Positron emission tomography in the evaluation of stage III and IV head and neck cancer

Pre-CCRT 18-fluorodeoxyglucose PET-CT improves survival in patients with advanced stages p16-negative oropharyngeal squamous cell carcinoma via accurate radiation treatment planning

PURPOSE

No large-scale prospective randomized study with a long-term follow-up period has evaluated the survival outcomes of preconcurrent chemoradiotherapy (CCRT) 18-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸FDG PET-CT) in patients with non-human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC).

PATIENTS AND METHODS

We included patients with stage I-IVA p16-negative OPSCC receiving definitive CCRT and categorized them into two groups according to pre-CCRT ¹⁸FDG PET-CT and compared their outcomes: the case group consisted of patients who underwent pre-CCRT ¹⁸FDG PET-CT, whereas the comparison group consisted of patients who did not receive pre-CCRT ¹⁸FDG PET-CT.

RESULTS

The final cohort consisted of 3942 patients (1663 and 2279 in the case and comparison groups, respectively). According to multivariable Cox regression analysis, pre-CCRT ¹⁸FDG PET-CT was not a significant prognostic factor for overall survival in patients with stages I-II of p16-negative OPSCC receiving standard CCRT. The adjusted hazard ratio (95% confidence interval) of all-cause death for the patients with advanced stages (III-IVA) of p16-negative OPSCC receiving pre-CCRT ¹⁸FDG PET-CT was 0.75 (0.87-0.94, P = 0.0236).

CONCLUSIONS

Routine use of pre-CCRT ¹⁸FDG PET-CT is not necessary for each patient with p16-negative OPSCC. Pre-CCRT ¹⁸FDG PET-CT is associated with improved survival in patients with stage III-IVA p16-negative OSCC, but might be not in those with stage I-II p16-negative OPSCC. No large-scale prospective randomized study with a long-term follow-up period has evaluated the survival outcomes of preconcurrent chemoradiotherapy (CCRT) 18-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸FDG PET-CT) in patients with p16-negative oropharyngeal squamous cell carcinoma (OPSCC). Our study is the first, largest, homogenous modality study on PET-CT including a long-term follow-up cohort to examine the survival outcomes of pre-CCRT ¹⁸FDG PET-CT or non-pre-CCRT PET-CT for patients with p16-negative OPSCC receiving standard CCRT stratified by different clinical stages. Routine use of pre-CCRT ¹⁸FDG PET-CT is not necessary for each patient with p16-negative OPSCC. Pre-CCRT ¹⁸FDG PET-CT is associated with improved survival in patients with stage III-IVA p16-negative OPSCC, but might be not in those with stage I-II p16-negative OPSCC.

Correlation between PET/CT and CT in the staging prior to the treatment of head and neck squamous cell carcinoma

Introduction

Head and neck squamous cell carcinoma is the seventh most common malignant tumor. The advances in treatment have improved the global survival rates in the past years, although the prognosis is still grave.

Objective

The aim of the present study is to evaluate the correlation between positron emission computed tomography and computed tomography at the time of staging a previously untreated head and neck squamous cell carcinoma, and to determine which of the two imaging techniques gives us more information at the time of initial diagnosis.

Methods

Data from all patients diagnosed in our hospital of head and neck squamous cell carcinoma by a biopsy of any location or unknown primary tumor was collected, between January 2012 and July 2017. In all cases, computed tomography and positron emission computed tomography were performed with a maximum of 30 days difference between them and patients had not received any prior treatment to staging. The stage given to each case was compared based solely on the physical examination, only on the computed tomography/positron emission computed tomography, with respect to the stage given by the tumor board, observing the concordance obtained through Cramer's V statistical test.

Results

We performed a comparative analysis obtaining a correlation of 0.729 between the stage given by the tumor board and the one assigned based on the physical examination without imaging techniques. When only using computed tomography as an imaging method, the correlation was 0.848, whereas with only the use of positron emission computed tomography it was estimated at 0.957. When comparing the statistical association between staging using exclusively one of the two imaging techniques, correlation was 0.855.

Conclusion

Positron emission computed tomography is useful for the diagnosis of head and neck squamous cell carcinoma, improving the patient's staging especially when detecting cervical and distant metastases. Therefore, we consider that the use of positron emission computed tomography for the staging of patients with head and neck squamous cell carcinoma is a diagnostic test to be considered.

Impact of PET/CT on Staging and Treatment of Advanced Head and Neck Squamous Cell Carcinoma

OBJECTIVE

To understand the effects of positron emission tomography/computed tomography (PET/CT) evaluation on patients with previously untreated head and neck squamous cell carcinoma (HNSCC) with clinical evidence of regional lymph node involvement.

STUDY DESIGN

Prospective blinded study.

SETTING

Tertiary care cancer center.

SUBJECTS AND METHODS

Informed consent was obtained and data collected from 52 consecutive previously untreated patients with HNSCC and clinical evidence of cervical metastasis. All patients underwent conventional evaluation for HNSCC and whole body PET/CT. Data were evaluated by 5 independent reviewers, who performed TNM staging per the American Joint Committee on Cancer (seventh edition) manual and proposed a treatment plan prior to viewing, and after reviewing, PET/CT. Cases where at least 3 of 5 reviewers agreed were considered significant.

RESULTS

There were 0 patients for whom review of the PET/CT altered the T-class assessment (95% CI, 0-6.8), 12 (23.1%) for whom PET/CT altered N classification (95% CI, 12.5-34.5), and 2 (3.8%) for whom PET/CT altered the M classification (95% CI, 0.5-13.2). For 5 patients (9.6%), overall stage was altered per PET/CT review (95% CI, 3.2-21). For 3 patients (5.8%), PET/CT findings prompted reviewers to alter treatment recommendations (95% CI, 1.2-15.9).

CONCLUSION

When added to more conventional patient evaluation, PET/CT results in changes to the TNM categories, but overall staging and treatment were less frequently affected. Whether PET/CT should be used routinely for patients with stage III and IV HNSCC is still subjective and merits further study.

Complete atrioventricular block as an initial manifestation of recurred oral cavity cancer: a case report

Background

Intracardiac invasion of head and neck cancer is extremely rare. Here, we report a case of recurred oral cavity cancer presenting with complete atrioventricular (AV) block caused by cardiac metastasis.

Case presentation

A 70-year-old male presented with dizziness for 2 days. He had a history of oral cavity cancer a year ago, and the tumor was treated by surgical excision after induction chemotherapy and concurrent chemoradiation therapy. Electrocardiography showed complete AV block with ventricular escape rate of 43 beats per minute. Cardiac imaging revealed about 4.0 × 2.0 cm-sized mass invading interventricular septum and AV nodes and protruding into the right ventricle. Magenetic resonance imaging of head and neck demonstrated recurred mass in oral cavity and maxillary sinus. Fluorodeoxyglucose-positron emission tomography showed hypermetabolic lesion in both oral cavity and the heart around interventricular septum and atrioventricular node indicating recurred oral cavity cancer with cardiac metastasis. Permament pacemaker of DDD type was implanted for the symptomatic complete AV block, and palliative chemotherapy was initiated.

