The role of PET-CT in the management of patients with advanced cancer of the head and neck

Diagnostic and treatment modalities for patients with cervical lymph node metastases of unknown primary site - current status and challenges

Background and Purpose

This review aims to provide a comprehensive overview of the literature and elucidate open questions for future clinical trials concerning diagnostics and treatment modalities for cervical cancer of unknown primary (CUP).

Methods

A literature search for head and neck CUP was performed with focus on diagnostics and therapies as well as molecular markers.

Results

High level evidence on CUP is limited. However, it seems that a consensus exists regarding the optimal diagnostic procedures. The correct implementation of biomarkers for patient stratification and treatment remains unclear. An even greater dispute dominates about the ideal treatment with publications ranging from sole surgery to surgery with postoperative bilateral radiotherapy with inclusion of the mucosa and concomitant chemotherapy.

Conclusions

Cervical CUP represents a very heterogeneous malignant disease. On this account many aspects concerning treatment optimization remain unclear, despite a considerable number of publications in the past. Future research in form of prospective randomized trials is needed in order to better define patient stratification criteria and enable tailored treatment.

Quo vadis radiotherapy? Technological advances and the rising problems in cancer management

Purpose. Despite the latest technological advances in radiotherapy, cancer control is still challenging for several tumour sites. The survival rates for the most deadly cancers, such as ovarian and pancreatic, have not changed over the last decades. The solution to the problem lies in the change of focus: from local treatment to systemic therapy. The aim of this paper is to present the current status as well as the gaps in radiotherapy and, at the same time, to look into potential solutions to improve cancer control and survival. Methods. The currently available advanced radiotherapy treatment techniques have been analysed and their cost-effectiveness discussed. The problem of systemic disease management was specifically targeted. Results. Clinical studies show limited benefit in cancer control from hadron therapy. However, targeted therapies together with molecular imaging could improve treatment outcome for several tumour sites while controlling the systemic disease. Conclusion. The advances in photon therapy continue to be competitive with the much more expensive hadron therapy. To justify the cost effectiveness of proton/heavy ion therapy, there is a need for phase III randomised clinical trials. Furthermore, the success of systemic disease management lies in the fusion between radiation oncology technology and microbiology.

Impact of positron emission tomography/computed tomography surveillance at 12 and 24 months for detecting head and neck cancer recurrence

BACKGROUND

In head and neck cancer (HNC), 3-month post-treatment positron emission tomography (PET)/computed tomography (CT) reliably identifies persistent/recurrent disease. However, further PET/CT surveillance has unclear benefit. The impact of post-treatment PET/CT surveillance on outcomes is assessed at 12 and 24 months.

METHODS

A 10-year retrospective analysis of HNC patients was carried out with long-term serial imaging. Imaging at 3 months included either PET/CT or magnetic resonance imaging, with all subsequent imaging comprised of PET/CT. PET/CT scans at 12 and 24 months were evaluated only if preceding interval scans were negative. Of 1114 identified patients, 284 had 3-month scans, 175 had 3- and 12-month scans, and 77 had 3-, 12-, and 24-month scans.

RESULTS

PET/CT detection rates in clinically occult patients were 9% (15 of 175) at 12 months, and 4% (3 of 77) at 24 months. No difference in outcomes was identified between PET/CT-detected and clinically detected recurrences, with similar 3-year disease-free survival (41% vs 46%, P = .91) and 3-year overall survival (60% vs 54%, P = .70) rates. Compared with 3-month PET/CT, 12-month PET/CT demonstrated fewer equivocal reads (26% vs 10%, P < .001). Of scans deemed equivocal, 6% (5 of 89) were ultimately found to be positive.

CONCLUSIONS

HNC patients with negative 3-month imaging appear to derive limited benefit from subsequent PET/CT surveillance. No survival differences were observed between PET/CT-detected and clinically detected recurrences, although larger prospective studies are needed for further investigation.

The role of PET imaging in overcoming radiobiological challenges in the treatment of advanced head and neck cancer

PURPOSE

Despite the large variety of treatment methods available for the management of advanced head and neck carcinomas, these tumours remain highly challenging due to their aggressiveness and complex anatomical location. Among the treatment challenges associated with head and neck cancers, hypoxia and tumour repopulation during treatment are, most likely, the main reason for locoregional treatment failure. Whilst the number of techniques and predictive assays designed to assess the oxygenation status or the proliferative ability of tumours is rather large, they all come with drawbacks which limit their implementation as routine clinical procedures. Latest developments in the field of nuclear medicine have opened the road to new possibilities in functional imaging, thus overcoming some of the confines imposed by the more conventional techniques.

MATERIALS AND METHODS

The current paper presents the role of PET imaging as a quantitative evaluation tool for hypoxia status and proliferative ability of advanced head and neck tumours. Traditional as well as novel radioisotopes with high affinity towards hypoxia and proliferative tumour activity are presented and their pre-clinical/clinical results analysed.

RESULTS

While the number of clinical studies which aimed to validate novel radiotracers for head and neck cancer is limited, a number of results show promising correlation between uptake/marker activity and treatment outcome.

CONCLUSION

There is need for further studies and well designed clinical trials to obtain more conclusive results.

