evaluation of cervical lymph nodes in patients with head and neck cancer (HNC). Data of 114 patients who underwent MRI and PET/CT prior to surgery in the time period between January 2010 and September 2021 in our center is analyzed retrospectively. Histopathological results of surgical preparations serve as the gold standard. The mean time from MRI to surgery is 22.9 (± 18.7) days, and from PET/CT to surgery 21.7 (± 19.9) days. Sensitivities of 80.4% and 80.4%, specificities of 85.7% and 87.3%, PPVs of 82.0% and 83.7% and NPVs of 84.4% and 84.6% are registered for MRI and PET/CT, respectively. 37 false results are further analyzed with respect to side and level of the affected lymph node, as well as intersections of the two imaging modalities. In 29 patients (25.4%), additional findings are described in PET/CT, 7 (6.1%) of which were histologically confirmed to be further malignancies. A combination of both MRI and PET/CT imaging modalities could improve diagnostic accuracy, especially with regard to sensitivity. A notable number of additional findings in whole body acquisition leads to the potential diagnosis of further malignancies.

Role of 18F-FDG PET/CT in Guiding Surgical Management of Clinically Node Negative Neck (cN0) in Carcinoma Oral Cavity

Conventional staging paradigm with clinical examination or imaging invariably leads to underestimation of occult metastatic neck disease in oral cavity carcinoma. The advantage of 18F-FDG PET/CT is in its ability to identify lymph nodes without morphological changes yet harboring occult metastases. We present findings of our study to evaluate diagnostic accuracy of 18F-FDG PET/CT, in detecting occult cervical lymph node metastasis in carcinoma oral cavity. In a single institution prospective study, 51 consecutive patients with histologically proven (cT1/T2) oral cavity carcinoma and clinically node negative neck (cNo), underwent 18F-FDG PET/CT before elective neck dissection of 58 neck sides. 18F-FDG PET/CT findings were compared with histopathology of dissected nodes, to calculate diagnostic accuracy. 18F-FDG PET/CT correctly characterized the occult lymph node metastasis status (true positive + true negative) in 51 of 58 neck sides, yielding diagnostic accuracy of 87.93%. Sensitivity of 18F-FDG PET/CT was 90% and specificity was 87.5%. While a positive 18F-FDG PET/CT accurately predicted the disease in only 60% (positive predictive value), a negative 18F-FDG PET/CT reasonably ruled out occult metastases in 97.67% (negative predictive value). If a decision regarding the need for neck dissection had been based solely on 18F-FDG PET/CT, the number of neck dissections would have been reduced by 74.13%. Based on diagnostic accuracy and high negative predictive value, incorporating 18F-FDG PET/CT in preoperative staging paradigm of cT1/T2 carcinoma oral cavity will guide in selection of patients in which cN0 neck can be safely observed.

Comparable Accuracy of Quantitative and Visual Analyses of [18F]FDG PET/CT for the Detection of Lymph Node Metastases from Head and Neck Squamous Cell Carcinoma

BACKGROUND

In head and neck squamous cell carcinoma (HNSCC), [18F]FDG PET/CT is recommended for detecting recurrent disease and in the initial staging for evaluating distant metastases, but its use in detecting cervical lymph metastases remains unclear. The aim of this study is to evaluate and compare the diagnostic accuracy of [8F]FDG-PET/CT using visual and semi-quantitative analyses for detecting the nodal involvement in HNSCC.

METHODS

We analyzed consecutive patients who underwent a preoperative [18F]FDG-PET/CT and neck dissection for HNSCC at our tertiary hospital. A blinded evaluation of the [18F]FDG uptake in each neck level was performed using a semi-quantitative approach (SUVmax and SUVR) and a visual grading system (uptake superior to the internal jugular vein for grade 1 and superior to the liver for grade 2). Analyses were compared to the histological results.

RESULTS

In our 211 patients, analyses demonstrated similar diagnostic accuracy using a semi-quantitative approach or a visual grading system. Regarding the visual grading system, [18F]FDG-PET/CT detected nodal metastases with a specificity of 83% for lymph nodes classified as grade 1 and 98% for those classified as grade 2. The sensitivity was moderate, ranging from 60 to 63%.

CONCLUSIONS

[18F]FDG PET/CT has a high specificity for detecting lymph node metastases in HNSCC and therefore must be considered in the nodal clinical staging.

Importance of PET/CT in Initial Workup of Head and Neck Squamous Cell Carcinoma

Objective

Assess the impact of positron emission tomography/computed tomography (PET/CT) on disease staging at presentation in patients with head and neck squamous cell carcinoma.

Study Design

Retrospective cross-sectional review.

Setting

Academic multicenter single institution (Geisinger Health System).

Methods

All patients who had PET/CT imaging during workup for head and neck squamous cell carcinoma were included in the study. Pre- and post-PET/CT clinical staging were recorded. Statistical analyses were performed for patients with a change in clinical staging or detection of second primary malignancies on PET/CT.

Results

A total of 292 patients were included in the study, 238 of whom underwent PET/CT imaging as part of their initial workup. Twenty-eight (11.9%) patients were clinically upstaged on PET/CT with 7 patients having treatment alterations based on imaging. Eighteen (7.6%) patients were found to have second primary malignancies on PET/CT.

Conclusion

The current study further illustrates the importance of PET/CT in the workup of head and neck squamous cell carcinoma. Without the inclusion of PET/CT imaging, 19.3% of patients would have either been staged inappropriately or had second primary malignancies missed, again confirming the necessity of comprehensive functional imaging during the initial pretreatment workup.

Imaging of Neck Nodes in Head and Neck Cancers - a Comprehensive Update

Cervical lymph node metastases from head and neck squamous cell cancers significantly reduce disease-free survival and worsen overall prognosis and, hence, deserve more aggressive management and follow-up. As per the eighth edition of the American Joint Committee on Cancer staging manual, extranodal extension, especially in human papillomavirus-negative cancers, has been incorporated in staging as it is important in deciding management and significantly impacts the outcome of head and neck squamous cell cancer. Lymph node imaging with various radiological modalities, including ultrasound, computed tomography and magnetic resonance imaging, has been widely used, not only to demonstrate nodal involvement but also for guided histopathological evaluation and therapeutic intervention. Computed tomography and magnetic resonance imaging, together with positron emission tomography, are used widely for the follow-up of treated patients. Finally, there is an emerging role for artificial intelligence in neck node imaging that has shown promising results, increasing the accuracy of detection of nodal involvement, especially normal-appearing nodes. The aim of this review is to provide a comprehensive overview of the diagnosis and management of involved neck nodes with a focus on sentinel node anatomy, pathogenesis, imaging correlates (including radiogenomics and artificial intelligence) and the role of image-guided interventions.

The Prognostic and Diagnostic Value of [18F]FDG PET/CT in Untreated Laryngeal Carcinoma

This study aims to determine the diagnostic accuracy of staging PET/CT and neck MRI in patients with laryngeal carcinoma and to assess the value of PET/CT in predicting progression-free survival (PFS) and overall survival (OS). Sixty-eight patients who had both modalities performed before treatment between 2014 and 2021 were included in this study. The sensitivity and specificity of PET/CT and MRI were evaluated. PET/CT had 93.8% sensitivity, 58.3% specificity, and 75% accuracy for nodal metastasis, whereas MRI had 68.8%, 61.1%, and 64.7% accuracy, respectively. At a median follow-up of 51 months, 23 patients had developed disease progression and 17 patients had died. Univariate-survival analysis revealed all utilized PET parameters as significant prognostic factors for OS and PFS (p-value < 0.03 each). In multivariate analysis, metabolic-tumor volume (MTV) and total lesion glycolysis (TLG) predicted better PFS (p-value < 0.05 each). In conclusion, PET/CT improves the accuracy of nodal staging in laryngeal carcinoma over neck MRI and adds to the prognostication of survival outcomes through the use of several PET metrics.

