Head and neck cancer: how imaging predicts treatment outcome

Imaging for Laryngeal Malignancies: Guidelines for Clinicians

Radiology has always been an important component in the evaluation of patients with head and neck cancers. Images that are appropriately acquired and systematically interpreted provide comprehensive information on local, regional, and distant disease extent. This impacts treatment decisions for primary or recurrent disease, and aids in prognostication and patient counselling. The recent significant advances in technology and instrumentation for treatment of head neck cancers have taken place in parallel with an increasing sophistication in radiodiagnostic systems. This is especially true for laryngeal neoplasms where there is now greater focus on functional outcomes and personalised treatment, thus expanding the scope and value of imaging.

PURPOSE

To formulate evidence-based guidelines on imaging for cancers of the larynx, from diagnosis and staging to monitoring of disease control after completion of treatment.

METHODS AND MATERIALS

A multidisciplinary analysis of current guidelines and published studies on the topic was performed.

RESULTS

On the basis of evidence gathered, guidelines were drawn up; optimal suggestions were included for low-resource situations.

CONCLUSION

These guidelines are intended as an aid to all clinicians dealing with patients of laryngeal cancers. It is hoped that these will be instrumental in facilitating patient care, and in improving outcomes.

Comparison of narrow-band imaging with autofluorescence imaging for endoscopic detection of squamous cell carcinoma of the tonsil

PURPOSE

Early detection of mucosal neoplastic lesions is crucial for a patient's prognosis. This has led to the development of effective optical endoscopic diagnostic methods such as narrow band imaging (NBI) and autofluorescence (AFI). Independent of each other, both of these methods were proven useful in the detection of mucosal neoplasias. There are limited reported data comparing both methods for oropharyngeal cancer diagnostics. The aim of the study was to compare NBI and AFI endoscopic visualization of signs in identifying tonsillar squamous cell carcinoma (SCC) and assessing its extent and to determine whether the score was related to the evaluator's experience.

METHODS

Patients with tonsillar SCC underwent endoscopic pharyngeal examination using NBI and AFI. Fiftyseven video sequences of examinations of lesions proven to be SCC were evaluated by three reviewers. The accuracy of determination of lesion extent and visualization of its endoscopic signs of malignancy were evaluated.

RESULTS

Endoscopic visualization of tumour spread was significantly better using AFI than NBI (p = 0.0003). No significant difference was found between NBI and AFI in the visualization of endoscopic malignancy determining signs (p = 0.1405). No significant difference was found among the three reviewers in the visualization of tumour spread and for identifying malignancy-determining signs in NBI endoscopy or AFI endoscopy.

CONCLUSIONS

The results show that AFI obtained better results for assessing the extent of tonsillar cancers than NBI. Both methods were proven to be equal in the visualization of endoscopic malignancy-determining signs. Both are useful even for less experienced evaluators.

Echo planar imaging with compressed sensitivity encoding (EPICS): Usefulness for head and neck diffusion-weighted MRI

PURPOSE

To evaluate diffusion-weighted imaging (DWI) using echo planar imaging (EPI) with compressed SENSE (EPICS) of the head and neck magnetic resonance imaging (MRI).

METHOD

We retrospectively observed 32 patients who underwent head and neck DWI according to either the conventional method (SENSE, reduction factor = 2), fast scanning method (SENSE, reduction factor = 4), or fast scanning method with EPICS (EPICS, reduction factor = 4). For quantitative analysis, contrast-to-noise-ratio (CNR), apparent diffusion coefficient (ADC) values, geometric distortion, and coefficient of variations (CV) were measured and compared. For qualitative analysis, all images were independently and blindly evaluated by two board-certified radiologists.

RESULTS

EPICS revealed the higher CNR between all location compared to those of SENSE with reduction factor = 4. Distortion in the anterior-posterior direction was significantly lower on EPICS than on the conventional scan (p = 0.02). A comparison between the ADC values of the EPICS and conventional scan revealed no significant differences. The CV was significantly lower for EPICS than the conventional scan [DWI: 0.22 (IQR: 0.15-0.30) vs 0.32 (IQR: 0.24-0.40), p = 0.02].

