Qualitative interpretation of PET scans using a Likert scale to assess neck node response to radiotherapy in head and neck cancer

Advances and residual knowledge gaps in the neck management of head and neck squamous cell carcinoma patients with advanced nodal disease undergoing definitive (chemo)radiotherapy for their primary

PURPOSE

Substantial changes have been made in the neck management of patients with head and neck squamous cell carcinomas (HNSCC) in the past century. These have been fostered by changes in cancer epidemiology and technological progress in imaging, surgery, or radiotherapy, as well as disruptive concepts in oncology. We aimed to review changes in nodal management, with a focus on HNSCC patients with nodal involvement (cN+) undergoing (chemo)radiotherapy.

METHODS

A narrative review was conducted to review current advances and address knowledge gaps in the multidisciplinary management of the cN+ neck in the context of (chemo)radiotherapy.

RESULTS

Metastatic neck nodes are associated with poorer prognosis and poorer response to radiotherapy, and have therefore been systematically treated by surgery. Radical neck dissection (ND) has gradually evolved toward more personalized and less morbid approaches, i.e., from functional to selective ND. Omission of ND has been made feasible by use of positron-emission tomography/computed tomography to monitor the radiation response in cN+ patients. Human papillomavirus-driven oropharyngeal cancers and their cystic nodes have shown dramatically better prognosis than tobacco-related cancers, justifying a specific prognostic classification (AJCC) creation. Finally, considering the role of lymph nodes in anti-tumor immunity, de-escalation of ND and prophylactic nodal irradiation in combination are intense areas of investigation. However, the management of bulky cN3 disease remains an issue, as aggressive multidisciplinary strategies or innovative combined treatments have not yet significantly improved their prognosis.

CONCLUSION

Personalized neck management is an increasingly important aspect of the overall therapeutic strategies in cN+ HNSCC.

Prediction of Patient Outcomes in Locally Advanced Cervical Carcinoma Following Chemoradiotherapy-Comparative Effectiveness of Magnetic Resonance Imaging and 2-Deoxy-2-[18F]fluoro-D-glucose Imaging

PURPOSE

To evaluate the utility and comparative effectiveness of three five-point qualitative scoring systems for assessing response on PET-CT and MRI imaging individually and in combination, following curative-intent chemoradiotherapy (CRT) in locally advanced cervical cancer (LACC). Their performance in the prediction of subsequent patient outcomes was also assessed; Methods: Ninety-seven patients with histologically confirmed LACC treated with CRT using standard institutional protocols at a single centre who underwent PET-CT and MRI at staging and post treatment were identified retrospectively from an institutional database. The post-CRT imaging studies were independently reviewed, and response assessed using five-point scoring tools for T2WI, DWI, and FDG PET-CT. Patient characteristics, staging, treatment, and follow-up details including progression-free survival (PFS) and overall survival (OS) outcomes were collected. To compare diagnostic performance metrics, a two-proportion z-test was employed. A Kaplan-Meier analysis (Mantel-Cox log-rank) was performed.

RESULTS

The T2WI (p < 0.00001, p < 0.00001) and DWI response scores (p < 0.00001, p = 0.0002) had higher specificity and accuracy than the PET-CT. The T2WI score had the highest positive predictive value (PPV), while the negative predictive value (NPV) was consistent across modalities. The combined MR scores maintained high NPV, PPV, specificity, and sensitivity, and the PET/MR consensus scores showed superior diagnostic accuracy and specificity compared to the PET-CT score alone (p = 0.02926, p = 0.0083). The Kaplan-Meier analysis revealed significant differences in the PFS based on the T2WI (p < 0.001), DWI (p < 0.001), combined MR (p = 0.003), and PET-CT/MR consensus scores (p < 0.001) and in the OS for the T2WI (p < 0.001), DWI (p < 0.001), and combined MR scores (p = 0.031) between responders and non-responders.

CONCLUSION

Post-CRT response assessment using qualitative MR scoring and/or consensus PET-CT and MRI scoring was a better predictor of outcome compared to PET-CT assessment alone. This requires validation in a larger prospective study but offers the potential to help stratify patient follow-up in the future.

Diagnostic accuracy of NI-RADS for prediction of head and neck squamous cell carcinoma: a systematic review and meta-analysis

OBJECTIVES

This study aimed to assess the diagnostic performance of NI-RADS for the prediction of recurrence in patients treated for Head and Neck Squamous Cell Carcinoma (HNSCC).

