Results of a prospective study of positron emission tomography-directed management of residual nodal abnormalities in node-positive head and neck cancer after definitive radiotherapy with or without systemic therapy

Quarter Century Positron Emission Tomography/Computed Tomography Transformation of Oncology: Head and Neck Cancer

During the last 2 decades, f-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F FDG PET/CT) has transformed the clinical head and neck cancer imaging for patient management and predicting survival outcomes. It is now widely used for staging, radiotherapy planning, posttherapy assessment, and for detecting recurrence in head and neck cancers and is widely included in NCCN and other evidence based clinical practice guidelines. Future Directions would include evaluating the potential value of FAPI PET/CT for head and neck cancers, opportunity to use volumetric and tumor heterogeneity parameters and deploying AI in diagnostic and therapeutic assessments.

Moving from conventional to adaptive risk stratification for oropharyngeal cancer

Oropharyngeal cancer (OPC) poses a complex therapeutic dilemma for patients and oncologists alike, made worse by the epidemic increase in new cases associated with the oncogenic human papillomavirus (HPV). In a counterintuitive manner, the very thing which gives patients hope, the high response rate of HPV-associated OPC to conventional chemo-radiation strategies, has become one of the biggest challenges for the field as a whole. It has now become clear that for ~30-40% of patients, treatment intensity could be reduced without losing therapeutic efficacy, yet substantially diminishing the acute and lifelong morbidity resulting from conventional chemotherapy and radiation. At the same time, conventional approaches to de-escalation at a population (selected or unselected) level are hampered by a simple fact: we lack patient-specific information from individual tumors that can predict responsiveness. This results in a problematic tradeoff between the deleterious impact of de-escalation on patients with aggressive, treatment-refractory disease and the beneficial reduction in treatment-related morbidity for patients with treatment-responsive disease. True precision oncology approaches require a constant, iterative interrogation of solid tumors prior to and especially during cancer treatment in order to tailor treatment intensity to tumor biology. Whereas this approach can be deployed in hematologic diseases with some success, our ability to extend it to solid cancers with regional metastasis has been extremely limited in the curative intent setting. New developments in metabolic imaging and quantitative interrogation of circulating DNA, tumor exosomes and whole circulating tumor cells, however, provide renewed opportunities to adapt and individualize even conventional chemo-radiation strategies to diseases with highly variable biology such as OPC. In this review, we discuss opportunities to deploy developing technologies in the context of institutional and cooperative group clinical trials over the coming decade.

Low contralateral neck recurrence risk with ipsilateral neck radiotherapy in N2b tonsillar squamous cell carcinoma

OBJECTIVES

To characterize factors including nodal burden, pre-treatment imaging, and other patient factors which may influence the role of ipsilateral neck radiotherapy (IRT) in tonsillar squamous cell carcinoma (SCC) with multiple involved ipsilateral nodes.

METHODS

Patients with cT1-2N0-2bM0 (AJCC 7th edition) tonsillar SCC treated with definitive radiation therapy (RT) at Duke University Medical Center from 1/1/1990-10/1/2019 were identified. Patient, tumor, and treatment characteristics were compared between those that received bilateral neck RT (BRT) versus IRT. Recurrence-free survival (RFS) was estimated with Kaplan-Meier method. A subset analysis of patients with N2b disease was performed. Patterns of recurrence were analyzed.

RESULTS

120 patients with cT1-2N0-2b tonsillar SCC were identified, including 71 with N2b disease (BRT: n = 30; IRT: n = 41). Median follow-up was 80 months (range: 7-209). No N2b patients who received IRT had > 1 cm of soft palate/base of tongue extension. N2b patients treated with IRT had a median of 3 (range 2-9) involved lymph nodes, with median largest nodal dimension of 2.8 cm (range 1.3-4.8 cm). 93 % of N2b patients who received IRT had staging by PET/CT, and 100 % received IMRT. For N2b patients treated with IRT, there were no contralateral neck recurrences, and 10 year RFS was 95 % (95 % CI 82 %-98 %).

CONCLUSIONS

For patients treated with IRT for well-lateralized N2b tonsillar SCC, we observed high rates of local control with no observed contralateral neck recurrence. These data suggest that BRT is not universally necessary for patients with multiple involved ipsilateral nodes, particularly in the setting of baseline staging with PET/CT.

Management of Recurrent HPV-Positive Oropharyngeal Squamous Cell Carcinoma: a Contemporary Review

PURPOSE OF REVIEW

To review the impact of contemporary treatment strategies on salvage outcomes in patients with recurrent human papilloma virus-positive oropharyngeal squamous cell carcinoma (HPV + OPSCC).

RECENT FINDINGS

Secondary to HPV, changes in disease biology have impacted primary treatments and subsequent approaches to patients with recurrence. With treatment strategies more inclusive of upfront surgery, the characteristics of patients with recurrence HPV + OPSCC have been further redefined. Less invasive endoscopic surgical approaches such as transoral robotic surgery (TORS), and the continued refinement of conformal radiotherapy techniques, have improved treatment options for patients with recurrent HPV + OPSCC. Systemic treatment options have continued to expand including potentially effective immune-based therapies. Effective surveillance with systemic and oral biomarkers offers hope of earlier detection of recurrence. Management of patients with recurrent OPSCC remains difficult. Modest improvements in salvage treatment have been observed within the HPV + OPSCC cohort largely reflecting disease biology and improved treatment techniques.

Persistent lymph nodes after curative chemoradiotherapy for head and neck cancer: imaging predictors of response for decision-making

PURPOSE

To identify response predictors in patients with head and neck squamous cell carcinoma (N + HNSCC) and persistent lymph nodes after curative chemoradiotherapy treatment (CCRT).

MATERIALS AND METHODS

Consecutive patients with N + HNSCC treated with CCRT and persistent lymph nodes at first follow-up between 2015 and 2021 were identified and analyzed. Complete response was defined as the absence of lymph node metastatic involvement in patients with salvage lymphadenectomy or the absence of progression after 1 year of successive follow-ups. Tumour type and location, staging, and human papillomavirus (HPV) status were considered for analysis. The number and size of lymph nodes, type, shape, enhancement and margins on diagnostic and follow-up CT were also analyzed.