Computer-aided diagnostic models to classify lymph node metastasis and lymphoma involvement in enlarged cervical lymph nodes using PET/CT

BACKGROUND

It is a clinical problem to identify histological component in enlarged cervical lymph nodes, particularly in differentiation between lymph node metastasis and lymphoma involvement.

PURPOSE

To construct two kinds of deep learning (DL)-based computer-aided diagnosis (CAD) systems including DL-convolutional neural networks (DL-CNN) and DL-machine learning for pathological diagnosis of cervical lymph nodes by positron emission tomography (PET)/computed tomography (CT) images.

METHODS

We collected CT, PET, and PET/CT images series from 165 patients with enlarged cervical lymph nodes receiving examinations from January 2014 to June 2018. Six CNNs pretrained on ImageNet as DL architectures were used for two kinds of DL-based CAD models, including DL-CNN and DL-machine learning models. The DL-CNN models were constructed via transfer learning for classification of lymphomatous and metastatic lymph nodes. The DL-machine learning models were developed by DL-based features extractors and support vector machine (SVM) classifier. As for DL-SVM models, we also evaluate the effect of handcrafted radiomics features in combination of DL-based features.

RESULTS

The DL-CNN model with ResNet50 architecture on PET/CT images had the best diagnostic performance among all six algorithms with an area under the receiver operating characteristic curve (AUC) of 0.845 and accuracy of 78.13% in the testing cohort. The DL-SVM model on ResNet50 extractor showed great performance for the testing cohort with an AUC of 0.901, accuracy of 86.96%, sensitivity of 76.09%, and specificity of 94.20%. The combination of DL-based and handcrafted features yielded the improvement of diagnostic performance.

CONCLUSIONS

Our DL-based CAD systems on PET/CT images were developed for classifying metastatic and lymphomatous involvement with favorable diagnostic performance in enlarged cervical lymph nodes. Further clinical practice of our systems may improve quality of the following therapeutic interventions and optimize patients' outcomes.

PET/MR versus PET/CT for locoregional staging of oropharyngeal squamous cell cancer

Background

The value of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for TN staging in head and neck cancer (HNC) has been proven in numerous studies. A few studies have investigated the value of FDG-PET/magnetic resonance imaging (MRI) in the staging of HNC; the combined results indicate potential for FDG-PET/MRI, but the scientific evidence remains weak.

Purpose

To compare performance of FDG-PET/CT and FDG-PET/MRI for locoregional staging in patients with oropharyngeal carcinomas.

Material and Methods

Two radiologists independently of each other retrospectively reviewed primary pre-therapeutic FDG-PET/CT and FDG-PET/MRI examinations from 40 individuals with oropharyngeal carcinomas. TN stage and primary tumor size were noted. The results were compared between observers and modalities and against TN stage set at a multidisciplinary conference.

Results

For nodal staging, PET/MRI had slightly higher specificity and accuracy than PET/CT for the most experienced observer. Both methods demonstrated excellent sensitivity (≥ 0.97 and 1.00, respectively), as well as high negative predictive values (≥ 0.95 and 1.00, respectively). No significant differences were found for tumor staging or measurement of maximum tumor diameter. There was a weak agreement (κ = 0.35–0.49) between PET/CT and PET/MRI for T and N stages for both observers. Inter-observer agreement was higher for PET/MRI than for PET/CT, both for tumor staging (κ = 0.57 vs. 0.35) and nodal staging (κ = 0.69 vs. 0.55). The agreement between observers was comparable to the agreement between methods.

Conclusion

PET/MRI may be a viable alternative to PET/CT for locoregional staging (TN staging) and assessment of maximal tumor diameter in oropharyngeal squamous cell cancer.

[Metabolic Tumor Imaging in Head and Neck Oncology]

Metabolic Tumor Imaging in Head and Neck Oncology Abstract. Fluorodeoxyglucose with position emission tomography combined with CT or MRI (FDG-PET) has become an important diagnostic and staging method in head and neck squamous cell carcinoma. Some regard FDG-PET merely as a tool able of displaying cancer cells as bright spots on imaging. However, quantification of FDG uptake can be used as a surrogate marker for tumor aggressiveness and predict tumor response before (chemo)-radiation. The FDG uptake of the primary tumor can also predict surgical outcome measures such as depth of invasion, occult nodal metastasis, or bone invasion for oral cancer and/or organ preservation in hypopharyngeal cancer.

Utilization of PET/CT Scan in Head and Neck Carcinoma: A Tertiary Care Hospital Experience

Objective

PET/CT scan has been increasingly used in assessment of Head and Neck cancer prior to treatment for evaluation and for surveillance. In this study we aim to assess the utilization of PET/CT scan at a tertiary care hospital.

Methods

Retrospectively data was reviewed of all patients of Head and Neck cancer who underwent PET/CT scan for workup or for follow-up between July 2018 and December 2019. PET/CT scan done in the pre-treatment assessment and post-treatment surveillance were analyzed for its utility.

Results

A total of 145 patients were included. The main indication for pre-treatment PET/CT scan was loco-regionally advanced disease (62 of 90 patients, 68.8%). No specific indication was noted in 19 patients (21%). A significant change in treatment decision was seen in pre-treatment patients based on M stage following a PET/CT scan. However, no change was noted on the basis of T or N stage. In the post-treatment surveillance there was a significant correlation of type of recurrence with clinical assessment and indication for PET/CT scan. 37 out of 87 patients (42.5%) underwent PET/CT scan for no specific reason, of which, 07 patients (18.9%) were detected to have distant metastasis.

Conclusion

Role of PET/CT in the pre-treatment assessment is very limited and maybe confined to advanced local or regional disease. Post-treatment surveillance with PET/CT scan has a promising role and must be done as a baseline during 1st follow up at 03 months in all patients who have advanced disease and have undergone multi-modality treatment for the same.

Assessment of Occult Nodal Micrometastases to the Clinically Negative Contralateral Neck in Locally Advanced Supraglottic Squamous Cell Carcinoma

The aim of this study is  to study the incidence of occult nodal micrometastases (ONM) in the contralateral neck and compare it to the laterality of the primary tumor. Retrospective analysis of the medical records of patients with locally advanced supraglottic squamous cell carcinoma and Clinically negative contralateral neck (cN0-CLN) - who had concurrent total laryngectomy and bilateral neck dissection as their primary treatment at the Otolaryngology Department, Al Kas Al Ainy School of Medicine-Cairo University between 2015 and 2020 - was conducted. Patients were divided into 3 groups according to the extent of the primary tumor. 28 patients met the inclusion criteria. Patients with well-lateralized tumors were 14 (Group A), tumors abutting the midline were 4 (Group B) and tumors significantly involving the contralateral side were 14 (Group C). There was no statistically significant difference in age of patients among the three groups. Eleven patients had cervical lymphadenopathy in the final pathology reports. Seven patients had ONM, all of whom were among group C patients (7/14; 50%). The degree of tumor differentiation was not associated with the presence of ONM. Treatment of the cN0-CLN is justified in locally advance supraglottic carcinoma significantly crossing the midline. The total number of patients with ONM in the cN0-CLN exceeds the threshold for observation, however the authors could not recommend or refute the practice of routine prophylactic treatment of the cN0-CLN as none of the patients-in this study-with well-lateralized tumors or tumors just abutting the midline showed ONM.

Nodal Disease and Survival in Oral Cancer: Is Occult Metastasis a Burden Factor Compared to Preoperatively Nodal Positive Neck?

