Optimal timing of first posttreatment FDG PET/CT in head and neck squamous cell carcinoma

Imaging Follow-Up of Nonsurgical Therapies for Lung Cancer: AJR Expert Panel Narrative Review

Lung cancer continues to be the most common cause of cancer-related death worldwide. In the past decade, with the implementation of lung cancer screening programs and advances in surgical and nonsurgical therapies, the survival of patients with lung cancer has increased, as has the number of imaging studies that these patients undergo. However, most patients with lung cancer do not undergo surgical re-section, because they have comorbid disease or lung cancer in an advanced stage at diagnosis. Nonsurgical therapies have continued to evolve with a growing range of systemic and targeted therapies, and there has been an associated evolution in the imaging findings encountered at follow-up examinations after such therapies (e.g., with respect to posttreatment changes, treatment complications, and recurrent tumor). This AJR Expert Panel Narrative Review describes the current status of nonsurgical therapies for lung cancer and their expected and unexpected imaging manifestations. The goal is to provide guidance to radiologists regarding imaging assessment after such therapies, focusing mainly on non-small cell lung cancer. Covered therapies include systemic therapy (conventional chemotherapy, targeted therapy, and immunotherapy), radiotherapy, and thermal ablation.

Review of Outcomes after Salvage Surgery for Recurrent Squamous Cell Carcinoma of the Head and Neck

Surgery with adjuvant chemoradiotherapy or chemoradiotherapy is the mainstay in treatment for advanced stage head and neck squamous cell carcinoma; however, locoregional recurrences are frequent. Salvage surgery could be proposed in selected patients to improve local control, disease-free, and overall survival. Factors for improved disease-free and overall survival in patients treated with salvage surgery include age, tumor location, the initial T stage, HPV status, resection margins, and the time elapsing from the initial treatment. Clinical trials with adjuvant therapies have shown promise after salvage surgery in terms of tolerance and response, but clinical guidelines for using these adjuvant treatments are currently lacking. The aim of this review is to present current knowledge concerning the incidence and management of recurrent head and neck squamous cell carcinoma and current data concerning survival and morbidity after salvage surgery.

[18F]FDG PET/CT in head and neck squamous cell carcinoma: a head-to-head between visual point-scales and the added value of multi-modality imaging

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) represents the 6th leading cancer worldwide. In most cases, patients present a locally advanced disease at diagnosis and non-surgical curative treatment is considered the standard of care. Nowadays, [¹⁸F]FDG PET/CT is a validated tool in post-treatment evaluation, with a high level of evidence. However, to standardize imaging response, several visual scales have been proposed with none of them approved yet. The study's aim is a head-to-head comparison between the diagnostic performance of the Hopkins criteria, the Deauville score, and the new proposed Cuneo score, to establish their prognostic role. Secondly, we investigate the possible value of semiquantitative analysis, evaluating SUV_max and ΔSUV_max of the lymph node with the highest uptake on the restaging PET scan. Moreover, we also considered morphological features using the product of diameters measured on the co-registered CT images to assess the added value of hybrid imaging.

METHODS

We performed a retrospective analysis on histologically proven HNSCC patients who underwent baseline and response assessment [¹⁸F]FDG PET/CT. Post-treatment scans were reviewed according to Hopkins, Deauville, and Cuneo criteria, assigning a score to the primary tumor site and lymph nodes. A per-patient final score for each scale was chosen, corresponding to the highest score between the two sites. Diagnostic performance was then calculated for each score considering any evidence of locoregional progression in the first 3 months as the gold standard. Survival analysis was performed using the Kaplan-Meier method. SUV_max and its delta, as well as the product of diameters of the lymph node with the highest uptake at post-treatment scan, if present, were calculated.

RESULTS

A total of 43 patients were finally included in the study. Sensitivity, specificity, PPV, NPV, and accuracy were 87%, 86%, 76%, 92%, and 86% for the Hopkins score, whereas 93%, 79%, 70%, 96%, and 84% for the Deauville score, respectively. Conversely, the Cuneo score reached the highest specificity and PPV (93% and 78%, respectively) but the lowest sensitivity (47%), NPV (76%), and accuracy (77%). Each scale significantly correlated with PFS and OS. The ROC analysis of the combination of SUV_max and the product of diameters of the highest lymph node on the restaging PET scan reached an AUC of 0.822. The multivariate analysis revealed the Cuneo criteria and the product of diameters as prognostic factors for PFS.