CONCLUSIONS

Compressed SENSE combined with the high acceleration factor can improve image quality, homogeneity, and distortion in the head and neck DWI maintaining ADC values and the scan time duration.

Implications of limited exolaryngeal disease and cricoarytenoid joint involvement in organ conservation protocols for laryngopharyngeal cancers: Results from a prospective study

BACKGROUND

To identify clinicoradiological factors that determine functional outcomes in laryngopharyngeal cancers treated with chemoradiotherapy.

METHODS

One hundred patients of locally advanced laryngopharyngeal cancers who were treated with chemoradiotherapy were accrued in this prospective study. The coprimary endpoint of the study was local control (LC) and functional larynx preservation survival (FLPS).

RESULTS

The median follow-up was 39 months. Thirty-nine patients had a local failure of which 17 underwent a salvage laryngectomy. A dysfunctional larynx with clinic-radiologically disease was seen in only 1 patient. Factors significant for LC were thyroid cartilage erosion/lysis and cricoarytenoid joint involvement. Within the T4a subset, patients with exolaryngeal disease through the soft tissue framework had significantly better LC and FLPS than those with cartilage erosion/lysis.

CONCLUSIONS

Patients with limited exolaryngeal disease through the soft-tissue framework can be considered for functional organ preservation, while those with thyroid cartilage involvement and cricoarytenoid joint involvement are not suitable.

Evaluating Imaging Biomarkers of Acquired Resistance to Targeted EGFR Therapy in Xenograft Models of Human Head and Neck Squamous Cell Carcinoma

Background: Overexpression of EGFR is a negative prognostic factor in head and neck squamous cell carcinoma (HNSCC). Patients with HNSCC who respond to EGFR-targeted tyrosine kinase inhibitors (TKIs) eventually develop acquired resistance. Strategies to identify HNSCC patients likely to benefit from EGFR-targeted therapies, together with biomarkers of treatment response, would have clinical value. Methods: Functional MRI and 18F-FDG PET were used to visualize and quantify imaging biomarkers associated with drug response within size-matched EGFR TKI-resistant CAL 27 (CALR) and sensitive (CALS) HNSCC xenografts in vivo, and pathological correlates sought. Results: Intrinsic susceptibility, oxygen-enhanced and dynamic contrast-enhanced MRI revealed significantly slower baseline R 2 ∗ , lower hyperoxia-induced Δ R 2 ∗ and volume transfer constant Ktrans in the CALR tumors which were associated with significantly lower Hoechst 33342 uptake and greater pimonidazole-adduct formation. There was no difference in oxygen-induced ΔR1 or water diffusivity between the CALR and CALS xenografts. PET revealed significantly higher relative uptake of 18F-FDG in the CALR cohort, which was associated with significantly greater Glut-1 expression. Conclusions: CALR xenografts established from HNSCC cells resistant to EGFR TKIs are more hypoxic, poorly perfused and glycolytic than sensitive CALS tumors. MRI combined with PET can be used to non-invasively assess HNSCC response/resistance to EGFR inhibition.

[Imaging for surgical planning : Tumor surgery including reconstructive procedures]

Alongside clinical investigation, imaging is an important diagnostic modality for guiding treatment decisions and particularly for surgical planning in head and neck cancer. The significance and type of imaging depends on localization of the primary tumor. Beside the primary tumor, each imaging procedure must also include the lymph nodes, in order to develop an overall concept of surgical treatment. In addition to the superficial growth of a tumor, it is of utmost importance that its infiltration also be detected by imaging, in order to define the extent of tumor resection and identify potentially necessary reconstructive procedures. The type of imaging needed to understand tumor localization and size, e.g., CT or MRI, depends on the region. In some cases the methods are complementary.