The impact of neck involvement and occult metastasis (OM) in patients with oral squamous cell carcinoma (OSCC) favors an elective neck dissection. However, there are barely any existing data on survival for patients with OM compared with patients with positive lymph nodes detected preoperatively. This study aims to compare survival curves of patients suffering from lymph nodal metastases in a preoperatively N+ neck with those suffering from OM. In addition, clinical characteristics of the primary tumor were analyzed to predict occult nodal disease. This retrospective cohort study includes patients with an OSCC treated surgically with R0 resection with or without adjuvant chemoradiotherapy between 2010 and 2016. Minimum follow-up was 60 months. Kaplan–Meier analysis was used to compare the survival between patients with and without occult metastases and patients with N+ neck to those with occult metastases. Logistic regression was used to detect potential risk factors for occult metastases. The patient cohort consisted of 226 patients. Occult metastases occurred in 16 of 226 patients. In 53 of 226 patients, neck lymph nodes were described as suspect on CT imaging but had a pN0 neck. Higher tumor grading increased the chance of occurrence of occult metastasis 2.7-fold (OR = 2.68, 95% CI: 1.07–6.7). After 12, 24, 48 and 60 months, 82.3%, 73.8%, 69% and 67% of the N0 patients, respectively, were progression free. In the group with OM occurrence, for the same periods 66.6%, 50%, 33.3% and 33.3% of the patients, respectively, were free of disease. For the same periods, respectively, 81%, 63%, 47% and 43% of the patients in the N+ group but without OM remained disease free. The predictors for progression-free survival were a positive N status (HR = 1.44, 95% CI: 1.08–1.93) and the occurrence of OM (HR = 2.33, 95% CI: 1.17–4.64). The presence of occult metastasis could lead to decreased survival and could be a burdening factor requiring treatment escalation and a more aggressive follow-up than nodal disease detected in the preoperative diagnostic imaging.

Real-Life Performance of F-18-FDG PET/CT in Patients with Cervical Lymph Node Metastasis of Unknown Primary Tumor

Background: Neoplasms in the head and neck region possess higher glycolytic activity than normal tissue, showing increased glucose metabolism. F-18-Flourodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) can identify an unknown primary tumor (CUP). Aim: The aim of this study was to assess the real-life performance of F-18-FDG-PET/CT in detecting primary sites in patients with cervical lymph node metastasis of CUP. Methods: A retrospective data analysis of 31 patients who received FDG-PET/CT between June 2009 and March 2015 in a CUP context with histologically confirmed cervical lymph node metastasis was included. Results: In 48% of the patients (15/31), PET/CT showed suspicious tracer accumulation. In 52% of the patients (16/31), there was no suspicious radiotracer uptake, which was confirmed by the lack of identification of any primary tumor in 10 cases until the end of follow-up. FDG-PET/CT had a sensitivity of 67%, specificity of 91%, PPV of 92%, and NPV of 63% in detecting the primary tumor. Additionally, PET/CT showed suspicious tracer accumulation according to further metastasis in 32% of the patients (10/31). Conclusion: FDG-PET/CT imaging is a useful technique for primary tumor detection in patients in a cervical CUP context. Furthermore, it provides information on the ulterior metastasis of the disease.

ADC Values of Cytologically Benign and Cytologically Malignant 18 F-FDG PET-Positive Lymph Nodes of Head and Neck Squamous Cell Carcinoma

Simple Summary

In squamous cell carcinoma of the head and neck, 18F-fluordeoxyglucose positron emission tomography (FDG-PET), diffusion-weighted magnetic resonance imaging (DW-MRI) and ultrasound-guided fine needle aspiration are commonly used imaging tools for nodal staging (N-staging). Although FDG-PET has good performance in nodal detection, it is still difficult to distinguish between PET-positive reactive and malignant nodes for the purpose of selecting nodes to be aspirated. DW-MRI can help to detect small lymph node metastases, and an inverse correlation with FDG uptake is expected. We found a mild negative correlation between SUVmax and ADC. Comparing the apparent diffusion coefficient (ADC) values between PET-positive and PET-negative nodes, ADC was significantly higher in PET-negative nodes. Whereas no significantly lower ADC value of cytological malignant nodes could be found overall, in the subgroup of non-HPV-related nodes, the ADC values of cytologically malignant PET-positive nodes were significantly lower than in cytologically benign nodes. This finding might be helpful in selecting nodes for puncture.

Abstract

Nodal staging (N-staging) in head and neck squamous cell carcinoma (HNSCC) is essential for treatment planning and prognosis. 18F-fluordeoxyglucose positron emission tomography (FDG-PET) has high performance for N-staging, although the distinction between cytologically malignant and reactive PET-positive nodes, and consequently, the selection of nodes for ultrasound-guided fine needle aspiration cytology (USgFNAC), is challenging. Diffusion-weighted magnetic resonance imaging (DW-MRI) can help to detect nodal metastases. We aim to investigate the potential of the apparent diffusion coefficient (ADC) as a metric to distinguish between cytologically reactive and malignant PET-positive nodes in order to improve node selection criteria for USgFNAC. PET-CT, real-time image-fused USgFNAC and DW-MRI to calculate ADC were available for 78 patients offered for routine N-staging. For 167 FDG-positive nodes, differences in the ADC between cytologically benign and malignant PET-positive nodes were evaluated, and both were compared to the ADC values of PET-negative reference nodes. Analyses were also performed in subsets of nodes regarding HPV status. A mild negative correlation between SUVmax and ADC was found. No significant differences in ADC values were observed between cytologically malignant and benign PET-positive nodes overall. Within the subset of non-HPV-related nodes, ADC_b0-200-1000 was significantly lower in cytologically malignant PET-positive nodes when compared to benign PET-positive nodes. ADC_b0-1000 and ADCb_0-200-1000 were significantly lower (p = 0.018, 0.016, resp.) in PET-negative reference nodes than in PET-positive nodes. ADC was significantly higher in PET-negative reference nodes than in PET-positive nodes. The non-HPV-related subgroup showed significantly (p = 0.03) lower ADC values in cytologically malignant than in cytologically benign PET-positive nodes, which should help inform the node selection procedure for puncture.

Comparison of Volumetric Quantitative PET Parameters Before and After a CT-Based Elastic Deformation on Dual-Time 18FDG-PET/CT Images: A Feasibility Study in a Perspective of Radiotherapy Planning in Head and Neck Cancer

Background

The use of 18FDG-PET/CT for delineating a gross tumor volume (GTV, also called MTV metabolic tumor volume) in radiotherapy (RT) planning of head neck squamous cell carcinomas (HNSCC) is not included in current recommendations, although its interest for the radiotherapist is of evidence. Because pre-RT PET scans are rarely done simultaneously with dosimetry CT, the validation of a robust image registration tool and of a reproducible MTV delineation method is still required.

Objective

Our objective was to study a CT-based elastic registration method on dual-time pre-RT 18FDG-PET/CT images to assess the feasibility of PET-based RT planning in patients with HNSCC.

Methods

Dual-time 18FDG-PET/CT [whole-body examination (wbPET) + 1 dedicated step (headPET)] were selected to simulate a 2-times scenario of pre-RT PET images deformation on dosimetry CT. ER-headPET and RR-headPET images were, respectively, reconstructed after CT-to-CT rigid (RR) and elastic (ER) registrations of the headPET on the wbPET. The MTVs delineation was performed using two methods (40%SUVmax, PET-Edge). The percentage variations of several PET parameters (SUVmax, SUVmean, SUVpeak, MTV, TLG) were calculated between wbPET, ER-headPET, and RR-headPET. Correlation between MTV values was calculated (Deming linear regression). MTVs intersections were assessed by two indices (OF, DICE) and compared together (Wilcoxon test). Additional per-volume analysis was evaluated (Mann-Whitney test). Inter- and intra-observer reproducibilities were evaluated (ICC = intra-class coefficient).