Conclusion

The present case demonstrated that oral cavity cancer can metastasize to the heart, and complete AV block may be an initial manifestation of the recurrence of extracardiac cancer with intracardiac invasion.

Contribution of 18F-FDG PET/CT to Staging of Head and Neck Malignancies

OBJECTIVES

Accurate staging of head and neck cancer (HNC) plays an important role in patient management as well as protection of functional characteristics of the head and neck region. Our aim was to investigate the contribution of 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) as part of HNC staging to clinical evaluation and treatment planning.

METHODS

Clinical records of 138 HNC cases who has undergone ¹⁸F-FDG PET/CT imaging were retrospectively reviewed. Sixty-five cases who had accessible clinical follow-up data were included in the study group, and their PET/CT and conventional imaging findings were evaluated.

RESULTS

In the case group with a PET/CT and magnetic resonance imaging (MRI) for evaluation of primary lesion the sensitivity rates for PET/CT and MRI were calculated as 91.3% and 82.6%, the positive predictive values (PPV) as 91.3% and 82.6%, specificity as 71.4% and 42.8%, and the negative predictive value (NPV) as 71.4% and 42.8%, respectively. In terms of metastatic lymph node evaluation, the sensitivity was calculated as 100% and 88.8%, the NPV as 100% and 83.3%, respectively. The PPV and specificity was 100% for both modalities. In the case group with CT for primary lesion evaluation, the sensitivity and PPV were found as 95.2% and 100% for PET/CT, and as 85.7% and 94.7% for CT, respectively. in metastatic lymph node evaluation, the sensitivity was found as 100% for PET/CT and 50% for CT, and the PPV, specificity and NPV were determined as 100% for both methods. PET/CT findings resulted in a change in 'tumor, node, metastasis' staging in 5 cases.

CONCLUSIONS

PET/CT in HNC contributes to staging, thus playing a role in treatment planning, especially in patients with locally advanced disease.

AHNS Series: Do you know your guidelines? Evidence-based management of oral cavity cancers

Oral cavity squamous cell carcinoma (OCSCC) is the most common nonmelanoma head and neck cancer in the world, with an estimated 405 000 new cases expected each year. Subsites of the oral cavity include the alveolar ridge, buccal mucosa, anterior tongue, tonsillar pillar, retromolar trigone, hard palate, gingiva, and floor of the mouth. In this issue of the AHNS "Do you know your guidelines?" series, we review the evidence-based approach to the management of oral cavity carcinomas based on the framework provided by the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology.

Prognostic value of pre-treatment 18F-FDG PET uptake for nasopharyngeal carcinoma

PURPOSE

To evaluate the prognostic value of maximal standardized uptake values (SUVmax) from serial fluor-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

Fifty-two patients with NPC who underwent 18F-FDG PET/CT scan before radiotherapy with/without chemotherapy were reviewed retrospectively. Twenty-seven patients (52%) were applied 3-D conformal radiotherapy and 25 patients (48%) applied intensity-modulated radiotherapy (IMRT). Fourteen (27%) patients were given neoadjuvant chemotherapy and forty-four (84.6%) patients were given concomitant and adjuvant chemotherapy.

RESULTS

Median follow-up time was 34 months (range 5.6-66.4 months). Forty-four (84.6%) patients were alive at last follow-up and eight (15.4%) had died. The best cut-off value of the SUVmax for the primary tumor site (SUVmax-PT) was 13 and 9 for the lymph nodes (SUVmax-LN). Patients with SUVmax-PT ≥ 13.0 and SUVmax-LN ≥ 9 had a significantly higher risk for the development of the distant metastases (p = 0.044 and p = 0.038). DFS was affected in patients with SUVmax-PT ≥ 13 (log rank χ 2 = 2.54, p = 0.017) and was significantly lower in patients with SUVmax-LN ≥ 9 for the lymph nodes (log rank χ 2 = 5.81, p = 0.013). OS was not affected by SUV levels. A multivariate Cox proportional hazard model of DFS included age (≥ 40), SUVmax-LN (< 9), T stage (T1-2) and neoadjuvant chemotherapy are significantly better prognosis for the DFS.

CONCLUSION

18F-FDG PET/CT uptake before treatment, as determined by SUVmax, may be a valuable tool to evaluate prognosis in NPC patients.

The adverse impact of surveillance intervals on the sensitivity of FDG-PET/CT for the detection of distant metastases in head and neck cancer patients

The presence of distant metastases at initial evaluation influences treatment selection, since no effective systemic treatment for disseminated head and neck squamous cell carcinoma (HNSCC) is currently available. The reported sensitivity for the detection of distant metastases by contrast-enhanced (ce)CT and FDG-PET(/CT) differs substantially between studies. We hypothesized that these sensitivity values are highly dependent on the reference standard use, e.g., follow-up term. Therefore, we analyze our results of FDG-PET/CT (including chest ceCT) with long-term follow-up and compare these findings with data from the literature, with particular interest in the different reference standards. Forty-six HNSCC patients with high-risk factors underwent pretreatment screening for distant metastases by FDG-PET/CT (including chest ceCT). In 16 (35%) patients, distant metastases were detected during screening (6 patients) or during a mean follow-up of 39.4 months after screening (10 patients). The sensitivity and negative predictive value were 83.3 and 97.2% when 6 months, 60.0 and 89.9% when 12 months, and 37.5 and 72.2% when 30 months follow-up were used as reference standard, respectively. This is comparable with reported studies with similar reference standards. This critical appraisal on the reference standards used in our and reported studies shows room for improvement for the detection of distant metastases to refrain more patients from unnecessary extensive locoregional treatment for occult metastatic HNSCC.

Application of fluorodeoxyglucose positron emission tomography in the management of head and neck cancers

The use of fluorodeoxyglucose positron emission tomography (FDG PET) scan technology in the management of head and neck cancers continues to increase. We discuss the biology of FDG uptake in malignant lesions and also discuss the physics of PET imaging. The various parameters described to quantify FDG uptake in cancers including standardized uptake value, metabolic tumor volume and total lesion glycolysis are presented. PET scans have found a significant role in the diagnosis and staging of head and neck cancers. They are also being increasingly used in radiation therapy treatment planning. Many groups have also used PET derived values to serve as prognostic indicators of outcomes including loco-regional control and overall survival. FDG PET scans are also proving very useful in assessing the efficacy of treatment and management and follow-up of head and neck cancer patients. This review article focuses on the role of FDG-PET computed tomography scans in these areas for squamous cell carcinoma of the head and neck. We present the current state of the art and speculate on the future applications of this technology including protocol development, newer imaging methods such as combined magnetic resonance and PET imaging and novel radiopharmaceuticals that can be used to further study tumor biology.

