Over the last few decades, significant improvements have been made in the radiotherapy (RT) treatment of head and neck malignancies. The progressive introduction of intensity-modulated RT and the use ...of multimodality imaging for target volume and organs at risk delineation, together with the use of altered fractionation regimens and concomitant administration of chemotherapy or targeted agents, have accompanied efficacy improvements in RT. Altogether, such improvements have translated into improvement in locoregional control and overall survival probability, with a decrease in the long-term adverse effects of RT and an improvement in quality of life. Further progress in the treatment of head and neck malignancies may come from a better integration of molecular imaging to identify tumor subvolumes that may require additional radiation doses (ie, dose painting) and from treatment adaptation tracing changes in patient anatomy during treatment. Proton therapy generates even more exquisite dose distribution in some patients, thus potentially further improving patient outcomes. However, the clinical benefit of these approaches, although promising, for patients with head and neck cancer need to be demonstrated in prospective randomized studies. In this context, our article will review some of these advances, with special emphasis on target volume and organ-at-risk delineation, use of molecular imaging for tumor delineation, dose painting for dose escalation, dose adaptation throughout treatment, and potential benefit of proton therapy.
•Updated proposal for the selection of nodal target volumes in definitive radiotherapy is provided.•Recommendations for both negative and positive neck are provided.•The locations addressed are: oral ...cavity, oropharynx, hypopharynx, larynx, nasopharynx, paranasal sinuses, nasal cavity and carcinoma of unknown primary.•Recommendations are according to the latest neck node level terminology and staging.
In 2000, a panel of experts published a proposal for the selection of lymph node target volumes for definitive head and neck radiation therapy (Radiother Oncol, 2000; 56: 135–150). Hereunder, this selection is updated and extended to also cover primary sites not previously covered.
The lymphatic spread of head and neck cancers into neck lymph nodes was comprehensively reviewed based on radiological, surgical and pathological literature regarding both initial involvement and patterns of failure. Then a panel of worldwide head and neck radiotherapy experts agreed on a consensus for the selection of both high- and low-risk lymph node target volumes for the node negative and the node positive neck.
An updated selection of lymph node target volumes is reported for oral cavity, oropharynx, hypopharynx, larynx, nasopharynx, paranasal sinuses, nasal cavity and carcinoma of unknown primary as a function of the nodal staging (UICC 8th edition).
The selection of lymph node target volumes for head and neck cancers treated with IMRT/VMAT or other highly conformal techniques (e.g. proton therapy) requires a rigorous approach. This updated proposal of selection should help clinicians for the selection of lymph nodes target volumes and contribute to increase consistency.
•Deep learning can be used to contour organs at risk for numerous patients.•Deep learning outperforms atlas based auto-segmentation in head and neck organs at risk contouring.•Subjective analysis ...indicated no need manual corrections in many deep learning generated contours.•Deep learning auto-contouring has the potential to decrease the clinical burden.
Adequate head and neck (HN) organ-at-risk (OAR) delineation is crucial for HN radiotherapy and for investigating the relationships between radiation dose to OARs and radiation-induced side effects. The automatic contouring algorithms that are currently in clinical use, such as atlas-based contouring (ABAS), leave room for improvement. The aim of this study was to use a comprehensive evaluation methodology to investigate the performance of HN OAR auto-contouring when using deep learning contouring (DLC), compared to ABAS.
The DLC neural network was trained on 589 HN cancer patients. DLC was compared to ABAS by providing each method with an independent validation cohort of 104 patients, which had also been manually contoured. For each of the 22 OAR contours – glandular, upper digestive tract and central nervous system (CNS)-related structures – the dice similarity coefficient (DICE), and absolute mean and max dose differences (|Δmean-dose| and |Δmax-dose|) performance measures were obtained. For a subset of 7 OARs, an evaluation of contouring time, inter-observer variation and subjective judgement was performed.
DLC resulted in equal or significantly improved quantitative performance measures in 19 out of 22 OARs, compared to the ABAS (DICE/|Δmean dose|/|Δmax dose|: 0.59/4.2/4.1 Gy (ABAS); 0.74/1.1/0.8 Gy (DLC)). The improvements were mainly for the glandular and upper digestive tract OARs. DLC significantly reduced the delineation time for the inexperienced observer. The subjective evaluation showed that DLC contours were more often preferable to the ABAS contours overall, were considered to be more precise, and more often confused with manual contours. Manual contours still outperformed both DLC and ABAS; however, DLC results were within or bordering the inter-observer variability for the manual edited contours in this cohort.