Results

36 patients (30M/6F; median age = 65 y) were retrospectively included. The changes in SUVmax, SUVmean and SUVpeak values between ER-headPET and RR-headPET images were <5%. The variations in MTV values between ER-headPET and wbPET images were −6 and −3% with 40%SUVmax and PET Edge, respectively. Their correlations were excellent whatever the delineation method (R² > 0.99). The ER-headPET MTVs had significant higher mean OF and DICE with the wbPET MTVs, for both delineation methods (p ≤ 0.002); and also when lesions had a volume > 5cc (excellent OF = 0.80 with 40%SUVmax). The inter- and intra-observer reproducibilities for MTV delineation were excellent (ICC ≥ 0.8, close to 1 with PET-Edge).

Conclusion

Our study demonstrated no significant changes in MTV after an elastic deformation of pre-RT 18FDG-PET/CT images acquired in dual-time mode. This opens possibilities for HNSCC radiotherapy planning improvement by transferring GTV-PET on dosimetry CT.

SUVmax for predicting regional control in oropharyngeal cancer

PURPOSE

To investigate the predictive value of pretherapeutic metabolic tumor imaging using 18-fluorodeoxyglucose positron emission tomography (FDG-PET) for regional response in oropharyngeal cancer patients undergoing primary (chemo)radiation.

METHODS

Retrospective analysis of oropharyngeal cancer patients treated with primary (chemo)radiation at the University Hospital Zurich from 2010 to 2019 with available FDG-PET. The SUV_max of the largest lymph node metastases was recorded. Regional response was assessed using posttherapeutic FDG-PET at 12 weeks and regional recurrence-free survival.

RESULTS

95 patients with a mean age of 68.5 years (SD 10.3) were included. The median pretherapeutic nodal SUV_max was 8.3 (interquartile range 4.4-13.3). A pretherapeutic nodal SUV_max above 6 significantly predicted poorer regional recurrence-free survival (log-rank test, P = 0.009) in univariate analysis. However, in multivariate analysis SUV_max above 6 was not significant in predicting regional recurrence-free survival (Cox regression P = 0.189). Clinical N category showed a trend in which a more severe stage had a poorer regional survival (Cox regression P = 0.073).

CONCLUSION

The SUV_max of the largest lymph node metastasis seems to play a role in predicting regional response in oropharyngeal cancer patients, after stratifying for N category. More research is needed to investigate whether highly metabolically active disease is less likely to respond to chemoradiation.

Value of Assessing Peripheral Vascularization with Micro-Flow Imaging, Resistive Index and Absent Hilum Sign as Predictor for Malignancy in Lymph Nodes in Head and Neck Squamous Cell Carcinoma

Simple Summary

Ultrasound-guided fine needle aspiration cytology (USgFNAC) is commonly used for N-staging in head and neck squamous cell carcinoma (HNSCC). The specificity of USgFNAC is always in the order of 100% as false positive cytology is rare. The difference in sensitivity is mainly attributable to selection of the lymph nodes to aspirate and aspiration technique. The aim of this study was to improve the selection criteria of lymph nodes to aspirate. Ultrasound features of nodes such as a short axis diameter, S/L ratio, loss of a fatty hilum sign, resistive index, and peripheral or mixed hilar and peripheral vascularization, obtained by Micro-flow imaging (MFI), which is a new technique to obtain micro-vascularization, were evaluated. To calculate the sensitivity and PPV of each feature, data of sonographic findings and cytological results of all aspirated nodes were statistically analyzed. We found that next to size, peripheral vascularisation obtained by MFI and absent hilum sign have a high predictive value for malignancy and should be added as selection criteria for fine needle aspiration in lymph nodes.

Abstract

Ultrasound-guided fine needle aspiration cytology (USgFNAC) is commonly used for nodal staging in head and neck squamous cell cancer (HNSCC). Peripheral vascularity is a described feature for node metastasis. Micro-flow imaging (MFI) is a new sensitive technique to evaluate micro-vascularization. Our goal is to assess the additional value of MFI to detect malignancy in lymph nodes. A total of 102 patients with HNSCC were included prospectively. USgFNAC was performed with the Philips eL18–4 transducer. Cytological results served as a reference standard to evaluate the prediction of cytological malignancy depending on ultrasound features such as resistive index (RI), absence of fatty hilum sign, and peripheral vascularization. Results were obtained for all US examinations and for the subgroup of clinically node-negative neck (cN0). USgFNAC was performed in 211 nodes. Peripheral vascularization had a positive predictive value (PPV) of 83% (cN0: 50%) and the absence of a fatty hilum had a PPV of 82% (cN0 50%) The combination of peripheral vascularization and absent fatty hilum had a PPV of 94% (cN0: 72%). RI (threshold: 0.705) had a PPV of 61% (cN0: RI-threshold 0.615, PPV 20%), whereas the PPV of short axis diameter (threshold of 6.5mm) was 59% for all patients and 19% in cN0 necks (threshold of 4 mm). Peripheral vascularization assessed by MFI and absent hilum has a high predictive value for cytological malignancy in neck metastases. Next to size, both features should be used as additional selection criteria for USgFNAC.

Impact of pretreatment second look 18FDG-PET/CT on stage and treatment changes in head and neck cancer

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The potential value of a second look PET/CT prior to radiotherapy was investigated.

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New lymph node metastases were discovered in half of the patients.

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Progression of the primary tumor and distant metastases were also observed.

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This strategy led to changes in treatment planning in more than half of the cases.

Background

Patients diagnosed with locoregionally advanced head and neck squamous cell carcinoma (LAHNSCC) regularly undergo staging with ¹⁸F-FDG PET/CT in our center. In cases of delays in radiotherapy (RT) planning CT more than 4 weeks after initial PET/CT or clinically suspected progress, PET/CT is repeated for restaging and as an RT planning reference. Our aim was to determine the impact of second-look PET/CT on stage migration, treatment change and RT planning.

Methods

Consequent treatment changes were categorized as minor and major. Minor changes were defined as PET/CT-based modifications of RT plans, e.g., the addition of anatomical compartments, changes in high- and low-risk dose levels or both. Major changes included changes from curative to palliative treatment intent and alterations of interdisciplinary treatment plans, such as the addition of induction chemotherapy, switch to primary surgery, no treatment and/or the necessity of additional diagnostic work-up resulting in the postponement or cancellation of treatment.

Results

Thirty-two newly diagnosed LAHNSCC patients who were treated between 2014 and 2018 underwent second-look PET/CT (median interval 42.5 days). Second-look PET/CT led to locoregional and distant upstaging in 3/32 and 1/32 patients, respectively. In 1/32 patients (3%), second-look PET/CT led to a palliative approach with systemic treatment. New lymph node metastases were discovered in 16 patients, 6 of whom also showed significant progression of the primary tumor, resulting in minor changes in 16 of the remaining 31 patients (52%) who were treated curatively.

Conclusion

If RT treatment planning of LAHNSCC was delayed by more than 4 weeks after initial PET/CT staging or when progression was clinically suspected, a second look at ¹⁸FDG-PET/CT was performed. This led to changes in treatment planning in more than half of the cases, which is expected to directly influence oncologic outcomes.