METHODS

A literature search was conducted using various databases to identify relevant articles published from June 2016 onwards. We included studies reporting the diagnostic accuracy of NI-RADS in distinguishing recurrence in patients undergoing imaging surveillance, with pathologic results and/or follow-up as the reference standard. Summary estimates of diagnostic accuracy in terms of sensitivity, specificity, positive likelihood ratio (LR +), negative likelihood ratio (LR -), and diagnostic odds ratio (DOR) were calculated with the hierarchical summary receiver operating characteristic (HSROC) model. Meta-regression and subgroup analyses were conducted to investigate different clinical settings. Study quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

RESULTS

A total of 12 studies were included in the current meta-analysis. The pooled sensitivity and specificity were 0.69 (95% CI 0.59-0.79) and 0.94 (95% CI 0.89-0.97), respectively. For the primary site, the pooled summary estimates were 0.67 (95% CI 0.53-0.78) and 0.95 (95% CI 0.90-0.97), for the nodal sites were 0.64 (95% CI 0.44-0.80) and 0.99 (95% CI 0.98-0.99), respectively. The recurrence rate for NI-RADS categories 1-3 was 0.03 (95% CI 0.02-0.05), 0.13 (95% CI 0.10-0.15), and 0.77 (95% CI 0.73-0.81). Meta-regression revealed that the type of analysis (per person vs. per site) and number of sites (≤ 200 vs. > 200) were significant factors associated with heterogeneity.

CONCLUSIONS

NI-RADS demonstrated high specificity but moderate sensitivity in patients after treatment for HNSCC. Summary estimates showed a significantly higher malignancy rate for NI-RADS category 3 compared to category 2.

Diagnostic Performance of Response Assessment FDG-PET/CECT in HNSCC Treated With Definitive Radio(chemo)therapy Using NI-RADS

OBJECTIVE

To assess the diagnostic performance of response assessment 18F-fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography (FDG-PET/CECT) following definitive radio(chemo)therapy in head and neck squamous cell carcinoma (HNSCC) using Neck Imaging Reporting and Data System (NI-RADS).

STUDY DESIGN

A retrospective analysis from a prospectively maintained dataset.

SETTING

Tertiary-care comprehensive cancer center in a low-middle-income country.

METHODS

Adults with newly diagnosed, biopsy-proven, nonmetastatic HNSCC treated with definitive radio(chemo)therapy were included. Posttreatment response assessment FDG-PET/CECT scans were retrospectively assigned NI-RADS categories (1-3) for the primary site, neck, and both sites combined. Locoregional recurrence occurring within 2-years was defined as the event of interest. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were calculated. Locoregional control stratified by NI-RADS categories was computed with the Kaplan-Meier method and compared using the log-rank test.

RESULTS

Posttreatment FDG-PET/CECT scans were available in 190 patients constituting the present study cohort. Sensitivity, specificity, PPV, NPV, and overall accuracy of the NI-RADS template for the primary site was 73.5%, 81.4%, 46.3%, 93.4%, and 80.0%, respectively. Similar metrics for the neck were 72.7%, 87.5%, 43.2%, 96.1%, and 85.8%, respectively. Combining primary site and neck, the corresponding metrics of diagnostic accuracy were 84.4%, 69.7%, 46.3%, 93.5%, and 73.2%, respectively. At a median follow-up of 40 months, Kaplan-Meier estimates of 2-year locoregional control were significantly higher for NI-RADS category 1 (94.2%) compared to NI-RADS category 2 (69.4%) and category 3 (20.4%), respectively (stratified log-rank p < .0001).

CONCLUSION

FDG-PET/CECT using the NI-RADS template is associated with good diagnostic performance and prognostic utility in HNSCC treated with definitive radio(chemo)therapy.

Sub-minute acquisition with deep learning-based image filter in the diagnosis of colorectal cancers using total-body 18F-FDG PET/CT

BACKGROUND

This study aimed to retrospectively evaluate the feasibility of total-body ¹⁸F-FDG PET/CT ultrafast acquisition combined with a deep learning (DL) image filter in the diagnosis of colorectal cancers (CRCs).

METHODS

The clinical and preoperative imaging data of patients with CRCs were collected. All patients underwent a 300-s list-mode total-body ¹⁸F-FDG PET/CT scan. The dataset was divided into groups with acquisition durations of 10, 20, 30, 60, and 120 s. PET images were reconstructed using ordered subset expectation maximisation, and post-processing filters, including a Gaussian smoothing filter with 3 mm full width at half maximum (3 mm FWHM) and a DL image filter. The effects of the Gaussian and DL image filters on image quality, detection rate, and uptake value of primary and liver metastases of CRCs at different acquisition durations were compared using a 5-point Likert scale and semi-quantitative analysis, with the 300-s image with a Gaussian filter as the standard.

