NTCP modelling of xerostomia after radiotherapy for oropharyngeal cancer using the PRO-CTCAE and CTCAE scoring systems at different time-points post-RT

PURPOSE

This study aims at determining the parameter values of three normal tissue complication probability (NTCP) models for the contralateral parotid gland, contralateral submandibular gland (SMG) and contralateral salivary glands regarding the endpoint of xerostomia 6-24 months after radiotherapy for oropharynx cancer.

METHODS

The treatment and outcome data of 231 patients with favorable risk, HPV-associated oropharyngeal squamous cell carcinoma are analyzed. 60 Gy intensity modulated radiotherapy was delivered to all the patients. The presence and severity of xerostomia was recorded (pre- and post- radiotherapy) by the PRO-CTCAE and the CTCAE scoring systems. In both scoring systems, patients with a change in symptom severity (from baseline) of ≥ 2 were considered responders.

RESULTS

Xerostomia was observed in 61.3 %, 39.2 %, 28.6 % and 27.0 % of the patients based on the PRO-CTCAE scoring system at 6-, 12-, 18- and 24-months post-RT, respectively. The AUCs of the contralateral salivary glands ranged between 0.58-0.64 in the LKB model with the gEUD ranging between 20.3 Gy and 24.7 Gy.

CONCLUSIONS

Based on the PRO-CTCAE scores, mean dose < 22 Gy, V50 < 10 % for the contralateral salivary glands and mean dose < 18 Gy, V45 < 10 % for the contralateral parotid were found to significantly reduce by a factor of 2-3 the risk for radiation induced xerostomia that is observed at 6-24 months post-RT, respectively. Also, gEUD < 22 Gy to the contralateral salivary glands and < 18 Gy to the contralateral parotid was found to significantly reduce the risk for radiation induced xerostomia that is observed at 6-24 months post-RT by 2.0-2.3 times.

Clinical impact of peri-device leaks following percutaneous left atrial appendage occlusion: a systematic review and meta-analysis

Background

Peri-device leaks (PDL) are quite common after left-atrial appendage occlusion (LAAO) given the complex anatomy of LAA and surrounding structures. However, there is uncertainty regarding the prognostic implications of PDL.

Material and methods

Literature search was conducted in MEDLINE (PubMed), EMBASE, Scopus by ELSEVIER and Cochrane Central Register of Controlled Trials (CENTRAL) databases until 12 October 2021. A random-effects meta-analysis was performed to assess the effect of PDL presence on thromboembolism, all-cause mortality and major bleeding occurrence. Sensitivity analyses accounted for: i. the combined AF ablation performance, ii. the anticoagulation strategy followed after LAAO, iii. mean PDL size, and iv. mean female percentage.

Results

Of 699 articles initially retrieved, 46 were deemed eligible for this analysis (9,184 AF patients undergoing LAAO out of whom 1,446 had PDL). PDL presence was significantly associated with elevated odds of thromboembolism (FIgure 1) [pooled odds ratio (pOR) 3.05, 95% confidence interval (CI) 1.94–4.81; I2=37%]; yet PDL was not significantly linked with mortality (pOR=0.86, 95% CI: 0.25–2.95; I2=69%) and major bleeding rates (0.95, 95% CI: 0.27–3.35; I2=72%). AF-ablation did not significantly interact with the prognostic impact of PDL when performed in conjunction with LAAO (p for subgroup= 0.17). Antiplatelet discharge medication affected the prognostic value of PDL (p for subgroup &lt;0.01 and =0.04, respectively). The prognostic significance of mean PDL size [peri-procedural or at 1–3 months or D(mean size)/D(time of follow-up)] on the risk of thromboembolism did not yield any significant association (p values &gt;0.05). Meta-regression analysis of the mean female percentage demonstrated a non-significant trend towards a positive linear correlation between female percentage and risk of thromboembolism (p=0.10) (FIgure 2).

Conclusions

This is the first meta-analysis on the prognostic impact of PDL after LAAO. The findings highlighted a significant association between PDL and thromboembolic events, warranting careful post-LAAO device surveillance.

Funding Acknowledgement

Type of funding sources: None.

A Cybersecurity Culture Survey Targeting Healthcare Critical Infrastructures

Recent studies report that cybersecurity breaches noticed in hospitals are associated with low levels of personnel’s cybersecurity awareness. This work aims to assess the cybersecurity culture in healthcare institutions from middle- to low-income EU countries. The evaluation process was designed and performed via anonymous online surveys targeting individually ICT (internet and communication technology) departments and healthcare professionals. The study was conducted in 2019 for a health region in Greece, with a significant number of hospitals and health centers, a large hospital in Portugal, and a medical clinic in Romania, with 53.6% and 6.71% response rates for the ICT and healthcare professionals, respectively. Its findings indicate the necessity of establishing individual cybersecurity departments to monitor assets and attitudes while underlying the importance of continuous security awareness training programs. The analysis of our results assists in comprehending the countermeasures, which have been implemented in the healthcare institutions, and consequently enhancing cybersecurity defense, while reducing the risk surface.