Tumour volumes: Predictors of early treatment response in locally advanced head and neck cancers treated with definitive chemoradiation

AIM

To analyse and predict early response 3 months post definitive chemoradiation (CCRT) utilising tumour volume (TV) measurement in locally advanced head and neck cancers (LAHNC).

BACKGROUND

LAHNC are 3-dimentional lesions. The largest diameter of these tumours measured for T-classification may not necessarily reflect the true tumour dimensions. TV accurately reflects the tumour burden because it is a measurement of tumour burden in all three dimensions.

MATERIALS AND METHODS

It is a single institutional prospective study including 101 patients with LAHNC treated with definitive CCRT. TV data noted were primary tumour volume (PTV), total nodal volume (TNV) and total tumour volume (TTV). Response evaluation was done at 3 months after the completion of definitive CCRT and patients were categorised either having achieved complete response (CR) or residual disease.

RESULTS

Patients who had not achieved CR were found to have larger TV compared with those who had achieved CR. There were significant inverse correlations between PTV and response (median 16.37 cm(3) vs. 45.2 cm(3); p = 0.001), and between TTV and response (median 36.14 cm(3) vs. 66.06 cm(3); p < 0.001). Receiver operating characteristic (ROC) analysis identified an "optimal cut-off" value of 41 cm(3) for PTV and 42 cm(3) for TTV above and below which the magnitude of difference in response was the greatest.

CONCLUSIONS

If response evaluation 3 months post CCRT is to be predicted it is simply not enough to measure the largest single dimension of the tumour. TV seems to be a better and more accurate reflection of the true total tumour burden or extent of the disease.

Head and neck cancers: a clinico-pathological profile and management challenges in a resource-limited setting

BACKGROUND

Head and neck cancer (HNC) is one of the most common cancers worldwide and its incidence is reported to be increasing in resource-limited countries. There is a paucity of published data regarding head and neck cancers in Tanzania, and Bugando Medical Centre in particular. This study describes the clinicopathological profile of HNC in our local setting and highlights the challenges in the management of this disease.

METHODS

This was a retrospective study of histopathologically confirmed cases of head and neck cancers treated at Bugando Medical Center between January 2009 and December 2013.

RESULTS

A total of 346 patients (M:F = 2.1:1) were studied representing 9.5 % of all malignancies. The median age of patients was 42 years. Cigarette smoking (76.6 %) and heavy alcohol consumption (69.9 %) were the most frequently identified risk factors for head and neck cancer. The majority of patients (95.9 %) presented late with advanced stages. Twenty-five (7.2 %) patients were HIV positive with a median CD4+ count of 244 cells/μl. The oral cavity (37.3 %) was the most frequent anatomical site affected. The most common histopathological type was carcinomas (59.6 %) of which 75.7 % were squamous cell carcinoma. A total of 196 (56.6 %) patients underwent surgical procedures for HNC. Radiotherapy and chemotherapy was reported in 9.5 and 16.8 % of patients, respectively. Only 2 (0.6 %) patients received chemo-radiation therapy. The mortality rate was 24.4 %. The overall 5-year survival rate (5-YSR) was 20.6 %. The predictors of overall 5-YSR were age of patient at diagnosis, stage of disease, extent of lymph node involvement, HIV seropositivity and CD4+ count <200 cells/μl (P < 0.001). Local recurrence was reported in 22 (23.4 %) patients and this was significantly associated with positive resection margins, stage of the tumor and presence of metastasis at diagnosis and non-adherence to adjuvant therapy (P < 0.001).

CONCLUSION

Head and neck cancers are not uncommon at Bugando Medical Centre and show a trend towards a relative young age at diagnosis and the majority of patients present late with advanced stage cancer. Therefore, public enlightenment, early diagnosis, and effective cost-effective treatment and follow-up are urgently needed to improve outcomes of these patients in our environment.

