Patient Preparation and Radiation Protection Guidance for Adult Patients Undergoing Radioiodine Treatment for Thyroid Cancer in the UK.

Radioactive iodine is a highly effective treatment for thyroid cancer and has now been used in clinical practice for more than 80 years. In general, the treatment is well tolerated. However, it can be logistically quite complex for patients due to the need to reduce iodine intake and achieve high levels of thyroid-stimulating hormone prior to treatment. Radiation protection precautions must also be taken to protect others from unnecessary radiation exposure following treatment. It has been well documented by thyroid cancer patient support groups that there is significant variation in practice across the UK. It is clear that some patients are being asked to observe unnecessarily burdensome restrictions that make it more difficult for them to tolerate the treatment. At the instigation of these support groups, a multidisciplinary group was assembled to examine the evidence and generate guidance on best practice for the preparation of patients for this treatment and the management of subsequent radiation protection precautions, with a focus on personalising the advice given to individual patients. The guidance includes advice about managing particularly challenging situations, for example treating patients who require haemodialysis. We have also worked together to produce a patient information leaflet covering these issues. We hope that the guidance document and patient information leaflet will assist centres in improving our patients' experience of receiving radioactive iodine. The patient information sheet is available as Supplementary Material to this article.

Dabrafenib and Trametinib Therapy for Advanced Anaplastic Thyroid Cancer - Real-World Outcomes From UK Centres.

AIMS: Anaplastic thyroid cancer (ATC) is a rare but aggressive form of thyroid cancer with a median survival of 4 months. Recent advances in molecular profiling have shown that up to half of ATCs harbour the BRAF-V600E mutation. The aim of this study was to provide real-world data and experience on the use of combination therapy dabrafenib and trametinib in patients with BRAF-V600E-mutated advanced ATC. MATERIALS AND METHODS: We retrospectively evaluated patients with confirmed BRAF-V600E-mutated ATC, defined as patients with locally advanced or metastatic ATC with no locoregional, radical treatment options. Outcomes measured were overall survival, progression-free survival, response rate, discontinuation rate, dose reduction rate and toxicity data. RESULTS: Seventeen patients were evaluated and the mean age was 68 years. Ten patients died by the time of censoring. The median duration of follow-up was 12 months (3-43 months). The estimated median overall survival was 6.9 months (95% confidence interval 2.46 months - upper confidence interval not reached) and the median progression-free survival was 4.7 months (95% confidence interval 1.4-7.8 months). Dose interruptions and/or reductions were common, but none of the patients had to permanently discontinue treatment because of toxicities. Severe toxicities (grades 3 and 4) were uncommon. CONCLUSIONS: This study supports the indication of dabrafenib and trametinib in BRAF-V600E-mutated ATC as an effective and well-tolerated treatment in an historically difficult to treat cancer.

Guidelines on the Use of Systemic Therapy in Patients with Advanced Thyroid Cancer.

With increasing understanding of the molecular alterations leading to thyroid cancers in recent years we have seen a rapid increase in the number of effective targeted systemic therapies available for patients with advanced thyroid cancer; firstly with the advent of the multi-kinase inhibitors and more recently with more specific RET, BRAF, MEK, ALK and NTRK inhibitors. Although these developments are very welcome, they have resulted in a paradigm shift in the management of advanced thyroid cancer to which thyroid oncologists have had to rapidly adapt, learning how to supervise treatment safely with novel agents, the management of novel toxicities, when and how to arrange molecular genetic testing of cancers and, perhaps most importantly, determining when the optimum time is to start these treatments in what can often be a relatively indolent, if progressive, disease. We hope that these guidelines will support clinicians in making these decisions with their patients, as well as signposting and providing useful supporting information both for patients and clinicians.

A Predictive Model for Reactive Tube Feeding in Head and Neck Cancer Patients Undergoing Definitive (Chemo) Radiotherapy.

