Head and neck intensity modulated radiotherapy parotid glands: time of re-planning

Time-Course of Salivary Metabolomic Profiles during Radiation Therapy for Head and Neck Cancer

Oral mucositis (OM) is one of the most frequently observed adverse oral events in radiation therapy for patients with head and neck cancer. Thus, objective evaluation of OM severity is needed for early and timely intervention. Here, we analyzed the time-course of salivary metabolomic profiles during the radiation therapy. The severity of OM (National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events v3.0) of nine patients with head and neck cancer was evaluated. Partial least squares regression-discriminant analysis, using samples collected before radiation therapy, showed that histidine and tyrosine highly discriminated high-grade OM from low-grade OM before the start of radiation therapy (significant difference, p = 0.048 for both metabolites). Further, the pretreatment concentrations of gamma-aminobutyric acid and 2-aminobutyric acids were higher in the high-grade OM group. Although further validations are still necessary, this study showed potentially associated metabolites with worse radiotherapy-related OM among patients with head and neck cancer.

Investigation of Radiation-Induced Toxicity in Head and Neck Cancer Patients through Radiomics and Machine Learning: A Systematic Review

Background. Radiation-induced toxicity represents a crucial concern in oncological treatments of patients affected by head and neck neoplasms, due to its impact on survivors' quality of life. Published reports suggested the potential of radiomics combined with machine learning methods in the prediction and assessment of radiation-induced toxicities, supporting a tailored radiation treatment management. In this paper, we present an update of the current knowledge concerning these modern approaches.

MATERIALS AND METHODS

A systematic review according to PICO-PRISMA methodology was conducted in MEDLINE/PubMed and EMBASE databases until June 2019. Studies assessing the use of radiomics combined with machine learning in predicting radiation-induced toxicity in head and neck cancer patients were specifically included. Four authors (two independently and two in concordance) assessed the methodological quality of the included studies using the Radiomic Quality Score (RQS). The overall score for each analyzed study was obtained by the sum of the single RQS items; the average and standard deviation values of the authors' RQS were calculated and reported.

RESULTS

Eight included papers, presenting data on parotid glands, cochlea, masticatory muscles, and white brain matter, were specifically analyzed in this review. Only one study had an average RQS was ≤ 30% (50%), while 3 studies obtained a RQS almost ≤ 25%. Potential variability in the interpretations of specific RQS items could have influenced the inter-rater agreement in specific cases.

CONCLUSIONS

Published radiomic studies provide encouraging but still limited and preliminary data that require further validation to improve the decision-making processes in preventing and managing radiation-induced toxicities.

Principal component analysis modeling of Head-and-Neck anatomy using daily Cone Beam-CT images

PURPOSE

To model Head-and-Neck anatomy from daily Cone Beam-CT (CBCT) images over the course of fractionated radiotherapy using principal component analysis (PCA).

METHODS AND MATERIALS

Eighteen oropharyngeal Head-and-Neck cancer patients, treated with volumetric modulated arc therapy (VMAT), were included in this retrospective study. Normal organs, including the parotid and submandibular glands, mandible, pharyngeal constrictor muscles (PCMs), and spinal cord were contoured using daily CBCT image datasets. PCA models for each organ were developed for individual patients (IP) and the entire patient cohort/population (PP). The first 10 principal components (PCs) were extracted for all models. Analysis included cumulative and individual PCs for each organ and patient, as well as the aggregate organ/patient population; comparisons were made using the root-mean-square (RMS) of the percentage predicted spatial displacement for each PC.

RESULTS

Overall, spatial displacement prediction was achieved at the 95% confidence level (CL) for the first three to four PCs for all organs, based on IP models. For PP models, the first four PCs predicted spatial displacement at the 80%-89% CL. Differences in percentage predicted spatial displacement between mean IP models for each organ ranged from 2.8% ± 1.8% (1st PC) to 0.6% ± 0.4% (4th PC). Differences in percentage predicted spatial displacement between IP models vs the mean IP model for each organ based on the 1st PC were <12.9% ± 6.9% for all organs. Differences in percentage predicted spatial displacement between IP and PP models based on all organs and patients for the 1st and 2nd PC were <11.7% ± 2.2%.