CONCLUSIONS

Each visual score statistically correlated with prognosis thus demonstrating the reliability of point-scale criteria in HNSCC. The novel Cuneo score showed the highest specificity, but the lowest sensibility compared to Hopkins and Deauville criteria. Furthermore, the combination of PET data with morphological features could support the evaluation of equivocal cases.

Clinical Utility of Second-Look FDG PET-CT to Stratify Incomplete Metabolic Response Post (Chemo) Radiotherapy in Oropharyngeal Squamous Cell Carcinoma

BACKGROUND

Incomplete response on FDG PET-CT following (chemo)radiotherapy (CRT) for head and neck squamous cell carcinoma (HNSCC) hinders optimal management. The study assessed the utility of an interval (second look) PET-CT.

METHODS

Patients with oropharyngeal squamous cell carcinoma cancer (OPSCC) treated with CRT at a single centre between 2013 and 2020 who underwent baseline, response, and second-look PET-CT were included. Endpoints were conversion rate to complete metabolic response (CMR) and test characteristics of second-look PET-CT.

RESULTS

In total, 714 patients with OPSCC underwent PET-CT post-radiotherapy. In total, 88 patients with incomplete response underwent second-look PET-CT a median of 13 weeks (interquartile range 10-15 weeks) after the initial response assessment. In total, 27/88 (31%) second-look PET-CTs showed conversion to CMR, primary tumour CMR in 20/60 (30%), and nodal CMR in 13/37 (35%). In total, 1/34 (3%) with stable tumour/nodal uptake at the second-look PET-CT relapsed. Sensitivity, specificity, positive (PPV), and negative predictive value (NPV) of second-look PET-CT were 95%, 49%, 50%, and 95% for tumour and 92%, 50%, 50%, and 92% for nodes, respectively. Primary tumour progression following CMR occurred in one patient, two patients with residual nodal uptake at second-look PET-CT progressed locoregionally, and one patient developed metastatic disease following CMR in residual nodes.

CONCLUSION

Most patients undergoing second-look PET-CT converted to CMR or demonstrated stable PET signal. NPV was high, suggesting the potential to avoid unnecessary surgical intervention.

Personalizing Surveillance in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) encompasses a spectrum of heterogeneous diseases originating in the oral cavity, pharynx, and larynx. Within the United States, head and neck cancer (HNC) accounts for 66,470 new cases, or 3% of all malignancies, annually.¹ The incidence of HNC is rising, largely driven by increases in oropharyngeal cancer.^2-4 Recent molecular and clinical advancements, particularly with regard to molecular and tumor biology, reflect the heterogeneity of the subsites contained within the head and neck. Despite this, existing guidelines for post-treatment surveillance remain broad without much consideration given to different anatomic subsites and etiologic factors (such as human papillomavirus [HPV] status or tobacco exposure).⁵ Surveillance incorporating the physical examination, imaging, and emerging molecular biomarkers is an essential part of care for patients treated for HNC and allows for the detection of locoregional recurrence, distant metastases, and second primary malignancies aiming for better functional and survival outcomes. Additionally, it allows for evaluation and management of post-treatment complications.

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.

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.

Performance of NI-RADS on CECT Alone to Predict Recurrent Head and Neck Squamous Cell Carcinoma after Chemoradiotherapy: Added Value of RECIST 1.1

Background  The Head and Neck Imaging Reporting and Data System (NI-RADS) is a standardized reporting format for the categorization of the degree of suspicion for recurrent head and neck malignancies on positron emission tomography/computed tomography.

Purpose  The purpose of our study was to analyze the efficacy of the NI-RADS rating scale and criteria for contrast-enhanced computed tomography (CECT) alone in predicting the local and regional recurrence of malignancies after chemoradiotherapy.