AIMS: Careful management of a patient's nutritional status during and after treatment for head and neck squamous cell cancers (HNSCC) is crucial for optimal outcomes. The aim of this study was to develop a model for stratifying a patient's risk of requiring reactive enteral feeding through a nasogastric tube during radiotherapy for HNSCC, based on clinical and treatment-related factors. MATERIALS AND METHODS: A cohort of consecutive patients treated with definitive (chemo)radiotherapy for HNSCC between January 2016 and January 2018 was identified in the institutional electronic database for retrospective analysis. Patients requiring enteral feeding pretreatment were excluded. Clinical and treatment data were obtained from prospectively recorded electronic clinical notes and planning software. RESULTS: Baseline patient characteristics and tumour-related parameters were captured for 225 patients. Based on the results of the univariate analysis and using a stepwise backwards selection process, clinical and dosimetric variables were selected to optimise a clinically predictive multivariate model, fitted using logistic regression. The parameters found to affect the probability, P, of requiring a nasogastric feeding tube for >4 weeks in our clinical multivariate model were: tumour site, tumour stage (early T0/1/2 stage versus advanced T3/T4 stage), chemotherapy drug (none versus any drug) and mean dose to the contralateral parotid gland. A scoring model using the regression coefficients of the selected variables in the clinical multivariate model achieved an area under the curve (AUC) of 0.745 (95% confidence interval 0.678-0.812), indicating good discriminative performance. Internal validation of the model involved splitting the dataset 80:20 into training and test datasets 10 times and assessing differences in AUC of the model fitted to these. CONCLUSIONS: We developed an easy-to-use prediction model based on both clinical and dosimetric parameters, which, once externally validated, can lead to more personalised treatment planning and inform clinical decision-making on the appropriateness of prophylactic versus reactive enteral feeding.

Improved survival prediction for oropharyngeal cancer beyond TNMv8.

PURPOSE: For oropharynx squamous cell carcinoma (OPSCC) this study aimed to: (i) compare 5-year overall survival (OS) stratification by AJCC/UICC TNM versions 7 (TNMv7) and 8 (TNMv8), (ii) determine whether changes to T and N stage groupings improve prognostication and (iii) develop and validate a model incorporating additional clinical characteristics to improve 5-year OS prediction. MATERIAL AND METHODS: All OPSCC treated with curative-intent at our institution between 2011 and 2017 were included. The primary endpoint was 5-year OS. Survival curves were produced for TNMv7 and TNMv8. A three-way interaction between T, N stage and p16 status was evaluated for improved prognostication. Cox proportional hazards modelling was used to derive a new predictive model. RESULTS: Of 750 OPSCC cases, 574 (77%) were p16-positive. TNMv8 was more prognostic than TNMv7 (concordance probability estimate [CPE] ±â€¯SE = 0.72 ±â€¯0.02 vs 0.53 ±â€¯0.02). For p16-positive disease, TNMv8 discriminated stages II vs I (HR 2.32, 95% CI 1.47-3.67) and III vs II (HR 1.75, 95% CI 1.13-2.72). For p16-negative disease, TNMv7 and TNMv8 demonstrated poor hazard discrimination. Different T, N stage and p16-status combinations did not improve prognostication after adjusting for other factors (CPE = 0.79 vs 0.79, p = 0.998). A model for p16-positive and p16-negative OPSCC including additional clinical characteristics improved 5-year OS prediction beyond TNMv8 (c-index 0.76 ±â€¯0.02). CONCLUSIONS: TNMv8 is superior to TNMv7 for p16-positive OPSCC, but both performed poorly for p16-negative disease. A novel model incorporating additional clinical characteristics improved 5-year OS prediction for both p16-positive and p16-negative disease.

Prospects for Personalised Treatment of Patients with Radioiodine-avid Locally Recurrent or Metastatic Thyroid Cancer.

Although most patients with metastatic or inoperable locally recurrent differentiated thyroid cancer have radioiodine-avid disease, the outcome for patients who do not achieve remission with radioiodine therapy is poor. Most centres use fixed empirical activities of radioiodine to treat these patients, which is in contrast to other areas of oncology, where there is a shift to more individualised treatment. The use of dosimetry techniques to calculate a more appropriate activity of radioiodine for each patient may increase the effectiveness of radioiodine therapy but is more complex, time-consuming and of unproven benefit. This review addresses some of the limitations of empirical radioiodine therapy, discusses existing dosimetry-based approaches to individualising therapy and proposes further work in this area. A prospective randomised controlled trial comparing empirical activities of radioiodine with activities guided by a combination of lesional dosimetry and maximum safe dose has not been carried out previously. Although considerable challenges in the design of such a study remain, a network of centres in the UK now has the potential to take this forward.

Ninety Day Mortality After Radical Radiotherapy for Head and Neck Cancer.

