Integrated PET/CT system for staging and surveillance of skull base tumors

International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors

BACKGROUND

Sinonasal neoplasms, whether benign and malignant, pose a significant challenge to clinicians and represent a model area for multidisciplinary collaboration in order to optimize patient care. The International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors (ICSNT) aims to summarize the best available evidence and presents 48 thematic and histopathology-based topics spanning the field.

METHODS

In accordance with prior International Consensus Statement on Allergy and Rhinology documents, ICSNT assigned each topic as an Evidence-Based Review with Recommendations, Evidence-Based Review, and Literature Review based on the level of evidence. An international group of multidisciplinary author teams were assembled for the topic reviews using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses format, and completed sections underwent a thorough and iterative consensus-building process. The final document underwent rigorous synthesis and review prior to publication.

RESULTS

The ICSNT document consists of four major sections: general principles, benign neoplasms and lesions, malignant neoplasms, and quality of life and surveillance. It covers 48 conceptual and/or histopathology-based topics relevant to sinonasal neoplasms and masses. Topics with a high level of evidence provided specific recommendations, while other areas summarized the current state of evidence. A final section highlights research opportunities and future directions, contributing to advancing knowledge and community intervention.

CONCLUSION

As an embodiment of the multidisciplinary and collaborative model of care in sinonasal neoplasms and masses, ICSNT was designed as a comprehensive, international, and multidisciplinary collaborative endeavor. Its primary objective is to summarize the existing evidence in the field of sinonasal neoplasms and masses.

The Role of Positron Emission Tomography for the Management of Sinonasal Malignancies: A Systematic Review

BACKGROUND

Positron emission tomography (PET) scan is a valuable imaging modality widely used in the management of cancers. Its usage is well defined for most head and neck malignancies. However, there is a lack of consensus regarding the utility of PET scan for sinonasal malignancies. This is highlighted by the latest international consensus statement on endoscopic skull base surgery.

OBJECTIVE

This systematic review aims to clarify the role of PET scan in the management of sinonasal malignancies.

METHODS

We conducted a comprehensive literature search using PubMed, MEDLINE, EMBASE, Web of Science, CINAHL, and Cochrane databases for research studies of interest. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) updated statement was used to guide the review.

RESULTS

In total, 1807 articles were assessed for eligibility. Thirty-nine original papers, published between 2004 and 2021, met inclusion criteria. Seven articles focused on the role of PET scan for inverted papilloma, 23 for sinonasal carcinoma, 4 for melanoma, and 3 for lymphoma, and finally, 3 articles focused on the use of specific PET scan tracers for sinonasal malignancies. Qualitative summaries for each potential role of PET scans were provided. In general, included studies were retrospective in nature with low level of evidence.

CONCLUSIONS

In general, and across all types of sinonasal malignancies, PET scan yielded positive results regarding detection and initial staging. It was also considered as the modality of choice for detection of distant metastases, except in the case of sinonasal lymphoma. PET scan's main limit resides in its inability to detect lesions in or close to the metabolic activity of the brain.

PET/CT Imaging in Treatment Planning and Surveillance of Sinonasal Neoplasms

Sinonasal cancers are uncommon malignancies with a generally unfavorable prognosis, often presenting at an advanced stage. Their high rate of recurrence supports close imaging surveillance and the utilization of functional imaging techniques. Whole-body 18F-FDG PET/CT has very high sensitivity for the diagnosis of sinonasal malignancies and can also be used as a "metabolic biopsy" in the characterization of some of the more common subgroups of these tumors, though due to overlap in uptake, histological confirmation is still needed. For certain tumor types, radiotracers, such as 11C-choline, and radiolabeled somatostatin analogs, including 68Ga-DOTATATE/DOTATOC, have proven useful in treatment planning and surveillance. Although serial scans for posttreatment surveillance allow the detection of subclinical lesions, the optimal schedule and efficacy in terms of survival are yet to be determined. Pitfalls of 18F-FDG, such as post-surgical and post-radiotherapy crusting and inflammation, may cause false-positive hypermetabolism in the absence of relapse.

Neoplastic nerve lesions

Though metastasis and malignant infiltration of the peripheral nervous system is relatively rare, physicians should have a familiarity with their presentations to allow for prompt diagnosis and initiation of treatment. This article will review the clinical presentations, diagnostic evaluation, and treatment of neoplastic involvement of the cranial nerves, nerve roots, peripheral nerves, and muscle. Due to the proximity of the neural structure traversing the skull base, metastasis to this region results in distinctive syndromes, most often associated with breast, lung, and prostate cancer. Metastatic involvement of the nerve roots is uncommon, apart from leptomeningeal carcinomatosis and bony metastasis with resultant nerve root damage, and is characterized by significant pain, weakness, and numbness of an extremity. Neoplasms may metastasize or infiltrate the brachial and lumbosacral plexuses resulting in progressive and painful sensory and motor deficits. Differentiating neoplastic involvement from radiation-induced injury is of paramount importance as it dictates treatment and prognosis. Neurolymphomatosis, due to malignant lymphocytic infiltration of the cranial nerves, nerve roots, plexuses, and peripheral nerves, deserves special attention given its myriad presentations, often mimicking acquired demyelinating neuropathies.