RESULTS

All 34 recruited patients with CRCs had single colorectal lesions, and the diagnosis was verified pathologically. Of the total patients, 11 had liver metastases, and 113 liver metastases were detected. The 10-s dataset could not be evaluated due to high noise, regardless of whether it was filtered by Gaussian or DL image filters. The signal-to-noise ratio (SNR) of the liver and mediastinal blood pool in the images acquired for 10, 20, 30, and 60 s with a Gaussian filter was lower than that of the 300-s images (P < 0.01). The DL filter significantly improved the SNR and visual image quality score compared to the Gaussian filter (P < 0.01). There was no statistical difference in the SNR of the liver and mediastinal blood pool, SUVmax and TBR of CRCs and liver metastases, and the number of detectable liver metastases between the 20- and 30-s DL image filter and 300-s images with the Gaussian filter (P > 0.05).

CONCLUSIONS

The DL filter can significantly improve the image quality of total-body ¹⁸F-FDG PET/CT ultrafast acquisition. Deep learning-based image filtering methods can significantly reduce the noise of ultrafast acquisition, making them suitable for clinical diagnosis possible.

Determining the suitability of definitive radiation therapy in patients with metastatic nasopharyngeal carcinoma based on PET/CT: a large cohort study

OBJECTIVES

To determine patients with de novo metastatic nasopharyngeal carcinoma (mNPC) who would benefit from receiving definitive radiation therapy (DRT) along with their pre-existing palliative chemotherapy (PCT) by evaluating their post-PCT Deauville scores and EBV DNA.

METHODS

A total of 570 mNPC patients, treated with PCT or PCT+DRT, were studied. EBV DNA levels, along with post-PCT Deauville scores, were used to stratify risk based on the recursive partitioning analysis (RPA).

RESULTS

Significant differences were observed in the survival rates of patients with Deauville scores of 1-3 and 4-5 (2-year progression-free survival (PFS): 23.4% versus 8.5%, p < 0.001; 2-year overall survival (OS): 56.8% versus 18.8%, p < 0.001). RPA yielded three distinct groups in the increasing order of risk (Deauville scores of all RPA I-II were within the range of 1-3): (1) RPA I: EBV DNA levels at a pretreatment concentration ≤ 4000 copies/mL and undetectable post-PCT; (2) RPA II: EBV DNA levels either at a pretreatment concentration > 4000 copies/mL or at a pretreatment concentration ≤ 4000 copies/mL and detectable post-PCT; (3) RPA III: Deauville scores 4-5. While patients in RPA I and RPA II had significantly PFS rates when treated with PCT+DRT than when treated with PCT alone (RPA I: 72.7% versus 13.4%, RPA II: 37.8% versus 6.3%), those in RPA III did not experience such PFS benefits (6.5% versus 9.7%).

CONCLUSION

PCT+DRT might improve the survival rates in mNPC patients in the low- and mid-risk strata but not those of patients in the high-risk strata.

KEY POINTS

We use the Deauville scores and the concentrations of the Epstein-Barr virus (EBV) DNA to determine those patients with de novo metastatic NPC who would benefit from radiation therapy.

Discordance Between Oncology Clinician-Perceived and Radiologist-Intended Meaning of the Postradiotherapy Positron Emission Tomography/Computed Tomography Freeform Report for Head and Neck Cancer

Importance

Assessment of response after radiotherapy (RT) using 18F-fluorodeoxyglucose positron emission tomography (PET) with computed tomography (CT) is routine in managing head and neck squamous cell carcinoma (HNSCC). Freeform reporting may contribute to a clinician's misunderstanding of the nuclear medicine (NM) physician's image interpretation, with important clinical implications.

Objective

To assess clinician-perceived freeform report meaning and discordance with NM interpretation using the modified Deauville score (MDS).

Design, Setting, and Participants

In this retrospective cohort study that was conducted at an academic referral center and National Cancer Institute-designated Comprehensive Cancer Center and included patients with HNSCC treated with RT between January 2014 and December 2019 with a posttreatment PET/CT and 1 year or longer of follow-up, 4 masked clinicians independently reviewed freeform PET/CT reports and assigned perceived MDS responses. Interrater reliability was determined. Clinician consensus-perceived MDS was then compared with the criterion standard NM MDS response derived from image review. Data analysis was conducted between December 2021 and February 2022.

Exposures

Patients were treated with RT in either the definitive or adjuvant setting, with or without concurrent chemotherapy. They then underwent posttreatment PET/CT response assessment.

Main Outcomes and Measures

Clinician-perceived (based on the freeform PET/CT report) and NM-defined response categories were assigned according to MDS. Clinical outcomes included locoregional control, progression-free survival, and overall survival.

Results

A total of 171 patients were included (45 women [26.3%]; median [IQR] age, 61 [54-65] years), with 149 (87%) with stage III to IV disease. Of these patients, 52 (30%) received postoperative RT and 153 (89%) received concurrent chemotherapy. Interrater reliability was moderate (κ = 0.68) among oncology clinicians and minimal (κ = 0.36) between clinician consensus and NM. Exact agreement between clinician consensus and the NM was 64%. The NM-rated MDS was significantly associated with locoregional control, progression-free survival, and overall survival.