RESULTS

The cohort included 46 patients with 134 pathological lymph nodes. Logistic regression models showed the following variables to be significant: performance of salvage lymphadenectomy (OR 0.094, [CI 95% 0.004-0.61], p = 0.037); the type of lymphadenopathy on diagnostic CE-CT (solid vs. cystic) (N1: OR = 4.11, [CI 95% 1.11-17.93], p = 0.042 and N3: OR 6.42, [CI 95% 1.2-42.56], p = 0.036); the change of shape (round to oval) on the follow-up CE-CT (OR 9.76, [CI 95% 1.79-8.57], p = 0.016) and the time in days between CCRT and the first follow-up CE-CT (OR 1.06, [CI 95% 1.004-1.13], p = 0.048).

CONCLUSIONS

In our experience, the presence of solid lymph nodes on pre-treatment CT and the change in shape from round to oval on post-treatment CT are predictors of response to treatment in patients with N + HNSCC persistent lymph nodes after CCRT. Increasing the temporal interval between treatment and follow-up CT should be considered to avoid unnecessary nodal dissections.

Does Bulky Adenopathy in Human Papilloma Virus-Positive Oropharyngeal Squamous Cell Carcinoma Require a Planned Post-Treatment Neck Dissection for Occult Residual Disease?

PURPOSE

A planned neck dissection was traditionally considered for a large nodal disease after definitive chemoradiation, yet controversy exists for the human papilloma virus-positive oropharyngeal squamous cell carcinoma (HPV OPSCC). We aimed to measure the frequency of persistent occult neck disease in planned neck dissection for HPV OPSCC presenting with a large (≥3.0 cm) nodal burden.

METHODS

We designed a retrospective cohort study at a single tertiary referral institution. The study population was sampled from 2006 to 2018 and subjects with HPV OPSCC and adenopathy ≥3.0 cm. Inclusion criteria encompassed subjects who completed primary chemoradiation therapy (CRT) or primary radiation therapy (RT), and subsequently underwent a planned neck dissection. We excluded subjects who did not complete therapy or had less than 1-year follow-up. Our primary predictor variable was the size of cervical adenopathy on presentation (3.0-3.9 cm, 4.0-4.9 cm, 5.0-5.9 cm, and ≥6.0 cm). Our primary outcome of interest was the presence of disease based on the histopathology review. Other variables included the demographics, primary treatment with CRT or RT, and post-treatment clinical or radiographic evidence of disease. Chi-square testing was used to compare rates of persistent disease, with varying sizes of cervical adenopathy on presentation. The alpha level for statistical significance was set at 0.05.

RESULTS

A total of 86 subjects were analyzed, with forty-one females and forty-five males, ranging from 36 to 77 years (mean 54.6 years). From the total study sample, 35% showed persistent disease, and 67% of those subjects had occult disease at the time of planned neck dissection. Greater than 20% of subjects had persistent disease when the nodal burden was ≥3.0 cm at presentation. Furthermore, there was a statistically significant difference in the rates of persistent microscopic disease among subjects with nodal burden of different sizes based on chi-square testing (P = .01, χ2 = 10.66).

CONCLUSIONS

Our data suggest that subjects with HPV OPSCC presenting with a nodal burden ≥3.0 cm are likely to have 23% chance of persistent occult neck disease after primary CRT or RT. These findings may support the routine treatment of these subjects with a planned neck dissection after initial therapy to confirm or surgically complete disease eradication.

18F-FDG PET/CT Staging of Head and Neck Cancer: Interobserver Agreement and Accuracy-Results from Multicenter ACRIN 6685 Clinical Trial

To our knowledge, no prior multicenter clinical trial has reported interobserver agreement of 18F-FDG PET/CT scans for staging of clinical N0 neck in head and neck cancer. Methods: A total of 287 participants were recruited. For visual analysis, positive nodal uptake of 18F-FDG was defined as uptake visually greater than activity seen in the blood pool. Results: The negative predictive value of the 18F-FDG PET/CT for N0 clinical neck was 86% or above for visual assessment (95% CI, 86%-88%) for the 2 central readers and above 90% (95% CI, 90%-95%) for SUVmax for central reads and site reads dichotomized at the optimal cutoff value of 1.8 and the prespecified cutoff value of 3.5, respectively. The κ coefficients between the 2 expert readers and between central reads and site reads varied between 0.53 and 0.78. Conclusion: The NPV of the 18F-FDG PET/CT for N0 clinical neck was 86% or above for visual assessment and above 90% for SUVmax cut points of 1.8 and 3.5 with moderate to substantial agreements.

Accuracy of Response Assessment FDG PET-CT Post (Chemo)Radiotherapy in HPV Negative Oropharynx Squamous Cell Carcinoma

Background: Data on the accuracy of response assessment 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography-computed tomography (PET-CT) following (chemo)radiotherapy in patients with oropharynx squamous cell carcinoma (OPSCC) is predominantly based on HPV-positive disease. There is a paucity of data for HPV-negative disease, which has a less favourable prognosis. Methods: 96 patients treated with (chemo)radiotherapy for HPV-negative OPSCC with baseline and response assessment FDG PET-CT between 2013−2020, were analysed. PET-CT response was classified as negative, equivocal, or positive based on qualitative reporting. PET-CT response categories were analysed with reference to clinicopathological outcomes. Test characteristics were evaluated, comparing negative results to equivocal and positive results together. Post-test probabilities were calculated separately for positive and equivocal or negative results. Results: Median follow-up was 26 months. The negative predictive value of a negative scan was 93.7 and 93.2%, respectively, for primary tumour and nodal disease. For a negative scan, the post-test probability was 0.06 for primary and 0.07 for nodal disease. The post-test probability of an equivocal scan was 0.51 and 0.72 for primary and lymph node, respectively. The post-test probability of a positive scan approached 1. For patients with/without a negative scan, two-year overall survival and progression-free survival were 83% versus 30% and 79% versus 17% (p < 0.001), respectively. Conclusion: The NPV of a negative response assessment PET-CT in HPV-negative OPSCC is high, supporting a strategy of clinical monitoring. Contrasting with the published literature for HPV-positive OPSCC, an equivocal response scan was associated with a moderate rate of residual disease.