The feasibility of 18F-fluorodeoxyglucose-positron emission tomography uptake as a prognostic factor for paranasal sinus malignancy

BACKGROUND

There is a correlation between (18)F-fluorodeoxyglucose (FDG) uptake and the level of intracellular metabolic tumor activity, which in turn may be associated with active proliferation, invasion, and prognosis as well as distant metastases in head and neck cancer. This study was designed to assess whether tumor uptake of FDG positron emission tomography (PET) expressed as the maximum standardized uptake value (SUVmax) can be used to predict survival in subjects with paranasal sinus malignancy.

METHODS

We enrolled 42 consecutive subjects with a histological diagnosis of squamous cell carcinoma in paranasal sinus malignancy, into a retrospective institutional imaging trial. Thirty-eight subjects (90.5%) underwent a baseline FDG-PET scan before curative treatment and were eligible for analysis.

RESULTS

A total of 38 subjects with paranasal sinus malignancy undergoing PET/computed tomography imaging in the initial stages were assessed separately for a potential correlation between SUVmax and T staging, histological grading, and overall survival. Log-rank testing revealed a significant correlation between overall survival and histological grading (p = 0.046); and there was some correlation between SUVmax and histological grading, but not significantly different. The receiver operation characteristic curve was identified for cutoff value of SUVmax as a prognostic factor. We compared the low tumor of the SUVmax group with the high tumor of the SUVmax group divided by the cutoff value of SUVmax. We did find a significant correlation between SUVmax and disease control and mortality (p = 0.003, p < 0.001).

CONCLUSION

In our study, we concluded that subjects with higher tumor FDG uptakes should be considered for a more aggressive disease.

Variety and complexity of fluorine-18-labelled fluoro-2-deoxy-D-glucose accumulations in the oral cavity of patients with oral cancers

OBJECTIVES

To elucidate the points that require attention when interpreting fluorine-18-labelled fluoro-2-deoxy-d-glucose ((18)F-FDG)/positron emission tomography (PET) images by demonstration of (18)F-FDG accumulation in various areas of the oral cavity other than primary lesions in patients with oral cancers.

METHODS

(18)F-FDG accumulations with a maximal standardized uptake value of over 2.5 in various areas of the oral cavity other than primary lesions were identified in 82 patients with oral cancers.

RESULTS

(18)F-FDG/PET-positive areas, excluding primary tumours, included the front intrinsic muscles of the tongue (89.0%), upper and lower marginal parts of the orbicularis oris muscle (64.6%), sublingual glands, palatine tonsil, pharyngeal tonsil, and lingual tonsil. In addition, some areas in the jaws also showed accumulation.

CONCLUSIONS

In patients with oral cancers, areas of (18)F-FDG accumulation in the oral cavity should be precisely identified and appropriately diagnosed, because accumulations can be seen in areas other than the primary tumour.

Value of fluoro-2-deoxy-D-glucose-positron emission tomography for detecting metastatic lesions in head and neck cancer

OBJECTIVES

The role of positron emission tomography (PET) scans in the staging of head and neck cancer (HNC) is unclear. The National Comprehensive Cancer Network guidelines do not recommend routine metastatic workup beyond physical examination, chest x-ray, and laboratory tests. The purpose of this report is to examine the accuracy of staging PET scans for detecting distant metastatic disease in patients with HNC.

METHODS

Retrospective review of 182 consecutive newly diagnosed HNC patients who had a staging PET scan at Thomas Jefferson University Hospital between 2003 and 2007.

RESULTS

The overall incidence of confirmed distant metastatic disease in this population was 5.0%. About 26 of the staging PET scans had areas suspicious for a metastatic lesion(s). Of total, 23 patients were further evaluated with imaging and/or biopsy, revealing 9 (39%) true positives, and 14 (60%) false positives. Of the 156 negative PET scans, there was 1 false negative and 155 true negatives. Thus, the sensitivity of PET was 90% and specificity was 92%. Positive predictive value was 39% and negative predictive value was 99.4%. No patients with pre-PET clinical stage I or II cancer had confirmed distant metastases. The only statistically significant predictor for metastatic disease was clinical stage IV versus all other stages (P=0.03).

CONCLUSIONS

Given the marked differences in the treatment of locally advanced/nonmetastatic HNC versus metastatic HNC, we recommend PET for clinical stage IV disease. Although the sensitivity, specificity, and negative predictive value rates were acceptable, the positive predictive value was suboptimal. Patients found to have a PET scan "positive" for metastatic disease require confirmatory imaging or ideally biopsy.

Reflection of ¹⁸F-FDG accumulation in the evaluation of the extent of periapical or periodontal inflammation

OBJECTIVES

To elucidate whether fluorine-18-labeled ((18)F) fluoro-2-deoxy-d-glucose (FDG) accumulation can reflect the extent of periodontal inflammation, periapical inflammation, or dental caries.

STUDY DESIGN

(18)F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) were retrospectively compared with the size of the bone resorption areas caused by periodontal inflammation, periapical inflammation, or dental caries on panoramic radiographs, CT, and magnetic resonance imaging (MRI) in 44 subjects.

RESULTS

A significant correlation was found between the size of the bone resorption area caused by periodontal (r = 0.595, P < .01) or periapical (r = 0.560, P < .01) inflammation and the highest standardized uptake value (SUVmax) of (18)F-FDG accumulation. A significant correlation was found between the periodontal (r = 0.622, P < .01) or periapical (r = 0.394, P < .01) inflammatory findings on MRI and the SUVmax of (18)F-FDG accumulation. The SUVmax of (18)F-FDG around most teeth with caries was under 1.5.

CONCLUSIONS

(18)F-FDG accumulation reflects the extent of dental inflammation, not dental caries.

Distant metastases from head and neck squamous cell carcinoma. Part II. Diagnosis

The detection of distant metastases is critical for prognostication and for the choice of treatment in patients with head and neck squamous cell carcinoma (HNSCC). Pretreatment screening for distant metastases should be conducted particularly for patients with high risk factors, prior to locoregional treatment decisions. Different diagnostic techniques are discussed. Unfortunately, most studies lack sufficient follow-up to reliably assess false-negative results. Moreover, the designs of most studies vary substantially with regard to homogeneity of groups (tumor types and stages), timing (pretreatment, follow-up) and definition of risk factors (patient selection). Therefore, only a few studies are comparable. The combination of F-18 fluoro-d-glucose-positron emission tomography (FDG-PET) and a dedicated CT (at least of the chest) is the most important imaging protocol at the present time. Eventually, whole-body-MRI (WB-MRI) may possibly replace PET-CT for screening patients for distant metastases.

Diagnostic modalities for distant metastasis in head and neck squamous cell carcinoma: are we changing life expectancy?

OBJECTIVES/HYPOTHESIS

To determine if the various imaging modalities for distant metastasis (DM) diagnosis alters life expectancy in head and neck squamous cell carcinoma (HNSCC).

STUDY DESIGN

Retrospective.