Intravoxel incoherent motion imaging kinetics during chemoradiotherapy for human papillomavirus-associated squamous cell carcinoma of the oropharynx: preliminary results from a prospective pilot study

This study aims to identify the temporal kinetics of intravoxel incoherent motion (IVIM) MRI in patients with human papillomavirus-associated (HPV+) oropharyngeal squamous cell carcinoma. Patients were enrolled under an Institutional Review Board (IRB)-approved protocol as part of an ongoing prospective clinical trial. All patients underwent two MRI studies: a baseline scan before chemoradiotherapy and a mid-treatment scan 3-4 weeks after treatment initiation. Parametric maps representing pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f) and apparent diffusion coefficient (ADC) were generated. The Mann-Whitney U-test was used to assess the temporal variation of IVIM metrics. Bayesian quadratic discriminant analysis (QDA) was used to evaluate the extent to which mid-treatment changes in IVIM metrics could be combined to predict sites that would achieve complete response (CR) in multivariate analysis. Thirty-one patients were included in the final analysis with 59 lesions. Pretreatment ADC and D values of the CR lesions (n = 19) were significantly lower than those of non-CR lesions (n = 33). Mid-treatment ADC, D and f values were significantly higher (p < 0.0001) than pretreatment values for all lesions. Each increase in normalized ΔADC of size 0.1 yielded a 1.45-fold increase in the odds of CR (p < 0.0003), each increase in normalized ΔD of size 0.1 yielded a 1.53-fold increase in the odds of CR (p < 0.0002), and each unit increase in Δf yielded a 2.29-fold increase in the odds of CR (p < 0.02). Combined ΔD and ΔADC were integrated into a multivariate prediction model and attained an AUC of 0.87 (95% confidence interval: 0.79, 0.96), as well as a sensitivity of 0.63, specificity of 0.85 and accuracy of 0.78, under leave-one-out cross-validation. In conclusion, IVIM is feasible and potentially useful in the prediction and assessment of the early response of HPV+ oropharyngeal squamous cell carcinoma to chemoradiotherapy.

A prognostic volumetric threshold of gross tumor volume in head and neck cancer patients treated with radiotherapy

OBJECTIVES

To determine the prognostic utility of a volumetric threshold for gross tumor volume (GTV) of the primary and nodal disease when accounting for the TNM classification in head and neck cancer (HNC) patients treated with definitive radiotherapy (RT).

MATERIALS AND METHODS

From 2004 to 2011, 79 HNC patients were treated to a median dose of 70 Gy, using intensity-modulated RT in 78.5% and 3-dimensional conformal RT in 21.5% with 83.5% receiving concurrent chemotherapy. Primary (GTV-P) and nodal (GTV-N) GTVs were derived from computed tomography (CT)-based contours for RT planning, of which 89.7% were aided by positron emission tomography-computed tomography. Local (LC), nodal (NC), distant (DC) control, and overall survival (OS) were assessed using the Kaplan-Meier product-limit method.

RESULTS

With a median follow-up of 27.1 months GTV-P, threshold of <32.9 mL (mean value) compared with ≥32.9 mL, correlated with improved 2-year LC (96.2% vs. 63.9%, P<0.0001), NC (100% vs. 69.2%, P<0.0001), DC (87.9% vs. 64.2%, P=0.001), and OS (88.4% vs. 58.6%, P=0.001). GTV-P demonstrated its prognostic utility in multivariate analyses when adjusted for tumor category, cancer site, and chemotherapy regimen. Nodal GTV (mean, 34.0 mL) was not predictive of nodal control and survival.

CONCLUSIONS

A volumetric threshold of the primary tumor may be used as an independent prognostic factor in patients with HNC undergoing definitive RT.