Posttreatment FDG-PET/CT Hopkins criteria predict locoregional recurrence after definitive radiotherapy for oropharyngeal squamous cell carcinoma

BACKGROUND

Metabolic response assessment for oropharyngeal squamous cell carcinoma (OPSCC) aids in identifying locoregional persistence/recurrence (LRR). The Hopkins Criteria are a standardized qualitative response assessment system using posttreatment FDG-PET/CT.

METHODS

We conducted a retrospective cohort study of patients with node-positive OPSCC treated with definitive (chemo)radiotherapy. We assessed Hopkins Criteria performance for LRR, then developed and validated a competing-risks model.

RESULTS

Between 2004 and 2018, 259 patients were included with median follow-up of 43 months. The Hopkins Criteria sensitivity, specificity, negative predictive value, and accuracy were 68%, 88%, 95%, and 85%. The 36-month cumulative incidence of LRR was greater with positive scores (45% vs. 5%, HR 12.60, p < 0.001). PET/CTs performed ≤10 weeks after radiotherapy were associated with a four-fold increase in pathologically negative biopsies/surgeries (36% vs. 9%, p = 0.03). The AUC for LRR was 0.89 using a model integrating the Hopkins score.

CONCLUSIONS

The Hopkins Criteria predict LRR with high accuracy for OPSCC response assessment.

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.

Correlations between DW-MRI and 18 F-FDG PET/CT parameters in head and neck squamous cell carcinoma following definitive chemo-radiotherapy

BACKGROUND

Posttreatment diffusion-weighted magnetic resonance imaging (DW-MRI) and 18F-fluorodeoxygluocose (18 F-FDG) positron emission tomography (PET) with computed tomography (PET/CT) have potential prognostic value following chemo-radiotherapy (CRT) for head and neck squamous cell carcinoma (HNSCC). Correlations between these PET/CT (standardized uptake value or SUV) and DW-MRI (apparent diffusion coefficient or ADC) parameters have only been previously explored in the pretreatment setting.

AIM

To evaluate stage III and IV HNSCC at 12-weeks post-CRT for the correlation between SUVmax and ADC values and their interval changes from pretreatment imaging.

METHODS

Fifty-six patients (45 male, 11 female, mean age 59.9 + - 7.38) with stage 3 and 4 HNSCC patients underwent 12-week posttreatment DW-MRI and 18 F-FDG PET/CT studies in this prospective study. There were 41/56 patients in the cohort with human papilloma virus-related oropharyngeal cancer (HPV OPC). DW-MRI (ADCmax and ADCmin) and 18 F-FDG PET/CT (SUVmax and SUVmax ratio to liver) parameters were measured at the site of primary tumors (n = 48) and the largest lymph nodes (n = 52). Kendall's tau evaluated the correlation between DW-MRI and 18 F-FDG PET/CT parameters. Mann-Whitney test compared the post-CRT PET/CT and DW-MRI parameters between those participants with and without 2-year disease-free survival (DFS).

RESULTS

There was no correlation between DW-MRI and 18 F-FDG PET/CT parameters on 12-week posttreatment imaging (P = .455-.794; tau = -0.075-0.25) or their interval changes from pretreatment to 12-week posttreatment imaging (P = .1-.946; tau = -0.194-0.044). The primary tumor ADCmean (P = .03) and the interval change in nodal ADCmin (P = .05) predicted 2-year DFS but none of the 18 F-FDG PET/CT parameters were associated with 2-year DFS.

CONCLUSIONS

There is no correlation between the quantitative DWI-MRI and 18 F-FDG PET/CT parameters derived from 12-week post-CRT studies. These parameters may be independent biomarkers however in this HPV OPC dominant cohort, only selected ADC parameters demonstrated prognostic significance. Study was prospectively registered at http://www.controlled-trials.com/ISRCTN58327080.

A cost-utility analysis comparing CT surveillance, PET-CT surveillance, and planned postradiation neck dissection for advanced nodal HPV-positive oropharyngeal cancer

BACKGROUND

The cost utility of image-guided surveillance using computed tomography (CT) and positron emission tomography (PET)-CT to planned postradiation neck dissection (PRND) was compared for the management of advanced nodal human papillomavirus-positive oropharyngeal cancer following chemoradiation.

METHODS

A universal payer perspective was adopted. A Markov model was designed to simulate four treatment approaches with 3-month cycles over a lifetime horizon: 1) CT surveillance, 2) standard PET-CT surveillance, 3) a novel PET-CT approach with repeat PET at 6 months postchemoradiation for equivocal responders, and 4) PRND. Parameters including probabilities of CT nodal progression/resolution, PET avidity, recurrence, and survival were obtained from the literature. Costs were reported in 2019 Canadian dollars and utilities were expressed in quality-adjusted life years (QALYs). Deterministic and probabilistic sensitivity analyses were performed to evaluate model uncertainty.

RESULTS

PET-CT surveillance dominated CT surveillance and PRND in the base case scenario, and the novel PET-CT approach was the most cost-effective strategy across a wide range of variables tested in one-way sensitivity analysis. On probabilistic sensitivity analysis, novel PET-CT surveillance was the most cost-effective strategy in 78.1% of model iterations at a willingness-to-pay of $50,000/QALYs. Novel PET-CT surveillance resulted in a 49% lower rate of neck dissection compared with traditional PET-CT, and yielded an incremental benefit of 0.14 QALYs with average cost savings of $1309.

CONCLUSIONS

Image-guided surveillance including PET-CT and CT are more cost effective than PRND. The novel PET-CT approach with repeat PET for equivocal responders was the dominant strategy and yielded both higher benefit and lower costs compared with standard PET-CT surveillance.

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.

Analysis of PET parameters as prognosticators of survival and tumor extent in Oropharyngeal Cancer treated with surgery and postoperative radiotherapy

BACKGROUND

Positron-emission tomography (PET) is widely used to detect malignancies, but consensus on its prognostic value in oropharyngeal cancer has not been established. The purpose of this study was to analyze the PET parameters associated with tumor extent and survival in resectable oropharyngeal cancer.

METHODS

The PET parameters in oropharyngeal cancer patients with regional node metastasis who underwent surgery and postoperative radiotherapy between January 2005 and January 2019 were analyzed. We calculated the SUVmax, tumor-to-liver ratio (TLR), metabolic tumor volume (MTV, volume over SUV 2.5), and total lesion glycolysis (TLG, MTV x mean SUV) of the primary lesion and metastatic nodes. Histologic findings, patient survival, and recurrence were reviewed in the medical records.