Evaluation of accuracy for 18 F-FDG positron emission tomography and computed tomography for detection of lymph node metastasis in canine oral malignant melanoma

Tumour stage has been demonstrated to have prognostic significance in canine oral malignant melanoma (OMM). Various evaluation techniques of positron emission tomography/computed tomography (PET/CT) have been reported for staging of head-and-neck tumours in people, but canine-specific data are limited, and reports for CT accuracy have been variable. In this prospective study, the head/neck of client-owned dogs with cytologically or histologically diagnosed OMM were imaged with 18 Fluorine-fluorodeoxyglucose (18 F-FDG) PET/ CT. Bilateral mandibular lymphadenectomy was performed for histopathologic assessment. Two evaluation techniques for CT and PET were applied by four independent observers. CT evaluation utilized both a standardized grading scheme and a subjective clinical interpretation. PET evaluation was first performed solely on 18 F-FDG-uptake in lymph nodes compared to background on a truncated scan excluding the oral cavity. Subsequently, the entire head/neck scan and standardized uptake value (SUV) measurements were available. Receiver operating characteristic analysis was performed with histopathology as gold standard. Twelve dogs completed the study and metastatic OMM was identified in six mandibular lymph nodes from five dogs. Of the CT-interpretation techniques, use of clinical grading performed best (sensitivity = 83% and specificity = 94%). Both PET techniques resulted in 100% sensitivity, but primary tumour site evaluation and use of SUV increased specificity from 78% to 94%. The SUVmax cut-point, 3.3, led to 100% sensitivity and 83% specificity. In this population of dogs, PET appeared to be highly sensitive but at risk of being less specific without use of appropriate parameters and thresholds.

Attention Guided Lymph Node Malignancy Prediction in Head and Neck Cancer

PURPOSE

Accurate lymph node (LN) malignancy classification is essential for treatment target identification in head and neck cancer (HNC) radiation therapy. Given the constraints imposed by relatively small sample sizes in real-world medical applications, to classify LN malignancy status accurately, we proposed an attention-guided classification (AGC) scheme that (1) incorporates human knowledge (ie, LN contours) into model training to guide model's "learning" direction, alleviating the critical requirement of large training samples by deep learning approaches; and (2) does not require accurate delineation of LNs in the inference stage but can highlight the discriminative region nearby the LN, which is important for malignancy determination.

METHODS AND MATERIALS

In the proposed AGC scheme, there is an attention-guided convolutional neural network (agCNN) module, followed by a classification convolutional neural network (cCNN) module. The input of the proposed AGC scheme is a region of interest (ROI) containing the LN and its surrounding tissues. The agCNN is designed to find the discriminative region in the ROI, which outputs an activation map whose voxel values indicate the importance of the voxels in malignancy prediction. Through multiplying the activation map with the ROI, we obtain the input for the cCNN, which finally outputs the LN malignancy probability. To demonstrate the effectiveness of the proposed scheme, we performed experimental studies using positron emission tomography and contrast-enhanced computed tomography from 129 surgical HNC patients, including 791 LNs, with pathologic ground truth of malignancy status. To evaluate the performance, 5-folder cross validation was used.

RESULTS

The sensitivity, specificity, accuracy, and area under the receiver operating characteristic (ROC) curve values obtained by the proposed AGC scheme were 0.91, 0.93, 0.92, and 0.98, respectively, significantly outperforming conventional convolutional neural network and radiomics approaches at a significance level of .05 under a paired ROC comparison statistical test.

CONCLUSIONS

We developed an AGC scheme that can highlight the discriminative region in an image for LN malignancy prediction, outperforming a conventional radiomics method that requires accurate segmentation and a standard convolutional neural network model without involving segmentation.

Recurrence of Lymph Node Micrometastases After Radiotherapy for Head and Neck Carcinoma: A Propensity Score-matched Study

BACKGROUND

The standard irradiation dose to the elective lymph node area (ELNA) in locally patients with advanced head and neck squamous cell carcinoma (LA-HNSCC) to control lymph node micrometastases (LN-MM) has not changed since it was empirically determined in the 1950s. We investigated the optimal irradiation dose for controlling LN-MM in ELNAs.

PATIENTS AND METHODS

The pattern of recurrence of LA-HNSCC was retrospectively evaluated in patients who underwent concurrent chemoradiotherapy with cisplatin or radiation therapy alone.

RESULTS

In total, 162 patients were enrolled. The median observation period was 34 months. No recurrence was found in ELNAs. After propensity score matching, a cisplatin dose of ≥200 mg/m ² yielded a significantly higher overall survival rate (p≤0.001) and locoregional control rate (p=0.034) than did a dose of <100 mg/m ² .

CONCLUSION

CCRT with a cisplatin dose of ≥200 mg/m ² can reduce the irradiation dose to 40-44 Gy at 2 Gy per fraction to control LN-MM.

FDG-PET-CT/MRI in head and neck squamous cell carcinoma: Impact on pretherapeutic N classification, detection of distant metastases, and second primary tumors

BACKGROUND

To assess the effect of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) in the pretherapeutic staging of N classification, detection rate of distant metastases, and second primaries.

METHODS

Retrospective study on patients with head and neck carcinoma. We compared pretherapeutic N classification by ultrasound, computed tomography (CT)/magnetic resonance imaging (MRI), and FDG-PET-CT/MRI.

RESULTS

A change in the N classification due to FDG-PET-CT/MRI was observed in 116 patients (39.5%) compared to N classification by ultrasound and fine-needle aspiration cytology. Patients with advanced nodal classification (>N2a) were more likely to be reclassified. Distant metastases were detected in 19 patients and a total of 36 second primaries were diagnosed by FDG-PET-CT/MRI. Detection of distant metastases was more likely in regional advanced disease (>N2a). Smokers (>10 py) had a significantly higher risk of second primary.

CONCLUSION

FDG-PET-CT/MRI leads to a significant change in pretherapeutic N classification. The cumulative incidence of distant metastases and second primaries was 18.7%.

Positron emission tomography for radiotherapy planning in head and neck cancer: What impact?

PET-computed tomography (CT) plays a growing role to guide target volume delineation for head and neck cancer in radiation oncology. Pretherapeutic [18F]FDG PET-CT adds information to morphological imaging. First, as a whole-body imaging modality, it reveals regional or distant metastases that induce major therapeutic changes in more than 10% of the cases. Moreover, it allows better pathological lymph node selection which improves overall regional control and overall survival. Second, locally, it allows us to define the metabolic tumoral volume, which is a reliable prognostic feature for survival outcome. [18F]FDG PET-CT-based gross tumor volume (GTV) is on average significantly smaller than GTV based on CT. Nevertheless, the overlap is incomplete and more evaluation of composite GTV based on PET and GTV based on CT are needed. However, in clinical practice, the study showed that using GTV PET alone for treatment planning was similar to using GTVCT for local control and dose distribution was better as a dose to organs at risk significantly decreased. In addition to FDG, pretherapeutic PET could give access to different biological tumoral volumes - thanks to different tracers - guiding heterogeneous dose delivery (dose painting concept) to resistant subvolumes. During radiotherapy treatment, follow-up [18F]FDG PET-CT revealed an earlier and more important diminution of GTV than other imaging modality. It may be a valuable support for adaptative radiotherapy as a new treatment plan with a significant impact on dose distribution became possible. Finally, additional studies are required to prospectively validate long-term outcomes and lower toxicity resulting from the use of PET-CT in treatment planning.

18F-FDG-PET/CT in laryngeal cancer: Comparison with conventional imaging and prognostic role

OBJECTIVE

The aim of this study was to investigate the diagnostic accuracy of staging ¹⁸F-FDG-PET/CT in laryngeal cancer, compare these results with conventional imaging (CI) and assess the value of ¹⁸F-FDG-PET/CT features to predict survival.

METHODS

Fifty-four patients with laryngeal squamous cell cancer and baseline ¹⁸F-FDG-PET/CT were retrospectively enrolled. The PET images were analyzed visually and semi-quantitatively by measuring several metabolic parameters. A combination of clinical follow-up/imaging follow-up and/or histopathology was taken as reference standard. Progression free survival (PFS) and disease specific survival (DSS) were computed using Kaplan-Meier curves.

