Radiologic extranodal spread and matted nodes: Important predictive factors for development of distant metastases in patients with high-risk head and neck cancer

Diagnostic challenges and prognostic implications of extranodal extension in head and neck cancer: a state of the art review and gap analysis

Extranodal extension (ENE) is a pattern of cancer growth from within the lymph node (LN) outward into perinodal tissues, critically defined by disruption and penetration of the tumor through the entire thickness of the LN capsule. The presence of ENE is often associated with an aggressive cancer phenotype in various malignancies including head and neck squamous cell carcinoma (HNSCC). In HNSCC, ENE is associated with increased risk of distant metastasis and lower rates of locoregional control. ENE detected on histopathology (pathologic ENE; pENE) is now incorporated as a risk-stratification factor in human papillomavirus (HPV)-negative HNSCC in the eighth edition of the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC) TNM classification. Although ENE was first described almost a century ago, several issues remain unresolved, including lack of consensus on definitions, terminology, and widely accepted assessment criteria and grading systems for both pENE and ENE detected on radiological imaging (imaging-detected ENE; iENE). Moreover, there is conflicting data on the prognostic significance of iENE and pENE, particularly in the context of HPV-associated HNSCC. Herein, we review the existing literature on ENE in HNSCC, highlighting areas of controversy and identifying critical gaps requiring concerted research efforts.

Inter-rater concordance and operating definitions of radiologic nodal feature assessment in human papillomavirus-positive oropharyngeal carcinoma

BACKGROUND AND PURPOSE

This study aims to evaluate the reliability of radiologic nodal feature assessment in clinical node-positive human papillomavirus-positive oropharyngeal carcinoma.

MATERIALS AND METHODS

Baseline CTs or MRIs of clinical node-positive human papillomavirus-positive oropharyngeal carcinoma diagnosed between 2012 and 2015 were reviewed independently by two neuroradiologists for seven nodal features: radiologic nodal involvement, cystic change, presence of necrosis, clustering, conglomeration, coalescence, and extranodal extension. Consensus operating definitions were derived after discussion. The features were re-reviewed in a randomly selected cohort. Levels of certainty (probability of presence: <25%, ∼50%, ∼75%, and >90%) were recorded. Interrater concordance was calculated using Cohen's kappa coefficient.

RESULTS

A total of 413 patients (826 necks) were eligible. At initial review, the inter-rater kappa values for: radiologic nodal involvement, cystic change, necrosis, clustering, conglomeration, coalescence, and extranodal extension were 0.92, 0.64, 0.48, 0.32, 0.32, 0.62, and 0.56, respectively. A re-review of 94 randomly selected cases (188 necks) after consolidation of operating definitions for nodal features showed that the inter-rater kappa values of these features were 0.83, 0.62, 0.58, 0.32, 0.18, 0.68, and 0.74 when considering ≥50% certainty as positive, and improved to 0.94, 0.66, 0.59, 0.33, 0.19, 0.76, and 0.86 when considering ≥75% certainty as positive.

CONCLUSION

Clearly defined nomenclature results in improved interrater reliability when assessing radiologic nodal features, especially for coalescent adenopathy and extranodal extension. Higher levels of certainty are associated with higher inter-rater agreement. Radiology reporting should include clear definitions of clinically relevant nodal features as well as levels of certainty to serve various needs in clinical care and research.

Prognostic impact of matted lymphadenopathy in patients with oropharyngeal squamous cell carcinoma treated with definitive chemoradiotherapy

OBJECTIVE

To determine whether cervical matted lymphadenopathy (ML) is associated with outcomes in patients with oropharyngeal squamous cell carcinoma (OPSCC) treated with definitive chemoradiotherapy (CRT).

MATERIALS AND METHODS

OPSCC patients treated at our institution with CRT were included (n = 417). ML was defined by three adjacent nodes without an intervening fat plane. Patients were stratified into favorable OPSCC (p16 + with ≤ 10 pack-years smoking history) or unfavorable OPSCC (p16- and/or > 10 pack years). Primary outcomes were overall survival (OS) and progression-free survival (PFS) and the cumulative incidences of regional recurrence (RR) and distant metastasis (DM).

RESULTS

The median follow-up time for the surviving cohort was 49.9 months. In favorable OPSCC (n = 220), there were no significant associations between ML and any outcome. In unfavorable OPSCC (n = 197), ML had a significant negative impact on OS and PFS, with 3-year OS for patients without and with matted nodes at 74% and 56% (HR, 1.61, 95% CI 1.01-2.58). On multivariable Cox regression, patients with ML experienced significantly worsened OS (HR 1.65, 95% CI 1.03-2.65) and PFS (HR 1.94, 95% CI 1.28-2.93). The cumulative incidence of DM was also higher with ML (31% vs. 9%, adjusted HR 3.3, 95% CI 1.71-6.48).

CONCLUSION

ML carries no prognostic importance in patients with favorable OPSCC. However, ML portends significantly worse outcomes in individuals with HPV-negative disease or a significant smoking history. Thus, ML may help risk-stratify this latter population for treatment intensification, but does not seem to be a contraindication for treatment de-escalation in the former.