METHODS

One hundred seventy patients (mean age, 59.1 years; male:female, 135:35) with HNSCC who developed DM were reviewed. The main outcome measures were the method of DM diagnosis and time from DM diagnosis to death while controlling for clinical parameters (age, gender, tobacco status, primary tumor site, initial TNM classification, number and site of DM, administration of palliative chemotherapy).

RESULTS

Tumor subsites were: 40 oral cavity, 75 oropharynx, 36 larynx, 10 hypopharynx, one nasopharynx, and eight unknown primary. Of the patients, 16.5% (28/170) had distant metastasis at presentation; the remaining 142 patients were diagnosed with DM at a median of 324 days from diagnosis. Although patients diagnosed with DM by positron-emission tomography (PET) scan were more likely to have multiple DM sites (P = .0001), there were no differences in life expectancy in patients who were diagnosed with or without PET scan (median, 185 vs. 165 days, P = .833). There were no differences in life expectancy based on age, gender, site of primary tumor, or number/site of DM. The use of palliative chemotherapy resulted in a significantly longer life expectancy (median, 285 vs. 70 days; P = .001).

CONCLUSIONS

Although a PET scan is more likely to diagnose multiple DM sites, there was no difference in life expectancy based on imaging modality. Patients who are symptomatic from their distant metastasis have a worse life expectancy, and palliative chemotherapy was able to increase life expectancy, even in patients who were symptomatic from the distant metastasis.

Liver Function Tests

Objective. Report the prevalence and risk factors of liver metastasis in head and neck squamous cell carcinoma (HNSCC) while evaluating the utility of liver function tests (LFTs) in detection of such metastases.

Study Design. Case series with chart review.

Setting. Tertiary referral center.

Subjects and Methods. Of 745 patients with newly diagnosed HNSCC (oral cavity, oropharynx, hypopharynx, larynx) treated at University of North Carolina hospitals from 1989 to 2005, 655 had sufficient data for analysis.

Results. Prevalence of liver metastasis was 3% (20/655) with 7 patients demonstrating early metastasis and 12 with late metastasis. Oropharyngeal and hypopharyngeal lesions constituted 65% of identified liver metastasis but only 39% of the study population. Patients with oropharyngeal lesions were most likely to develop liver metastasis ( P = .047). Abnormal LFTs were seen in 26% of all patients. Overall sensitivity and specificity were 45% and 75%. Seventy-five percent of patients with liver metastasis had stage IV disease at diagnosis and were more likely to have abnormal LFTs than other stages ( P = .048). In these patients, 2.2% (8/365) had liver metastases and abnormal LFTs, whereas 1.9% (7/365) had liver metastases and normal LFTs. Sensitivity for alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase 0%, 10%, 20%, and 30%, respectively. Specificities ranged from 88.0% to 94.3%. Positive predictive values were poor, with the highest being 10.5%.

Conclusions. Liver metastases are rare in HNSCC and often delayed in presentation. This study clearly reveals that LFTs do not reliably identify patients with liver metastasis and do not provide physicians with an adequate screening modality in this population.

Role of Positron Emission Tomography-Computed Tomography in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNC) is the sixth most common cancer worldwide. In the United States, it accounts for approximately 2% of all cancers and 2% of cancer deaths. The introduction of integrated positron emission tomography and computed tomography (PET/CT) has revolutionized imaging by permitting improved and more accurate anatomic localization of functional abnormalities in the complex territory of the head and neck region, and PET/CT has become a standard clinical imaging modality in patients with HNC. The main indications for PET/CT in HNC are in pretherapy staging, detection of unknown primaries, and monitoring of therapy response or disease surveillance. Although PET/CT is a promising tool in diagnosis and surveillance of HNC, there is lack of consensus as to its use, accuracy, and implications for patient management. The existing literature on the role of PET/CT in the management of HNC is reviewed, and a summary of the current debate is provided. Second primary cancers are the main cause of death among HNC patients with early disease, and the presence of distant metastases greatly impairs the survival of patients with advanced HNC. Therefore, early detection of second primary and metastatic tumors is imperative for optimizing survival outcome. However, given the lack of randomized, prospective trials addressing the role of PET/CT after chemoradiotherapy, the ideal function of PET/CT in disease surveillance has yet to be defined.

The value of (18)F-FDG PET/CT for the detection of distant metastases in high-risk patients with head and neck squamous cell carcinoma

The aims of this study were to assess a cohort of patients with head and neck squamous cell carcinoma (HNSCC) for: (1) the prevalence of synchronous distant metastases (DM) as detected by the initial staging by using (18)F-FDG PET/CT, (2) the prevalence of metachronous DM, and (3) the validity of published risk factors with special emphasis on the maximum standardized uptake value (SUV max) for the prediction of DM. Two hundred and ninety nine patients with advanced HNSCC were included. Following risk factors at the time of diagnosis and during follow-up were analyzed: advanced T/N stage, poor histological differentiation, level IV/Vb lymph nodes, primary site in the larynx/hypopharynx, and SUV max. The prevalence of DM at initial staging and during follow-up was 10% and 11%, respectively. At initial staging, primary site in the larynx/hypopharynx and neck nodes in level IV/Vb, and during follow-up only level IV/Vb nodes achieved statistical significance. The sensitivity for (18)F-FDG PET/CT with regard to the detection of DM was 96.8%, the specificity 95.4%, the positive predictive value (PV) 69.8%, and the negative PV 99.6%. Patients without DM showed a significantly better overall survival (OS) than patients developing DM (p<0.001). There was no significant difference in OS with regard to the time of diagnosis of DM. The prevalence for synchronous and metachronous DM in advanced HNSCC is considerable. (18)F-FDG PET/CT is highly accurate for initial staging and follow-up. DM carries a bad prognosis regardless of the time of diagnosis.

Accuracy of whole-body PET and PET-CT in initial M staging of head and neck cancer: a meta-analysis

BACKGROUND

A meta-analysis was conducted to evaluate the accuracy of whole-body positron emission tomography (PET) and PET-CT in initial M staging of head and neck cancer.

METHODS

After a systematic review of English language studies, sensitivity, specificity, and other measures of whole-body PET and PET-CT were pooled. Summary receiver operating characteristic (SROC) curves were also used to summarize overall test performance.

RESULTS

Eight PET and 7 PET-CT studies were identified. The pooled sensitivity estimates for PET and PET-CT were 0.848 (95% confidence interval [CI], 0.776-0.905) and 0.875 (95% CI, 0.787-0.936). The pooled specificity estimates were 0.952 (95% CI, 0.933-0.967) and 0.950 (95% CI, 0.931-0.964). The Q* index estimates for PET-CT (0.9409) were not significantly higher than for PET (0.9154; p > .05).

CONCLUSION

Whole-body PET and PET-CT have good diagnostic performance in initial M staging of head and neck cancer; although PET-CT tends to have higher accuracy than PET.