Material and Methods  CECT of the patients with head and neck cancers receiving radiotherapy and concurrent chemotherapy as a primary treatment was obtained 3 months after the completion of radiotherapy and NI-RADS scoring was done using components of Response Evaluation Criteria in Solid Tumors (RECIST 1.1) criteria. Their management was guided according to the recommendations based on their NI-RADS score.

Results  Thirty patients with squamous cell carcinoma of the neck were included in this study. The positive or negative status of the recurrent disease was based on biopsy results or follow-up protocol as recommended in NI-RADS rating scale. Fifteen patients had path proven recurrence at the primary tumor site. For primary tumor site, disease persistence rates of 4% for NI-RADS 1, 24% for NI-RADS 2, and 80% for NI-RADS 3 scores were seen. Five patients had recurrent lymph nodal disease. For lymph nodal assessment, NI-RADS categories 1, 2, and 3 revealed nodal disease recurrence rates of 5.3, 25, and 66.7%, respectively.

Conclusion  CECT alone may be used to assign the NI-RADS rating scale using RECIST 1.1 criteria to predict the presence or absence of recurrent tumor in patients with neck malignancies.

Interrater Reliability of NI-RADS on Posttreatment PET/Contrast-enhanced CT Scans in Head and Neck Squamous Cell Carcinoma

Purpose To evaluate the interrater reliability among radiologists examining posttreatment head and neck squamous cell carcinoma (HNSCC) fluorodeoxyglucose PET/contrast-enhanced CT (CECT) scans using Neck Imaging Reporting and Data System (NI-RADS). Materials and Methods In this retrospective study, images in 80 patients with HNSCC who underwent posttreatment surveillance PET/CECT and immediate prior comparison CECT or PET/CECT (from June 2014 to July 2016) were uploaded to the American College of Radiology's cloud-based website, Cortex. Eight radiologists from seven institutions with variable NI-RADS experience independently evaluated each case and assigned an appropriate prose description and NI-RADS category for the primary site and the neck site. Five of these individuals were experienced readers (> 5 years of experience), and three were novices (< 5 years of experience). In total, 640 lexicon-based and NI-RADS categories were assigned to lesions among the 80 included patients by the eight radiologists. Light generalization of Cohen κ for interrater reliability was performed. Results Of the 80 included patients (mean age, 63 years ± 10 [standard deviation]), there were 58 men (73%); 60 patients had stage IV HNSCC (75%), and the most common tumor location was oropharynx (n = 32; 40%). Light κ for lexicon was 0.30 (95% CI: 0.23, 0.36) at the primary site and 0.31 (95% CI: 0.24, 0.37) at the neck site. Light κ for NI-RADS category was 0.55 (95% CI: 0.46, 0.63) at the primary site and 0.60 (95% CI: 0.48, 0.69) at the neck site. Percent agreement between lexicon and correlative NI-RADS category was 84.4% (540 of 640) at the primary site and 92.6% (593 of 640) at the neck site. There was no significant difference in interobserver agreement among the experienced versus novice raters. Conclusion Moderate agreement was achieved among eight radiologists using NI-RADS at posttreatment HNSCC surveillance imaging. Keywords: CT, PET/CT, Head/Neck, Neck, Neoplasms-Primary, Observer Performance Supplemental material is available for this article. © RSNA, 2021.

Best Practices: Application of NI-RADS for Posttreatment Surveillance Imaging of Head and Neck Cancer

Imaging surveillance is an important component of posttreatment management of head and neck cancers. There is variability in the surveillance regimen used by various practitioners and institutions, with no official National Comprehensive Cancer Network guidelines for patients showing no symptoms beyond 6 months posttreatment. Moreover, imaging of the neck after treatment is a complex examination with significant interreader heterogeneity, particularly in terms of the manner in which degree of suspicion for disease recurrence is expressed. The Neck Imaging Reporting and Data System (NI-RADS) was introduced by the American College of Radiology (ACR) in 2018 as a practical guide for the interpreting radiologist. NI-RADS is a proposed interpretive framework that can be applied to any standardized or institutional surveillance imaging protocol. NI-RADS simplifies communication between radiologists and referring clinicians and provides management guidance linked to specific levels of suspicion. The ACR NI-RADS Committee also provided general best practice recommendations for imaging surveillance modality and timing in the 2018 white paper. This article will review existing literature regarding choice of modality and timeline for surveillance in treated cancer of the head and neck. NI-RADS will then be presented as an approach to imaging reporting, interpretation, and design of next steps in management.

