Multicenter Trial of [18F]fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Staging of Head and Neck Cancer and Negative Predictive Value and Surgical Impact in the N0 Neck: Results From ACRIN 6685

Prospective Phase 2 Study of Radiation Therapy Dose and Volume De-escalation for Elective Neck Treatment of Oropharyngeal and Laryngeal Cancer

PURPOSE

The required elective nodal dose and volumes for head and neck intensity modulated radiation therapy have largely been extrapolated from conventional radiation therapy fields. In this prospective, dual-center, phase 2 study, we investigated the efficacy and tolerability of reduced elective nodal volume and dose in oropharyngeal and laryngeal squamous cell carcinoma.

METHODS AND MATERIALS

Patients with newly diagnosed squamous cell carcinoma of the oropharynx and larynx were eligible for enrollment. Each lymph node was characterized as involved or suspicious based on imaging criteria. For oropharynx cancer, only involved and immediately adjacent stations were treated to 40 Gy in 20 fractions. In larynx patients, at least bilateral levels II and III were treated to 40 Gy, with level IV treated only if level III was involved. Involved and suspicious nodes were then boosted with 30 Gy and 24 Gy in 15 fractions, respectively. Concurrent chemotherapy was required for stage T3N0-1 and IVA/B patients. The primary endpoint of the study was solitary elective volume recurrence, with secondary endpoints including patterns of failure and patient-reported outcomes.

RESULTS

A total of 72 (51 oropharynx, 21 larynx) patients completed treatment on this trial from January 2017 through November 2018. The stages at presentations were 5, 17, and 50 stage I-II, III, and IV, respectively, with 90% treated with chemoradiation therapy. At a median follow-up of 24.7 months for surviving patients, there have been no solitary elective nodal recurrences. Seven patients developed a nodal recurrence, 5 of which were in-field and 2 were elective with synchronous in-field recurrence. Patient-reported outcomes assessment at 1 year showed superior or equivalent outcomes compared with baseline, except for saliva and taste measures.

CONCLUSIONS

The results of this trial suggest that elective dose and volume reduction is oncologically sound for oropharyngeal and laryngeal cancer treated with intensity modulated radiation therapy, with promising quality-of-life outcomes.

Decision Modeling for Economic Evaluation in Otolaryngology-Head and Neck Surgery: Review of Techniques

Decision making in health care is complex, and substantial uncertainty can be involved. Structured, systematic approaches to the integration of available evidence, assessment of uncertainty, and determination of choice are of significant benefit in an era of "value-based care." This is especially true for otolaryngology-head and neck surgery, where technological advancements are frequent and applicable to an array of subspecialties. Decision analysis aims to achieve these goals through various modeling techniques, including (1) decision trees, (2) Markov process, (3) microsimulation, and (4) discrete event simulation. While decision models have been used for decades, many clinicians and researchers continue to have difficulty deciphering them. In this review, we present an overview of various decision analysis modeling techniques, their purposes, how they can be interpreted, and commonly used syntax to promote understanding and use of these approaches. Throughout, we provide a sample research question to facilitate discussion of the advantages and disadvantages of each technique.

[PET technology: Latest advances and potential impact on radiotherapy]

Multimodal imaging has become a standard for planning radiation therapy via magnetic resonance imaging (MRI) or positron emission tomography (PET) in many cancers. However, its use is now old, and its impact has not been much discussed in light of technological improvements in imaging and advances in radiotherapy. However, in 20 years, the exclusive functional imaging has been replaced by hybrid imaging (functional and anatomical) with successive improvements (flight time, detector modifications, digitisation, etc.) have enabled us to go from centimetric resolution to the current 3 to 4mm resolution. This article will specifically review PET technology, its latest advances and the potential impact on radiotherapy, particularly head and neck cancers.

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.

Role of Non-FDG-PET/CT in Head and Neck Cancer

Head and neck cancers are commonly encountered malignancies in the United States, of which the majority are attributed to squamous cell carcinoma. ¹⁸F-FDG-PET/CT has been well established in the evaluation, treatment planning, prognostic implications of these tumors and is routinely applied for the management of patients with these cancers. Many alternative investigational PET radiotracers have been extensively studied in the evaluation of these tumors. Although these radiotracers have not been able to replace ¹⁸F-FDG-PET/CT in routine clinical practice currently, they may provide important additional information about the biological mechanisms of these tumors, such as foci of tumor hypoxia as seen on hypoxia specific PET radiotracers such as ¹⁸F-Fluoromisonidazole (¹⁸F-FMISO), which could be useful in targeting radioresistant hypoxic tumor foci when treatment planning. There are multiple other hypoxia-specific PET radiotracers such as ¹⁸F-Fluoroazomycinarabinoside (FAZA), ¹⁸F-Flortanidazole (HX4), which have been evaluated similarly, of which ¹⁸F-Fluoromisonidazole (¹⁸F-FMISO) has been the most investigated. Other radiotracers frequently studied in the evaluation of these tumors include radiolabeled amino acid PET radiotracers, which show increased uptake in tumor cells with limited uptake in inflammatory tissue, which can be useful especially in differentiating postradiation inflammation from residual and/or recurrent disease. ¹⁸F-Fluorothymidine (FLT) is localized intracellularly by nucleoside transport and undergoes phosphorylation thereby being retained within tumor cells and can serve as an indicator of tumor proliferation. Decrease in radiotracer activity following treatment can be an early indicator of treatment response. This review aims at synthesizing the available literature on the most studied non-FDG-PET/CT in head and neck cancer.

