Dual-Fields Rotational Total Skin Electron Therapy: Investigation and Implementation

Purpose: To present a protocol of a dual-field rotational (DFR) total skin electron therapy (TSET) and to provide an assessment of clinical implementation, dosimetry properties, and skin dose evaluation. Methods and Materials: The DFR-TSET combined the Stanford 6-field and McGill rotational methods. Dual 6 MeV electron beams in high dose total skin electron mode were used for DFR-TSET on a commercial linac. Beam profiles and dosimetric properties were measured using solid phantoms. The dose rate at expanded source-to-surface distance (SSD) was a combination of static rate and rotational rate. In vivo dosimetry of patient skin was performed on patients’ skin using film, metal oxide semiconductor field-effect transistors (MOSFET), and optically stimulated luminescent dosimeters (OSLD). Results: Dual field rotational total skin electron therapy exhibited good (≤±10%) uniformity in the beam profiles in the vertical direction at an extended SSD of 332 cm with a gantry angulation of ±20˚ deviated from the horizontal direction. In-vivo measurements confirmed acceptable uniformity of the patients’ total body surfaces and revealed anatomically self-blocked or shielded areas where underdosing occurred. Conclusions: The clinical implementation of DFR-TSET effectively utilizes the special mode on a linac. This technique provides short beam-on times, uniform dose distribution, large treatment field, and reduced dose of x-ray contamination to the patients. In-vivo measurements indicate satisfactory delivery and dose uniformity of the prescribed dose. Electron boost fields are recommended at normal SSDs to address underdosed areas.

Novel therapeutic agents in the treatment of metastatic colorectal cancer

Over the past couple of decades considerable progress has been made in the management of metastatic colorectal cancers(mCRC) leading to a significant improvement in five-year survival. Although part of this success has been rightly attributed to aggressive surgical management and advances in other adjunct treatments, our understanding of the pathogenesis of cancer and emergence of newer molecular targets for colon cancer has created a powerful impact. In this review article we will discuss various targeted therapies in the management of mCRC. Newer agents on the horizon soon to be incorporated in clinical practice will be briefly reviewed as well.

Characteristics of clear cell renal cell carcinoma metastases to the thyroid gland: A systematic review

BACKGROUND Thyroid gland is an uncommon site for metastases from clear cell renal cell carcinoma(CCRCC)and literature is scarce.Due to the variable and often long lag time before development of metastases in patients with CCRCC,thyroid nodules may be misdiagnosed initially as benign.This systematic review aims at a better understanding of the nature of these metastases.METHODS A bibliographic search was performed using PubMed(1990-2019),key words being“renal cell carcinoma,thyroid,kidney cancer,clear cell.”147 cases were analyzed.The patient’s characteristics assessed were:age,sex,stage,size of metastases,lag time,diagnostic modality,initial symptoms,treatment and outcome in last documented follow up.Binary logistic regression,Spearman’s rho and ANOVA were used to identify differences between the existing variables.RESULTS The mean age(±SD)was 64±(10)years in males and 64(±11)in females.The mean lag time to diagnosis of thyroid metastases was 8.7(±6.3)years.Gender distribution of the patients was 46.3%male,52.4%female.There was a weak correlation between lag time and size of metastases,not statistically significant.Size of metastases was significantly higher in symptomatic patients(6.06±3.51 cm)compared to those with painless mass(4.6±0.29 cm)and asymptomatic ones(3.93±1.99 cm)(P=0.03).Fine Needle Aspiration was diagnostic in 29.4%of cases,47.1%were non diagnostic.Most patients(80.3%)underwent thyroid surgery.At 1 year follow up,55.6%of patients operated were alive versus 35.3%who did not have surgery,though this was not statistically significant(P=0.1).CONCLUSION A larger size of thyroid metastasis was more likely to present with symptomatology.A high index of suspicion is warranted when evaluating thyroid nodules in CCRCC patients.There was no significant difference in outcome between patients who underwent surgery and those who did not.With the wider use of immune check-point inhibitors and tyrosine kinase inhibitors in metastatic CCRCC,surgery may eventually be reserved only for palliative purposes.