RESULTS

All primary tumors were clearly identified by CI, and 52/54 by ¹⁸F-FDG-PET/CT with a sensitivity of 96.3%. Cervical nodal metastases were detected in 40/54 patients at ¹⁸F-FDG-PET/CT and in 34/49 patients at CI. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy on a patient-based analysis for nodal disease were 100%, 85.7%, 94.6%, 100% and 95.9% at ¹⁸F-FDG-PET/CT, and 91.4%, 85.7%, 94.1%, 80%, 89.8% at CI. Diagnostic performances of PET/CT and CI were not significantly different on a patient-based, side-by-side and level-by-level analysis. ¹⁸F-FDG-PET/CT recognized distant metastases in 7 patients allowing to an upstaging. At a median follow-up of 27 months, relapse/progression of disease occurred in 31 patients and death occurred in 32. Metabolic tumor volume (MTV T), MTV total and total lesion glycolysis (TLG) showed to be independent prognostic factors for PFS.

CONCLUSIONS

Both CI and PET/CT had good diagnostic performances for the staging of laryngeal cancer; baseline metabolic features (MTV and TLG) showed an important prognostic value in assessing the rate of PFS.

Predictive Value of Occult Metastasis and Survival Significance of Metabolic Tumor Volume Determined by PET-CT in cT1-2N0 Squamous Cell Carcinoma of the Tongue

Objectives

Our goal was to analyze the possibility of using metabolic tumor volume (MTV) to predict occult cervical metastasis and survival in cT1-2N0 squamous cell carcinoma (SCC) of the tongue.

Methods

Data on the primary tumor MTV and cervical node status as determined by the maximum standardized uptake value were retrieved. The sensitivity and specificity in predicting occult metastasis were calculated with a fourfold table. Associations between occult metastasis and clinicopathological variables were evaluated by univariate and multivariate analyses. The main study endpoints were locoregional control (LRC) and disease-specific survival (DSS).

Results

A total of 24 (20.3%) of 118 patients had occult metastasis. An MTV cutoff value of 4.3 cm³ showed a sensitivity of 50.0% and a specificity of 76.6% in predicting occult metastasis. The sensitivity and specificity of PET-CT in predicting occult metastasis in cT1 tumors were 66.6 and 89.8%, respectively, with values of 83.3 and 67.3%, respectively, when combined with the MTV. The sensitivity and specificity of PET-CT in predicting occult metastasis in cT2 tumors were 72.2 and 82.2%, respectively, with values of 88.9 and 57.8%, respectively, when combined with the MTV. Patients with MTV ≥4.3 cm³ had a higher occult metastasis rate than patients with MTV <4.3 cm³. The 5-year LRC and DSS rates were 86 and 94%, respectively, in patients with MTV <4.3 cm³ and 54 and 72%, respectively, in patients with MTV ≥4.3 cm³. Both differences were found to be significant in univariate and multivariate analyses.

Conclusions

MTV ≥4.3 cm³ was associated with an increased probability of occult metastasis and lower LRC and DSS rates in early-stage SCC of the tongue.

Predicting lymph node metastasis in patients with oropharyngeal cancer by using a convolutional neural network with associated epistemic and aleatoric uncertainty

There can be significant uncertainty when identifying cervical lymph node (LN) metastases in patients with oropharyngeal squamous cell carcinoma (OPSCC) despite the use of modern imaging modalities such as positron emission tomography (PET) and computed tomography (CT) scans. Grossly involved LNs are readily identifiable during routine imaging, but smaller and less PET-avid LNs are harder to classify. We trained a convolutional neural network (CNN) to detect malignant LNs in patients with OPSCC and used quantitative measures of uncertainty to identify the most reliable predictions. Our dataset consisted of images of 791 LNs from 129 patients with OPSCC who had preoperative PET/CT imaging and detailed pathological reports after neck dissections. These LNs were segmented on PET/CT imaging and then labeled according to the pathology reports. An AlexNet-like CNN was trained to classify LNs as malignant or benign. We estimated epistemic and aleatoric uncertainty by using dropout variational inference and test-time augmentation, respectively. CNN performance was stratified according to the median epistemic and aleatoric uncertainty values calculated using the validation cohort. Our model achieved an area under the receiver operating characteristic (ROC) curve (AUC) of 0.99 on the testing dataset. Sensitivity and specificity were 0.94 and 0.90, respectively. Epistemic and aleatoric uncertainty values were statistically larger for false negative and false positive predictions than for true negative and true positive predictions (p < 0.001). Model sensitivity and specificity were 1.0 and 0.98, respectively, for cases with epistemic uncertainty lower than the median value of the incorrect predictions in the validation dataset. For cases with higher epistemic uncertainty, sensitivity and specificity were 0.67 and 0.41, respectively. Model sensitivity and specificity were 1.0 and 0.98, respectively, for cases with aleatoric uncertainty lower than the median value of the incorrect predictions in the validation dataset. For cases with higher aleatoric uncertainty, sensitivity and specificity were 0.67 and 0.37, respectively. We used a CNN to predict the malignant status of LNs in patients with OPSCC with high accuracy, and we showed that uncertainty can be used to quantify a prediction's reliability. Assigning measures of uncertainty to predictions could improve the accuracy of LN classification by efficiently identifying instances where expert evaluation is needed to corroborate a model's prediction.

Predictive value of suvmax changes between two sequential post-therapeutic FDG-pet in head and neck squamous cell carcinomas

18-flurodesoxyglucose position emission tomography (FDG-PET) with computed tomography (CT) or magnetic resonance imaging (MRI) is a broadly accepted tool for pretherapeutic staging and post-therapeutic assessment of response. The prognostic value of sequential post-therapeutic FDG-PETs and the impact of change in metabolic activity has been scarcely reported so far. We hypothesized that an increase in metabolic activity (as measured by maximum standardized uptake value, SUVmax) would be predictive for recurrence. We retrospectively assessed all oral, oropharyngeal, laryngeal, and hypopharyngeal squamous cell carcinoma patients treated at the Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital Zurich between April 1st, 2010 and September 30th, 2018 (N = 337). After a negative post-treatment FDG-PET at 3 months, we measured the SUVmax of the local tumor area and the regional lymph nodes on follow-up FDG-PET at 9 months. We then correlated SUVmax difference between 9 and 3 months with tumor recurrence using Kaplan Meier analysis. During follow-up, 68 patients (20.2%) had local recurrence and 53 had regional recurrence (15.7%) at a median time of 9.0 (IQR 4.25-14) and 7.0 (IQR 5.25-23) months, respectively. An increase in local and/or regional SUVmax from the 3 months to the 9 months post-therapeutic FDG-PET resulted in a poorer recurrence-free survival (Log rank, P = 0.001, for both). An increase in local SUVmax between 3 and 9 months was associated with a hazard ratio of 4.17 for recurrence (95%CI 1.89-9.2, P = 0.0003). In conclusion, an increase in metabolic activity/SUVmax between two post-therapeutic FDG-PETs requires a histological examination as it is associated with tumor recurrence.

The Pattern of Cervical Lymph Node Metastasis and Risk Factors of Retropharyngeal Lymph Node Metastasis Based on Magnetic Resonance Imaging in Different Sites of Hypopharyngeal Carcinoma

Background

This study was to determine the patterns of regional lymph node (LN) spread and the risk factors of retropharyngeal lymph node (RPLN) metastasis based on magnetic resonance imaging (MRI) in hypopharyngeal squamous carcinoma (HPC) to improve clinical target volume (CTV) delineation.

Methods

A cohort of 326 consecutive patients of HPC in a single institute were retrospectively reviewed. All patients underwent MRI prior to initial treatment, and the diagnosis based on MRI of the LN metastasis was confirmed by all radiation oncologists in the head and neck group during twice weekly chat rounds. Statistical analysis of data was using chi-square test and multivariant logistic regression model in SPSS 22.0 software.

