Viability of focal dose escalation to prostate cancer intraprostatic lesions using HDR prostate brachytherapy.

PURPOSE: This study aimed to determine the viability of focal dose escalation to prostate cancer intraprostatic lesions (IPLs) from multiparametric magnetic resonance (mpMRI) and prostate-specific membrane antigen positron emission tomography (PSMA-PET) images using high-dose-rate (HDR) prostate brachytherapy (pBT). METHODS AND MATERIALS: Retrospective data from 20 patients treated with HDR pBT was utilized. The interobserver contouring variability of 5 observers was quantified using the dice similarity coefficient (DSC) and mean distance to agreement (MDA). Uncertainty in propagating IPL contours to trans-rectal ultrasound (TRUS) was quantified using a tissue equivalent prostate phantom. Feasibility of incorporating IPLs into HDR pBT planning was tested on retrospective patient data. RESULTS: The average observer DSC was 0.65 (PSMA-PET) and 0.52 (mpMRI). The uncertainty in propagating IPL contours was 0.6 mm (PSMA-PET), and 0.4 mm (mpMRI). Uncertainties could be accounted for by expanding IPL contours by 2 mm to create IPL PTVs. The mean D98% achieved using HDR pBT was 166% and 135% for the IPL and IPL PTV contours, respectively. CONCLUSIONS: Focal dose escalation to IPLs identified on either PSMA-PET or mpMRI is viable using TRUS-based HDR pBT. Utilizing HDR pBT allows dose escalation of up to 166% of the prescribed dose to the prostate.

Evaluation of the introduction of a 'traffic light protocol' for dose-volume histogram constraints of organs at risk in definitive radiotherapy at Liverpool and Macarthur Cancer Therapy Centres.

INTRODUCTION: Protocols have been developed in our department with recommended dose constraints for organs at risk (OAR) for each tumour site receiving definitive radiotherapy. We have developed a colour coding system to indicate when constraints are meeting objectives (green), have minor variation from planning objectives (yellow) and have major variation from planning objectives (red). We performed a quality audit to assess adherence to the protocol and to determine the rate of acute and subacute toxicities. METHODS: All definitive radiotherapy dose-volume histogram (DVH) reports generated in the first 6 months of 2017 at Liverpool and Macarthur cancer therapy centres were collected. For each radiotherapy group, the overridden dose constraints were evaluated and categorized to red and yellow. For all patients in our data set, follow-up documents/assessments were searched for grade 3 or higher acute or subacute radiotherapy toxicity and compared with those who had overridden dose constraints. RESULTS: There were 210 (34%) plans accepted with at least one major variation and 161 (26%) plans with minor variation. Head and neck group had the most rate of major variations (77%). The best groups in adherence to protocol were lymphoma and breast groups. In general, grade 3 toxicity was observed in 1%, 4% and 9% of patients who were in green, yellow and red categories. Overall, we noted a correlation with grade 3 toxicities between acceptable plans (green) and ones with a minor or major variation (yellow or red) (1% vs. 7% P = 0.0001). CONCLUSION: In conclusion this study showed an increased risk of higher grade toxicities when DVHs were beyond our departmental constraints using a 'Traffic Light System'. With this new colour coding system, we can facilitate auditing of the dose constraints in order to improve the quality of radiotherapy plans and potentially provide benchmarking for reducing toxicities in radiotherapy treatments.

High prevalence of chronic kidney disease in Iran: a large population-based study.

BACKGROUND: Chronic kidney disease (CKD) is a global public health threat, associated with an alarming increase in morbidity and mortality. The importance is the worldwide increase in its incidence and prevalence. METHODS: In this cross-sectional study, we estimate the prevalence and determine the associated factors of chronic kidney disease in a representative sample of 10063 participants aged over 20 years, in Tehran, Iran. Chronic kidney disease was defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m2. Glomerular filtration rate was estimated from abbreviated prediction equation provided by the Modification of Diet in Renal Disease study (MDRD). RESULTS: Overall prevalence of CKD with the abbreviated MDRD equation was 18.9% (95% confidence interval (CI) 18.2, 20.6). Age adjusted prevalence of CKD was 14.9% (95%CI 14.2, 15.6). Factors associated to CKD include age(years)(odds ratio(OR) 1.1, 95% CI 1.0 to 1.2), female gender (OR 3.1, 95% CI 2.6, 3.7), BMI (BMI 25 to <30 OR 1.5, 95% CI 1.3, 1.8 and BMI > or = 30 OR 1.6, 95% CI 1.3, 2.0), high waist circumference (OR 1.2, 95% CI 1.1, 1.4), hypertension (OR 1.2, 95% CI 1.1, 1.4), and dyslipidemia (OR 1.3, 95% CI 1.1, 1.5). CONCLUSION: CKD with its high prevalence poses a definite health threat in Iran.

Merkel Cell Carcinoma: When Does Size Matter for Radiotherapy?

Merkel cell carcinoma is a very aggressive, rare cancer of the skin. It has a high propensity for local, regional, and distant recurrence and has recently been associated with a viral etiology from the recently diagnosed Merkel Cell Polyoma Virus. The optimal management remains controversial. We discuss the case of a man with a 26 cm axillary lymph node metastasis of unknown primary treated with radiotherapy.