F-18 FDG PET-CT for response evaluation in head and neck malignancy: Experience from a tertiary level hospital in south India

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) accounts for 90% of head and neck cancers. There has been no established qualitative system of interpretation for therapy response assessment using PET-CT for HNSCC.

AIM

To assess response evaluation of nodal status in post-treatment PET-CT scans in HNSCC using a 5-point Likert scale (Deauville score [DS]).

METHODS AND RESULTS

Retro-prospective analysis was performed of the nodal status of pre and post-RT PET-CT in patients diagnosed with HNSCC (n = 43) from May 2013 to March 2018. All eligible patients underwent a pre-RT PET-CT scan before the start of RT. Another post-RT PET-CT scan was performed 12 weeks after the completion of RT. The median time from completion of radiotherapy (RT) to post-RT PET-CT was 92 days; 80% of the patients had their post-RT PET-CT scan between 77 and 147 days after therapy. Of 43 patients (M/33, F/10, age range 18 to 80 years (median 54 years) selected for the study, good concordance was noted between DS and clinical response in these patients. The change in SUV from pre-RT PET to post-RT PET was analyzed using a paired t-test. The P-value was found to be statistically significant while comparing pre and post-RT SUVmax levels showing that RT had significantly reduced the SUVmax levels of the nodes in DS 2-3 groups whereas the number of patients was too small to allow a reliable calculation in DS 4-5 groups. It was found that 36/39 patients with DS 1-3 had no nodal recurrence showing a high NPV of 92.3%. Of the four patients with DS 4-5, all had active disease showing PPV of 100%. Applying Fisher's exact test, the P-value was found to be .004.

CONCLUSION

DS seems to satisfy the requirements for a simple qualitative method of interpreting PET scans and for identifying patients requiring neck dissection. Consensus regarding qualitative assessment would facilitate standardization of PET reporting in clinical practice and enable comparative multicentric studies.

Posttreatment Imaging in Patients with Head and Neck Cancer without Clinical Evidence of Recurrence: Should Surveillance Imaging Extend Beyond 6 Months?

BACKGROUND AND PURPOSE

Early detection of residual or recurrent disease is important for effective salvage treatment in patients with head and neck cancer. Current National Comprehensive Cancer Network guidelines do not recommend standard surveillance imaging beyond 6 months unless there are worrisome signs or symptoms on clinical examination and offer vague guidelines for imaging of high-risk patients beyond that timeframe. Our goal was to evaluate the frequency of clinically occult recurrence in patients with head and neck squamous cell carcinoma with positive imaging findings (Neck Imaging Reporting and Data Systems scores of 2-4), especially after 6 months.

MATERIALS AND METHODS

This institutional review board-approved, retrospective data base search queried neck CT reports with Neck Imaging Reporting and Data Systems scores of 2-4 from June 2014 to March 2018. The electronic medical records were reviewed to determine outcomes of clinical and radiologic follow-up, including symptoms, physical examination findings, pathologic correlation, and clinical notes within 3 months of imaging.

RESULTS

A total of 255 cases, all with Neck Imaging Reporting and Data Systems scores of 2 or 3, met the inclusion criteria. Fifty-nine patients (23%) demonstrated recurrence (45 biopsy-proven, 14 based on clinical and imaging progression), and 21 patients (36%) had clinically occult recurrence (ie, no clinical evidence of disease at the time of the imaging examination). The median overall time to radiologically detected, clinically occult recurrence was 11.4 months from treatment completion.

CONCLUSIONS

Imaging surveillance beyond the first posttreatment baseline study was critical for detecting clinically occult recurrent disease in patients with head and neck squamous cell carcinoma. More than one-third of all recurrences were seen in patients without clinical evidence of disease; and 81% of clinically occult recurrences occurred beyond 6 months.

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.