Sinonasal Squamous Cell Carcinoma, a Narrative Reappraisal of the Current Evidence

Simple Summary

Sinonasal squamous cell carcinomas are a group of diverse tumors affecting the nasal cavity and paranasal sinuses. As a direct consequence of their rarity and heterogeneity, diagnosis is challenging, and treatment does not follow universally accepted protocols. Though surgery represents the mainstay of treatment, neoadjuvant and adjuvant therapies have pivotal roles in improving outcomes of patients treated with curative intent. Indications to endoscopic surgery have been expanding over the last three decades, but a considerable number of patients affected by sinonasal squamous cell carcinoma still need open surgical procedures. Management of the neck in patients affected by sinonasal squamous cell carcinoma is controversial. Curative-intended treatment of recurrent and/or metastatic tumors, alongside palliation of uncurable cases, represent poorly explored aspects of this disease.

Abstract

Sinonasal squamous cell carcinoma is a rare tumor affecting the nasal cavity and paranasal sinuses. Several aspects of this disease, ranging from epidemiology to biology, pathology, diagnosis, staging, treatment, and post-treatment surveillance are controversial, and consensus on how to manage this sinonasal cancer is lacking. A narrative literature review was performed to summarize the current evidence and provide the reader with available data supporting the decision-making process in patients affected by sinonasal squamous cell carcinoma, alongside the authors’ personal opinion on the unsolved issues of this tumor. The review has highlighted several advances in molecular definition of epithelial cancers of the sinonasal tract. Surgery represents the pivot of treatment and is performed through an endoscopic transnasal approach whenever feasible. Open surgery is required for a large proportion of cases. Reconstruction of the defect follows principles of skull base and cranio-maxillo-facial reconstruction. Chemotherapy is given as neoadjuvant treatment or concomitantly to radiotherapy. Photon-based radiation therapy has a crucial role in the adjuvant setting. Particle therapy is providing promising results. Management of the neck should be planned based on the presence of clinically appreciable metastases, primary tumor extension, and need for recipient vessels. Biotherapy and immunotherapy are still underexplored therapeutical modalities.

Appropriate timing of surveillance intervals with whole-body 18F-FDG PET/CT following treatment for sinonasal malignancies

PURPOSE

To assess the ideal timing of posttreatment whole-body ¹⁸F-FDG PET/CT examination as routine surveillance to determine local recurrence (R), lymph node metastasis (LM), and distant metastasis (DM) of sinonasal malignancies and to investigate the effect of ¹⁸F-FDG PET/CT on survival.

METHODS

An overall 80 patients who had undergone a total of 197 posttreatment whole-body ¹⁸F-FDG PET/CT examinations for sinonasal malignancy were retrospectively examined after institutional review board approval. Patients were grouped regarding the time intervals (<1 month, 1-3 months, 3-6 months, 6-12 months, 12-18 months and >18 months) after the conclusion of treatment. Differences in diagnostic accuracy due to different follow-up intervals were calculated by receiver operator curves (ROC) and a Cox proportional hazards model was used to assess the prognostic value of surveillance ¹⁸F-FDG PET/CT.

RESULTS

Considering the time intervals of posttreatment ¹⁸F-FDG PET/CT scans, the negative predictive value and positive predictive value of the ¹⁸F-FDG PET/CT examinations to predict overall recurrence in 1-3 months (100 and 100%, respectively) and >18 months (100 and 95%, respectively) were higher than for recurrence detection in <1 month (50 and 100%, respectively), 3-6 months (81 and 93%, respectively), 6-12 months (79 and 87%, respectively), and 12-18 months (75 and 80%, respectively) (p < 0.05). Positive findings on ¹⁸F-FDG PET/CT scans were also independent predictors of poorer overall survival (OS) (p < 0.05).

CONCLUSIONS

Whole-body ¹⁸F-FDG PET/CT is capable of identifying recurrences following treatment, using an optimal time interval for scanning of 1-3 months and >18 months after therapy.

Performance of whole-body 18F-FDG PET/CT as a posttreatment surveillance tool for sinonasal malignancies

PURPOSE

To determine the diagnostic utility of posttreatment surveillance whole-body ¹⁸F-FDG PET/CT in detecting local tumor recurrence (R), regional lymph-node metastasis (LM), and distant metastasis (DM) in asymptomatic sinonasal cancer patients.