Clinical and histopathological risk factors for distant metastasis in head and neck cancer patients

The incidence of distant metastasis (DM) in head and neck squamous cell cancer (HNSCC) is relatively low. Multiple risk factors have been described for development of DM at baseline and after treatment. However, to date, there is no meta-analysis or systematic review investigating the relationships between clinical and histopathological factors and the appearance of DM in HNSCC patients. Among 1,272 eligible articles, 23 met inclusion criteria for qualitative analysis, and 6 for quantitative analysis. The meta-analysis on 5,353 patients showed that hypopharyngeal site, T3-T4 categories, extranodal extension, positive lymph node size > 6 cm, locoregional failure after previous treatment(s) and poor differentiation all significantly increase the risk of DM. According to our results, patients with the above-mentioned clinical and histopathological risk factors should be considered at high risk for DM and therefore submitted to strict pre-treatment assessment and undergo careful post-therapeutic follow-up.

Novel imaging classification system of nodal disease in human papillomavirus-mediated oropharyngeal squamous cell carcinoma prognostic of patient outcomes

BACKGROUND

Matted nodes in human papillomavirus (HPV)-mediated oropharyngeal squamous cell carcinoma (OPC) is an independent predictor of distant metastases and decreased overall survival. We aimed to classify imaging patterns of metastatic lymphadenopathy, analyze our classification system for reproducibility, and assess its prognostic value.

METHODS

The metastatic lymphadenopathy was classified based on radiological characteristics for 216 patients with HPV-mediated OPC. Patient outcomes were compared and inter-rater reliability was calculated.

RESULTS

The presence of ≥3 abutting lymph nodes with imaging features of surrounding extranodal extension (ENE), one subtype of matted nodes, was associated with worse 5-year overall survival, overall recurrence-free survival, regional recurrence-free survival, and distant recurrence-free survival (p ≤ 0.03). Other patterns were not significantly associated with outcome measures. Overall inter-rater agreement was substantial (κ = 0.73).

CONCLUSION

One subtype of matted nodes defined by ≥3 abutting lymph nodes with imaging features of surrounding ENE is the radiological marker of worst prognosis.

Predictive factors for simultaneous distant metastasis in head and neck cancer patients during the diagnostic work-up

INTRODUCTION

The incidence of distant metastasis (DM) in patients affected by head and neck squamous cell carcinoma (HNSCC) is relatively low, and multiple risk factors were described for the development of distant metastasis.

MATERIALS AND METHODS

Retrospective study of patients diagnosed with a HNSCC between July 2016 and July 2020 in a tertiary university hospital.

RESULTS

Five-Hundred and sixty-nine patients meet inclusion criteria. In the univariate analysis we found a statistical correlation in those patients affected by a hypopharyngeal tumour (p = < 0.0001), patients older than 60 years old (p = 0.01), advanced T stage (p = < 0.0001), a proven positive lymph node (p = 0.02), poorly differentiated tumour (p = < 0.0001), patients with 3 or more positive lymph nodes (p = 0.0001), with ECS (p = 0.0001) and a second primary tumour (p = 0.03). However, according to those results from our multivariable analysis, the factor related to an increased or higher chance to detect a DM during the diagnosis work-up were the presence of a hypopharyngeal primary tumor with a hazard ratio (HR) of 1.14, p =  < 0.0001, advanced T stage (T3-T4) with a HR of 1.21, p = 0.001, poorly differentiated tumor with a HR of 1.04, p =  < 0.0001, have proven positive lymph node with a HR of 1.03, p = 0.04, have more than three positive lymph node metastases with a HR of 1.25, p = 0.003, the presence of ECS with a HR of 1.40, p = 0.002, and have a second primary tumor with a HR of 1.05, p = 0.01.

CONCLUSION

According to the present study, factors such as hypopharyngeal tumours, advanced T-stage, poor differentiation grade, have more than three positive lymph nodes, ECS and have a second primary tumour should be considered as high-risk indicators for screening. Based on these results, the authors recommend considered an extensive diagnostic work-up in all patients with a high risk of DM development.

Prognostic Value of Nodal Matting on MRI in Nasopharyngeal Carcinoma Patients

BACKGROUND

Nodal (N) stage is one of the most important predictors for distant metastasis in nasopharyngeal carcinoma (NPC) patients. It may ignore potentially useful nodal features, such as nodal matting (three or more lymph nodes abutting together with the absence of intervening fat planes).

PURPOSE

To explore the prognostic value of nodal matting in NPC patients and construct a nomogram with nodal matting for predicting distant metastasis-free survival (DMFS).

STUDY TYPE

Retrospective.

POPULATION

In all, 792 NPC patients treated with intensity modulated radiation therapy from 2010 to 2013 were enrolled with 2:1 training (n = 527) and validation (n = 65) cohorts.

FIELD STRENGTH/SEQUENCE

T₁ - and T₂ -weighted imaging at 1.5 or 3.0T.

ASSESSMENT

Nodal matting and other nodal characteristics were assessed with MRI. MR images were evaluated separately by three radiologists. The association between nodal matting and DMFS was analyzed.