RESULTS

Fifty patients were included, and the PET parameters were extracted for 50 primary lesions and 104 nodal lesions. In the survival analysis, MTV and TLG of the primary lesions showed significant differences in overall survival (OS) and recurrence-free survival (RFS). In the multiple regression analysis, TLG of the primary lesion was associated with the depth of invasion (DOI). MTV of the nodes was a significant factor affecting extranodal extension (ENE).

CONCLUSIONS

PET parameters could be related with OS, RFS, DOI of the primary tumor, and ENE. PET would be expected to be a useful diagnostic tool as a prognosticator of survival and pathologic findings in oropharyngeal cancer.

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.

Total lesion glycolysis in oral squamous cell carcinoma as a biomarker derived from pre-operative FDG PET/CT outperforms established prognostic factors in a newly developed multivariate prediction model

PURPOSE

Retrospective study to investigate the impact of image derived biomarkers from [¹⁸F]FDG PET/CT prior to surgical resection in patients with initial diagnosis of oral squamous cell carcinoma (OSCC), namely SUV_max, SUV_mean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of the primary tumor to predict overall survival (OS).

MATERIALS AND METHODS

127 subsequent patients with biopsy-proven OSCC were included who underwent [¹⁸F]FDG PET/CT before surgery. SUV_max, SUV_mean, MTV and TLG of the primary tumor were measured. OS was estimated according to Kaplan-Meier and compared between median-splitted groups by the log-rank test. Prognostic parameters were analyzed by uni-/multivariate Cox-regression.

RESULTS

During follow-up 52 (41%) of the patients died. Median OS was longer for patients with lower MTV or lower TLG. SUV_max and SUV_mean failed to be significant predictors for OS. Univariate Cox-regression identified MTV, TLG, lymph node status and UICC stage as prognostic factors. By multivariate Cox-regression MTV and TLG turned out to be independent prognostic factors for OS.

CONCLUSIONS

The pre-therapeutic [¹⁸F]FDG PET/CT parameters MTV and TLG in the primary tumor are prognostic for OS of patients with an initial diagnosis of OSCC. TLG is the strongest independent prognostic factor for OS and outperforms established prognostic parameters in OSCC.

Comparative effectiveness of posttreatment imaging modalities for Medicare patients with advanced head and neck cancer

BACKGROUND

Persistent controversy exists with regard to how and when patients with head and neck cancer should undergo imaging after definitive therapy. The current study was conducted to evaluate whether the type of imaging modality used in posttreatment imaging impacts cancer-specific survival for patients with advanced head and neck squamous cell carcinoma.

METHODS

A retrospective study of National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program-Medicare-linked data in patients with an advanced stage of the 3 most common head and neck malignancies (oral cavity, oropharynx, and larynx) was conducted. Hazard ratios and 95% CIs for cancer-specific survival were estimated for patients diagnosed with any of these cancers between 2006 and 2015.

RESULTS

Significant improvement with regard to cancer-specific survival was observed among patients with American Joint Committee on Cancer stage III and stage IVA laryngeal cancer who underwent positron emission tomography (PET) and/or computed tomography (CT) imaging during the first 6 months after receipt of definitive treatment (hazard ratio, 0.517; 95% CI, 0.33-0.811) compared with those who underwent CT. There was a trend toward an improvement in cancer-specific survival among patients with oral cavity or oropharyngeal malignancies who underwent PET/CT imaging, but it did not reach statistical significance.

CONCLUSIONS

Compared with CT imaging, posttreatment imaging with PET was associated with improved survival in patients with advanced laryngeal carcinoma.

PET-CT for Staging and Detection of Recurrence of Head and Neck Cancer

FDG PET-CT is one the main investigations for squamous cell (Sq) head and neck (H&N) cancer patients. FDG PET-CT has a key role for the staging of patients with T4 cancer of the hypopharynx and nasopharynx and patients with N3 nodal disease. It is effective in detecting recurrent disease accurately. In addition, it has an emerging role in the surveillance of Sq H&N cancer survivors. In patients with advanced neck nodal disease treated with chemoradiotherapy, there is compelling evidence that patients with no FDG uptake in the neck 12 weeks following completion of treatment do not require neck dissection. There is considerable interest in using FDG PET-CT for develop more effective clinical pathways for the surveillance of Sq H&N cancer. Currently, the detection rate of recurrence in patients who attend regular clinical follow-up is poor, less than 1% in asymptomatic patients. FDG PET-CT may enable survivors to be stratified into groups based on the likelihood of having recurrent disease. Optimal surveillance pathways can be developed, reserving most intense imaging regimes and most frequent follow-up for survivors at high risk of recurrence. FDG PET CT is sometimes considered for patients with non Sq H&N cancer. If used in this context, a baseline FDG PET-CT should be done to ensure that the tumour is avid. Most H&N malignant tumours are avid. However, salivary gland cancers, and tumours with muco-epidermoid, adenoid cystic and clear cell histology show paucity of FDG avidity, especially when they recur. In addition, peri-neural invasion cannot be detected reliably with FDG PET-CT.

The declining role of post-treatment neck dissection in human papillomavirus-associated oropharyngeal cancer

BACKGROUND AND PURPOSE

Human papillomavirus-associated oropharyngeal cancer (HPV+ OPC) with regional lymph node metastases has a good prognosis following (chemo)radiation therapy (C/RT) but lymph nodes may remain detectable for several months. Delayed [¹⁸F]-Fluorodeoxyglucose positron emission tomography/computed tomography (PET) can identify patients who may avoid post-treatment neck dissection (PTND). We investigated the rate of PTND in HPV+ OPC treated with C/RT and delayed PET-directed management of the neck.

MATERIALS AND METHODS

This is a retrospective cohort study from a prospectively updated institutional database. Eligible patients were treated between January 2005 and July 2017 with a minimum of 18 months follow up, had node-positive, non-distant metastatic HPV+ OPC and were treated with RT (70 Gy/35#/5 per week) with concurrent Cisplatin or Cetuximab, or accelerated RT alone (68 Gy/34#/6 per week). The primary endpoint was rate of PTND. Secondary endpoints were locoregional failure free survival (LRFFS), regional failure free survival (RFFS), distant metastatic failure free survival (DMFFS), overall survival (OS) and oropharyngeal cancer-specific survival (CSS).