METHODS

Eighty consecutive patients (53 men, 27 women; mean age, 60 years; range, 28-92 years) who had undergone 197 posttreatment whole-body ¹⁸F-FDG PET/CT examinations for sinonasal malignancies between January 2009 and August 2017 were retrospectively reviewed. ¹⁸F-FDG PET/CT findings were categorized as positive or negative for R, LM, and DM, separately. Outcomes of ¹⁸F-FDG PET/CT scans were compared with the final diagnosis confirmed by histological analysis or follow-up period for a minimum 12 months. The diagnostic accuracy of scans was calculated for each site using contingency tables. Impact on the management of ¹⁸F-FDG PET/CT examinations was additionally evaluated.

RESULTS

¹⁸F-FDG PET/CT scans identified 37/44 of local recurrences, 21/23 of LMs, and 30/37 of DMs. For local recurrence, sensitivity, specificity, positive predictive value, and negative predictive value were 84% (68-97%), 95% (80-100%), 84% (68-97%), and 95% (80-100%), respectively. For LM, the respective values were 91% (75-100%), 99% (83-100%), 91% (75-100%), and 99% (83-100%). For DM, the values were 81% (64-97%), 99% (85-100%), 97% (81-100%), and 96% (81-100%), respectively. ¹⁸F-FDG PET/CT accounted for a change in management of 85% patients with recurrences.

CONCLUSIONS

Whole-body ¹⁸F-FDG PET/CT is a suitable surveillance tool for sinonasal malignancies in detecting locoregional and distant recurrences in asymptomatic patients without any evidence of recurrence on regular follow-up and endoscopy during the posttreatment period.

Utility of first positron emission tomography-computed tomography scan as a prognostic tool following treatment of sinonasal and skull base malignancies

BACKGROUND

The prognostic value of the first posttreatment whole body integrated positron emission tomography-computed tomography (PET/CT) scanning in patients with sinonasal/skull base malignancies is undetermined.

METHODS

We retrospectively reviewed the data of all patients that underwent surgery for sinonasal/skull base malignancies in 2000-2015. The results of the pretreatment and posttreatment PET/CT findings and the clinical course were retrieved.

RESULTS

Thirty-eight patients (average age 60.6 years, 20 males) were included. Sensitivity and specificity, positive predictive value, and negative predictive value of the first PET/CT scan for predicting persistent/recurrent disease were 85.7%, 87.5%, 80%, and 91.3%, respectively. Overall 5-year survival was significantly lower in the first posttreatment PET/CT-positive group (35%) compared to the PET/CT-negative group (93%) (P = .0008).

CONCLUSION

Posttreatment PET/CT findings are highly prognostic in patients with sinonasal/skull base malignancies. Negative findings on the first posttreatment PET/CT scan predict a significantly better overall survival.

Clival metastasis of renal clear cell carcinoma: Case report and literature review

The clivus is an atypical metastatic site for renal clear cell carcinoma (RCCC). Here we report a 54 year old man with acute cavernous sinus syndrome. Brain magnetic resonance imaging identified a clival-based lesion with associated bony erosion. The patient underwent endoscopic endonasal biopsy and partial resection of the clival mass. Because histologic examination of the resected specimen resulted in a diagnosis of RCCC, contrast-enhanced computed tomography scan of the abdomen was performed and showed an enhanced left renal mass. The patient subsequently underwent laparoscopic left radical nephrectomy and gamma knife was planned for the residual clival lesion. We also retrospectively reviewed available published reports on clival metastases, specifically those from RCCC, since 1990.

Posttreatment surveillance for sinonasal malignancy

PURPOSE OF REVIEW

Sinonasal neoplasms have a high rate of recurrence following treatment, and clinicians utilize a variety of surveillance techniques. Generally, surveillance modality and frequency of follow-up are determined by the guidelines for head and neck cancer as a broad category. However, recent studies have demonstrated that a more tailored approach to follow-up may be necessary.

RECENT FINDINGS

Endoscopy has low sensitivity in recurrence detection, especially in the asymptomatic patient. However, it is able to identify superficial recurrences that may be more amenable to repeat resection. Conversely, imaging [computed tomography (CT), MRI, and F-fluorodeoxyglucose-PET/CT] is useful in ruling out disease, but the inflammatory environment of the posttreatment sinonasal cavity leads to a high number of false positives. This is especially notable in PET/CT, which has worse specificity and positive predictive value in sinonasal malignancy than in head and neck malignancy overall, especially in the early posttreatment period. Little data are available on optimal timing and duration of follow-up, but tumor histology and aggressiveness should be considered when choosing a surveillance approach.

SUMMARY

Sinonasal malignancy surveillance strategies may warrant modifications of current protocols used for head and neck malignancy. This is due to a number of factors, including a greater diversity of sinonasal disorder and increased duration of posttreatment sinonasal inflammation. Clinicians should be aware of the performance parameters of commonly used surveillance techniques and adjust follow-up regimens based on this information.