Conclusions and Relevance

The results of this cohort study suggest that considerable variation in perceived meaning exists among oncology clinicians reading freeform HNSCC post-RT PET/CT reports, with only minimal agreement between MDS derived from clinician perception and NM image interpretation. The NM use of a standardized reporting system, such as MDS, may improve clinician-NM communication and increase the value of HNSCC post-RT PET/CT reports.

Advances in Imaging for HPV-Related Oropharyngeal Cancer: Applications to Radiation Oncology

While there has been an overall decline of tobacco and alcohol-related head and neck cancer in recent decades, there has been an increased incidence of HPV-associated oropharyngeal cancer (OPC). Recent research studies and clinical trials have revealed that the cancer biology and clinical progression of HPV-positive OPC is unique relative to its HPV-negative counterparts. HPV-positive OPC is associated with higher rates of disease control following definitive treatment when compared to HPV-negative OPC. Thus, these conditions should be considered unique diseases with regards to treatment strategies and survival. In order to sufficiently characterize HPV-positive OPC and guide treatment strategies, there has been a considerable effort to diagnose, prognose, and track the treatment response of HPV-associated OPC through advanced imaging research. Furthermore, HPV-positive OPC patients are prime candidates for radiation de-escalation protocols, which will ideally reduce toxicities associated with radiation therapy and has prompted additional imaging research to detect radiation-induced changes in organs at risk. This manuscript reviews the various imaging modalities and current strategies for tackling these challenges as well as provides commentary on the potential successes and suggested improvements for the optimal treatment of these tumors.

The ability of post-chemoradiotherapy DWI ADCmean and 18F-FDG SUVmax to predict treatment outcomes in head and neck cancer: impact of human papilloma virus oropharyngeal cancer status

OBJECTIVES

To evaluate the ability of post-chemo-radiotherapy (CRT) diffusion-weighted-MRI apparent diffusion coefficient (ADCmean) and 18F-FDG PET maximum standardized uptake value (SUVmax) to predict disease-free survival (DFS) in head and neck squamous cell carcinoma (HNSCC), and to determine whether this ability is influenced by human papillomavirus oropharyngeal cancer (HPV-OPC) status.

METHODS

This prospective cohort observational study included 65 participants (53 male, mean ± SD age 59.9 ± 7.9 years, 46 HPV-OPC) with stage III or IV HNSCC. Primary tumour and nodal ADCmean (pre-treatment, 6- and 12-weeks post-CRT) and SUVmax (12-weeks post-CRT) were measured. Variables were compared with 2-year DFS (independent t-test/Mann-Whitney test) and overall DFS (Cox regression), before and after accounting for HPV-OPC status. Variables were also compared between HPV-OPC and other HNSCC subgroups after stratifying for DFS.

RESULTS

Absolute post-CRT ADCmean values predicted 2-year DFS and overall DFS for all participants (p = 0.03/0.03, 6-week node; p = 0.02/0.03 12-week primary tumour) but not in the HPV-OPC subgroup. In participants with DFS, percentage interval changes in primary tumour ADCmean at 6- and 12-weeks were higher in HPV-OPC than other HNSCC (p = 0.01, 6 weeks; p = 0.005, 12 weeks). The 12-week post-CRT SUVmax did not predict DFS.

CONCLUSION

Absolute post-CRT ADCmean values predicted DFS in HNSCC but not in the HPV-OPC subgroup. Amongst participants with DFS, post-CRT percentage interval changes in primary tumour ADCmean were significantly higher in HPV-OPC than in other HNSCC. Knowledge of HPV-OPC status is crucial to the clinical utilisation of post-CRT DWI-MRI for the prediction of outcomes.