Molecular and cellular processes underlying the hallmarks of head and neck cancer

The hallmarks of cancer were updated by Hanahan and Weinberg in 2011. Here we discuss the updated hallmarks in relation to what is known of the molecular and cellular processes underlying the development of head and neck squamous cell carcinoma (HNSCC). Several mechanisms are described, and recent surveys of HNSCC suggest a limited number of mutations, from which more mechanisms may emerge. There are also epigenetic changes to the control of normal processes. More than one mechanism underlies each hallmark. Processes essential to the development of HNSCC need not be essential to the proliferation of the fully developed tumour. Attention is paid to the emerging hallmarks, deregulation of cellular energy metabolism and evasion of immune destruction, and enabling characteristics, genome instability and mutation and tumour-promoting inflammation. HNSCC may adapt to hypoxia, suppress HLA expression, and express Toll-like receptors to facilitate inflammation, which support the proliferation of the tumour.

Syphilis manifesting as a nasopharyngeal carcinoma with cervical lymphadenopathy: A case report

The present case report describes a case of syphilitic lymphadenopathy and raises the awareness of the differential diagnosis of cervical lymphadenopathy. A 50-year-old male worker presented with a 6-month history of enlarged and growing lymph nodes in the right upper neck and a blood-tinged post-nasal drip. Physical examination showed multiple enlarged lymph nodes located in the right upper neck. On nasopharyngoscopy, a mass was found in the nasopharynx. The histopathology of both the nasopharyngeal mass and the enlarged lymph nodes revealed non-specific inflammation. Rapid plasma reagin test results (titer, 1:1280) and Treponema pallidum particle assay results (titer, 1:2560) were positive. Subsequently, a diagnosis of syphilis was confirmed clinically and serologically. The reaction after penicillin treatment further confirmed the syphilis diagnosis. Thus, syphilis should be considered as a possibility in the differential diagnosis of cervical lymphadenopathy.

The challenges of managing malignant head and neck tumors in a tropical tertiary health center in Nigeria

INTRODUCTION

In developing countries, factors such as late patient presentation, inaccessible and limited health facilities contribute to the poor outcome in the management of patients with head and neck malignant tumors. This study presents the challenges faced by the otorhinolaryngologist in our environment in the management of patients with head and neck malignant tumors.

METHODS

This is a ten-year retrospective chart review of patients with histopathologically confirmed head and neck malignancies in the Jos University Teaching Hospital, Jos, Nigeria.

RESULTS

Eighty nine patients, with male predominance (gender ratio of 2.7:1) aged between 23 and 78 years had head and neck malignancies. Eighty eight (99%) patients had histopathological diagnosis. Most patients were from rural areas and had seen the herbalist prior to presentation. Thirty four (38.2%) patients were in the 4th decade of life. Eighteen (20.2%) patients presented within 6 months of onset of illness and 71 (79.8%) patients after 6 months with 38/89 patients having cervical lymphadenopathy at presentation. Four (4.5%) patients were able to afford CT scan. Twenty eight deaths were recorded. Ten patients were lost to follow-up.

CONCLUSION

The challenges faced in managing patients with head and neck malignant tumors in our environment are enormous but surmountable. Therefore urgent efforts should be made by health workers and government to ensure a better outcome for these patients.

Gd-DOTA administration at MRI in children younger than 18 months of age: immediate adverse reactions

BACKGROUND

There is a paucity of evidence with regard to the safety of contrast medium administration at MRI in neonates and infants.

PURPOSE

To assess immediate adverse reactions in children younger than 18 months of age during routine clinical utilization of gadoteric acid (Gd-DOTA) in a cohort of patients with nonselected indications.

MATERIALS AND METHODS

One hundred and four neonates and infants were enrolled in a postmarketing survey with Gd-DOTA (Dotarem, Guerbet, Roissy, France) from a single pediatric hospital. A standardized questionnaire was used to collect the patient information.

RESULTS

All included children, ages 3 days to 18 months, received one injection of Gd-DOTA (volume 0.6-4 ml). No immediate adverse event was reported.

CONCLUSION

This postmarketing study involving neonates and infants suggests a favorable safety profile of Gd-DOTA in routine practice.