Results

The LN metastasis rate of all patients in this cohort was 90.5% (295/326). Level IIa/b and level III were the most frequently involved regions followed by level IV and retropharyngeal region. Skip metastasis only occurred in 6.4% (19/295). Univariate and multivariate analysis demonstrated that primary tumor subsites were located in the posterior pharyngeal wall (P=0.002), bilateral cervical LN metastasis (P=0.020), larger volume of primary gross target (GTVp, P=0.003), and larger volume of LN gross target (GTVnd, P=0.023) were significantly associated with RPLN metastasis.

Conclusion

The regional LN spread of HPC follows an ordered pattern as level II is the most frequently involved area followed by level III, level IV, and RPLN. RPLN metastasis is more likely to occur in patients with primary site of posterior pharyngeal wall, large tumor burden, or bilateral neck LN metastasis. Therefore, it is highly recommended that the RPLN should be included into CTV for patients who have these risk factors.

Distant metastases and synchronous malignancies on FDG-PET/CT in patients with head and neck cancer: a retrospective study

Background

Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has been proven to be a good method to detect distant spread of head and neck cancer (HNC). However, most prior studies are based on Asian populations and may not be directly transferable to western populations.

Purpose

To investigate the frequency and distribution of distant metastases and synchronous malignancies detected by PET/CT in HNC in a northern Swedish population.

Material and Methods

All primary whole-body FDG-PET/CT examinations performed on the suspicion of HNC (n = 524 patients) between 1 January 2013 and 31 December 2016 at Umeå University Hospital in Sweden were retrospectively reviewed . After the exclusion of 189 examinations without evidence of primary HNC, 335 examinations were analyzed.

Results

Distant metastases were detected in 10 (3%) patients, all with advanced primary tumors corresponding to TNM stage 3–4, most frequently in salivary gland adenocarcinoma, where 50% of patients had distant spread. Four patients had metastases below the diaphragm, representing 20% of the salivary gland malignancies. In the remaining six patients, metastases were supraphrenic, of which all but one were identified by CT alone. Synchronous malignancies were discovered in 14 (4.2%) patients, of which five were below the diaphragm.

Conclusion

The overall frequency of distant spread and synchronous malignancy in primary HNC was generally low. However, the risk for distant metastases below the diaphragm was relatively higher in salivary gland adenocarcinoma, supporting whole-body FDG-PET/CT in the primary diagnostic work-up in these patients.

Histometabolic Tumor Imaging of Hypoxia in Oral Cancer: Clinicopathological Correlation for Prediction of an Aggressive Phenotype

Introduction

Fluorodeoxyglucose-positron emission tomography (FDG-PET) is a widely used imaging tool for oral squamous cell carcinoma (OSCC). Preliminary studies indicate that quantification of tumor metabolic uptake may correlate with tumor hypoxia and aggressive phenotypes.

Methods

Retrospective review of a consecutive cohort of OSCC (n = 98) with available pretherapeutic FDG-PET/CT, treated at the University Hospital Zurich. Clinico-pathologico-radiological correlation between maximum standard uptake value (SUV_max) of the primary tumor, immunohistochemical staining for hypoxia-related proteins glucose transporter 1 (GLUT1) and hypoxia-inducible factor 1-alpha (HIF1a), depth of invasion (DOI), lymph node metastasis, and outcome was examined.

Results

Positive staining for GLUT1 and HIF1a on immunohistopathological analysis correlated with increased SUV_max on pretherapeutic imaging and with increased DOI (Kruskal–Wallis, P = 0.037, and P = 0.008, respectively). SUV_max and DOI showed a strong positive correlation (Spearman Rho, correlation coefficient = 0.451, P = 0.0003). An increase in SUV_max predicted nodal metastasis (Kruskal–Wallis, P = 0.017) and poor local control (log rank, P = 0.047).

Conclusion

In OSCC, FDG-PET-derived metabolic tumor parameter SUV_max serves as a surrogate marker for hypoxia and can be used to predict tumor aggressiveness, with more invasive phenotypes and poorer local control.

18F-FDG-PET/CT in laryngeal cancer: comparison with conventional imaging and prognostic role

OBJECTIVE

The aim of this study was to investigate the diagnostic accuracy of staging 18 F-FDG-PET/CT in laryngeal cancer, compare these results with conventional imaging (CI) and assess the value of 18 F-FDG-PET/CT features to predict survival.

METHODS

Fifty-four patients with laryngeal squamous cell cancer and baseline 18 F-FDG-PET/CT were retrospectively enrolled. The PET images were analyzed visually and semi-quantitatively by measuring several metabolic parameters. A combination of clinical follow-up/imaging follow-up and/or histopathology was taken as reference standard. Progression free survival (PFS) and disease specific survival (DSS) were computed using Kaplan-Meier curves.

RESULTS

All primary tumors were clearly identified by CI, and 52/54 by 18 F-FDG-PET/CT with a sensitivity of 96.3%. Cervical nodal metastases were detected in 40/54 patients at 18 F-FDG-PET/CT and in 34/49 patients at CI. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy on a patient-based analysis for nodal disease were 100%, 85.7%, 94.6%, 100% and 95.9% at 18 F-FDG-PET/CT, and 91.4%, 85.7%, 94.1%, 80%, 89.8% at CI. Diagnostic performances of PET/CT and CI were not significantly different on a patient-based, side-by-side and level-by-level analysis. 18 F-FDG-PET/CT recognized distant metastases in 7 patients allowing to an upstaging. At a median follow-up of 27 months, relapse/progression of disease occurred in 31 patients and death occurred in 32. Metabolic tumor volume (MTV T), MTV total and total lesion glycolysis (TLG) showed to be independent prognostic factors for PFS.

CONCLUSIONS

Both CI and PET/CT had good diagnostic performances for the staging of laryngeal cancer; baseline metabolic features (MTV and TLG) showed an important prognostic value in assessing the rate of PFS.

PET/CT in Surgical Planning for Head and Neck Cancer

Fluorine-18 (¹⁸F)-fluorodeoxyglucose (FDG) positron emission tomography fused with computed tomography (PET/CT) is a valuable tool in surgical planning for head and neck squamous cell carcinoma (HNSCC). If performed prior to biopsy or other surgical intervention, FDG-PET/CT has high sensitivity for the detection of the primary site in patients with cervical lymph node metastases from unknown primary origin and can be used to direct the surgical workup. FDG-PET/CT is superior to CT alone for detection of nodal metastases outside the expected pattern or distant metastases or second primary cancers and can greatly affect determination of appropriate management including surgical eligibility. Prior to the advent of PET/CT, many patients undergoing (chemo)radiation-based therapy had planned post-treatment neck dissection; FDG-PET/CT now has a proven role in the evaluation of recurrent or persistent disease amenable to salvage surgery and enables safe avoidance of planned postradiation neck dissection with a high negative predictive value. Specifically for this important application, two standardized reporting metrics may be used in the head and neck anatomic region: the "Hopkins criteria" and the "Neck Imaging Reporting and Data System"; both systems produce a formalized evaluation and recommendation based on PET/CT findings. The role of PET/CT as a replacement for elective neck dissection or examination under anesthesia remains controversial but deserves further study. FDG-PET/CT has a wide-ranging impact on the surgical management of patients with HNSCC and should be used routinely in patients with unknown primary nodal disease and those presenting with advanced-stage cancers at initial staging and to assess treatment response.

The value of CT, MRI, and PET-CT in detecting retropharyngeal lymph node metastasis of head and neck squamous cell carcinoma

BACKGROUND

The diagnostic accuracies of the imaging studies should be clearly acknowledged in managing head and neck cancer patients; however, the accuracies of preoperative imaging studies in detecting retropharyngeal lymph node (RPLN) metastasis are still not clarified. This study was to evaluate diagnostic accuracies of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT) in detecting RPLN metastasis of head and neck squamous cell carcinomas.