Neck dissection can be avoided after sequential chemoradiotherapy and negative post-treatment positron emission tomography-computed tomography in N2 head and neck squamous cell carcinoma

AIMS

This study assessed neck control in patients with N2 head and neck squamous cell carcinoma (HNSCC) treated with sequential chemoradiotherapy (SCRT) and the incidence of neck recurrence when neck dissection was withheld in those with negative post-treatment fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET).

MATERIALS AND METHODS

Thirty-four consecutive patients with N2 HNSCC who were treated with radical intent using SCRT were included. Twenty-seven patients received concomitant platinum-based chemotherapy with their radiotherapy. Nineteen patients were treated with intensity-modulated radiotherapy. PET-computed tomography (PET-CT) was obtained 3 months after the completion of radical radiotherapy. Neck dissection was carried out only in those with increased FDG uptake in the neck.

RESULTS

The median follow-up was 39.1 months. One patient had increased FDG uptake in the neck post-treatment, which was false positive for malignancy. The remaining 33 patients were observed without neck dissection. No regional recurrence occurred. The negative predictive value (NPV) of post-treatment PET-CT was 100%.

CONCLUSIONS

Good disease control in the neck can be achieved in patients with N2 HNSCC with SCRT. Post-treatment PET-CT has a high NPV. Neck dissection can be avoided if post-treatment PET-CT is negative.

FDG PET with contrast-enhanced CT: a critical imaging tool for laryngeal carcinoma

Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has evolved to be an essential imaging modality in the evaluation of laryngeal carcinoma. Although the modality has limited utility in assessing the extent of the primary tumor, FDG PET has proved to be superior to anatomic modalities in the detection of lymph node and distant metastases. The role of FDG PET in the evaluation of patients with laryngeal tumors that are clinically classified as N0 has not shown consistent usefulness because of the innate resolution limitations of the camera. In the posttherapy setting, however, FDG PET has consistently demonstrated a high negative predictive value in the identification of recurrent disease, both during the course of therapy and during long-term follow-up. In addition, contrast material-enhanced computed tomography (CT) in conjunction with FDG PET has demonstrated a complementary role by allowing for superior anatomic coregistration and therefore more definitive diagnosis. There is sufficient evidence that with further advances in PET technology, this modality will likely become more useful in the detection of small lesions and occult nodal disease, as well as in guiding the management of laryngeal carcinoma.

FDG PET imaging of head and neck cancers

In initial staging of head and neck cancers, the addition of FDG PET to conventional imaging improves the accuracy for cervical nodal metastases. The sensitivity of FDG PET is, however, limited in nodes <1 cm and in completely necrotic nodes. In the posttherapy setting, PET scans obtained at least 10 weeks after radiotherapy have an excellent predictive value to rule out residual disease. Due to the limited positive predictive value of FDG PET after radiation therapy, a positive PET scan needs to be confirmed before management decisions are made.

Glucose deprivation-induced metabolic oxidative stress and cancer therapy

Cancer cells (vs. normal cells) demonstrate evidence of oxidative stress, increased glycolysis, and increased pentose cycle activity. The oxidative stress in cancer cells has been hypothesized to arise from mitochondrial dysfunction leading to increased levels of hydroperoxides, and cancer cells have been proposed to compensate for this defect by increasing glucose metabolism. Glucose metabolism has also been shown to play a role in hydroperoxide detoxification via the formation of pyruvate (from glycolysis) and NADPH (from the pentose cycle). Furthermore, in cancer cells, glucose deprivation as well as treatment with 2-deoxyglucose (2 DG) has been shown to induce oxidative stress and cytotoxicity. Additionally, transformed cells have been shown to be more susceptible to glucose deprivation (and 2DG-)-induced cytotoxicity and oxidative stress than untransformed cells. These results support the hypothesis that cancer cells have a defect in mitochondrial respiration leading to increased steady state levels of O2*- and H2O2, and glucose metabolism is increased to compensate for this defect. The application of these findings to developing cancer therapies using 2DG combined with inhibitors of hydroperoxide metabolism to induce radio/chemosensitization is discussed, as well as the possibility that FDG-PET imaging may predict tumor responses to these therapies.

Hybrid imaging (SPECT/CT and PET/CT): improving therapeutic decisions

The incremental diagnostic value of integrated positron emission tomography-computed tomography (PET/CT) or single-photon emission computed tomography (SPECT)/CT images compared with PET or SPECT alone, or PET or SPECT correlated with a CT obtained at a different time includes the following: (1) improvement in lesion detection on both CT and PET or SPECT images, (2) improvement in the localization of foci of uptake resulting in better differentiation of physiological from pathologic uptake, (3) precise localization of the malignant foci, for example, in the skeleton vs soft tissue or liver vs adjacent bowel or node (4) characterization of serendipitous lesions, and (5) confirmation of small, subtle, or unusual lesions. The use of these techniques can occur at the time of initial diagnosis, in assessing the early response of disease to treatment, at the conclusion of treatment, and in continuing follow-up of patients. PET/CT and SPECT/CT fusion images affect the clinical management in a significant proportion of patients with a wide range of diseases by (1) guiding further procedures, (2) excluding the need of further procedures, (3) changing both inter- and intramodality therapy, including soon after treatment has been initiated, and (4) by providing prognostic information. PET/CT fusion images have the potential to provide important information to guide the biopsy of a mass to active regions of the tumor and to provide better maps than CT alone to modulate field and dose of radiation therapy. It is expected that the role of PET/CT and SPECT/CT in changing management will continue to evolve in the future and that these tools will be fundamental components of the truly "personalized medicine" we are striving to deliver.

PET/CT-MR Imaging in Head and Neck Cancer Including Pitfalls and Physiologic Variations

This article emphasizes the strengths and potential pitfalls of functional and anatomic imaging in patients who have head and neck cancer with an emphasis on the treated neck, including patients who have undergone surgery and/or radiation therapy. Anatomic and molecular imaging together allow optimal evaluation and interpretation of a patient who has cancer. Effective assessment of patients who have head and neck cancer can be achieved through a careful review of pertinent anatomy, with awareness of the physiologic variations (especially those in the treated head and neck) seen in PET imaging, and analysis of both the PET and cross-sectional images.

Identification of distant metastases with PET-CT in patients with suspected recurrent head and neck cancer

OBJECTIVES

To investigate the utility of positron-emission tomography/computed tomography (PET-CT) in identifying distant metastatic disease in patients with suspected recurrent head and neck squamous cell cancer (HNSCC).

STUDY DESIGN

Retrospective analysis.

METHODS

Retrospective analysis of 64 consecutive patients with suspected recurrent HNSCC following definitive treatment who underwent PET-CT imaging were eligible for inclusion. Patients with previous known distant metastatic disease were excluded.