PET/CT Variants and Pitfalls in Head and Neck Cancers Including Thyroid Cancer

PET/CT imaging is a dual-modality diagnostic technology that merges metabolic and structural imaging. There are several currently available radiotracers, but ¹⁸F-FDG is the most commonly utilized due to its widespread availability. ¹⁸F-FDG PET/CT is a cornerstone of head and neck squamous cell carcinoma imaging. ⁶⁸Ga-DOTA-TOC is another widely used radiotracer. It allows for whole-body imaging of cellular somatostatin receptors, commonly expressed by neuroendocrine tumors and is the standard of reference for the characterization and staging of neuroendocrine tumors. The normal biodistribution of these PET radiotracers as well as the technical aspects of image acquisition and inadequate patient preparation affect the quality of PET/CT imaging. In addition, normal variants, artifacts and incidental findings may impede accurate image interpretation and can potentially lead to misdiagnosis. In order to correctly interpret PET/CT imaging, it is necessary to have a comprehensive knowledge of the normal anatomy of the head and neck and to be cognizant of potential imaging pitfalls. The interpreter must be familiar with benign conditions which may accumulate radiotracer potentially mimicking neoplastic processes and also be aware of malignancies which can demonstrate low radiotracer uptake. Appropriate use of structural imaging with either CT, MR or ultrasound can serve a complimentary role in several head and neck pathologies including local tumor staging, detection of bone marrow involvement or perineural spread, and classification of thyroid nodules. It is important to be aware of the role of these complementary modalities to maximize diagnostic accuracy and patient outcomes. The purpose of this article is to outline the basic principles of PET/CT imaging, with a focus on ¹⁸F-FDG PET/CT and ⁶⁸Ga-DOTA PET/CT. Basic physiology, variant imaging appearances and potential pitfalls of image interpretation are presented within the context of common use cases of PET technology in patients with head and neck cancers and other pathologies, benign and malignant.

Impact of EBUS-TBNA in addition to [18F]FDG-PET/CT imaging on target volume definition for radiochemotherapy in stage III NSCLC

Purpose/introduction

[¹⁸F]FDG-PET/CT is the standard imaging-technique for radiation treatment (RT) planning in locally advanced non-small cell lung cancer (NSCLC). The purpose of this study was to examine the additional value of endobronchial-ultrasound transbronchial needle aspiration (EBUS-TBNA) to standard PET/CT for mediastinal lymph-node (LN) staging and its impact on clinical target volume (CTV).

Materials and methods

All consecutive patients with primary stage III NSCLC who underwent [¹⁸F]FDG-PET/CT and EBUS-TBNA prior to RT were analyzed from 12/2011 to 06/2018. LN-stations were assessed by an expert-radiologist and a nuclear medicine-physician. CTV was evaluated by two independent radiation oncologists. LNs were grouped with increasing distance along the lymphatic chains from primary tumor into echelon-1 (ipsilateral hilum), echelon-2 (LN-station 7 and ipsilateral 4), and echelon-3 (remaining mediastinum and contralateral hilum).

Results

A total of 675 LN-stations of which 291 were positive for tumor-cells, were sampled by EBUS-TBNA in 180 patients. The rate of EBUS-positive LNs was 43% among all sampled LNs. EBUS-positivity in EBUS-probed LNs decreased from 85.8% in echelon-1 LNs to 42.4%/ 9.6% in echelon-2/ -3 LNs, respectively (p < 0.0001, Fisher’s exact test). The false discovery rate of PET in comparison with EBUS results rose from 5.3% in echelon-1 to 32.9%/ 69.1% in echelon-2/ -3 LNs, respectively (p < 0.0001, Fisher’s exact test). Sensitivity and specificity of FDG-PET/CT ranged from 85 to 99% and 67 to 80% for the different echelons. In 22.2% patients, EBUS-TBNA finding triggered changes of the treated CTV, compared with contouring algorithms based on FDG-avidity as the sole criterion for inclusion. CTV was enlarged in 6.7% patients due to EBUS-positivity in PET-negative LN-station and reduced in 15.5% by exclusion of an EBUS-negative but PET-positive LN-station.

Conclusion

The false discovery rate of [¹⁸F]FDG-PET/CT increased markedly with distance from the primary tumor. Inclusion of systematic mediastinal LN mapping by EBUS-TBNA in addition to PET/CT has the potential to increase accuracy of target volume definition, particularly in echelon-3 LNs. EBUS-TBNA is recommended as integral part of staging for radiochemotherapy in stage III NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05204-7.

It's About Quality, Not Quantity: Qualitative FDG PET/CT Criteria for Therapy Response Assessment in Clinical Practice

OBJECTIVE. FDG PET/CT has emerged as an effective tool for the timely accurate assessment of how tumors respond to therapy. To standardize interpretation and reporting, numerous response criteria have been developed. This article will review the evolution of these criteria along with their strengths and weaknesses. CONCLUSION. Several qualitative assessments applicable to common malignancies have been developed in recent years that solve many of the challenges faced by their quantitative predecessors. These are reviewed, and information is provided regarding individual treatment efficacy and prognosis.

Primary vs nodal site PET/CT response as a prognostic marker in oropharyngeal squamous cell carcinoma treated with intensity-modulated radiation therapy

BACKGROUND

Positron emission tomography/computed tomography (PET/CT) in staging of advanced oropharyngeal squamous cell carcinoma (OPSCC) and at 3 months posttreatment (PETpost) is often utilized to assess response. The significance of lymph node vs primary site treatment response is incompletely understood.

METHODS

We reviewed 230 patients treated with radiation therapy. PETpost response was graded at primary and nodal sites and correlated with survival.