Glecaprevir/pibrentasvir+sofosbuvir for post-liver transplant recurrent hepatitis C virus treatment

Glecaprevir/pibrentasvir in combination with sofosbuvir may serve as a safe and effective option for treatment of recurrent hepatitis C virus post-liver transplant in patients who previously failed direct-acting antivirals.

Bioresorbable Multilayer Photonic Cavities as Temporary Implants for Tether-Free Measurements of Regional Tissue Temperatures

Objective and Impact Statement.Real-time monitoring of the temperatures of regional tissue microenvironments can serve as the diagnostic basis for treating various health conditions and diseases.Introduction.Traditional thermal sensors allow measurements at surfaces or at near-surface regions of the skin or of certain body cavities.Evaluations at depth require implanted devices connected to external readout electronics via physical interfaces that lead to risks for infection and movement constraints for the patient.Also,surgical extraction procedures after a period of need can introduce additional risks and costs.Methods.Here,we report a wireless,bioresorbable class of temperature sensor that exploits multilayer photonic cavities,for continuous optical measurements of regional,deep-tissue microenvironments over a timeframe of interest followed by complete clearance via natural body processes.Results.The designs decouple the influence of detection angle from temperature on the reflection spectra,to enable high accuracy in sensing,as supported by in vitro experiments and optical simulations.Studies with devices implanted into subcutaneous tissues of both awake,freely moving and asleep animal models illustrate the applicability of this technology for in vivo measurements.Conclusion.The results demonstrate the use of bioresorbable materials in advanced photonic structures with unique capabilities in tracking of thermal signatures of tissue microenvironments,with potential relevance to human healthcare.

Migraine and stroke

Migraines are generally considered a relatively benign neurological condition.However,research has shown an association between migraines and stroke,and especially between migraine with aura and ischaemic stroke.Patients can also suffer from migrainous infarction,a subset of ischaemic stroke that often occurs in the posterior circulation of younger women.The exact pathogenesis of migrainous infarct is not known,but it is theorised that the duration and local neuronal energy level from cortical spreading depression may be a key factor.Other factors contributing to migrainous infarct may include vascular,inflammatory,endothelial structure,patent foramen ovale,gender,oral contraceptive pill use and smoking.Vasoconstrictors such as the triptan and ergot class are commonly used to treat migraines and may also play a role.Migraine is also shown to be correlated to haemorrhagic stroke,although studies do not demonstrate causation versus association,and further studies are warranted.There are also some rare genetic diseases such as cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy,retinal vasculopathy with cerebral leukodystrophy and others,which can cause both migraines and infarcts.On imaging,many migraineurs are found to have white matter changes similar to those seen in patients with stroke.These may be caused in part by alterations in resting cerebral blood flow and vasoconstrictor use.In treating patients with migraines,it is important to identify and modify any vascular risk factors such as hypertension,smoking,oral contraceptive pill use and lifestyle factors.Further studies will determine if more aggressive treatment of migraines can ultimately lead to fewer strokes in this population.

DNA damage and metabolic mechanisms of cancer drug resistance

Cancer drug resistance is one of the main barriers to overcome to ensure durable treatment responses.While many pivotal advances have been made in first combination therapies,then targeted therapies,and now broadening out to immunomodulatory drugs or metabolic targeting compounds,drug resistance is still ultimately universally fatal.In this brief review,we will discuss different strategies that have been used to fight drug resistance from synthetic lethality to tumor microenvironment modulation,focusing on the DNA damage response and tumor metabolism both within tumor cells and their surrounding microenvironment.In this way,with a better understanding of both targetable mutations in combination with the metabolism,smarter drugs may be designed to combat cancer drug resistance.

Utility of circulating tumor DNA for predicting prognosis in the management of resectable pancreatic cancer

Background:The measurement of circulating tumor DNA(ctDNA)has been studied in several malignancies,including metastatic pancreatic cancer,but less is known about its utility in monitoring treatment response and recurrence in resectable pancreatic cancer.Methods:We conducted a systematic review of the literature examining the association of ctDNA with overall survival(OS)and disease-free survival.Results:Five articles met our exclusion criteria.Baseline and/or postoperative ctDNA was found to be associated with decreased OS and recurrence-free survival.Discussion:ctDNA has the potential to be used as a prognostic biomarker and to guide therapy in resectable pancreatic cancer.