RESULTS

The majority of patients (81%) had TNM stage III or IV disease. PET-CT was suspicious for pulmonary malignancy in 14 patients (22%) and indeterminate in 6 patients (9%). Pulmonary metastases or a new lung primary were present in 10 patients (16%): 7 of 14 patients with positive PET-CT scans (50%) and 3 of 50 patients with negative or indeterminate PET-CT scans (6%). Including nonpulmonary sites, the overall incidence of distant disease was 23% (15/64) with 20% (13/64) unsuspected prior to PET-CT. The sensitivity and specificity of PET-CT in predicting distant malignancy was 86% and 84%, respectively, with a positive predictive value of 60% and a negative predictive value of 95%. There was a significant correlation between standardized uptake value (SUV) on PET-CT and positive histology, with a mean SUV of 8.5 (range, 4.7-16.2) in patients with distant metastases compared with a mean SUV of 2.9 (range, 1.9-4.2) in patients with benign pathology (r = 0.87, P < .0001).

CONCLUSIONS

A significant number of patients with recurrent HNSCC have distant metastases at the time of recurrence. These data suggest that PET-CT improves detection of metastatic disease in the high-risk patient and should be performed as part of the routine evaluation of patients with suspected recurrence prior to salvage surgery.

Definitive chemoirradiation for resectable head and neck cancer: treatment outcome and prognostic significance of MRI findings

The aim of this study was to evaluate the outcome and prognosticators for patients with resectable head and neck cancer (RHNC) undergoing definitive concurrent chemotherapy and radiotherapy (CCRT). In total, 110 RHNC patients receiving definitive CCRT to defer radical surgery were enrolled. Radiotherapy was given as either 2 Gy once daily with 70 Gy, or 1.2 Gy twice daily with 74.4 Gy. Chemotherapy involved the administration of 5-fluorouracil and cisplatin in two concomitant and two post-radiotherapy adjuvant cycles. 3 months after CCRT, MRI was performed to evaluate the response and determine further treatment plans. Survival outcome was calculated by the Kaplan-Meier method. Log-rank test and Cox regression analyses were used to estimate the significance of prognosticators. 4-year local-regional control, distant metastasis-free survival, disease-free survival and overall survival rates were 76.1%, 85.6%, 67.5% and 53.2%, respectively. Local recurrence (odds ratio = 4.09; p < 0.0001) and T3/T4 stage (odds ratio = 2.34; p = 0.01) were the independent factors associated with poor survival. T stage (odds ratio = 3.29; p = 0.03) and/or remission status on post-CCRT MRI (odds ratio = 7.22; p < 0.0001) were significantly associated with local control, distant metastasis-free survival and disease-free survival. 13 of 20 patients with imaging residuum had local recurrence, compared with 12 of 89 with complete remission (4-year local control rate of 27% vs 86%; p < 0.0001). Post-CCRT MRI may thus be used to predict the chance of a successful non-surgical approach.

Squamous Cell Carcinoma: Initial Diagnosis and Staging with PET/CT

Squamous cell carcinoma is the most frequent malignancy of the head and neck region, accounting for 5% of all malignant tumors worldwide. Accurate staging at diagnosis is critical for selection of appropriate treatment strategy. A variety of therapeutic options are used for treatment, including surgery with or without radical dissection, lymph node dissections of various severities, radiotherapy, chemotherapy, and combinations of these. Precise prediction of the extent of primary tumors, detection of unknown primary tumor, cervical lymph node status, and distant metastatic spread is important for treatment planning and prognosis. Accurate evaluation of these factors prior to treatment helps guide surgical extent or radiation porta, minimizing locoregional treatment failure.

PET changes management and improves prognostic stratification in patients with head and neck cancer: results of a multicenter prospective study

The primary aim of this study was to determine the impact of PET in changing initial management plans in patients with untreated head and neck cancer. Secondary aims were to determine the incremental staging information provided by PET and to document the effect of PET on treatment outcomes.

METHODS

Patients with untreated head and neck cancer underwent PET scans. Pre-PET management plans were documented by referring clinicians unaware of the PET results, and management plan changes due to PET scan findings were documented. Follow-up to 12 mo after treatment was performed to determine actual management and clinical outcomes.

RESULTS

A total of 71 patients (median age, 56 y; 69% male) were studied. PET scans resulted in management change in 33.8% of patients. Moreover, PET was able to detect additional sites of disease in 39.4% of patients. Follow-up data showed that PET improved the classification of patients into curative and palliative categories. Trends toward inferior disease-free survival and lower complete response rates in patients with additional lesions detected on PET were demonstrated. In addition, a trend toward inferior disease-free survival in patients with a higher maximum standardized uptake value was shown.

CONCLUSION

These data unequivocally demonstrate the significant impact of PET on management and outcomes in patients with untreated head and neck cancer.

Head and neck squamous cell carcinoma: usefulness of diffusion-weighted MR imaging in the prediction of a neoadjuvant therapeutic effect

The purpose of our study was to evaluate the usefulness of diffusion-weighted imaging in predicting the responses to neoadjuvant therapy for head and neck squamous cell carcinomas. Diffusion-weighted, T2-weighted, and gadolinium-enhanced T1-weighted images were obtained from 28 patients with untreated head and neck squamous cell carcinomas with histological proof. A blinded radiologist evaluated the quantitative and qualitative signal intensities and apparent diffusion coefficients (ADCs) in the lesions on each sequence. All patients were treated by neoadjuvant therapies, and the post-therapeutic tumor regression rate was determined. Both the quantitative and qualitative signal intensities on diffusion-weighted images showed positive correlations (r = 0.367 and 0.412, p < .05), and the ADCs showed a weak, inversed correlation (r = -0.384, p < .05) with the tumor regression rates. Diffusion-weighted imaging including an assessment by ADCs may be able to predict tumor response to neoadjuvant therapy for head and neck squamous cell carcinomas.

Distant metastases and synchronous second primary tumors in patients with newly diagnosed oropharyngeal and hypopharyngeal carcinomas: evaluation of (18)F-FDG PET and extended-field multi-detector row CT

INTRODUCTION

Patients with oropharyngeal or hypopharyngeal squamous cell carcinoma (SCC) have a high risk of having distant metastases or second primary tumors. We prospectively evaluate the clinical usefulness of (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET), extended-field multi-detector computed tomography (MDCT), and their side-by-side visual correlation for the detection of distant malignancies in these two tumors at presentation.

MATERIALS AND METHODS

A total of 160 patients with SCC of the oropharynx (n = 74) or hypopharynx (n = 86) underwent (18)F-FDG PET and extended-field MDCT to detect distant metastases or second primary tumors. Suspected lesions were investigated by means of biopsy, clinical, or imaging follow-up.

RESULTS

Twenty-six (16.3%) of our 160 patients were found to have distant malignancy. Diagnostic yields of (18)F-FDG PET and MDCT were 12.5% and 8.1%, respectively. The sensitivity of (18)F-FDG PET for detection of distant malignancies was 1.5-fold higher than that of MDCT (76.9% vs. 50.0%, P = 0.039), while its specificity was slightly lower (94.0% vs. 97.8%, P = 0.125). Side-by-side visual correlation of MDCT and (18)F-FDG PET improved the sensitivity and specificity up to 80.8% and 98.5%, respectively, leading to alteration of treatment in 13.1% of patients. A significant difference in survival rates between its positive and negative results was observed.