RESULTS

418 patients were eligible. Nineteen patients (4.5%) received a PTND. None of the tested variables were associated with an increased risk of PTND. Five-year probabilities for LRFFS, RFFS, DMFS, OS and CSS were, 91.2% (95% CI 88.3-94.2), 93.4% (95% CI 90.8-96.0), 91.2% (95% CI 88.3-94.2), 86.4% (95% CI 83.0-90.1) and 90.2% (95% CI 87.1-93.4), respectively.

CONCLUSION

In a large cohort with good median follow up and protocolized C/RT, delayed PET-directed management of the neck affords a lower rate of PTND than reported in historical series without compromising disease control and survival.

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

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

Post-treatment 18F-FDG PET/CT for predicting survival and recurrence in patients with advanced-stage head and neck cancer undergoing curative surgery

OBJECTIVES

Pre- and post-treatment ¹⁸F-FDG PET/CT may have a prognostic role in human cancers. ¹⁸F-FDG PET/CT after primary surgery for head and neck cancer might also predict survival. Therefore, we evaluated the prognostic value of post-treatment ¹⁸F-FDG PET/CT in primary surgical patients with advanced-stage head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

This prospective study involved 225 patients with previously untreated advanced-stage HNSCC who underwent primary surgery with or without postoperative radiotherapy or chemoradiotherapy. The patients also had ¹⁸F-FDG PET/CT scanning at a median 6 months after surgery. Post-treatment ¹⁸F-FDG PET/CT was considered positive, based on interpretation by experienced nuclear medicine physicians with integrating clinical information. Positive and negative predictive values (PPV and NPV) for positive ¹⁸F-FDG PET/CT in association with recurrence were calculated. Predictors for positive post-treatment ¹⁸F-FDG PET/CT were evaluated using binary logistic regression. Survival analysis was performed using Cox proportional hazard regression analysis.

RESULTS

PPV and NPV for post-treatment PET/CT for overall recurrence were 75.8% and 98.7%, respectively. A positive post-treatment PET/CT was an independent predictive factor for overall and disease-free survival (both P < 0.001). Five-year overall survival rates for patients with positive and negative PET/CT were 48.1% and 92.3%, respectively. Corresponding 5-year disease-free survival rates were 22.5% and 82.4%, respectively. Perineural invasion, positive resection margin, positive pathological node, and extranodal extension were the independent predictors of positive ¹⁸F-FDG PET/CT (all P < 0.05).

CONCLUSIONS

Post-treatment ¹⁸F-FDG PET/CT predicts survival and recurrence in patients undergoing curative surgery for advanced-stage HNSCC.

FDG-PET/CT scan assessment of response 12 weeks post radical radiotherapy in oropharynx head and neck cancer: The impact of p16 status

PURPOSE

To evaluate the predictive value of FDG-PET/CT for detection of residual disease after radical radiotherapy for patients with squamous cell carcinoma (SCC) of the oropharynx, comparing p16 positive (+) versus p16 negative (-) disease.

METHODS AND MATERIALS

A retrospective analysis of patients with SCC of the oropharynx at our institution treated with radical radiotherapy between 2012 and 2016 was performed. The primary and lymph node metabolic responses were evaluated independently on the post-treatment FDG-PET/CT. The reference standard was pathology when available, subsequent post-treatment FDG-PET/CT results or clinical follow-up.

RESULTS

Median follow-up time was 32 (30-34) months. 556 patients had p16+ disease and 92 had p16- disease. The median time of post-treatment FDG-PET/CT was 96 (45-744) days after radiotherapy completion: 68% had complete metabolic response (CMR) defined as mild non-focal or no uptake, 10% residual primary disease, 11% residual regional lymph node disease, 5% residual primary and regional disease, and 6% distant metastatic disease. The local positive predictive value (PPV) was 26% for p16+ versus 54% for p16- (p = 0.01) and the regional PPV was 31% for p16+ versus 58% for p16- (p = 0.01). The local negative predictive value (NPV) was 100% regardless of p16 status and the regional NPV was 100% for p16+ versus 99% for p16- (p = 0.33). For p16+ cases, regional specificity was 76.2% versus 91.1% (p = 0.0003), local PPV was 0 versus 30% (p = 0.06) and the regional PPV was 12% versus 35% (p = 0.06) for FDG-PET/CT scans performed at ≤12 weeks versus >12 weeks. Five-year overall survival for those with CMR was 87% versus 51% without CMR (p ≤ 0.001).

CONCLUSIONS

Metabolic response on post-treatment FDG-PET/CT has excellent NPV regardless of p16 status. The PPV is significantly lower in those with p16+ versus p16- disease, with a significantly reduced regional specificity and a trend towards inferior predictive value if performed ≤12 weeks. CMR predicts for a significantly improved overall survival.

Clinical and dosimetric risk stratification for patients at high-risk of feeding tube use during definitive IMRT for head and neck cancer

•

Understanding feeding tube risk is critical to optimal weight maintenance during radiotherapy.

•

T-stage, Level II lymphadenopathy risk stratify feeding tube use into 4 groups.

•

The addition of cervical oesophagus dose can further refine these risk stratified groups.

Introduction

To identify organs to which dose limitation using intensity modulated radiotherapy (IMRT) can potentially modify the incidence and duration of feeding tube use, during and immediately following therapy for head and neck cancer.

Materials and methods

One hundred and fourteen patients treated with definitive IMRT (± concurrent chemotherapy) head and neck mucosal cancers were included. Patients received a prophylactic feeding tube and followed up by a dietician for at least eight weeks post-radiotherapy. Salivary and swallowing organs were delineated for each patient. Tumour and dosimetric variables were recorded for all patients and analysed for incidence and duration of feeding tube use for at least 25% of dietary requirements.

Results

Multivariate analysis showed T-classification ≥3 and level II lymphadenopathy as independent significant predictors of incidence and duration of feeding tube use in oral cavity, pharyngeal and supraglottic primaries. Mean dose deposited in the cervical oesophagus over 36Gy further increased the incidence and duration of feeding tube use. Mean dose deposited in the base of tongue and superior pharyngeal constrictor muscles affected incidence and duration of feeding tube use, respectively.