Hopkins criteria for residual disease assessment after definitive radiotherapy in nasopharyngeal carcinoma

Objectives

Assessment of viable tumor residue after definitive radiotherapy is essential in patients with nasopharyngeal carcinoma (NPC). This study aimed to investigate the use of Hopkins criteria on positron emission tomography/computed tomography (PET/CT) for posttreatment response evaluation and whether plasma Epstein‐Barr virus (EBV) DNA could bring additional value.

Materials and methods

NPC patients who underwent FDG‐PET/CT scan within 26 weeks after definitive radiotherapy were retrospectively reviewed. Residual disease was evaluated by Hopkins 5‐point score. Accuracy of Hopkins criteria before and after incorporating EBV DNA was calculated. Prognostic value for locoregional failure‐free survival (LRFFS) and disease‐free survival (DFS) was analyzed.

Results

One hundred and sixteen patients were evaluated. Median follow‐up time was 28.3 months (range 3.3‐92.0 months). Residual disease was found in 19 (16.4%) patients. Overall, Hopkins criteria had high specificity (86.6%; 95% CI, 78.2%‐92.7%) and negative prognostic value (NPV) (94.4%; 95% CI, 88.7%‐97.3%), while sensitivity and positive prognostic value (PPV) was 73.7% (95% CI, 48.8%‐90.9%), 51.9% (95% CI, 37.8%‐65.6%), respectively. Posttreatment plasma EBV DNA was not predictive of residual tumor (P = .272). PPV and accuracy were 50.0% (95% CI, 32.1%‐67.9%) and 83.0% (95% CI, 73.8%‐90.0%) after incorporating detectable EBV DNA into the scoring system. Positive PET/CT results were significantly correlated with inferior 3‐year LRFFS (95.7% vs 79.5%, P = .043) and 3‐year DFS (84.6% vs 54.4%, P = .028).

Conclusions

The Hopkins criteria demonstrated high NPV and specificity in posttreatment assessment, with the potential to be a reliable prognostic indicator for locoregional failure. Combining EBV DNA with PET/CT did not improve diagnostic accuracies. PET/CT should not be performed less than 12 weeks after treatment.

Second-look PET-CT following an initial incomplete PET-CT response to (chemo)radiotherapy for head and neck squamous cell carcinoma

OBJECTIVES

The limited positive predictive value of an incomplete response on PET-CT following (chemo)radiotherapy for head and neck squamous cell carcinoma (HNSCC) means that the optimal management strategy remains uncertain. The aim of the study is to assess the utility of a 'second-look' interval PET-CT.

METHODS

Patients with HNSCC who were treated with (chemo)radiotherapy between 2008 and 2017 and underwent (i) baseline and (ii) response assessment PET-CT and (iii) second-look PET-CT following incomplete (positive or equivocal scan) response were included. Endpoints were conversion rate to complete response (CR) and test characteristics of the second-look PET-CT.

RESULTS

Five hundred sixty-two patients with HNSCC underwent response assessment PET-CT at a median of 17 weeks post-radiotherapy. Following an incomplete response on PET-CT, 40 patients underwent a second-look PET-CT at a median of 13 weeks (range 6-25) from the first response PET-CT. Thirty-four out of 40 (85%) patients had oropharyngeal carcinoma. Twenty-four out of 40 (60%) second-look PET-CT scans converted to a complete locoregional response. The primary tumour conversion rate was 15/27 (56%) and the lymph node conversion rate was 14/19 (74%). The sensitivity, specificity, positive predictive value and negative predictive value (NPV) of the second-look PET-CT were 75%, 75%, 25% and 96% for the primary tumour and 100%, 92%, 40% and 100% for lymph nodes. There were no cases of progression following conversion to CR in the primary site or lymph nodes.

CONCLUSIONS

The majority of patients who undergo a second-look PET-CT convert to a CR. The NPV of a second-look PET-CT is high, suggesting the potential to avoid surgical intervention.

KEY POINTS

• PET-CT is a useful tool for response assessment following (chemo)radiotherapy for head and neck squamous cell carcinoma. • An incomplete response on PET-CT has a limited positive predictive value and optimal management is uncertain. • These data show that with a 'second-look' interval PET-CT, the majority of patients convert to a complete metabolic response. When there is doubt about clinical and radiological response, a 'second-look' PET-CT can be used to spare patients unnecessary surgical intervention.