The DLC, trained on a large HN cancer patient cohort, outperformed the ABAS for the majority of HN OARs.
Abstract Most new radiation techniques, have been introduced primarily to reduce the dose to normal tissues in order to prevent radiation-induced side effects. Radiotherapy with protons is such a ...radiation technique that due to its superior beam properties compared to photons enables better sparing of normal tissues. This paper describes a stepwise methodology to select patients for proton therapy when the primary aim is to reduce side effects. This method has been accepted by the Dutch health authorities to select patients for proton therapy. In addition, an alternative method is described in case randomised controlled trials are considered not appropriate.
Abstract In 2003, a panel of experts published a set of consensus guidelines for the delineation of the neck node levels in node negative patients (Radiother Oncol, 69: 227–36, 2003). In 2006, these ...guidelines were extended to include the characteristics of the node positive and the post-operative neck (Radiother Oncol, 79: 15–20, 2006). These guidelines did not fully address all nodal regions and some of the anatomic descriptions were ambiguous, thereby limiting consistent use of the recommendations. In this framework, a task force comprising opinion leaders in the field of head and neck radiation oncology from European, Asian, Australia/New Zealand and North American clinical research organizations was formed to review and update the previously published guidelines on nodal level delineation. Based on the nomenclature proposed by the American Head and Neck Society and the American Academy of Otolaryngology-Head and Neck Surgery, and in alignment with the TNM atlas for lymph nodes in the neck, 10 node groups (some being divided into several levels) were defined with a concise description of their main anatomic boundaries, the normal structures juxtaposed to these nodes, and the main tumor sites at risk for harboring metastases in those levels. Emphasis was placed on those levels not adequately considered previously (or not addressed at all); these included the lower neck (e.g. supraclavicular nodes), the scalp (e.g. retroauricular and occipital nodes), and the face (e.g. buccal and parotid nodes). Lastly, peculiarities pertaining to the node-positive and the post-operative clinical scenarios were also discussed. In conclusion, implementation of these guidelines in the daily practice of radiation oncology should contribute to the reduction of treatment variations from clinician to clinician and facilitate the conduct of multi-institutional clinical trials.
Abstract Purpose The objective of this project was to define consensus guidelines for delineating organs at risk (OARs) for head and neck radiotherapy for routine daily practice and for research ...purposes. Methods Consensus guidelines were formulated based on in-depth discussions of a panel of European, North American, Asian and Australian radiation oncologists. Results Twenty-five OARs in the head and neck region were defined with a concise description of their main anatomic boundaries. The Supplemental material provides an atlas of the consensus guidelines, projected on 1 mm axial slices. The atlas can also be obtained in DICOM-RT format on request. Conclusion Consensus guidelines for head and neck OAR delineation were defined, aiming to decrease interobserver variability among clinicians and radiotherapy centers.
Radiotherapy (RT) is used to treat approximately 80% of patients with cancer of the head and neck. Despite enormous advances in RT planning and delivery, a significant number of patients will ...experience radiation-associated toxicities, especially those treated with concurrent systemic agents. Many effective management options are available for acute RT-associated toxicities, but treatment options are much more limited and of variable benefit among patients who develop late sequelae after RT. The adverse impact of developing late tissue damage in irradiated patients may range from bothersome symptoms that negatively affect their quality of life to severe life-threatening complications. In the region of the head and neck, among the most problematic late effects are impaired function of the salivary glands and swallowing apparatus. Other tissues and structures in the region may be at risk, depending mainly on the location of the irradiated tumor relative to the mandible and hearing apparatus. Here, we review the available evidence on the use of different therapeutic strategies to alleviate common late sequelae of RT in head and neck cancer patients, with a focus on the critical assessment of the treatment options for xerostomia, dysphagia, mandibular osteoradionecrosis, trismus, and hearing loss.