STATISTICAL TESTS

Univariate and multivariate analyses were performed using the Cox proportional hazards regression model. Nomograms were constructed from a multivariate logistic regression model with and without nodal matting. The predictive accuracy and discriminative ability of the nomograms were determined by concordance index (C-index) and calibration curves. The results were validated using bootstrap resampling and validation cohort.

RESULTS

The incidence of nodal matting was 24.6% (195/792) in all patients. In the training cohort, nodal matting was independently associated with DMFS (hazard ratio [HR] = 1.97 [1.05-3.69], P < 0.05). N1 patients with nodal matting had worse DMFS than N1 patients without (P < 0.05). However, no significant difference was observed when comparing N1 patients with nodal matting to N2 patients (P = 0.464). The C-index of the nomogram with nodal matting was higher than the nomogram without (0.717 vs. 0.699, P = 0.084).

DATA CONCLUSION

Nodal matting was an independent prognostic factor for DMFS in NPC patients. It may help to select patients at high risk of distant metastasis.

Predictive value of computed tomography in identifying extranodal extension in human papillomavirus-positive versus human papillomavirus-negative head and neck cancer

Pathologic extranodal extension (pENE) impacts treatment planning and is an important prognostic indicator for patients with head and neck squamous cell carcinoma (HNSCC). Computed tomography (CT) is a commonly used modality for assessment of radiographic ENE (rENE). To determine the predictive value of CT-identified rENE in predicting pENE, we performed a systematic review through a search of 4 databases (PubMed, Scopus, Cochrane, and OVID). Meta-analysis of diagnostic performance based on human papillomavirus (HPV) status was conducted. For HPV-negative HNSCC, pooled sensitivity, specificity, and accuracy were 60.6%, 93.3%, and 82.6%, respectively. Overall positive predictive value (PPV) was 82.7%. For HPV-positive HNSCC, pooled sensitivity, specificity, and accuracy were 77.7%, 72.2%, and 63.8%, respectively. Overall PPV was 68.6%. Significant differences were observed in diagnostic performance parameters between the two cohorts. The radiographic characteristics of HPV-positive and HPV-negative nodal metastases in HNSCC differ and radiographic evaluation of ENE in HPV-positive nodes is challenging. Development of refined imaging characteristics of HPV-positive nodes is needed to improve diagnostic performance.

The interplay of IMRT and transoral surgery in HPV-mediated oropharyngeal cancer: Getting the balance right

Transoral surgery (TOS) and IMRT represent two primary local ablative treatment modalities for oropharyngeal cancer (OPC). The choice of one over the other represents an interplay between the chance of cure vs risk of late sequelae. HPV-mediated (HPV+) OPC patients generally have excellent outcomes, especially in TNM-8 stage I disease. Controversies exist over which treatment has a more favorable toxicity profile and equal efficacy in the management of this population. Non-randomized retrospective data show comparable oncological and functional outcomes between TOS-based vs IMRT-based treatment for this disease. Several de-intensification concepts have been explored in this subset in both primary surgery-based vs primary radiotherapy-based trials. However, no robust mature trial data are available to convincingly guide treatment selection. TOS is often presented as one of the de-intensification options although the majority of series also describe the use of adjuvant treatments which inevitably result in non-negligible toxicities. Patient selection and surgeons' training are paramount. Understanding tumor biology and the prognostic value of traditional 'adverse' features will further guide trial design for refinement of risk tailored approach. In conclusion, comparative data suggests TOS and IMRT are both effective treatment for TNM-8 stage I HPV+ OPC with similar oncological and functional outcomes. TOS as a single modality has potential advantages in mitigating radiation included toxicities. TOS should be avoided in the presence of clinically overt extranodal extension or when negative margins are unlikely to be achieved. TOS is also less ideal for cases with radiological features predicting a high risk of distant metastasis.

Detection of Distant Metastases in Head and Neck Cancer: Changing Landscape

As head and neck squamous cell carcinoma (HNSCC) patients with distant metastases (DM) were generally treated only palliatively, the value of screening for DM was usually limited to attempts to avoid extensive locoregional treatment when DM were present pretreatment. Recently, the concept of treating oligometastases, e.g., by metastatectomy or stereotactic body radiotherapy, has been reintroduced for HNSCC and may cause a change in the treatment paradigm. Although whole body ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) combined with computed tomography (CT; WB-FDG-PET/CT) is still the mainstay diagnostic technique, there is a growing body of evidence supporting implementation of whole body magnetic resonance imaging (WB-MRI) as an important diagnostic technique for screening for DM. Also, FDG-PET/MRI may become a valuable technique for the detection of DM in HNSCC patients. Because the yield of examinations for detection of DM is too low to warrant routine screening of all HNSCC patients, only patients with high risk factors should be selected for intense screening for DM. Clinical and histopathological risk factors are mainly related to the extent of lymph node metastases. Risk for development of DM may also be assessed by molecular characterization of the primary tumor using genomic and proteomic technologies and radiomics. More research is needed to develop a new protocol for screening for DM after introduction of the concept of treating oligometastases in HNSCC.