Primitive Squamous Cell Carcinoma of Pterygopalatine Fossa

Primitive tumors of pterygopalatine fossa (PPF) are often benign tumors or extension of a malignant sinonasal tract. Primitive tumors may rarely occur in PPF.The authors present a 71-year-old woman with a 6-month history of left cranial nerve palsy. Magnetic resonance imaging and positron emission tomography-computed tomography showed an enhancing isolated lesion at the PPF. A transmaxillary biopsy was performed, leading to diagnosis of primitive squamous cell carcinoma. The patient underwent radiotherapy treatment.Primitive tumors of PPF are rare and diagnosis may be difficult. Endoscopic access for diagnosis can be performed. Squamous cell carcinoma occurring in PPF is associated with poor prognosis.

Plexus and peripheral nerve metastasis

Cancer in the form of solid tumors, leukemia, and lymphoma can infiltrate and metastasize to the peripheral nervous system, including the cranial nerves, nerve roots, cervical, brachial and lumbosacral plexuses, and, rarely, the peripheral nerves. This review discusses the presentation, diagnostic evaluation, and treatment options for metastatic lesions to these components of the peripheral nervous system and is organized based on the anatomic distribution. As skull base metastases (also discussed in Chapter 14) result in cranial neuropathies, these will be covered in detail, as well as cancers that directly infiltrate the cranial nerves. Particular emphasis is placed on the clinical, imaging, and electrodiagnostic features that differentiate neoplastic plexopathies from radiation-induced plexopathies. Neurolymphomatosis, in which malignant lymphocytes invade the cranial nerves, nerve roots, brachial and lumbosacral plexuses, and peripheral nerves, is a rare manifestation of lymphoma and leukemia. Diagnoses of neurolymphomatosis are often missed or delayed given its varied presentations, resulting in poorer outcomes. Thus this disease will also be discussed in depth.

18FDG PET/CT in Routine Surveillance of Asymptomatic Patients following Treatment of Sinonasal Neoplasms

Objective Sinonasal neoplasms have a high rate of recurrence following treatment, and current guidelines support the use of a variety of surveillance techniques. Recent work demonstrates that performance parameters of surveillance modalities may differ with sinonasal tumors in particular when compared with head and neck tumors overall. This study aims to characterize the value of ¹⁸fluorodeoxyglucose (¹⁸FDG) positron emission tomography/computed tomography (PET/CT) as a screening tool in asymptomatic patients. Study Design Retrospective cohort study. Setting Hospital of the University of Pennsylvania and Pennsylvania hospital. Methods Records of asymptomatic patients without suspicious endoscopy or suspicious imaging other than PET during the first 3 years following definitive treatment for sinonasal malignancy were screened and analyzed for inclusion in the cohort. Disease recurrence was determined by biopsy following suspicious PET evaluation. Results PET/CT scans (n = 111) were performed for 45 disease-free asymptomatic patients with no evidence of disease on endoscopy, and 6.3% were suspicious and prompted biopsy during this period, revealing 3 cases of disease recurrence. Overall specificity for PET/CT alone was 96.3% (95% CI, 90.7%-99.0%), with a negative predictive value of 99% (95% CI, 94.8%-100%). All recurrences were detected between 7 and 12 months, and all patients with true recurrence diagnosed by PET/CT had extrasinonasal involvement of tumor at the time of surgery. Conclusion We examined performance parameters of ¹⁸FDG PET/CT in asymptomatic patients with no evidence of disease on endoscopy during the posttreatment period for sinonasal malignancy. The ability of PET/CT to detect recurrences that may be missed by structural imaging or endoscopy makes it a valuable tool for clinicians.

Clival Metastasis of a Duodenal Adenocarcinoma: A Case Report and Literature Review

BACKGROUND

Clival metastases of adenocarcinomas are exceptionally rare tumors, especially when they arise from the small intestine. We present the first, to our knowledge, report of a metastasis of a duodenal adenocarcinoma to the clivus. We also present a systematic review detailing metastasis to the clivus.

METHODS

Studies were identified using the search terms "clival metastasis," "skull base metastasis," and "clivus" in PubMed. We collected the following information: histopathology of the primary tumor, symptoms, history, treatment, and follow-up.

RESULTS

A comprehensive review of the literature yielded 56 cases. Patients developed the first symptoms of clival metastasis at a mean age of 58 years. The most common primary neoplasms originated from the prostate, kidney, or liver. Most patients presented with an isolated sixth nerve palsy or diplopia. The time interval from diagnosis of the primary tumor to symptomatic presentation of clival metastasis ranged from 2 months to 33 years. Sixteen patients initially presented with symptoms of clival metastasis without a previously diagnosed primary tumor. Survival data were available for 35 patients, of which 63% died within a range of 2 days to 31 months after initial presentation.