In-room imaging is a prerequisite for adaptive proton therapy. The use of onboard cone-beam computed tomography (CBCT) imaging, which is routinely acquired for patient position verification, can ...enable daily dose reconstructions and plan adaptation decisions. Image quality deficiencies though, hamper dose calculation accuracy and make corrections of CBCTs a necessity. This study compared three methods to correct CBCTs and create synthetic CTs that are suitable for proton dose calculations. CBCTs, planning CTs and repeated CTs (rCT) from 33 H&N cancer patients were used to compare a deep convolutional neural network (DCNN), deformable image registration (DIR) and an analytical image-based correction method (AIC) for synthetic CT (sCT) generation. Image quality of sCTs was evaluated by comparison with a same-day rCT, using mean absolute error (MAE), mean error (ME), Dice similarity coefficient (DSC), structural non-uniformity (SNU) and signal/contrast-to-noise ratios (SNR/CNR) as metrics. Dosimetric accuracy was investigated in an intracranial setting by performing gamma analysis and calculating range shifts. Neural network-based sCTs resulted in the lowest MAE and ME (37/2 HU) and the highest DSC (0.96). While DIR and AIC generated images with a MAE of 44/77 HU, a ME of −8/1 HU and a DSC of 0.94/0.90. Gamma and range shift analysis showed almost no dosimetric difference between DCNN and DIR based sCTs. The lower image quality of AIC based sCTs affected dosimetric accuracy and resulted in lower pass ratios and higher range shifts. Patient-specific differences highlighted the advantages and disadvantages of each method. For the set of patients, the DCNN created synthetic CTs with the highest image quality. Accurate proton dose calculations were achieved by both DCNN and DIR based sCTs. The AIC method resulted in lower image quality and dose calculation accuracy was reduced compared to the other methods.
Reducing dose to normal tissues is the advantage of protons versus photons. We aimed to describe a method for translating this reduction into a clinically relevant benefit.
Dutch scientific and ...health care governance bodies have recently issued landmark reports regarding generation of relevant evidence for new technologies in health care including proton therapy. An approach based on normal tissue complication probability (NTCP) models has been adopted to select patients who are most likely to experience fewer (serious) adverse events achievable by state-of-the-art proton treatment.
By analogy with biologically targeted therapies, the technology needs to be tested in enriched cohorts of patients exhibiting the decisive predictive marker: difference in normal tissue dosimetric signatures between proton and photon treatment plans. Expected clinical benefit is then estimated by virtue of multifactorial NTCP models. In this sense, high-tech radiation therapy falls under precision medicine. As a consequence, randomizing nonenriched populations between photons and protons is predictably inefficient and likely to produce confusing results.
Validating NTCP models in appropriately composed cohorts treated with protons should be the primary research agenda leading to urgently needed evidence for proton therapy.
Tube feeding dependence is a commonly observed debilitating side-effect of curative (chemo-) radiation in head and neck cancer patients that severely affects quality of life. Prevention of this ...side-effect can be obtained using advanced radiation techniques, such as IMRT. For radiotherapy treatment plan optimization, it has become increasingly important to develop prediction models that enable clinicians to predict the risk of tube feeding dependence for individual patients. To develop such a tool, information regarding the most relevant prognostic factors for tube feeding dependence is necessary.
The primary aim of this systematic review, conducted according to PRISMA guidelines, was to identify prognostic factors that are consistently found to be associated with tube feeding dependence at ≥6months after treatment. The secondary aim was to identify prognostic factors found to be associated with tube feeding placement and use at <6months.
Articles were identified through a search in MEDLINE, EMBASE and the Cochrane Library. Approximately 2600 articles were screened and selected by inclusion and exclusion criteria.
Fourteen retrospective studies were identified that fulfilled the inclusion criteria and reported on prognostic factors for tube feeding dependence at ≥6months. The studies reported on patient and disease variables, treatment variables and DVH parameters. Two of these studies reported on a model for tube feeding dependence, one including DVH parameters. Additionally, 18 studies were identified that reported on prognostic factors for tube feeding placement and use at <6months.
Prognostic factors that were consistently associated with the risk of tube feeding dependence at ≥6months for head and neck cancer patients treated with (chemo-) radiotherapy were DVH parameters, including dose to the larynx, the pharyngeal constrictor muscle inferior and superior, and the dose to the contralateral parotid gland. Furthermore, advanced tumor and nodal stage, pretreatment weight loss, (concomitant) chemotherapy and prophylactic gastrostomy policy were prognostic for tube feeding dependence ≥6months. For tube feeding use at less than 6months, prognostic DVH parameters included dose and volume to the oral mucosa, dose to the contralateral submandibular gland, and also dose to the larynx and the pharyngeal constrictor muscle inferior and superior. Prognostic patients/disease and treatment factors for tube feeding placement and use at less than 6months were similar to the prognostic factors for tube feeding dependence at ≥6months, but also included several unique variables such as the use of narcotics prior to treatment and living alone at the time of treatment.
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