RESULTS

Median age was 58, and 83% were p16-positive. Median follow-up was 24.3 months. Nodal response at PETpost predicted improved 2-year local recurrence-free survival (LRFS) (93% vs 72%, P =.004), 2-year disease-free survival (DFS) (80% vs 61.3%, P =.021), and 2-year overall survival (OS) (89% vs 83%, P =.051), while primary response only predicted improved 2-year LRFS (91% vs 76% P = .035).

CONCLUSION

In OPSCC patients, both nodal and primary response at 3 months on PET/CT predicted for improved LRFS, but only nodal response predicted DFS and OS.

Post-treatment FDG PET-CT in head and neck carcinoma: comparative analysis of 4 qualitative interpretative criteria in a large patient cohort

There is no consensus regarding optimal interpretative criteria (IC) for Fluorine-18 fluorodeoxyglucose (FDG) Positron Emission Tomography – Computed Tomography (PET-CT) response assessment following (chemo)radiotherapy (CRT) for head and neck squamous cell carcinoma (HNSCC). The aim was to compare accuracy of IC (NI-RADS, Porceddu, Hopkins, Deauville) for predicting loco-regional control and progression free survival (PFS). All patients with histologically confirmed HNSCC treated at a specialist cancer centre with curative-intent non-surgical treatment who underwent baseline and response assessment FDG PET-CT between August 2008 and May 2017 were included. Metabolic response was assessed using 4 different IC harmonised into 4-point scales (complete response, indeterminate, partial response, progressive disease). IC performance metrics (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy) were compared. Kaplan-Meier and Cox proportional hazards regression analyses were performed for survival analysis. 562 patients were included (397 oropharynx, 53 hypopharynx, 48 larynx, 64 other/unknown primary). 420 patients (75%) received CRT and 142 (25%) had radiotherapy alone. Median follow-up was 26 months (range 3–148). 156 patients (28%) progressed during follow-up. All IC were accurate for prediction of primary tumour (mean NPV 85.0% (84.6–85.3), PPV 85.0% (82.5–92.3), accuracy 84.9% (84.2–86.0)) and nodal outcome (mean NPV 85.6% (84.1–86.6), PPV 94.7% (93.8–95.1), accuracy 86.8% (85.6–88.0)). Number of indeterminate scores for NI-RADS, Porceddu, Deauville and Hopkins were 91, 25, 20, 13 and 55, 70, 18 and 3 for primary tumour and nodes respectively. PPV was significantly reduced for indeterminate uptake across all IC (mean PPV primary tumour 36%, nodes 48%). Survival analyses showed significant differences in PFS between response categories classified by each of the four IC (p <0.001). All four IC have similar diagnostic performance characteristics although Porceddu and Deauville scores offered the best trade off of minimising indeterminate outcomes whilst maintaining a high NPV.

Physician Review of a Celiac Disease Risk Estimation and Decision-Making Expert System

Objective: Celiac disease is a genetic disease affecting people of all ages, resulting in small intestine enteropathy. It is considered to be a clinical chameleon. Average prevalence of celiac disease is 1 out of 100 people with data indicating the risk may be as high as 22% for those with first-degree relatives with the disease. Eighty-three percent of people with celiac disease may be undiagnosed. Average duration to diagnosis is 10 years. Data indicate that there is a lack of consensus regarding diagnostics and symptomatology.Method: A clinical decision support system (CDSS) was developed using Exsys Corvid for expert analysis (CD-CDSS). The CD-CDSS was divided into symptoms and manifestations with 80 points of navigation, and a serology section, and was validated by 13 experts in the field of celiac disease using a 10-statement 5-point Likert scale.Results: This scale was analyzed using Cronbach's alpha reliability coefficient, which was calculated using SPSS and revealed good internal consistency and reliability with a result of 0.813. One hundred percent of experts agreed that the CD-CDSS is capable of guiding a health care professional through the diagnostic process, contains an accurate list of symptoms based on the clinical literature, and can foster improved awareness and education about celiac disease and that there is a need for this system.Conclusions: A celiac disease risk estimation and decision-making expert system was successfully developed and evaluated by medical professionals, with 100% agreeing that this CD-CDSS is medically accurate and can guide health care professionals through the diagnostic process.

Utility of Likert scale (Deauville criteria) in assessment of Chemoradiotherapy response of primary oropharyngeal squamous cell Cancer site

INTRODUCTION

The aim of this study is to determine whether Likert scale (Deauville criteria) can be used to classify oropharyngeal squamous cell cancer (OPSCC) patients as 'responders' and 'nonresponders' by utilizing FDG-PET/CT for primary tumor site. The second aim is to compare the performance of methods used in interpretation of posttreatment PET/CT scans (Likert scale, SUVmax, ratios of SUVmax primary lesion to mediastinum 'SUVmax P/M' and SUVmax primary lesion to liver 'SUVmax P/L') in predicting treatment response.