METHODS

For 123 patients who had performed RPLN dissection during the surgery of their squamous cell carcinoma of the head and neck, preoperative CT, MRI, and/or PET-CT were reviewed for RPLN metastasis in a blinded fashion by one experienced radiologist. Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of each imaging modality were assessed, by comparing with the histopathologic findings of the resected RPLNs that served as the standard of reference.

RESULTS

RPLNs were pathologically positive for metastasis in 43 of the 123 patients (35%). Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in detecting metastasis to RPLN were 65, 94, 85, 83, and 84% for CT; 74, 94, 87, 87 and 87% for MRI; 83, 93, 89, 89 and 89% for PET-CT, respectively. When all the three imaging modalities were considered together (n = 74), they offered sensitivity of 90%, specificity of 91%, positive predictive value of 87%, negative predictive value of 93%, and accuracy of 91%.

CONCLUSIONS

The preoperative imaging studies offered relatively high specificity rates, but rather low sensitivity rates. The three imaging modalities altogether increased diagnostic accuracies, which highlights the potential of the three studies when used altogether can minimize missed diagnoses of RPLN metastasis.

Integration of 18-FDG PET/CT in the Initial Work-Up to Stage Head and Neck Cancer: Prognostic Significance and Impact on Therapeutic Decision Making

Background: The objective of this study was to assess the therapeutic and prognostic impact of integrating18F-fluorodeoxyglucose (18-FDG) positron emission tomography (PET)/computed tomography (CT) into work-up (WU) at initial staging of patients with head and neck squamous cell carcinoma (HNSCC).

Method: 477 consecutive patients (414M/63F, mean age 62.3 ± 9.7 years) with newly diagnosed HNSCC who underwent pre-treatment 18-FDG PET/CT were retrospectively included. The 18-FDG PET/CT stage (sPET) was compared to the conventional work-up stage (sCWU). A group of cancer specialists determined whether integrating PET/CT into WU at initial staging had an impact on the therapeutic decision, classifying the clinical impact as high (change in therapeutic modality), medium (change in the radiotherapy or surgical procedure), or low (modification of TNM staging and/or detection of synchronous cancer without high or medium impact). Three-year overall survival (OS) was considered as primary endpoint of the prognostic analysis.

Results: 18-FDG PET/CT had a clinical impact in 221 patients (46.3%) with a medium or high impact on management in 94 (19.5%) patients. Medium and high impact of 18-FDG PET/CT was statistically equivalent between sCWU-stage I/II and III/IV subgroups (p = 0.02). 42 patients were PET/CT-upstaged from early stage I/II to advanced stage III/IV and had a significantly lower 3-year OS than those with concordant CWU and 18-FDG PET/CT early stage (54.8 vs. 82.6%, p = 0.001).

Conclusion: This study demonstrated that implementing 18-FDG PET/CT in the initial WU of HNSCC provides valuable staging information with a better prognostic stratification. Patient management was modified for any disease stage, even for early stage I-II, with consequences on survival.

Head and Neck Cancers, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

Treatment is complex for patients with head and neck (H&N) cancers with specific site of disease, stage, and pathologic findings guiding treatment decision-making. Treatment planning for H&N cancers involves a multidisciplinary team of experts. This article describes supportive care recommendations in the NCCN Guidelines for Head and Neck Cancers, as well as the rationale supporting a new section on imaging recommendations for patients with H&N cancers. This article also describes updates to treatment recommendations for patients with very advanced H&N cancers and salivary gland tumors, specifically systemic therapy recommendations.

Prospective evaluation of the impact of human papilloma virus status and small node size on the diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography for primary head and neck squamous cell carcinoma

BACKGROUND

Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is well validated in the staging of pre-treatment head and neck squamous cell carcinoma (HNSCC), although the impact of human papilloma virus (HPV) status and node size on accuracy remains unclear. The aim of this study was to assess the diagnostic accuracy of PET/CT based on HPV status and node size and determine the effects of maximum standardized uptake value thresholds on sensitivity, specificity and positive predictive value.

METHODS

A total of 38 patients with primary HNSCC were recruited. All patients underwent primary tumour resection and cervical node dissection following FDG-PET/CT.

RESULTS

A total of 38 patients including 68 dissected necks, representing 353 nodal levels and a total of 2701 lymph nodes were included. Histopathological analysis revealed lymph node metastases in 4.3% (116/2701) of dissected lymph nodes. Forty-four percent of patients had HPV-positive tumours. Sixty-four percent of involved lymph nodes were <1 cm. The sensitivity and specificity for HPV-positive nodes were 67.2% and 99.3% versus 35.6% and 98.2% in HPV-negative nodes, respectively (P < 0.001). Mean maximum standardized uptake value in HPV-positive nodes was 6.3 versus 3.5 in HPV-negative nodes (P < 0.001). Sensitivity and specificity were 30.7% and 99.2% in <1 cm nodes versus 90.2% and 84.8% in ≥1 cm nodes, respectively (P < 0.001).

CONCLUSION

FDG-PET/CT has significantly higher diagnostic accuracy in determining nodal metastases in HPV-positive HNSCC versus HPV-negative disease. Accuracy was lower in <1 versus ≥1 cm nodes.

A Pilot Study: N-Staging Assessment of Shear Wave Elastrography in Small Cervical Lymph Nodes for Nasopharyngeal Carcinoma

Purpose: To investigate N-staging Assessment of pretreatment Shear wave elastrography (SWE) in small cervical lymph nodes (0. 5 cm ≤ maximum diameter < 1 cm, intact capsule, no central necrosis, sCLNs) in nasopharyngeal carcinoma (NPC) patients. Methods: Pathological biopsy proven 28 NPC patients with sCLNs shown in pretreatment magnetic resonance (MR) images and 40 target lymph nodes were enrolled. All target lymph nodes were divided into metastasis and benign lymph node groups according to pathology. SWE was used to exam the real time SWE imaging of each target lymph nodes before conducting ultrasonography guided fine needle biopsy. The minimum (Emin), maximum (Emax), and mean (Emean) elasticity indices (kPa) of target lymph nodes were recorded. The SWE examination was repeated three times for the same target lymph node and each elasticity indices for statistic was determined by average of three measurements. SPSS 21.0 statistics software is used for statistical analysis. The receiver operating characteristic (ROC) curve was performed to obtain the cutoff value of elasticity indices of metastatic sCLNs. Statistical significance was assumed when the P < 0.05. Results: Nine lymph nodes were metastatic and 31 were benign. The Emin, Emax, and Emean of benign group were 8.15 ± 6.12, 25.05 ± 12.37, and 16.05 ± 8.29 kPa, respectively; Emin, Emax, and Emean of metastasis group were 11.5 ± 6.17, 41.38 ± 17.87, and 23.48 ± 6.50 kPa, respectively. The difference of the Emax and Emean between metastasis and benign group were statistically significant (P = 0.003 and 0.018). The area under the ROC curve of Emin, Emax, and Emean of metastasis lymph node were 0.685 (P = 0.095), 0.785 (P = 0.010), and 0.765 (P = 0.017), respectively. Emax of 27 kPa and Emean of 17 kPa were taken as the cutoff value of diagnosis for metastasis sCLNs: the sensitivity, specificity, and accuracy were 77.8 and 100%, 71.0 and 61.3%, 75.0 and 70.0%, respectively. Conclusions: Pretreatment SWE has high accuracy in evaluating the sCLNs in NPC patients and is helpful for accurate N-staging and survival prognosis. It can be used as a clinical supplementary examination.