Predictive Value of First Posttreatment Imaging Using Standardized Reporting in Head and Neck Cancer

OBJECTIVE

The Neck Imaging Reporting and Data System (NI-RADS) is a standardized numerical reporting template for surveillance of head and neck squamous cell carcinoma (HNSCC). Our aim was to analyze the accuracy of NI-RADS on the first posttreatment fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography (PET/CECT).

STUDY DESIGN

Retrospective cohort study.

SETTING

Academic tertiary hospital.

SUBJECT AND METHODS

Patients with HNSCC with a 12-week posttreatment PET/CECT interpreted using the NI-RADS template and 9 months of clinical and radiologic follow-up starting from treatment completion between June 2014 and July 2016 were included. Treatment failure was defined as positive tumor confirmed by biopsy or Response Evaluation Criteria in Solid Tumors criteria. Cox proportional hazards models were performed.

RESULTS

This study comprised 199 patients followed for a median of 15.5 months after treatment completion (25% quartile, 11.8 months; 75% quartile, 20.2 months). The rates of treatment failure increased with each incremental increase in NI-RADS category from 1 to 3 (4.3%, 9.1%, and 42.1%, respectively). A Cox proportional hazards model demonstrated a strong association between NI-RADS categories and treatment failure at both primary and neck sites (hazard ratio [HR], 2.60 and 5.22, respectively; P < .001). In the smaller treatment subgroup analysis, increasing NI-RADS category at the primary site in surgically treated patients and treatment failure did not achieve statistically significant association (HR, 0.88; P = .82).

CONCLUSION

Increasing NI-RADS category at the baseline posttreatment PET/CECT is strongly associated with increased risk of treatment failure in patients with HNSCC.

Detection of loco-regional recurrence in malignant head and neck tumors: a comparison of CT, MRI, and FDG PET-CT

BACKGROUND

The early and accurate detection of local or regional recurrence of head and neck tumor is critically important.

PURPOSE

To compare the diagnostic accuracy of contrast-enhanced computed tomography (CT), contrast-enhanced magnetic resonance imaging (MRI), and fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT, alone and in combination, in detecting the locoregional recurrence of malignant head and neck tumor.

MATERIAL AND METHODS

A total of 93 patients with loco-regional recurrence of malignant head and neck tumors underwent CT, MRI, and PET-CT within 30 days before surgery. CT, MRI, and PET-CT for each patient were retrospectively reviewed to determine the presence of recurrent tumors in the primary site on a patient-by-patient basis and that of regional lymph nodes on a level-by-level basis. The diagnostic accuracy of CT, MRI, and PET-CT, alone and combined, were accessed with the postoperative histopathological findings or with 12-month follow-up results as the standard of reference.

RESULTS

The sensitivity/specificity/and accuracy of CT, MRI, and PET-CT for the detection of primary site recurrence was 89.9/85.7/89.3%, 94.9/85.7/93.6%, and 97.5/92.9/96.8%, respectively. The sensitivity/specificity/accuracy of CT, MRI, and PET-CT for the detection of nodal recurrence was 66.3/99.4/92.4%, 74.7/99.4/94.2%, and 85.5/94.9/93.0%, respectively. MRI + PET-CT achieved the best performance in the receiver operating characteristics curve analysis (Az value = 0.958 for primary site recurrence and 0.929 for nodal recurrence).

CONCLUSION

MRI + PET-CT offered the highest diagnostic performance in the detection of loco-regional recurrence of malignant head and neck tumor, compared with CT, MRI, PET-CT, and other combinations including CT.

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.

Negative Predictive Value of NI-RADS Category 2 in the First Posttreatment FDG-PET/CT in Head and Neck Squamous Cell Carcinoma

BACKGROUND AND PURPOSE

FDG PET/CT has a high negative predictive value in patients with head and neck squamous cell carcinoma who responds completely to non-operative therapy. However, the treatment failure rate in patients with a partial but incomplete response is unclear. Our aim was to investigate the negative predictive value of the first posttreatment FDG-PET/CT in patients with head and neck squamous cell carcinoma with incomplete response interpreted as Neck Imaging Reporting and Data System (NI-RADS) category 2.