Diagnostic performance of post-treatment FDG PET or FDG PET/CT imaging in head and neck cancer: a systematic review and meta-analysis

PURPOSE

Our objective was to conduct a systematic review and meta-analysis of studies assessing the diagnostic performance of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) with or without computed tomography (CT) in post-treatment response assessment and/or surveillance imaging of head and neck squamous cell carcinoma (HNSCC).

METHODS

A systematic search of the indexed medical literature was done using appropriate keywords to identify relevant studies. Metrics of diagnostic test accuracy, viz. sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were extracted from individual studies and combined using a random effects model to yield weighted mean pooled estimates with 95% confidence intervals (95% CI). The impact of timing of post-treatment scan, study quality and advancements in PET technology was explored through meta-regression.

RESULTS

A total of 51 studies involving 2,335 patients were included in the meta-analysis. The weighted mean (95% CI) pooled sensitivity, specificity, PPV and NPV of post-treatment FDG PET(CT) for the primary site was 79.9% (73.7-85.2%), 87.5% (85.2-89.5%), 58.6% (52.6-64.5%) and 95.1% (93.5-96.5%), respectively. Similar estimates for the neck were 72.7% (66.6-78.2%), 87.6% (85.7-89.3%), 52.1% (46.6-57.6%) and 94.5% (93.1-95.7%), respectively. Scans done ≥ 12 weeks after completion of definitive therapy had moderately higher diagnostic accuracy on meta-regression analysis using time as a covariate.

CONCLUSION

The overall diagnostic performance of post-treatment FDG PET(CT) for response assessment and surveillance imaging of HNSCC is good, but its PPV is somewhat suboptimal. Its NPV remains exceptionally high and a negative post-treatment scan is highly suggestive of absence of viable disease that can guide therapeutic decision-making. Timing of post-treatment imaging has a significant, though moderate impact on diagnostic accuracy.

Can FDG PET predict radiation treatment outcome in head and neck cancer? Results of a prospective study

Purpose

In head and neck cancer (HNC) various treatment strategies have been developed to improve outcome, but selecting patients for these intensified treatments remains difficult. Therefore, identification of novel pretreatment assays to predict outcome is of interest. In HNC there are indications that pretreatment tumour ¹⁸F-fluorodeoxyglucose (FDG) uptake may be an independent prognostic factor. The aim of this study was to assess the prognostic value of FDG uptake and CT-based and FDG PET-based primary tumour volume measurements in patients with HNC treated with (chemo)radiotherapy.

Methods

A total of 77 patients with stage II–IV HNC who were eligible for definitive (chemo)radiotherapy underwent coregistered pretreatment CT and FDG PET. The gross tumour volume of the primary tumour was determined on the CT (GTV_CT) and FDG PET scans. Five PET segmentation methods were applied: interpreting FDG PET visually (PET_VIS), applying an isocontour at a standardized uptake value (SUV) of 2.5 (PET_2.5), using fixed thresholds of 40% and 50% (PET_40%, PET_50%) of the maximum intratumoral FDG activity (SUV_MAX) and applying an adaptive threshold based on the signal-to-background (PET_SBR). Mean FDG uptake for each PET-based volume was recorded (SUV_mean). Subsequently, to determine the metabolic volume, the integrated SUV was calculated as the product of PET-based volume and SUV_mean. All these variables were analysed as potential predictors of local control (LC), regional recurrence-free survival (RRFS), distant metastasis-free survival (DMFS), disease-free survival (DFS) and overall survival (OS).

Results

In oral cavity/oropharynx tumours PET_VIS was the only volume-based method able to predict LC. Both PET_VIS and GTV_CT were able to predict DMFS, DFS and OS in these subsites. Integrated SUVs were associated with LC, DMFS, DFS and OS, while SUV_mean and SUV_MAX were not. In hypopharyngeal/laryngeal tumours none of the variables was associated with outcome.