CONCLUSIONS

Most primary neoplasms originated from the prostate, kidney, and liver, which differ from previous reports on skull base metastases. Abducens nerve palsy is often the first presentation of clival metastasis. Clival metastasis from duodenal carcinoma, although very rare, should be considered in the differential diagnosis of bony lesions of the clivus in a patient with a history of duodenal adenocarcinoma.

Temporal patterns of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography sinonasal uptake after treatment of sinonasal malignancy

BACKGROUND

Current guidelines have identified 10 to 12 weeks posttreatment as the ideal time-point for improved diagnostic accuracy of positron emission tomography/computed tomography (PET/CT) for deep tissue sites of the head and neck. After treatment, the sinonasal skull base is predisposed to prolonged inflammation that may render this time-point inappropriate for initial posttreatment imaging surveillance for sinonasal malignancies. The purpose of this study is to evaluate temporal trends in ¹⁸ F-fluorodeoxyglucose (¹⁸ FDG) sinonasal uptake after treatment for sinonasal malignancies to better elucidate the optimal time-point for initial PET/CT posttreatment evaluation in this patient population.

METHODS

A retrospective analysis of all successfully treated and non-locally recurrent sinonasal malignancies over a 15-year study period (2000 to 2015) was performed at our institution. Posttreatment ¹⁸ FDG PET/CT standardized uptake value data were collected and compared between various time-points (2 to 4 months, 5 to 12 months, 5 to 24 months, and 13 to 24 months) using an independent-samples t test.

RESULTS

A statistically significant difference was noted between the posttreatment time windows 2 to 4 and 5 to 12 months (p = 0.048) as well as 2 to 4 and 5 to 24 months (p = 0.02). A trend toward significance was seen when comparing 2 to 4 and 13 to 24 months (p = 0.083).

CONCLUSION

Our analysis of PET/CT in patients previously treated for sinonasal malignancy suggests that the posttreatment sinonasal skull base is characterized by a prolonged period of hypermetabolism that endures beyond the period previously described for deep tissue sites of the head and neck. These findings prompt a reevaluation of the previously described 10- to 12-week cutoff point for initial posttreatment PET/CT for head and neck squamous cell carcinoma as applied to sinonasal malignancies.

Positive and Negative Predictive Value of PET-CT in Skull Base Lesions: Case Series and Systematic Literature Review

Objectives To study positive (PPV) and negative predictive value (NPV) of positron emission tomography with computed tomography (PET-CT) scans in determining malignancy in skull base lesions and perform a systematic literature review for optimal PET-CT interpretation. Design Retrospective case series and systematic literature review of the current English literature. Setting Tertiary referral academic medical center. Participants All patients with skull base lesions that underwent PET-CT and tissue biopsy from 2010 to 2013. Main Outcome Measures PPV and NPV of radiologist's report and standardized uptake value (SUV) cutoff of 2.5 and 3, biopsy with pathologic interpretation, clinical follow-up. Results A total of 31 PET-CT scans of 16 patients were studied; 10 PET-CT were performed upfront for diagnostic purposes and 21 were post-treatment surveillance scans. The PPV of radiologist's interpretation, SUV cutoff of 2.5, and SUV cutoff of 3.0 was 80%, 60%, and 68.4%, with a NPV of 100%, 83.3%, and 75%, respectively. Literature search yielded 500 abstracts; 7 studies met inclusion criteria for detailed review. No consensus or guidelines for optimal SUV cutoff value was found. Conclusions PET-CT based on SUV cutoff criteria alone has high NPV but low PPV in determining malignancy in skull base lesions. Interpretation by a radiologist experienced in nuclear medicine and neuroradiology, synthesizing clinical, SUV, and radiologic data are of superior value.

Surgical Techniques for Sinonasal Malignancies

Sinonasal malignancies are a rare subset of malignancies of the upper aerodigestive tract which had been traditionally approached via open techniques. This article primarily addresses a paradigm shift in endoscopic endonasal oncological resection utilizing principles of tumor disassembly and negative margins. The surgical steps to these endoscopic techniques are detailed, emphasizing principles of sound oncological resection.

Analysis of failure in patients with adenoid cystic carcinoma of the head and neck. An international collaborative study

BACKGROUND

Adenoid cystic carcinoma (ACC) is a locally aggressive tumor with a high prevalence of distant metastases. The purpose of this study was to identify independent predictors of outcome and to characterize the patterns of failure.

METHODS

An international retrospective review was conducted of 489 patients with ACC treated between 1985 and 2011 in 9 cancer centers worldwide.

RESULTS

Five-year overall-survival (OS), disease-specific survival (DSS), and disease-free survival (DFS) were 76%, 80%, and 68%, respectively. Independent predictors of OS and DSS were: age, site, N classification, and presence of distant metastases. N classification, age, and bone invasion were associated with DFS on multivariate analysis. Age, tumor site, orbital invasion, and N classification were independent predictors of distant metastases.