Discussion

In patients treated with definitive IMRT, T-classification and Level II lymphadenopathy, combined with a mean cervical oesophagus dose over 36Gy can a stratify patients into eight distinct risk groups for using feeding tubes for at least 25% of their dietary requirements.

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.

Outcomes and Predictive Value of Post-adjuvant Therapy PET/CT for Locally Advanced Oral Squamous Cell Carcinoma

OBJECTIVES/HYPOTHESIS

For locally advanced oral squamous cell carcinoma (OSCC) treated by surgery and adjuvant therapy, consensus has yet to be reached on whether the optimal time to initiate surveillance positron emission tomography/computed tomography (PET/CT) scan is before or after adjuvant therapy. In this study, we characterize the utility of PET/CT scans obtained 3 months after adjuvant therapy.

STUDY DESIGN

PET/CT scans were obtained for 220 patients with stage III, IVA, or IVB OSCC who underwent resection followed by adjuvant radiotherapy or chemoradiotherapy.

METHODS

Using the Neck Imaging Reporting and Data System, PET/CT scans were dichotomized as suspicious (primary or neck category ≥3, or distant lesion present) versus nonsuspicious. We then computed differences in locoregional progression, distant progression, and overall survival; positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity; and success rate of salvage.

RESULTS

Sixty-seven patients (30%) had suspicious PET/CT scans, which were significantly associated with local failure (hazard ratio [HR] 14.0, 95% confidence interval [CI] 7.3-26.6), distant failure (HR 18.4, 95% CI 9.6-35.3), and poorer overall survival (HR 9.5, 95% CI 5.0-17.9). Overall PPV, locoregional PPV, NPV, sensitivity, and specificity were 85%, 79%, 73%, 58%, and 92%, respectively. Among those with biopsy-confirmed progression, 37 patients (65%) underwent salvage therapy; four (11%) were without evidence of disease at last follow-up.

CONCLUSIONS

For locally advanced OSCC, PET/CT scan 3 months after adjuvant therapy is strongly predictive of disease recurrence and survival, demonstrating improved performance over postoperative imaging in previous studies. Following a suspicious post-adjuvant therapy PET/CT scan, cure of locoregional recurrence is possible but unlikely.

LEVEL OF EVIDENCE

4 Laryngoscope, 2020.

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.

Management of the Neck in Squamous Cell Carcinoma of the Oral Cavity and Oropharynx: ASCO Clinical Practice Guideline

PURPOSE

The aim of the current work is to provide evidence-based recommendations to practicing physicians and others on the management of the neck in patients with squamous cell carcinoma of the oral cavity and oropharynx.

METHODS

ASCO convened an Expert Panel of medical oncology, surgery, radiation oncology, and advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 1990 through 2018. Outcomes of interest included survival, regional disease control, neck recurrence, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 124 relevant studies to inform the evidence base for this guideline. Six clinical scenarios were devised; three for oral cavity cancer and three for oropharynx cancer, and recommendations were generated for each one.

RECOMMENDATIONS

For oral cavity cancers, clinical scenarios focused on the indications for and the hallmarks of a high-quality neck dissection, indications for postoperative radiotherapy or chemoradiotherapy, and whether radiotherapy alone is sufficient elective treatment of an undissected neck compared with high-quality neck dissection. For oropharynx cancers, clinical scenarios focused on hallmarks of a high-quality neck dissection, factors that would favor operative versus nonoperative primary management, and clarifying criteria for an incomplete response to definitive chemoradiation for which salvage neck dissection would be recommended. Consensus was reached and recommendations were made for all six clinical scenarios. Additional information is available at www.asco.org/head-neck-cancer-guidelines .

Post-radiotherapy PET/CT for predicting treatment outcomes in head and neck cancer after postoperative radiotherapy

PURPOSE

The purpose of this study was to retrospectively review the role of post-treatment (post-tx) FDG-PET/CT scans in patients receiving postoperative intensity-modulated radiotherapy (IMRT) for head and neck squamous cell carcinomas (HNSCC).

MATERIALS AND METHODS

Eighty-two patients with HNSCC treated with surgery and postoperative IMRT with or without chemotherapy from October 15, 2008 to December 31, 2014 that had post-tx PET/CT within 6 months of completing IMRT were included. PET/CT was considered positive based on multi-disciplinary review integrating clinical information. Survival analysis was performed using the Kaplan-Meier method. Categorical and continuous predictors of positive post-tx PET/CT were evaluated using Fisher's exact test and logistic regression, respectively. Predictors for survival outcomes were evaluated with log-rank testing. A p ≤ 0.05 was considered statistically significant.

RESULTS

Median follow-up was 3.88 years. For all patients, 3-year overall survival (OS) and recurrence-free survival (RFS) were 71.8% and 61.3%, respectively. Patients with positive post-tx PET/CT had worse OS compared to those with negative post-tx PET/CT (log rank p < 0.001). For patients with positive post-tx PET/CT, 3-year OS was 11.2% compared to 89.9% for patients with negative post-tx PET/CT. The positive predictive value (PPV) of PET/CT was 100% for local recurrence (LR), regional recurrence (RR) and distant metastasis (DM). The negative predictive values (NPV) for LR, RR and DM were 89.0%, 89.2%, and 85.9%, respectively. Perineural invasion (p = 0.009), p16 status (p = 0.009), non-oropharyngeal primary site (p = 0.002), and the use of chemotherapy (p = 0.01) were independent predictors of positive PET/CT.

CONCLUSIONS

Post-tx PET/CT after postoperative radiation is prognostic for survival outcomes. The PPV of post-tx PET for recurrence was excellent, allowing for early detection of recurrent disease. Post-tx PET/CT should be considered after postoperative radiation.

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 response assessment PET-CT to predict residual disease in neck nodes: A comparison with the Histopathology

OBJECTIVE

To assess the ability of Positron Emission Tomography-Computed Tomography (PET-CT) scans to detect residual disease in neck nodes with the Histopathology (HPR) as the gold standard. To obtain a Standardized Uptake Value max cutoff in these patients to predict residual disease in neck.