The promise and pitfalls of positron emission tomography and single-photon emission computed tomography molecular imaging-guided radiation therapy

External beam radiation therapy procedures have, until recently, been planned almost exclusively using anatomic imaging methods. Molecular imaging using hybrid positron emission tomography (PET)/computed tomography scanning or single-photon emission computed tomography (SPECT) imaging has provided new insights into the precise location of tumors (staging) and the extent and character of the biologically active tumor volume (BTV) and has provided differential response information during and after therapy. In addition to the commonly used radiotracer (18)F-fluoro- 2-deoxyD-glucose (FDG), additional radiopharmaceuticals are being explored to image major physiological processes as well as tumor biological properties, such as hypoxia, proliferation, amino acid accumulation, apoptosis, and receptor expression, providing the potential to target or boost the radiation dose to a biologically relevant region within a tumor, such as the most hypoxic or most proliferative area. Imaging using SPECT agents has furthered the possibility of limiting dose to functional normal tissues. PET can also portray the distribution of particle therapy by displaying activated species in situ. With both PET and SPECT imaging, fundamental physical issues of limited spatial resolution relative to the biological process, partial volume effects for quantification of small volumes, image misregistration, motion, and edge delineation must be carefully considered and can differ by agent or the method applied. Molecular imaging-guided radiation therapy (MIGRT) is a rapidly evolving and promising area of investigation and clinical translation. As MIGRT evolves, evidence must continue to be gathered to support improved clinical outcomes using MIGRT versus purely anatomic approaches.

Role of PET/CT imaging in stereotactic body radiotherapy

Stereotactic body radiotherapy (SBRT) is a relatively new technique that enables delivery of high doses of radiation to malignancies throughout the body with a higher degree of precision than conventional radiation modalities. PET and computed tomography are rapidly being adopted for the evaluation of patients with cancer, and its role in conjunction with SBRT is under active investigation. This article reviews the literature regarding the utility of PET and computed tomography in treatment planning, follow-up imaging, relationship with clinical outcomes, and other topics in patients treated with SBRT. These questions are investigated for cancers of the lung, head and neck, pancreas and liver. A brief overview of various commercially available SBRT treatment systems is also included.

MMP9 but Not EGFR, MET, ERCC1, P16, and P-53 Is Associated with Response to Concomitant Radiotherapy, Cetuximab, and Weekly Cisplatin in Patients with Locally Advanced Head and Neck Cancer

Concomitant administration of radiotherapy with cisplatin or radiotherapy with cetuximab appear to be the treatment of choice for patients with locally advanced head and neck cancer. In the present retrospective analysis, we investigated the predictive role of several biomarkers in an unselected cohort of patients treated with concomitant radiotherapy, weekly cisplatin, and cetuximab (CCRT). We identified 37 patients treated with this approach, of which 13 (35%) achieved a complete response and 10 (27%) achieved a partial response. Severe side effects were mainly leucopenia, dysphagia, rash, and anemia. Tumor EGFR, MET, ERCC1, and p-53 protein and/or gene expression were not associated with treatment response. In contrast, high MMP9 mRNA expression was found to be significantly associated with objective response. In conclusion, CCRT is feasible and active. MMP9 was the only biomarker tested that appears to be of predictive value in cetuximab treated patients. However, this is a hypothesis generating study and the results should not be viewed as definitive evidence until they are validated in a larger cohort.

A Markov decision process approach to temporal modulation of dose fractions in radiation therapy planning

The current state of the art in cancer treatment by radiation optimizes beam intensity spatially such that tumors receive high dose radiation whereas damage to nearby healthy tissues is minimized. It is common practice to deliver the radiation over several weeks, where the daily dose is a small constant fraction of the total planned. Such a 'fractionation schedule' is based on traditional models of radiobiological response where normal tissue cells possess the ability to repair sublethal damage done by radiation. This capability is significantly less prominent in tumors. Recent advances in quantitative functional imaging and biological markers are providing new opportunities to measure patient response to radiation over the treatment course. This opens the door for designing fractionation schedules that take into account the patient's cumulative response to radiation up to a particular treatment day in determining the fraction on that day. We propose a novel approach that, for the first time, mathematically explores the benefits of such fractionation schemes. This is achieved by building a stylistic Markov decision process (MDP) model, which incorporates some key features of the problem through intuitive choices of state and action spaces, as well as transition probability and reward functions. The structure of optimal policies for this MDP model is explored through several simple numerical examples.

[Radiological normal anatomy of the larynx and pharynx and imaging techniques]

The larynx and the pharynx represent anatomically as well as functionally a very complex organ which serves as an airway and a nutrition channel. Knowledge of anatomy and anatomical topography is therefore a fundamental basis for the evaluation of any pathological process. Beside the clinical examination and endoscopy performed by ear, nose and throat specialists, imaging techniques play a crucial role in pre-therapeutic and post-therapeutic diagnostics. The radiologist employs a conventional x-ray swallow examination, as well as contrast-enhanced multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), positron emission tomography (PET) and positron emission tomography-computed tomography (PET-CT), depending on the medical problem in question. The following article demonstrates the functional and especially the structural anatomy of the larynx and the pharynx. Furthermore, the broad range of imaging techniques in clinical use is discussed.