METHODS

Seventy-seven PET/CT scans were assessed by Deauville criteria, five-point Likert scale. SUVmax of primary lesion, SUVmax primary to mediastinum and SUVmax primary to liver ratios on first follow-up PET/CT were measured and calculated. Pathology results, clinical and imaging follow-up were used as standart reference.

RESULTS

Sensitivity, specificity, positive predictive and negative predictive value of Likert scale were found to be 80%, 89.5%, 53.3% and 96.8% respectively. When Likert scale and PET parameters were compared, no statistically significant difference was found. Receiver operating characteristic (ROC) was used to determine the optimal cut-off points for SUVmax (found as 4) and for ratios (SUVmax P/M = 1.67and SUVmax P/L = 1.7) with the highest specificity and NPV.

CONCLUSION

Likert scale adequately categorize patients as 'responders' and 'non-responders'. Since its NPV is high and interpretation is relatively easy, it can be utilized to evaluate OPSCC response to treatment in first follow up FDG PET/CT.

Utility of a repeat PET/CT scan in HPV-associated Oropharyngeal Cancer following incomplete nodal response from (chemo)radiotherapy

OBJECTIVES

To assess the utility of a repeat positron emission tomography/computed tomography (PET/CT) instead of immediate neck dissection (ND) for incomplete nodal response (IR) in Human Papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPC) following chemoradiotherapy/radiotherapy [(chemo)RT].

MATERIALS AND METHODS

Patients with non-distant metastatic, node positive (N+) disease treated between Jan/2005 to Jan/2016, achieved complete response at the primary with no distant relapse on a 12-week re-staging PET/CT were evaluated. Patients underwent surveillance after complete nodal response (CR). Patients with IR underwent repeat PET/CT at 16 weeks to direct neck management. Primary endpoints were CR conversion rate and subsequent regional failure following a 16-week PET/CT directed ND. Secondary endpoints were predictive values (PV) of the 12- and 16-week PET/CT for residual nodal disease, predictors for requiring the 16-week PET/CT, 5 year regional, locoregional failure free survival (FFS) and overall survival (OS).

RESULTS

235 patients were evaluated. Median follow up was 56 (range 19-60) months. 41 patients underwent 16-week re-staging PET/CT, 29 (71%) converted to CR. No subsequent regional failures occurred following a 16-week PET/CT directed ND. Positive and negative PV of the 12- and 16-week PET/CT for residual nodal disease was 12% & 98%, and 33% & 97%, respectively. N-category (AJCC/UICC 7th edition) predicted for requiring a 16-week PET/CT on univariate analysis (P-value 0.02). 5 year regional, locoregional FFS and OS was 95.8%, 93.4% and 90.8%, respectively.

CONCLUSION

For N+ HPV-associated OPC achieving IR on the 12-week re-staging PET/CT following (chemo)RT, a repeat 16-week PET/CT can spare patients from unnecessary surgery.

FDG-PET/CT for treatment response assessment in head and neck squamous cell carcinoma: a systematic review and meta-analysis of diagnostic performance

PURPOSE

18-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) is increasingly used to evaluate treatment response in head and neck squamous cell carcinoma (HNSCC). This analysis assessed the diagnostic value of FDG-PET/CT in detecting nodal disease within 6 months after treatment, considering patient and disease characteristics.

METHODS

A systematic review was performed using the MEDLINE and Web of Knowledge databases. The results were pooled using a bivariate random effects model of the sensitivity and specificity.

RESULTS

Out of 22 identified studies, a meta-analysis of 20 studies (1293 patients) was performed. The pooled estimates of sensitivity, specificity and diagnostic odds ratio (with 95% CI) were 85% (76-91%), 93% (89-96%) and 76 (35-165), respectively. With the prevalence set at 10%, the positive and negative predictive values were 58% and 98%. There was significant heterogeneity between the trials (p < 0.001). HPV positive tumors were associated with lower sensitivity (75% vs 89%; p = 0.01) and specificity (87% vs 95%; p < 0.005).

CONCLUSION

FDG-PET/CT within 6 months after (chemo)radiotherapy in HNSCC patients is a reliable method for ruling out residual/recurrent nodal disease and obviates the need for therapeutic intervention. However, FDG-PET/CT may be less reliable in HPV positive tumors and the optimal surveillance strategy remains to be determined.