METHODS

Head and neck squamous cell carcinoma patients who underwent Salvage neck dissection with or without primary site surgery post Concurrent Chemo-Radiotherapy (CCRT) during the period January 2008-December 2017 were included. All patients had response assessment PET-CT scan at 10-14 weeks. Agreement analysis was performed between PET-CT and HPR, fine needle aspiration cytology and HPR. Positive predictive value, Negative predictive value of PET-CT to detect residual neck nodal disease in comparison to HPR was analyzed. A Receiver Operating Characteristic (ROC) curve was plotted between the SUV max values and the HPR. A SUV max cutoff value was obtained from the ROC curve.

RESULTS

A total of 75 patients were included. Thirty-one underwent salvage neck dissection along with surgery for primary disease and 45 underwent salvage neck dissection alone. PET-CT showed good agreement with the HPR to detect residual disease in neck nodes (Kappa=0.604). PET-CT had a PPV and NPV of 87.5% and 79.15% respectively as compared against the HPR. A SUV max cutoff of 4.62 had a specificity of 92.3% and sensitivity of 73.5% to detect residual disease in neck nodes on the HPR.

CONCLUSION

PET-CT surveillance is an accepted treatment strategy. A neck node with SUV max of 4.62 and above is most likely to harbor residual nodal disease.

LEVEL OF EVIDENCE

Level 2b.

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.

Prognostic role of extracapsular spread in planned neck dissection after chemoradiotherapy

BACKGROUND

The purpose of this study is to evaluate the prognostic significance of nodes with extracapsular spread (ECS) in patients treated with a planned neck dissection after chemoradiotherapy.

METHODS

We carried out a retrospective study of 109 cN+ patients who achieved a complete response in the primary location after chemoradiotherapy and treated with a planned neck dissection.

RESULTS

The 5-year disease-specific survival for patients without residual metastatic nodes in the neck dissection (pN0, n = 69) was 75.7% (95% CI: 64.4%-87.0%). For patients with metastatic nodes without ECS (pN+/ECS-negative, n = 17), the corresponding figure was 74.0% (95% CI: 48.2%-99.8%), and for patients with metastatic neck nodes with ECS (pN+/ECS-positive, n = 23) it was 8.7% (95% CI: 0.0%-24.3%) (P = .0001).

CONCLUSION

The presence of ECS in the pathologic study of the planned neck dissections carried out after chemoradiotherapy in patients with human papillomavirus-negative (HPV-negative) head and neck squamous cell carcinoma (SCC) allows identification of a group of patients with a high risk of failure.

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).

Early metabolic 18F-FDG PET/CT response of locally advanced squamous-cell carcinoma of head and neck to induction chemotherapy: A prospective pilot study

Objective

The objective of this study was to assess the clinical value of 18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) after the first cycle of induction chemotherapy (IC) in locally advanced squamous cell carcinoma of the head and neck (LASCCHN).

Methods and findings

A prospective, single-arm, single center study was performed, with patients enrolled between February 2010 and July 2013.Patients (n = 49) with stage III/IVA–B LASCCHN who underwent IC with taxanes, cisplatin, and fluorouracil were recruited. Staging procedures included loco-regional and chest imaging, endoscopic examination, and PET/CT scan. On day 14 of the first cycle, a second PET/CT scan was performed. Patients with no early increase in regional lymph node maximum ¹⁸F-FDG standard uptake value (SUV), detected using ¹⁸F-FDG PET/CT after first IC had better progression-free survival (hazard ratio (HR) = 0.18, 95%, confidence interval (CI) 0.056–0.585; p = 0.004) and overall survival (HR = 0.14, 95% CI 0.040–0.498; p = 0.002), and were considered responders. In this subgroup, patients who achieved a reduction of ≥ 45% maximum primary tumor SUV experienced improved progression-free (HR = 0.23, 95% CI 0.062–0.854; p = 0.028) and overall (HR = 0.11, 95% CI 0.013–0.96; p = 0.046) survival.

Conclusions

These results suggest a potential role for early response evaluation with PET/CT examination in patients with LASCCHN undergoing IC. Increased regional lymph node maximum SUV and insufficient decrease in primary tumor uptake predict poorer outcomes.

Clinical significance of the post-radiotherapy 18F-fludeoxyglucose positron emission tomography response in nasopharyngeal carcinoma

Objective:

The aim of the present study was to evaluate the clinical significance of the post-radiotherapy ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) response for detecting residual disease and predicting survival outcome in patients with nasopharyngeal cancer.

Methods:

We reviewed 143 patients with nasopharyngeal cancer who underwent ¹⁸F-FDG PET within 6 months after completion of radiotherapy between 2001 and 2012. ¹⁸F-FDG PET findings at the primary tumor (T–) and regional lymph nodes (N–) were separately assessed and considered negative [PET (–)] or positive [PET (+)] depending on the remaining focal increased uptake of ¹⁸F-FDG that was greater than that of the surrounding muscle or blood vessels. The standard of reference was histopathological confirmation or clinical/imaging follow-up. Overall survival (OS), distant metastasis-free survival (DMFS), and locoregional recurrence-free survival (LRRFS) rates were estimated from the date of the start of radiotherapy.

Results:

The median follow-up period was 73 months (range, 9–182 months). Overall, 83 and 66% of patients achieved T–PET (-) and N–PET (-) responses, and the negative-predictive values (NPVs) for T– and N– were 100 and 99%, respectively. The sensitivity, specificity, and positive-predictive value were 100, 84, and 8% for T–, and 67, 80, and 7% for N–, respectively. The 5-year OS, DMFS, and LRRFS rates were 83, 83, and 87%, respectively, and patients with N–PET (+) with SUV_max >2.5 showed significantly inferior 5-year OS and DMFS rates than patients with N–PET (-) or N–PET (+) with SUV_max ≤2.5 (44 vs 86%, p = 0.004; 36 vs 85%, p < 0.001).

Conclusion:

In patients that have received definitive (chemo)radiotherapy for nasopharyngeal cancer, ¹⁸F-FDG PET within 6 months of completion of treatment has a high NPV for predicting residual disease and is prognostic for long-term treatment outcomes. Patients with remaining focal increased uptake of ¹⁸F-FDG at lymph nodes may benefit from more aggressive treatments, and further studies are needed to validate the clinical significance of post-radiotherapy ¹⁸F-FDG PET.