Conclusion

There is no role yet for pretreatment FDG PET as a predictor of (chemo)radiotherapy outcome in HNC in daily routine. However, this potential application needs further exploration, focusing both on FDG PET-based primary tumour volume, integrated SUV and SUV_MAX of the primary tumour.

Open cervical lymph node biopsy for head and neck cancers: any benefit?

Background

Most patients with head and neck cancers in our environment present late and usually first to the general surgeons whose practice is to subject these patients to open cervical lymph node biopsy without a prior examination under anesthesia and endoscopic biopsy from the primary tumor site in order to obtain a histological diagnosis.

This paper presents the influence of open cervical lymph node biopsy on the clinical outcome of patients with head and neck cancers in our environment.

Methods

This is a ten-year retrospective review of patients with head and neck cancers in the Jos University Teaching Hospital, Jos, Nigeria.

Results

Eighty nine patients aged between 23 and 78 years had head and neck cancers with 38/89 (42.7%) patients having cervical lymphadenopathy at presentation and these initially presented to the general surgeons. Twenty six (68.4%) patients had open cervical lymph node biopsy and 12/38 (31.6%) patients had FNAB. Eleven (28.9%) patients presented to the otolaryngology unit 6 months after they presented to the general surgeons and 27 (71.1%) patients beyond 6 months. Nine deaths were recorded. Ten patients were lost to follow-up.

Conclusion

All patients with head and neck lymphadenopathy who present to any physician for diagnostic examination should undergo formal ENT staging and FNAB to avoid the problems of tumor spread and the reduction in consequent prognosis.

Novel imaging approaches to head and neck cancer

An inadequate supply of oxygen, hypoxia, is an important factor contributing to resistance to treatment in a number of tumor types, including head and neck cancer. Novel imaging methods have been applied to studies of this important prognostic factor. Mammalian cells need oxygen to live but O2 also participates in the cytotoxic effects of ionizing radiation. Hypoxia is often the result of abnormal blood vessels supplying the tumor, increased diffusion distances to tumor cells, and reduced O2 transport capacity of the blood. Its consequences are mediated by a series of hypoxia-initiated genomic changes activating angiogenesis, glycolysis, and other processes that enable tumor cells to survive or escape the O2-deficient environment. Hypoxia has been shown to be important in overall diminished therapeutic response, malignant progression, increased probability of recurrence, locoregional spread, and distant metastases. Strategies are being developed to surmount the cure-limiting consequences of hypoxia, but methods are needed to select patients most likely to benefit from these new treatments. Even though hypoxia is a common tumor phenotype, it is by no means universal and is often heterogeneous within an individual patient. This review considers the biology of hypoxia, its consequences with respect to treatment, methods for measuring oxygenation in tissues, modern techniques for imaging of regional hypoxia, and how information about the oxygenation status of tumors might impact treatment.

Nasopharyngeal carcinoma

Imaging plays an important role in the staging of nasopharyngeal carcinoma. Accurate staging is necessary, as the treatment is directly dependent on stage. Clinical examination provides information on mucosal involvement but is unable to determine the deep extension or the presence of skull base invasion or intracranial spread. The intent of this manuscript is to provide information of the specific imaging findings that will directly affect the stage and treatment of nasopharyngeal carcinoma as well as post-treatment complications.

Tumour volume measurement in head and neck cancer

Tumour volume is a significant prognostic factor in the treatment of malignant head and neck tumours. Studies of laryngeal and pharyngeal tumours have shown tumour volume to be an important predictor for tumour recurrence. Some studies (for instance nasopharyngeal carcinoma) have shown through multivariate modelling that tumour volume is a dominant covariate that overwhelms T stage, N stage and stage group. The results of these studies have prompted several investigators to suggest the inclusion of tumour volume as an additional prognostic factor in future revisions of the TNM staging system. This paper briefly reviews the TNM system as a staging tool, the measurement of tumour volume and how tumour volume could possibly be incorporated in the system or used as an additional prognostic factor.