A Score-Based Approach to 18F-FDG PET Images as a Tool to Describe Metabolic Predictors of Myocardial Doxorubicin Susceptibility

Purpose: To verify the capability of ¹⁸F-fluorodeoxy-glucose positron emission tomography/computed tomography (FDG-PET/CT) to identify patients at higher risk of developing doxorubicin (DXR)-induced cardiotoxicity, using a score-based image approach. Methods: 36 patients underwent FDG-PET/CT. These patients had shown full remission after DXR-based chemotherapy for Hodgkin’s disease (DXR dose: 40–50 mg/m² per cycle), and were retrospectively enrolled. Inclusion criteria implied the presence of both pre- and post-chemotherapy clinical evaluation encompassing electrocardiogram (ECG) and echocardiography. Myocardial metabolism at pre-therapy PET was evaluated according to both standardized uptake value (SUV)- and score-based approaches. The capability of the score-based image assessment to predict the occurrence of cardiac toxicity with respect to SUV measurement was then evaluated. Results: In contrast to the SUV-based approach, the five-point scale method does not linearly stratify the risk of the subsequent development of cardiotoxicity. However, converting the five-points scale to a dichotomic evaluation (low vs. high myocardial metabolism), FDG-PET/CT showed high diagnostic accuracy in the prediction of cardiac toxicity (specificity = 100% and sensitivity = 83.3%). In patients showing high myocardial uptake at baseline, in which the score-based method is not able to definitively exclude the occurrence of cardiac toxicity, myocardial SUV mean quantification is able to further stratify the risk between low and intermediate risk classes. Conclusions: the score-based approach to FDG-PET/CT images is a feasible method for predicting DXR-induced cardiotoxicity. This method might improve the inter-reader and inter-scanner variability, thus allowing the evaluation of FDG-PET/CT images in a multicentral setting.

Clinical Practice in PET/CT for the Management of Head and Neck Squamous Cell Cancer

OBJECTIVE

The purpose of this article is to summarize the evidence for the value of PET/CT for the management of patients with head and neck squamous cell cancer and suggest best clinical practices.

CONCLUSION

FDG PET/CT is a valuable imaging tool for identifying unknown primary tumors in patients with known cervical node metastases leading to management change and is the standard of care for the initial staging of stage III and IV head and neck squamous cell carcinomas (HNSCCs), for assessing therapy response when performed at least 12 weeks after chemoradiation therapy, and for avoiding unnecessary planned neck dissection. Neck dissection is avoided if PET/CT findings are negative-regardless of the size of the residual neck nodes-because survival outcomes are not compromised. FDG PET/CT is valuable in detecting recurrences and metastases during follow-up when suspected because of clinical symptoms and serves as a prognostic marker for patient survival outcomes, for 5 years. Using FDG PET/CT for routine surveillance of HNSCC after 6 months of treatment without any clinical suspicion should be discouraged.

Efficacy of qualitative response assessment interpretation criteria at 18F-FDG PET-CT for predicting outcome in locally advanced cervical carcinoma treated with chemoradiotherapy

Objectives

To evaluate the utility of a standardized qualitative scoring system for treatment response assessment at 18F-FDG PET-CT in patients undergoing chemoradiotherapy for locally advanced cervical carcinoma and correlate this with subsequent patient outcome.

Methods

Ninety-six consecutive patients with locally advanced cervical carcinoma treated with radical chemoradiotherapy (CRT) in a single centre between 2011 and 2014 underwent 18F-FDG PET-CT approximately 3 months post-treatment. Tumour metabolic response was assessed qualitatively using a 5-point scale ranging from background level activity only through to progressive metabolic disease. Clinical and radiological (MRI pelvis) follow-up was performed in all patients. Progression-free (PFS) and overall survival (OS) was calculated using the Kaplan-Meier method (Mantel-Cox log-rank) and correlated with qualitative score using Chi-squared test.

Results

Forty patients (41.7 %) demonstrated complete metabolic response (CMR) on post-treatment PET-CT (Score 1/2) with 38 patients (95.0 %) remaining disease free after a minimum follow-up period of 18 months. Twenty-four patients (25.0 %) had indeterminate residual uptake (ID, Score 3) at primary or nodal sites after treatment, of these eight patients (33.3 %) relapsed on follow-up, including all patients with residual nodal uptake (n = 4Eleven11 of 17 patients (64.7 %) with significant residual uptake (partial metabolic response, PMR, Score 4) subsequently relapsed. In 15 patients (15.6 %) PET-CT demonstrated progressive disease (PD, Score 5) following treatment. Kaplan-Meier analysis showed a highly statistically significant difference in PFS and OS between patients with CMR, indeterminate uptake, PMR and PD (Log-rank, P < 0.0001). Chi-squared test demonstrated a highly statistically significant association between increasing qualitative score and risk of recurrence or death (P < 0.001).

Conclusion

Use of a 5-point qualitative scoring system to assess metabolic response to CRT in locally advanced cervical carcinoma predicts survival outcome and this prognostic information may help guide further patient management.