Advances in knowledge:

We found that post-radiotherapy ¹⁸F-FDG PET findings have a high NPV for detecting residual disease and are a significant prognostic factor for treatment outcomes.

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.

Viable tumor in salvage neck dissections in head and neck cancer: Relation with initial treatment, change of lymph node size and human papillomavirus

OBJECTIVES

To identify predictive factors for the presence of viable tumor and outcome in head and neck cancer patients who undergo therapeutic salvage neck dissections.

MATERIALS AND METHODS

Retrospective analysis of 76 salvage neck dissections after radiotherapy alone (n = 22), radiotherapy in combination with carboplatin/5-fluorouracil (n = 42) or with cetuximab (n = 12).

RESULTS

Viable tumor was detected in 41% of all neck dissections. Univariate analysis revealed initial treatment with radiotherapy without systemic therapy (OR 6.93, 95%CI: 2.28-21.07, p < .001), increased lymph node size after initial treatment compared to pretreatment CT scan (OR 20.48, 95%CI: 2.46-170.73, p = .005), more extensive neck dissections (OR 8.40, 95%CI: 2.94-23.98, p < .001), and human papillomavirus negative cancer (OR 4.22, 95%CI: 1.10-16.22, p = .036) as predictors of viable tumor. Patients with decreased or stable, but persistently enlarged lymph node size after chemoradiation had a significantly lower chance of viable tumor (OR 0.15, 95%CI: 0.05-0.41, p < .001). Disease-specific 5-year survival was 34% in case of viable tumor, and 78% when no viable tumor was found (p < .001).

CONCLUSIONS

Viable tumor in salvage neck dissections is associated with reduced survival. Radiotherapy alone, human papillomavirus negative cancer and increase in lymph node size, are associated with viable tumor in salvage neck dissections. In case of decreased or stable lymph node size after chemoradiation, watchful waiting could be considered.

PET/CT and PET/MRI in head and neck malignancy

Combined 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) has an established role in the staging of difficult cases of head and neck (HN) squamous cell carcinoma (SCC), looking for an unknown primary, assessing response post-chemotherapy at 3-6 months, and differentiating relapse from treatment effects in patients suspected to have tumour recurrence. The PET NECK trial, comparing PET/CT surveillance versus neck dissection in advanced head and neck cancer showed survival was similar among patients who underwent PET/CT-guided surveillance and those who underwent planned neck dissection, but surveillance was more cost-effective. There is growing interest in the use of hypoxia PET tracers, especially in targeting radiotherapy, where the radiotherapy dose can be boosted in regions of hypoxia; the use of 68Ga peptide tracers in neuroendocrine malignancy and also in the growing field of combined PET/magnetic resonance imaging (MRI). PET/MRI has the advantage of increased anatomical detail and radiation dose reduction combined with the molecular and metabolic data from PET, although PET/CT has the advantage in better sensitivity for imaging lung metastases. Thus far, there is good agreement between PET/CT and PET/MRI with high correlation between semi-quantitative measurements in primary, nodal, osseous, and soft-tissue lesions imaging. PET/MRI may indeed provide greater accuracy than the currently available imaging procedures in the staging and later treatment response evaluation in HNSCC.

Use of Larynx-Preservation Strategies in the Treatment of Laryngeal Cancer: American Society of Clinical Oncology Clinical Practice Guideline Update

Purpose To update the guideline recommendations on the use of larynx-preservation strategies in the treatment of laryngeal cancer. Methods An Expert Panel updated the systematic review of the literature for the period from January 2005 to May 2017. Results The panel confirmed that the use of a larynx-preservation approach for appropriately selected patients does not compromise survival. No larynx-preservation approach offered a survival advantage compared with total laryngectomy and adjuvant therapy as indicated. Changes were supported for the use of endoscopic surgical resection in patients with limited disease (T1, T2) and for initial total laryngectomy in patients with T4a disease or with severe pretreatment laryngeal dysfunction. New recommendations for positron emission tomography imaging for the evaluation of regional nodes after treatment and best measures for evaluating voice and swallowing function were added. Recommendations Patients with T1, T2 laryngeal cancer should be treated initially with intent to preserve the larynx by using endoscopic resection or radiation therapy, with either leading to similar outcomes. For patients with locally advanced (T3, T4) disease, organ-preservation surgery, combined chemotherapy and radiation, or radiation alone offer the potential for larynx preservation without compromising overall survival. For selected patients with extensive T3 or large T4a lesions and/or poor pretreatment laryngeal function, better survival rates and quality of life may be achieved with total laryngectomy. Patients with clinically involved regional cervical nodes (N+) who have a complete clinical and radiologic imaging response after chemoradiation do not require elective neck dissection. All patients should undergo a pretreatment baseline assessment of voice and swallowing function and receive counseling with regard to the potential impact of treatment options on voice, swallowing, and quality of life. Additional information is available at www.asco.org/head-neck-cancer-guidelines and www.asco.org/guidelineswiki .

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.

Impact and prognostic value of 18F-fluorodeoxyglucose positron emission tomography-computed tomography scan in the evaluation of residual head and neck cancer: Single-center experience from Pakistan

Background:

Overview of clinical impact of positron emission tomography-computed tomography (PET-CT) scans in patients with head and neck carcinomas at our center.

Methods:

Retrospective review of posttreatment ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET-CT scans in patients with head and neck carcinomas with risk of residual disease. Clinical outcome served as the reference standard.

Results:

This study included 93 patients (65.6% males, mean age: 48.8 years ± 17.2 standard deviation) with squamous cell carcinoma as most frequent histopathology (91.4%). PET-CT scans were performed on average 6 months posttreatment. Diagnostic accuracy, positive predictive value, and negative predictive value of PET-CT for disease were found to be 88%, 88%, and 92%, respectively. A median follow-up of 24 months was available for 91 patients. Kaplan–Meier curves showed significantly higher disease-free survival with negative PET-CT as compared to positive PET-CT (P = 0.01) and maximum standardized uptake values of <5.0 (P = 0.01).

Conclusion:

FDG PET-CT has diagnostic and prognostic implications in treated patient of head and neck cancers.