CONCLUSION

The clinical course of ACC is slow but persistent. Paranasal sinus origin is associated with the lowest distant metastases rate but with the poorest outcome. These prognostic estimates should be considered when tailoring treatment for patients with ACC.

Skull metastasis from intrahepatic cholangiocarcinoma: report of 3 cases and review of the literature

Skull metastases occur in patients with various malignancies; however, those resulting from intrahepatic cholangiocarcinoma (ICC) have been rarely reported. In our hospital, 324 patients were diagnosed with metastatic brain or skull tumors from June 1969 to June 2011, but only 3 of them (0.9%) developed skull metastases from ICC. We report the case of 3 patients with skull metastases from ICC. A combination of computed tomography (CT), contrast-enhanced magnetic resonance imaging (MRI), 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and methionine-PET were used for imaging. Sites of tumors were the lateral left orbit and right parietal bone in case 1, the left parietal bone, left temporal bone, and lateral left orbit in case 2, the right petrous bone, right occipital bone, and upper cervical vertebra in case 3. The metastases were confirmed to have originated from ICC by biopsy in two of the cases and diagnosed by MRI and FDG-PET in case 2. Radiosurgery and radiotherapy had positive effects on symptom improvement and cosmetic problems.

18-FDG-PET in the initial staging of sinonasal malignancy

OBJECTIVES/HYPOTHESIS

The utility of fluorine-18 fluorodeoxyglucose-positron emission tomography (PET) has been gradually defined for most head and neck cancers, However, its utility in the initial diagnosis of sinonasal malignancy has not been extensively studied. The aim of this study was to determine if PET scanning accurately diagnoses and stages malignant sinonasal lesions and if maximum standard uptake value (SUV max) correlates with clinically advanced disease.

STUDY DESIGN

Retrospective chart review.

METHODS

There were 51 patients with sinonasal malignancy who underwent diagnostic whole body PET or PET-computed tomography scans that were analyzed for patient and disease characteristics, SUV max, and staging.

RESULTS

Of the 51 patients, 48 scans were positive at the primary site, with a sensitivity of 94%. Four patients were found to have intensely avid uptake, in which the numerical SUV max was not documented, and three patients did not have any uptake in the region of their tumor. Mean SUV max at the primary site was 16.1 (range, 3.1-59). Metastasis was detected in 31% (16/51) of the patients. There was a potential positive correlation between SUV max at the primary site and detection of metastasis on univariate analysis (r = 0.19, P = .09), but on multivariate analysis, SUV max was not found to correlate with T staging or metastasis.

CONCLUSIONS

For diagnosis of sinonasal malignancy, PET scans have a high sensitivity, although false negatives occurred in 6% of cases. PET scanning detected metastasis in 31% of patients, but SUV max did not function as a marker for clinically advanced disease. The role of diagnostic PET for sinonasal malignancy is currently limited to cases with a high suspicion of metastatic disease.

Surgical approaches to resection of anterior skull base and paranasal sinuses tumors

Malignant tumours of the sinonasal tract comprise approximately 3% of the malignancies that arise in the upper aerodigestive tract. Approximately 10% of tumours that arise in the sinonasal tract originate in the ethmoid and/or frontal sinuses, and are likely to involve the anterior cranial base. The route of spread of tumours originating in the anterior skull base and paranasal sinuses is determined by the complex anatomy of the craniomaxillofacial compartments. These tumours may invade laterally into the orbit and middle fossa, inferiorly into the maxillary antrum and palate, posteriorly into the nasopharynx and pterygopalatine fossa, and superiorly into the cavernous sinus and brain. Recent improvements in endoscopic technology now allow the resection of the majority of benign neoplasms and some early malignant tumours with minor dural involvement. For advanced-stage malignant tumours and benign tumours with frontal bone involvement, the classical open approaches remain viable surgical techniques. In this paper, we review the open surgical resection approaches used for resections in the craniomaxillofacial area.

Evidence-based guideline recommendations on the use of positron emission tomography imaging in head and neck cancer

AIMS

To provide evidence-based practice guideline recommendations on the use of fluoro-2-deoxy-D-glucose positron emission tomography (PET) for diagnosis, staging and assessing treatment response, restaging or recurrence of head and neck cancer.

MATERIALS AND METHODS

A systematic review by Facey et al. (Health Technology Assessment 2007;11(44):iii-iv, xi-267) was used as the evidence base for recommendation development. As the review was limited to August 2005, the evidence base was updated to July 2011 using the same search strategies for MEDLINE and EMBASE used in the original review. The authors of the current systematic review drafted recommendations, which were reviewed, adapted and accepted by consensus by the Ontario provincial Head and Neck Disease Site Group and a special meeting of clinical experts.