MATERIALS AND METHODS

We retrospectively identified patients with head and neck squamous cell carcinoma treated with chemoradiation or radiation therapy with curative intent in our institution between 2008 and 2016. We included patients whose first posttreatment FDG-PET/CT was interpreted as showing marked improvement of disease but who had a mild residual mass or FDG avidity in either the primary tumor bed or lymph nodes (NI-RADS 2). The negative predictive value of FDG-PET/CT was calculated, including the 95% CI, using the Newcombe method. Two-year disease-free survival was the reference standard.

RESULTS

Seventeen of 110 patients (15%) experienced locoregional treatment failure within 2 years of completing treatment, yielding a negative predictive value of 85% (95% Cl, 77%-90%). The most common location of tumor recurrence was the cervical lymph nodes (59%). The median time interval between completion of therapy and treatment failure was 10 months (range, 5-24 months).

CONCLUSIONS

In patients with an incomplete response after treatment of head and neck squamous cell carcinoma, the negative predictive value of the first posttreatment FDG-PET/CT was 85%, which is lower than the 91% negative predictive value of FDG-PET/CT in patients with an initial complete response. Patients with an incomplete response (NI-RADS 2) should undergo more frequent clinical and imaging surveillance than patients with an initial complete response (NI-RADS 1).

Assessing Novel Drugs and Radiation Technology in the Chemoradiation of Oropharyngeal Cancer

Integrating immunotherapy, proton therapy and biological dose escalation into the definitive chemoradiation of oropharyngeal cancer poses several challenges. Reliable and reproducible data must be obtained in a timely fashion. However, despite recent international radiotherapy contouring guidelines, controversy persists as to the applicability of such guidelines to all cases. Similarly, a lack of consensus exists concerning both the definition of the organ at risk for oral mucositis and the most appropriate endpoint to measure for this critical toxicity. Finally, the correlation between early markers of efficacy such as complete response on PET CT following treatment and subsequent survival needs elucidation for biological subsets of oropharyngeal cancer.

18F-FDG-PET/CT for the detection of disease in patients with head and neck cancer treated with radiotherapy

Objective

The aim of this study is to evaluate the diagnostic performance of FDG-PET/CT for the detection of residual disease after (chemo)radiotherapy in patients with head and neck squamous cell carcinoma (HNSCC) and to evaluate the prognostic value of the FDG-PET/CT findings.

Methods

Patients with HNSCC who underwent FDG-PET/CT after (chemo)radiotherapy were studied retrospectively.

Results

104 FDG-PET/CT-scans were performed at a median of 13.2 weeks post-treatment (5.4–19.0 weeks). The diagnostic performance was time dependent with decreasing sensitivity and slightly increasing specificity over time. Sensitivity, specificity, PPV and NPV at 9 months after imaging were 91%, 87%, 77% and 95%, respectively. In a logistic regression model, the odds of a correct FDG-PET/CT increased with 33% every additional week after end of therapy (p = 0.01) and accuracy plateaued after 11 weeks (97%; p<0.001). A complete response on FDG-PET/CT was associated with an overall survival benefit (50.7 versus 10.3 months; p<0.001). Residual disease on FDG-PET/CT increased the risk of death 8-fold (p<0.001).

Conclusion

FDG-PET/CT is able to detect residual disease after (chemo)radiotherapy, with an optimal time point for scanning between 11–12 weeks after therapy. However, a reevaluation is probably necessary 10–12 months after the FDG-PET/CT to detect late recurrences. In addition, FDG-PET/CT can guide decisions about neck dissection and identifies patients with poor prognosis.

The Role of Positron Emission Tomography/Computed Tomography Imaging in Head and Neck Cancer after Radical Chemoradiotherapy: a Single Institution Experience

AIMS

Positron emission tomography/computed tomography (PET/CT) is used to restage head and neck cancer 3 months after chemoradiotherapy. The purpose of this study was to determine the negative predictive value (NPV) of a scan reported as having no abnormal uptake and the positive predictive values (PPV) for different maximum standardised uptake value (SUVmax) thresholds.