CONCLUSION

(18)F-FDG PET and extended-field MDCT had acceptable diagnostic yields for detection of distant malignancies in untreated oropharyngeal and hypopharyngeal SCC. (18)F-FDG PET was 1.5-fold more sensitive than MDCT, but had more false-positive findings. Their visual correlation improved the diagnostic accuracy, treatment planning, and prognosis prediction.

Identification of distant metastases with positron-emission tomography-computed tomography in patients with previously untreated head and neck cancer

OBJECTIVES

To investigate the utility of positron-emission tomography-computed tomography (PET-CT) in identifying distant metastatic disease in patients with previously untreated head and neck squamous cell cancer (HNSCC) prior to definitive treatment.

MATERIALS AND METHODS

Retrospective analysis of 27 consecutive patients with previously untreated HNSCC who underwent PET-CT imaging in addition to chest radiography (CXR) as part of their metastatic workup.

RESULTS

The majority of patients (89%) had TNM stage III or IV disease. PET-CT was suspicious for pulmonary malignancy in four (15%) patients and indeterminate in one (4%) patient. CXR was suspicious for pulmonary malignancy in two (7%) patients. Pulmonary metastases or a new lung primary was present in 3 (11%) patients: 3 of 4 (75%) patients with positive PET-CT scans and 0 of 23 (0%) patients with negative or indeterminate PET-CT scans compared with 2 of 2 (100%) patients with positive CXR and 1 of 25 (4%) patients with negative CXR. The sensitivity and specificity of PET-CT in predicting pulmonary malignancy was 100% and 96%, respectively, with a positive predictive value of 75% and a negative predictive value of 100%. The sensitivity and specificity of CXR in predicting pulmonary malignancy was 67% and 100%, respectively, with a positive predictive value of 100% and a negative predictive value of 96%. Including nonpulmonary sites, the overall incidence of distant metastatic disease was 19% (5/27) with 11% (3/27) unsuspected prior to PET-CT.

CONCLUSIONS

PET-CT improves detection of metastatic disease in the high-risk patient and should be performed as part of the routine pretreatment evaluation of patients with advanced stage HNSCC.

[18FDG] PET-CT-based intensity-modulated radiotherapy treatment planning of head and neck cancer

PURPOSE

To define the best threshold for tumor volume delineation of the (18) fluoro-2-deoxy-glucose positron emission tomography ((18)FDG-PET) signal for radiotherapy treatment planning of intensity-modulated radiotherapy (IMRT) in head and neck cancer.

METHODS AND MATERIALS

In 25 patients with head-and-neck cancer, CT-based gross tumor volume (GTV(CT)) was delineated. After PET-CT image fusion, window level (L) was adapted to best fit the GTV(CT), and GTV(PET) was delineated. Tumor maximum (S) and background uptake (B) were measured, and the threshold of the background-subtracted tumor maximum uptake (THR) was used for PET signal segmentation. Gross tumor volumes were expanded to planning target volumes (PTVs) and analyzed.

RESULTS

The mean value of S was 40 kBq/mL, S/B ratio was 16, and THR was 26%. The THR correlated with S (r = -0.752), but no correlation between THR and the S/B ratio was seen (r = -0.382). In 77% of cases, S was >30 kBq/mL, and in 23% it was </=30 kBq/mL, with a mean THR of 21.4% and 41.6%, respectively (p < 0.001). Using PTV(PET) in radiotherapy treatment planning resulted in a reduced PTV in 72% of cases, while covering 88.2% of GTV(CT), comparable to the percentage of GTV(PET) covered by PTV(CT) (p = 0.15).

CONCLUSIONS

A case-specific PET signal threshold is optimal in PET-based radiotherapy treatment planning. Signal gating using a THR of 20% in tumors with S >30% +/- 1.6% kBq/mL and 40% in tumors with S </=30% +/- 1.6% kBq/mL is suitable.

Clinical significance of intrathoracic lesions detected by 18F-fluorodeoxyglucose positron emission tomography in the management of patients with head and neck cancer

Few studies have used positron emission tomography (PET) to identify metastases or simultaneous thoracic malignancies in patients with head and neck cancer (HNC). We retrospectively investigated the role of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in detecting thoracic malignancies in patients with previously untreated HNC. Patients (n=86) with HNC and intrathoracic lesions on PET were divided into those who had abnormal FDG uptake in the mediastinum (n=29), lungs (n=34), or both (n=23). Whole body PET and chest computed tomography (CT) results were blindly reviewed and scored by two observers. The accuracy of FDG PET and CT were drawn from patients in whom diagnosis was confirmed, by histopathology or follow-up imaging, and risk factors for thoracic malignancy were analyzed. Malignancy was suspected in 23 of 86 patients (27%) with FDG uptake. Most of the lesions (83%) with abnormal FDG uptake were benign, with thoracic malignancy confirmed in 15 patients (17%). The overall sensitivity, specificity, and accuracy of FDG PET for intrathoracic malignancy in these patients were 80%, 85%, and 84%, respectively. The likelihood of thoracic malignancy in the HNC patients was associated with high FDG uptake of thoracic lesions. FDG PET may reveal lung and mediastinal malignancies with high accuracy in patients with HNC. The thoracic staging by FDG PET may be helpful in therapeutic planning for these patients.

Case Report: Fusion of positron emission tomography (PET) and computed tomography (CT) images for image-guided endoscopic navigation in maxillofacial surgery: Clinical application of a new technique

INTRODUCTION

Surgery based on computed tomography (CT) data is becoming increasingly important in the head and neck region. The technique for hardware fusion between positron emission tomography (PET) and computed tomography (CT) has only been established commercially in the last 4 years. The advantages over CT alone are obvious. The surgeon is simultaneously provided with a map of anatomical as well as of functional (metabolic) details. The fused images offer improved localization of malignant lesions and improved targeting of biopsy, especially for small lesions.

PURPOSE

A new technique for image-guided tumour localization for maxillofacial surgery based on PET/CT-image fusion is described.

PATIENT AND METHOD

A 78-year-old woman was admitted to this department with a tumour of the skull base. Three dimensional fusion of computed CT with positron PET images on a commercially available navigation system is described. After patient-to-image registration, a high-resolution endoscope was calibrated intraoperatively. Image-guided biopsy specimens were taken under direct visual control.

CONCLUSION

PET/CT-image fusion proved extremely helpful to navigate the endoscope to the target lesion and to identify the tumour.

Imaging of oral cancer

This article reviews imaging modalities commonly used to evaluate oral cavity cancers and their metastases to lymph nodes. It discusses how the studies are performed and their relative merits. It also presents new techniques for evaluating these neoplasms.

Pathology and FDG PET correlation of residual lymph nodes in head and neck cancer after radiation treatment

BACKGROUND

This study determines if postradiotherapy [18F]fluorodeoxyglucose positron emission tomography (FDG PET) can predict the pathology status of residual cervical lymph nodes in patients undergoing definitive radiotherapy for head and neck squamous cell carcinoma (HNSCC).