RESULTS

The results of the Facey et al. review for head and neck cancer included five other systematic reviews and 31 primary studies. The 2005 to 2011 update search included four additional systematic reviews and 53 primary studies. Recommendations were developed based on this evidence and accepted by consensus.

CONCLUSIONS

PET is recommended in the M and bilateral nodal staging of all patients with head and neck squamous cell carcinoma where conventional imaging is equivocal, or where treatment may be significantly modified. PET is recommended in all patients after conventional imaging and in addition to, or prior to, diagnostic panendoscopy where the primary site is unknown. PET is recommended for the staging and assessment of recurrence of patients with nasopharyngeal carcinoma if conventional imaging is equivocal. PET is recommended for restaging patients who are being considered for major salvage treatment, including neck dissection.

Combination of pet imaging with viral vectors for identification of cancer metastases

There are three main ways for dissemination of solid tumors: direct invasion, lymphatic spread and hematogenic spread. The presence of metastases is the most significant factor in predicting prognosis and therefore evidence of metastases will influence decision-making regarding treatment. Conventional imaging techniques are limited in the evaluation and localization of metastases due to their restricted ability to identify subcentimeter neoplastic disease. Hence, there is a need for an effective noninvasive modality that can accurately identify occult metastases in cancer patients. One such method is the combination of positron emission tomography (PET) with vectors designed for delivery of reporter genes into target cells. Vectors expressing the herpes simplex virus-1 thymidine kinase (HSV1-tk) reporter system have recently been shown to allow localization of micrometastases in animal models of cancer using non invasive imaging. Combination of HSV1-tk and PET imaging is based on the virtues of vectors which can carry and selectively express the HSV1-tk reporter gene in a variety of cancer cells but not in normal tissue. A radioactive tracer which is applied systemically is phosphorylated by the HSV1-tk enzyme, and as a consequence, the tracer accumulates in proportion to the level of HSV1-tk expression which can be imaged by PET. In this paper we review the recent developments in molecular imaging of micrometastases using replication-competent viral or nonviral vectors carrying the HSV1-tk gene using PET imaging. These diagnostic paradigms introduce an advantageous new concept in noninvasive molecular imaging with the potential benefits for improving patient care by providing guidance for therapy to patients with risk for metastases.

Role of positron emission tomography in management of sinonasal neoplasms--a single institution's experience

OBJECTIVE

The objective of the study is to examine the utility of positron emission tomography (PET) for staging and restaging after treatment of paranasal sinus carcinomas.

STUDY DESIGN

Retrospective data review was done.

SUBJECTS AND METHODS

Patients selected underwent PET for sinonasal neoplasms from 2003 to 2008 at a tertiary care referral center.

RESULTS

Seventy-seven scans were reviewed from 31 patients. The pathologies included olfactory neuroblastoma (n = 9), squamous cell carcinoma (n = 6), sinonasal undifferentiated carcinoma (n = 6), sinonasal melanoma (n = 6), and minor salivary gland carcinomas (n = 4). The positive predictive value of studies performed for restaging at the primary, neck, and distant sites were 56%, 54%, and 63%; negative predictive values were 93%, 100%, and 98%, respectively. During restaging, 32% of patients were accurately upstaged secondary to neck or distant site involvement.

CONCLUSION

Positron emission tomography serves as a useful adjunct to conventional imaging in the management of sinonasal malignancies. Negative studies are effective in predicting absence of disease as seen in the consistently high-negative predictive values. Positive studies need to be viewed cautiously given the high rate of false-positive studies. When viewed in conjunction with clinical examination, endoscopic assessment, and focused biopsies, they may effectively result in a more accurate assessment of the extent of disease.

FDG-PET/CT in cancers of the head and neck: what is the definition of whole body scanning?

PURPOSE

The role of 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET) was studied in a variety of cancers, including head and neck squamous cell carcinomas (HNSCC) and nasopharyngeal carcinomas (NPC), with several presentations indicating that for these clinical entities a "whole-body" (i.e., eyes to thighs) may yield little additional information. Therefore, we were prompted to review our experience with PET/computed tomography (CT) in the management of patients with HNSCC and NPC.

MATERIALS AND METHODS

This is a retrospective study of 133 patients with HNSCC, 23-90 years old (average: 58.2 ± 12.7) and 26 patients with NPC, ages 16-75 (average: 47.3 ± 17.1), who had whole body PET/CT at our institution from Jan 2003 to Nov 2006. Reinterpretation of the imaging studies for accuracy and data analysis from medical records was performed. Lesions identified on PET/CT below the level of the adrenal glands were recorded and tabulated.