AIMS: Treatment for head and neck cancers using definitive radiotherapy, with or without chemotherapy, is associated with significant acute toxicity. Our aim was to assess 90 day mortality after radical radiotherapy. A further aim was to identify patient, tumour or treatment factors associated with early death after treatment and whether these could be used to predict outcomes. MATERIALS AND METHODS: In total, 1116 patients with squamous cell pharyngeal and larynx cancer between January 2011 and December 2015 were included. Patients with T1 larynx cancer were excluded. Patients were treated using radical radiotherapy, with or without chemotherapy. Ninety day mortality was calculated using survival of less than 135 days from the planned start date for radical radiotherapy, to include early deaths during and up to 90 days after treatment. RESULTS: Overall, 90 day mortality was 4.7%. Among the subgroup of patients treated with concurrent platinum chemotherapy, the 90 day mortality rate was 0.4%. Overall survival at 1, 3 and 5 years was 84%, 62% and 53%, respectively. Factors associated with a higher risk of early death included performance status > 1, haemoglobin <100 g/l, weight < 60 kg, age > 80 years and presence of multiple comorbidities. CONCLUSION: We report excellent crude overall survival rates among our radically treated cohort of head and neck cancer patients. Several factors were associated with an increased risk of death within 90 days of completion of radical head and neck radiotherapy. Given the potential severe acute effects and the impact on patient quality of life associated with radical head and neck radiotherapy, this information is helpful to inform treatment-related discussions with patients.

Polyamorphism in tetrahedral substances: Similarities between silicon and ice.

Tetrahedral substances, such as silicon, water, germanium, and silica, share various unusual phase behaviors. Among them, the so-called polyamorphism, i.e., the existence of more than one amorphous form, has been intensively investigated in the last three decades. In this work, we study the metastable relations between amorphous states of silicon in a wide range of pressures, using Monte Carlo simulations. Our results indicate that the two amorphous forms of silicon at high pressures, the high density amorphous (HDA) and the very high density amorphous (VHDA), can be decompressed from high pressure (∼20 GPa) down to the tensile regime, where both convert into the same low density amorphous. Such behavior is also observed in ice. While at high pressure (∼20 GPa), HDA is less stable than VHDA, at the pressure of 10 GPa both forms exhibit similar stability. On the other hand, at much lower pressure (∼5 GPa), HDA and VHDA are no longer the most stable forms, and, upon isobaric annealing, an even less dense form of amorphous silicon emerges, the expanded high density amorphous, again in close similarity to what occurs in ice.

Carotid dosimetry for T1 glottic cancer radiotherapy.

OBJECTIVE: Radiotherapy for T1 glottic cancer is commonly delivered using a lateral parallel opposed pair of megavoltage photon fields. There is increasing reported evidence of cerebrovascular events due to radiation-induced carotid stenosis. An alternative field arrangement is to use an anterior oblique technique. This study compares the carotid dosimetry between the two techniques and reviews the evidence for the risk of radiation-induced vascular events. METHODS: The radiotherapy plans of 10 patients with T1 glottic cancer treated with an anterior oblique technique were examined for carotid dose. Alternative plans were then created using a parallel opposed pair of fields and the dose to the carotids compared. All patients received 50 Gy in 16 fractions treating once daily, for 5 days in a week. RESULTS: The average of the mean dose to the carotids with the anterior oblique technique was 21 Gy compared with 37 Gy using the lateral parallel opposed pair arrangement (p < 0.0001). CONCLUSION: An anterior oblique field arrangement for the treatment of T1 glottic cancer results in a significantly lower radiation dose to the carotid arteries, which may be clinically important in terms of reducing the risk of cerebrovascular events in long-term survivors. ADVANCES IN KNOWLEDGE: Although the anterior oblique technique for treating early glottic cancers is well described, and it is predictable that the dose received by the carotid arteries should be lower with this technique, to our knowledge this is the first study to quantify that reduction in dose with a series of patients.

Pressure effects on the transitions between disordered phases in supercooled liquid silicon.

We investigate the pressure effects on the transitions between the disordered phases in supercooled liquid silicon through Monte Carlo simulations and efficient methods to compute free energies. Our calculations, using an environment dependent interatomic potential for Si, indicate that at zero pressure the liquid-liquid phase transition, between the high density liquid and the low density liquid, occurs at a temperature 325K below melting. We found that the liquid-liquid transition temperature decreases with increasing pressure, following the liquid-solid coexistence curve. As pressure increases, the liquid-liquid coexistence curve approaches the region where the glass transition between the low density liquid and the low density amorphous takes place. Above 5 GPa, our calculations show that the liquid-liquid transition is suppressed by the glassy dynamics of the system. We also found that above 5 GPa, the glass transition temperature is lower than that at lower pressures, suggesting that under these conditions the glass transition occurs between the high density liquid and the high density amorphous.