CONCLUSION

Tissue changes during fractionated radiotherapy observed on daily CBCT in patients with Head-and-Neck cancers, were modeled using PCA. In general, spatial displacement for organs-at-risk was predicted for the first 4 principal components at the 95% confidence levels (CL), for individual patient (IP) models, and at the 80%-89% CL for population-based patient (PP) models. The IP and PP models were most predictive of changes in glandular organs and pharyngeal constrictor muscles, respectively.

Comprehensive evaluation of ten deformable image registration algorithms for contour propagation between CT and cone-beam CT images in adaptive head & neck radiotherapy

Deformable image registration (DIR) is a critical technic in adaptive radiotherapy (ART) for propagating contours between planning computerized tomography (CT) images and treatment CT/cone-beam CT (CBCT) images to account for organ deformation for treatment re-planning. To validate the ability and accuracy of DIR algorithms in organ at risk (OAR) contour mapping, ten intensity-based DIR strategies, which were classified into four categories—optical flow-based, demons-based, level-set-based and spline-based—were tested on planning CT and fractional CBCT images acquired from twenty-one head & neck (H&N) cancer patients who underwent 6~7-week intensity-modulated radiation therapy (IMRT). Three similarity metrics, i.e., the Dice similarity coefficient (DSC), the percentage error (PE) and the Hausdorff distance (HD), were employed to measure the agreement between the propagated contours and the physician-delineated ground truths of four OARs, including the vertebra (VTB), the vertebral foramen (VF), the parotid gland (PG) and the submandibular gland (SMG). It was found that the evaluated DIRs in this work did not necessarily outperform rigid registration. DIR performed better for bony structures than soft-tissue organs, and the DIR performance tended to vary for different ROIs with different degrees of deformation as the treatment proceeded. Generally, the optical flow-based DIR performed best, while the demons-based DIR usually ranked last except for a modified demons-based DISC used for CT-CBCT DIR. These experimental results suggest that the choice of a specific DIR algorithm depends on the image modality, anatomic site, magnitude of deformation and application. Therefore, careful examinations and modifications are required before accepting the auto-propagated contours, especially for automatic re-planning ART systems.

Head and neck adaptive radiotherapy: Predicting the time to replan

AIM

Head and neck (H&N) cancer patients can undergo anatomical change throughout radiotherapy treatment. Adaptive radiotherapy (ART) is effective in addressing the impact of this change on the planned dose distribution. The aim of this study was to identify pretreatment factors that influence the need for and timing of replanning for patients receiving chemoradiotherapy for node-positive nasopharyngeal (NPC) and oropharyngeal carcinoma (OPC).

METHODS

Of 110 patients enrolled in a prospective H&N ART study, 21 (19%) underwent a second planning scan (re-CT) and were included in this review. Univariate and multivariate analysis was used to compare those patients who were replanned with those that were not. Factors influencing the timing of replanning were assessed including patient and tumor characteristics and structure volume details.

RESULTS

Of the five replanned patients, three were diagnosed with NPC (P = 0.06) and had significantly larger initial nodal volumes (median volume 140.3 cc vs. 39.1 cc, P = 0.019). Overall the median time of re-CT was significantly different between replanned and non-replanned patients, with replanned patients having an earlier re-CT: median fraction 18 versus fraction 23 (P = 0.01). Specifically, NPC patients who were replanned had a re-CT performed earlier than OPC patients (median fraction 11 vs. 20).

CONCLUSION

For H&N patients with large nodes receiving definitive chemoradiotherapy, replanning may be considered at the commencement of week 3 for NPC patients and in week 4 of treatment for OPC patients. This information may facilitate a forward planning approach to H&N ART that enables allocation of departmental resources prior to treatment commencement.