MATERIALS AND METHODS

Patients with squamous cell carcinoma of the oro-/hypopharynx/larynx (n = 206) were included. SUVmax and subsequent locoregional recurrence were documented.

RESULTS

The median SUVmax was 11.2 (range 4-33)/4.6 (range 2-30), respectively, in patients with/without definite primary site recurrence (P = 0.004). The median SUVmax was 4.4 (range 2.6-15.6)/3.1 (range 2.1-4.6), respectively, in patients with/without definite nodal recurrence (P = 0.003). The NPV for a scan reported as having no abnormal uptake was 92%. The PPV for the SUVmax thresholds 4, 6 and 8, respectively, were 53, 65 and 92% (primary site) and 93, 100 and 100% (nodes).

CONCLUSIONS

The NPV of PET/CT after chemoradiation is consistent with the literature and underlines the importance of PET/CT in restaging the primary site if salvage neck dissection is considered. The overall PPV of PET/CT remains low but is high for nodal SUVmax > 4. These data could be used to design risk-stratified follow-up schedules.

Chapter 3 The Role of PET/CT in Squamous Cell Carcinoma of the Head and Neck

Head and neck squamous cell carcinoma is an important cause of cancer morbidity worldwide and has been stratified into human papillomavirus-related and human papillomavirus-unrelated subgroups that affect prognosis and now staging. Conventional anatomical imaging methods are suboptimal for the detection of regional and distant metastases that are important prognosticators associated with poor outcomes. Functional imaging with (F18)-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) is a useful tool in the management of head and neck squamous cell carcinoma, providing complementary physiological and anatomical information. In this article, optimal PET/CT technique will be reviewed and the pretreatment and posttreatment applications of PET/CT will be described. A simplified approach to imaging interpretation, including review of pearls and pitfalls will be discussed. An initial framework for follow-up evaluation will be provided.

Initial Performance of NI-RADS to Predict Residual or Recurrent Head and Neck Squamous Cell Carcinoma

BACKGROUND AND PURPOSE

The Head and Neck Imaging Reporting and Data System (NI-RADS) surveillance template for head and neck cancer includes a numeric assessment of suspicion for recurrence (1-4) for the primary site and neck. Category 1 indicates no evidence of recurrence; category 2, low suspicion of recurrence; category 3, high suspicion of recurrence; and category 4, known recurrence. Our purpose was to evaluate the performance of the NI-RADS scoring system to predict local and regional disease recurrence or persistence.

MATERIALS AND METHODS

This study was classified as a quality-improvement project by the institutional review board. A retrospective database search yielded 500 consecutive cases interpreted using the NI-RADS template. Cases without a numeric score, non-squamous cell carcinoma primary tumors, and primary squamous cell carcinoma outside the head and neck were excluded. The electronic medical record was reviewed to determine the subsequent management, pathology results, and outcome of clinical and radiologic follow-up.

RESULTS

A total of 318 scans and 618 targets (314 primary targets and 304 nodal targets) met the inclusion criteria. Among the 618 targets, 85.4% were scored NI-RADS 1; 9.4% were scored NI-RADS 2; and 5.2% were scored NI-RADS 3. The rates of positive disease were 3.79%, 17.2%, and 59.4% for each NI-RADS category, respectively. Univariate association analysis demonstrated a strong association between the NI-RADS score and ultimate disease recurrence, with P < .001 for primary and regional sites.

CONCLUSIONS

The baseline performance of NI-RADS was good, demonstrating significant discrimination among the categories 1-3 for predicting disease.

Molecular Imaging and Precision Medicine in Head and Neck Cancer

The concept of using tumor genomic profiling information has revolutionized personalized cancer treatment. Head and neck (HN) cancer management is being influenced by recent discoveries of activating mutations in epidermal growth factor receptor and related targeted therapies with tyrosine kinase inhibitors, targeted therapies for Kristen Rat Sarcoma, and MET proto-oncogenes. Molecular imaging using PET plays an important role in assessing the biologic behavior of HN cancer with the goal of delivering individualized cancer treatment. This review summarizes recent genomic discoveries in HN cancer and their implications for functional PET imaging in assessing response to targeted therapies, and drug resistance mechanisms.