METHODS

Patients with stage N2 or higher HNSCC underwent PET and CT imaging after definitive radiotherapy. Patients with radiographically persistent lymphadenopathy underwent either neck dissection or fine needle aspiration (FNA) of the lymph nodes under ultrasound guidance. PET scan results were correlated with the pathologic findings of the residual lymphadenopathy.

RESULTS

Twenty-four hemi-necks in 23 patients with residual lymphadenopathy had neck dissection or FNA. The pathology correlated strongly with the post-RT FDG PET studies. All patients with a negative post-RT FDG PET and those with a maximum standardized uptake value (SUVmax) of less than 3.0 in the post-RT FDG PET were found to be free from residual viable tumor. Using a SUVmax of less than 3.0 as the criterion for a negative FDG PET study, the sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 84.2%, 62.5%, and 100%, respectively.

CONCLUSIONS

A negative post-RT FDG PET is very predictive of negative pathology in the residual lymph node after definitive radiotherapy for advanced HNSCC. A prospective clinical trial is warranted to determine if neck dissection can be withheld in these patients.

Head and Neck Cancer: Dedicated FDG PET/CT Protocol for Detection—Phantom and Initial Clinical Studies

PURPOSE

To retrospectively compare the sensitivity of a dedicated fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) protocol versus a standard whole-body PET/CT protocol for detection of head and neck cancer, with biopsy and follow-up as reference standards.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. Dedicated and standard PET/CT protocols were performed in a phantom and in 55 patients suspected of having head and neck cancer (28 men, 27 women; age range, 21-79 years). The neck phantom contained four 4.4-9.8-mm-diameter spheres. Standard protocol consisted of a midcranium to proximal thigh emission scan of 2-4 minutes per bed position. Dedicated protocol was an 8-minute head and neck scan. Reconstructed field of view and pixel size, respectively, were 30 cm and 2.34 mm for the dedicated and 50 cm and 3.91 mm for the standard protocol. FDG uptake was evaluated visually and semiquantitatively by using standardized uptake values (SUVs). Mean SUV was compared between dedicated and standard protocols with a t test modified for clustered sampling. Receiver operating characteristic (ROC) curves were calculated. A two-tailed P value was used.

RESULTS

In the phantom study, a larger percentage difference (20%-27%) in sphere-to-background ratios with the dedicated than with the standard protocol was observed for 6.0-9.8-mm spheres. In the clinical study, a total of 149 lymph nodes were identified. Five malignant and six benign lymph nodes (mean diameter, 7.1 mm) were visually identified with the dedicated protocol only. SUVs with the dedicated protocol were significantly higher than those with the standard protocol (P<.001). Area under the ROC curve was 0.94 for the dedicated and 0.92 for the standard protocol (P=.56).

CONCLUSION

FDG PET with either the standard or dedicated protocol was more sensitive than CT for evaluating head and neck lymph nodes. The dedicated protocol improved the detectability of smaller nodes.

Impact of [18F]-2-Fluorodeoxyglucose???Positron Emission Tomography/Computed Tomography on Previously Untreated Head and Neck Cancer Patients

OBJECTIVES

The role of fused modality [F]-2-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) in diagnosing and accurately staging patients with primary, metastatic, and recurrent head and neck (HN) cancer is evolving, and the clinical implications need to be further defined. A few retrospective studies have been performed, but adequate sample sizes are lacking because the number of HN cancer patients is relatively small. This study evaluates the positive predictive value (PPV), sensitivity, specificity, and accuracy of PET/CT in previously untreated HN cancer patients at a single tertiary care institution. The purpose of this study is to evaluate the role of this new technology in the management of previously untreated HN cancer patients.

STUDY DESIGN

Retrospective cohort outcomes study at a tertiary National Cancer Institute Comprehensive Cancer Center.

MATERIALS AND METHODS

Institutional review board exemption #4 (45 CFR 46.101 [4]) criteria were applied for and accepted by the office of responsible research practices at the Ohio State University College of Medicine. The authors identified 268 consecutive PET/CT examinations between March 2005 and January 2006 for HN cancer ordered by the two senior authors at the James Cancer Hospital and Solove Research Institute of the Ohio State University Medical Center. PET/CT examinations were interpreted by one of three neuroradiologists. PPV, sensitivity, specificity, accuracy, diagnostic upstaging, and treatment management changes were determined from subset analysis of 123 previously untreated patients with HN cancer. Synchronous lesions were detected in 10 patients with use of this modality. PET/CT was also used to help manage 22 patients with unknown primary HN cancer. The statistics were verified by comparing PET/CT results with surgical specimen histopathology.

RESULTS

: PET/CT was true-positive in 82.9% (102/123), with a per patient PPV of 87.2% and a per lesion PPV of 89.4%. PET/CT was false-positive in 12.2% (15/123) of patients and had a false-positive rate of 8.3% when calculated per lesion. In 67 patients who underwent neck dissection, PET/CT had a PPV of 92.7%. The accuracy was 89.7% in 20 patients who had bilateral neck dissections. The unknown primary site was found in 72.7% (16/22) of patients with unknown primary HN cancer. Synchronous lesions were found in 8.1% of patients by PET/CT, with a PPV of 66.6%. Distant metastases were detected in 15.4% (19/123) of patients. Treatment was altered in 30.9% (38/123) of patients as a result of this imaging modality.

CONCLUSIONS

The benefit of the PET/CT imaging modality resides in its fusion of anatomic detail of the HN region with the sensitivity of detecting tumors with increased metabolic activity at distant sites. Treatment was altered in 30.9% of our previously untreated HN cancer patients because of this imaging technique, with altered treatment including upstaging, diagnosing distant and unresectable disease, and working-up second primary malignancies. The false-positive findings did not result in additional morbidity to these patients. Although PET/CT is sensitive in detecting occult cervical nodal metastases, it does not yet have the ability to replace neck dissection as the diagnostic standard of care. This study supports the use of PET/CT in patients with newly diagnosed HN cancer because of its high PPV and superiority of detecting distant metastases and synchronous lesions.

[Positron emission tomography in head and neck squamous cell carcinomas]

18F-Fluorodeoxyglucose positron emission tomography (PET) is an imaging modality which is becoming increasingly esential in oncology, especially in the management of head and neck squamous cell carcinomas (SCC). The most common uses of the PET are listed in this thematic study: initial staging, cervical lymph node metastases from an unknown primary tumor and post-therapeutic follow-up. The advantages and drawbacks of this imaging tool are exposed here according to both our experience and data from the literature. Decision schemes are suggested for each use so as to optimize the use of this imaging modality in the management of these SCC. Other fields of application for the PET are mentioned, such as the in-progress evaluation of response to chemotherapy, the interest of this imaging tool in radiotherapy as well as current biochemical developments concerning new tracers.