Cachexia induces head and neck changes in locally advanced oropharyngeal carcinoma during definitive cisplatin and image-guided volumetric-modulated arc radiation therapy

BACKGROUND/OBJECTIVES

Cancer cachexia is a syndrome characterized by weight loss (WL) and sarcopenia. Aim of the study was to assess the impact of cachexia on head and neck changes during definitive cisplatin and image-guided volumetric-modulated arc radiation therapy in a series of locally advanced oropharyngeal cancer.

SUBJECTS/METHODS

Volume variations of sternocleidomastoid muscle (SCM) were considered as surrogate of muscle changes related to sarcopenia. Two head and neck diameters, encompassing the cranial limits of II and III nodal levels (defined as 'head diameter' and 'neck diameter', respectively), were measured. All parameters were defined retrospectively by means of on-board cone beam computed tomography images at 1-8th to 15-22th and at last fraction (fx) of radiotherapy (RT). Cachexia was defined as WL >5% during treatment. Analysis was conducted correlating the parameter changes with three WL ranges: <5, 5-9 and>10%.

RESULTS

Thirty patients were evaluated. One hundred and fifty contoured SCMs and three hundred diameters were collected. Median WL was 6.5% (range, 0-16%). The most significant SCM shrinkage was recorded at 15th fx (mean 1.6 cc) related to WL 5-9% and WL >10% (P 0.001). For 'head diameter', the peak reduction was recorded at the 15th fx (mean 8 mm), statistically correlated to WL >10% (P 0.001). The peak reduction in 'neck diameter' was registered at the 22th fx (mean 6 mm), with a gradual reduction until the end of treatment for WL >5%.

CONCLUSIONS

In a homogeneous cohort of patients, present study quantified the impact of cachexia on head and neck changes. Present data could provide adaptive RT implications for further investigations.

Predicting the need for adaptive radiotherapy in head and neck cancer

BACKGROUND AND PURPOSE

Adaptive radiotherapy (ART) can account for the dosimetric impact of anatomical change in head and neck cancer patients; however it can be resource intensive. Consequently, it is imperative that patients likely to require ART are identified. The purpose of this study was to find predictive factors that identify oropharyngeal squamous cell carcinoma (OPC) and nasopharyngeal carcinoma (NPC) patients more likely to need ART.

MATERIALS AND METHODS

One hundred and ten patients with OPC or NPC were analysed. Patient demographics and tumour characteristics were compared between patients who were replanned and those that were not. Factors found to be significant were included in logistic regression models. Risk profiles were developed from these models. A dosimetric analysis was performed.

RESULTS

Nodal disease stage, pre-treatment largest involved node size, diagnosis and initial weight (categorised in 2 groups) were identified as significant for inclusion in the model. Two models were found to be significant (p=0.001), correctly classifying 98.2% and 96.1% of patients respectively. Three ART risk profiles were developed.

CONCLUSION

Predictive factors identifying OPC or NPC patients more likely to require ART were reported. A risk profile approach could facilitate the effective implementation of ART into radiotherapy departments through forward planning and appropriate resource allocation.

Organ sparing and clinical outcome with step-and-shoot IMRT for head and neck cancer: a mono-institutional experience

PURPOSE

Intensity-modulated radiotherapy has been suggested as the technique of choice for locally advanced head and neck cancer patients. In the last decade, most radiotherapy departments have focused their efforts in programs to implement this technique. We report our experience for parotid gland and constrictor muscle sparing with intensity-modulated radiotherapy in head and neck cancer using a step-and-shoot technique.

METHODS

Thirty-four consecutive patients with squamous cell carcinoma of the nasopharynx, oropharynx and larynx treated between June 2008 and June 2011 were retrospectively evaluated. A simultaneous integrated boost was adopted to treat different volumes in 30 fractions over 6 weeks. Priority as organs at risk was given to the parotid glands as well as the constrictor muscle of the pharynx in 53 % (n = 18). Dysphagia and xerostomia were evaluated according to RTOG/EORTC scale at 6, 12 and 24 months. Outcomes were analysed using Kaplan-Meier curves.