RESULTS

Lesions were identified below the adrenal glands in seven patients (5.2%) with HNSCC. These included hepatic and osseous metastases from HNSCC in two patients (1.5%), a new renal cancer (0.75%), a new pancreatic cancer (0.75%), a new colon cancer (0.75%) and findings proven benign on follow-up (focal colon uptake in one patient and an inflammatory inguinal lymph node in another patient; 1.5%). Lesions were identified below the adrenal glands in three patients (11.5%) with NPC. These included osseous metastases from NPC in two patients (7.7%) and findings proven benign on follow-up (focal colon uptake in one patient; 3.84%).

CONCLUSION

This study suggests that whole body PET/CT imaging in HNSCC has a relatively low yield (3%, 95% CI: 1.33-8.42) of significant findings below the level of the adrenal glands. Therefore, implementing a more limited protocol (through the level of adrenal glands), especially in low-risk cases of HNSCC, may be considered. However, whole body PET/CT imaging in NPC may have a significant yield (7.7%, 95% CI: 1.02-25.26) of medically relevant findings below the level of the adrenal glands. Thus, the whole body (i.e., vertex to thighs) PET/CT scan of NPC patients appears to be the appropriate imaging protocol for this population. This recommendation requires further evaluation and validation in larger prospective studies.

Stereotactic radiotherapy using Novalis for skull base metastases developing with cranial nerve symptoms

Skull base metastases are challenging situations because they often involve critical structures such as cranial nerves. We evaluated the role of stereotactic radiotherapy (SRT) which can give high doses to the tumors sparing normal structures. We treated 11 cases of skull base metastases from other visceral carcinomas. They had neurological symptoms due to cranial nerve involvement including optic nerve (3 patients), oculomotor (3), trigeminal (6), abducens (1), facial (4), acoustic (1), and lower cranial nerves (1). The interval between the onset of cranial nerve symptoms and Novalis SRT was 1 week to 7 months. Eleven tumors of 8-112 ml in volume were treated by Novalis SRT with 30-50 Gy in 10-14 fractions. The tumors were covered by 90-95% isodose. Imaging and clinical follow-up has been obtained in all 11 patients for 5-36 months after SRT. Seven patients among 11 died from primary carcinoma or other visceral metastases 9-36 months after Novalis SRT. All 11 metastatic tumors were locally controlled until the end of the follow-up time or patient death, though retreatment for re-growth was done in 1 patient. In 10 of 11 patients, cranial nerve deficits were improved completely or partially. In some patients, the cranial nerve symptoms were relieved even during the period of fractionated SRT. Novalis SRT is thought to be safe and effective treatment for skull base metastases with involvement of cranial nerves and it may improve cranial nerve symptoms quickly.

Imaging of lymph node micrometastases using an oncolytic herpes virus and [F]FEAU PET

Background

In patients with melanoma, knowledge of regional lymph node status provides important information on outlook. Since lymph node status can influence treatment, surgery for sentinel lymph node (SLN) biopsy became a standard staging procedure for these patients. Current imaging modalities have a limited sensitivity for detection of micrometastases in lymph nodes and, therefore, there is a need for a better technique that can accurately identify occult SLN metastases.

Methodology/Principal Findings

B16-F10 murine melanoma cells were infected with replication-competent herpes simplex virus (HSV) NV1023. The presence of tumor-targeting and reporter-expressing virus was assessed by [¹⁸F]-2′-fluoro-2′-deoxy-1-β-D-β-arabinofuranosyl-5-ethyluracil ([¹⁸F]FEAU) positron emission tomography (PET) and confirmed by histochemical assays. An animal foot pad model of melanoma lymph node metastasis was established. Mice received intratumoral injections of NV1023, and 48 hours later were imaged after i.v. injection of [¹⁸F]FEAU. NV1023 successfully infected and provided high levels of lacZ transgene expression in melanoma cells. Intratumoral injection of NV1023 resulted in viral trafficking to melanoma cells that had metastasized to popliteal and inguinal lymph nodes. Presence of virus-infected tumor cells was successfully imaged with [¹⁸F]FEAU-PET, that identified 8 out of 8 tumor-positive nodes. There was no overlap between radioactivity levels (lymph node to surrounding tissue ratio) of tumor-positive and tumor-negative lymph nodes.

Conclusion/Significance

A new approach for imaging SLN metastases using NV1023 and [¹⁸F]FEAU-PET was successful in a murine model. Similar studies could be translated to the clinic and improve the staging and management of patients with melanoma.

PET Imaging of Skull Base Neoplasms

The utility of 18-F-fluorodeoxyglucose-positron emission tomography (PET) and PET/CT for the evaluation of skull base tumors is incompletely investigated, as a limited number of studies specifically focus on this region with regard to PET imaging. Several patterns can be ascertained, however, by synthesizing the data from various published reports and cases of primary skull base malignancies, as well as head and neck malignancies that extend secondarily to the skull base, including nasopharyngeal carcinoma, nasal cavity and paranasal sinus tumors, parotid cancers, and orbital tumors.

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.