Comparison Between PET-CT-Guided Neck Dissection and Elective Neck Dissection in cT1-2N0 Tongue Squamous Cell Carcinoma

Objective: Neck management in cT1-2N0 tongue squamous cell carcinoma (SCC) remains controversial. Our goal was to compare the survival difference between PET-CT–guided neck dissection and elective neck dissection (END) for the treatment of cT1-2 tongue SCC.

Methods: Patients with surgically treated cT1-2N0 tongue SCC were retrospectively enrolled. These patients were divided into two groups. Group A: The decision of whether to perform neck dissection was mainly based on the results of preoperative PET-CT examinations. Group B: Patients received END treatment without preoperative PET-CT examinations. The study endpoints were regional control (RC) and disease-specific survival (DSS). The Kaplan–Meier method was used to calculate the survival rates.

Results: Group A consisted of 66 patients, and 16 patients underwent neck dissection owing to positive PET-CT results. Group B consisted of 169 patients. The 5-year RC rates in group A and group B were 86 and 87%, respectively, and the difference was not significant (p = 0.731). The 5-year DSS rates in group A and group B were 93 and 90%, respectively, and the difference was not significant (p = 0.583).

Conclusions: Neck dissection can be safely avoided when the PET-CT scan reveals no neck lymph node involvement.

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.

Pre-operative cellular dissociation grading in biopsies is highly predictive of post-operative tumour stage and patient outcome in head and neck squamous cell carcinoma

BACKGROUND

Pre-operative treatment planning in head and neck squamous cell carcinoma (HNSCC) is mainly dictated by clinical staging, which has major shortcomings. Histologic grading is irrelevant due to its lack of prognostic impact. Recently, a novel grading termed Cellular Dissociation Grade (CDG) based on Tumour Budding and Cell Nest Size was shown to be highly prognostic for resected HNSCC. We aimed to probe the predictive and prognostic impact of CDG in the pre-operative biopsies of HNSCC.

METHODS

We evaluated CDG in n = 160 pre-therapeutic biopsies from patients who received standardised treatment following German guidelines, and correlated the results with pre- and post-therapeutic staging data and clinical outcome.

RESULTS

Pre-operative CDG was highly predictive of post-operative tumour stage, including the prediction of occult lymph node metastasis. Uni- and multivariate analysis revealed CDG to be an independent prognosticator of overall, disease-specific and disease-free survival (p < 0.001). Hazard ratio for disease-specific survival was 6.1 (11.1) for nG2 (nG3) compared with nG1 tumours.

CONCLUSIONS

CDG is a strong outcome predictor in the pre-treatment scenario of HNSCC and identifies patients with nodal-negative disease. CDG is a purely histology-based prognosticator in the pre-therapeutic setting that supplements clinical staging and may aide therapeutic stratification of HNSCC patients.

The changing therapeutic landscape of head and neck cancer

Head and neck cancers are a heterogeneous collection of malignancies of the upper aerodigestive tract, salivary glands and thyroid. In this Review, we primarily focus on the changing therapeutic landscape of head and neck squamous cell carcinomas (HNSCCs) that can arise in the oral cavity, oropharynx, hypopharynx and larynx. We highlight developments in surgical and non-surgical therapies (mainly involving the combination of radiotherapy and chemotherapy), outlining how these treatments are being used in the current era of widespread testing for the presence of human papillomavirus infection in patients with HNSCC. Finally, we describe the clinical trials that led to the approval of the first immunotherapeutic agents for HNSCC, and discuss the development of strategies to decrease the toxicity of different treatment modalities.

PET/MRI vs PET/CT in Head and Neck Imaging: When, Why, and How?

The increasing availability of hybrid PET/MRI systems has led to a breadth of new publications and opportunities for use of PET/MRI. While PET/CT has been a valuable tool for oncologic staging, including head and neck malignancy, there are several theoretical and practical advantages a PET/MRI system would have over PET/CT in head and neck imaging. This review article discusses the established role of PET/CT, early evidence for the role of PET/MRI, and protocol considerations for both PET/CT and PET/MRI as they apply to head and neck imaging.