RESULTS

The median follow-up was 43 months. The 5-year overall survival was 70 %, and local control was 94 %. Grade 2 dysphagia and xerostomia at 6, 12 and 24 months were as follows: 26 % (n = 9), 23 % (n = 8), 23 % (n = 8) and 21 % (n = 7), 12 % (n = 4), 12 % (n = 4), respectively. No grade 3 or 4 toxicity was found. Ordinal logistic regression analysis demonstrated that hyposalivation was the main predictive factor for late dysphagia.

CONCLUSION

Excellent loco-regional results were achieved with acceptable acute and late toxicities. The low rate of late dysphagia was related to parotid gland sparing; we did not observe a correlation between late dysphagia and dose to pharyngeal constrictors.

Dose-volume-related dysphagia after constrictor muscles definition in head and neck cancer intensity-modulated radiation treatment

OBJECTIVE

Dysphagia remains a side effect influencing the quality of life of patients with head and neck cancer (HNC) after radiotherapy. We evaluated the relationship between planned dose involvement and acute and late dysphagia in patients with HNC treated with intensity-modulated radiation therapy (IMRT), after a recontouring of constrictor muscles (PCs) and the cricopharyngeal muscle (CM).

METHODS

Between December 2011 and December 2013, 56 patients with histologically proven HNC were treated with IMRT or volumetric-modulated arc therapy. The PCs and CM were recontoured. Correlations between acute and late toxicity and dosimetric parameters were evaluated. End points were analysed using univariate logistic regression.

RESULTS

An increasing risk to develop acute dysphagia was observed when constraints to the middle PCs were not respected [mean dose (Dmean) ≥50 Gy, maximum dose (Dmax) >60 Gy, V50 >70% with a p = 0.05]. The superior PC was not correlated with acute toxicity but only with late dysphagia. The inferior PC was not correlated with dysphagia; for the CM only, Dmax >60 Gy was correlated with acute dysphagia ≥ grade 2.

CONCLUSION

According to our analysis, the superior PC has a major role, being correlated with dysphagia at 3 and 6 months after treatments; the middle PC maintains this correlation only at 3 months from the beginning of radiotherapy, but it does not have influence on late dysphagia. The inferior PC and CM have a minimum impact on swallowing symptoms.

ADVANCES IN KNOWLEDGE

We used recent guidelines to define dose constraints of the PCs and CM. Two results emerge in the present analysis: the superior PC influences late dysphagia, while the middle PC influences acute dysphagia.

Outcomes of xerostomia-related quality of life for nasopharyngeal carcinoma treated by IMRT: based on the EORTC QLQ-C30 and H&N35 questionnaires

The aim of this study was to review the published literature addressing the question of whether intensity-modulated radiotherapy (IMRT) resulted in an improvement of quality of life (QoL), especially xerostomia-related QoL of all nasopharyngeal carcinoma patients as time progressed. A literature search of PubMed, Embase and Google Scholar was performed, only reports containing original data of the QoL scores after treated by IMRT were included. Two independent reviewers extracted information of study design, study population, interventions, outcome measures and conclusions for each article. The inclusion criteria were met by 14 articles covering outcomes based on the questionnaires treated by IMRT. Data from same questionnaires (European Organization of Research and Treatment of Cancer QLQ-C30 and H&N35 questionnaires) were exacted and we analyzed four items (global health status, dry mouth and sticky saliva, swallowing, social eating and social contact), which have a close relationship with xerostomia-related QoL. Results indicated that a maximal deterioration of most QoL scales including global health status developed during treatment or at the end of the treatment course and then followed by a gradual recovery to 1 year, 1-2 years after IMRT, compared with their baseline level, some specific head and neck items, most in the EORTC QLQ H&N35, remained worse for the surviving patients. In conclusion, the published data reasonably support the benefits of IMRT in improving QoL, but xerostomia-related items still had a significantly negative effect in 2 years to impact a survivor's QoL.