Prognostic implications of valvular heart disease in patients with non-valvular atrial fibrillation

Background

Atrial fibrillation (AF) and valvular heart disease (VHD) are frequently encountered in clinical practice, and often coexist, especially in the elderly population. Both conditions are associated with increased mortality and morbidity. Recent guidelines suggest careful evaluation of patients with AF and VHD due to the puzzling nature of their coexistence.

Purpose

To evaluate the prognostic effect of significant valvular heart disease (sVHD) among patients with non-valvular AF.

Methods

This is a post-hoc analysis of the MISOAC-AF trial (NCT02941978). Consecutive inpatients with non-valvular AF who underwent echocardiography were included. sVHD was defined as the presence of at least moderate aortic stenosis (AS) or aortic/mitral/tricuspid regurgitation (AR/MR/TR). Cox regression analyses with covariate adjustments were used for outcome prediction.

Results

In total, 983 patients with non-valvular AF (median age 76 years) were analyzed over a median follow-up period of 32 months. sVHD was diagnosed in 575 (58.5%) AF patients. sVHD was associated with all-cause mortality (21.6%/yr vs. 1.6%/yr; adjusted HR [aHR] 1.55, 95% confidence interval [CI] 1.17–2.06; p=0.02), cardiovascular mortality (16%/yr vs. 4%/yr; aHR1.70, 95% CI 1.09–2.66; p=0.02) and heart failure-hospitalization (5.8%/yr vs. 1.8%/yr; aHR 2.53, 95% CI 1.35–4.63; p=0.02). The prognostic effect of sVHD was particularly evident in patients aged &lt;80 years and in those without history of heart failure (p for interaction &lt;0.05, in both subgroups) [Figure 1]. After multivariable adjustment, moderate/severe AS and TR were associated with mortality, while AS and MR with heart failure-hospitalization [Figure 2]. AS was the only independent predictor of valve intervention during follow-up (aHR 10.78, 95% CI 4.80–24.22; p&lt;0.001). Mixed aortic valve disease (AS+AR) had superior prognostic power across patterns of combined VHD.

Conclusions

Among patients with non-valvular AF, sVHD was highly prevalent, and beared high prognostic value across a wide spectrum of clinical outcomes. AS, MR, TR and mixed aortic valve disease were associated with worse prognosis.

Funding Acknowledgement

Type of funding sources: None. Subgroup analyses by VHD statusPrognostic impact of valve lesions

Hospitals' Cybersecurity Culture during the COVID-19 Crisis

The coronavirus pandemic led to an unprecedented crisis affecting all aspects of the concurrent reality. Its consequences vary from political and societal to technical and economic. These side effects provided fertile ground for a noticeable cyber-crime increase targeting critical infrastructures and, more specifically, the health sector; the domain suffering the most during the pandemic. This paper aims to assess the cybersecurity culture readiness of hospitals' workforce during the COVID-19 crisis. Towards that end, a cybersecurity awareness webinar was held in December 2020 targeting Greek Healthcare Institutions. Concepts of cybersecurity policies, standards, best practices, and solutions were addressed. Its effectiveness was evaluated via a two-step procedure. Firstly, an anonymous questionnaire was distributed at the end of the webinar and voluntarily answered by attendees to assess the comprehension level of the presented cybersecurity aspects. Secondly, a post-evaluation phishing campaign was conducted approximately four months after the webinar, addressing non-medical employees. The main goal was to identify security awareness weaknesses and assist in drafting targeted assessment campaigns specifically tailored to the health domain needs. This paper analyses in detail the results of the aforementioned approaches while also outlining the lessons learned along with the future scientific routes deriving from this research.

Prognostic significance of diabetes mellitus in patients with atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Background

Despite the plethora of studies on atrial fibrillation (AF) and diabetes mellitus (DM), there is still no sufficient data on the blood glucose regulation as a prognostic modifier in DM patients with AF.

Purpose

The purpose of this study was to investigate the association of DM and levels of glycated hemoglobin (HbA1c) with outcomes in patients with AF.

Methods

This retrospective cohort study included patients who were recently hospitalized with a primary or secondary diagnosis of AF from December 2015 through June 2018. Kaplan-Meier curves and Cox-regression adjusted hazard ratios (aHR) were calculated for the primary outcome of all-cause mortality and for the secondary outcomes of cardiovascular (CV) mortality, stroke and the composite outcome of CV death or hospitalization. Spline curve models were fitted to investigate associations of HbA1c values and mortality among patients with AF and DM.

Results

In total 1140 AF patients were included, of whom 373 (32.7%) had DM. During a median follow-up of 2.6 years, 414 (37.3%) patients died. The presence of DM was associated with a higher risk of all-cause mortality (aHR = 1.44, 95% confidence intervals [CI]: 1.12-1.85), CV mortality (aHR = 1.44, 95% CI: 1.08-1.93), stroke (aHR = 2.62, 95% CI: 1.24-5.53) and the composite outcome of hospitalization or CV death (aHR = 1.28, 95% CI: 1.06-1.54). In AF patients with comorbid DM, the spline curves showed a positive linear association between HbA1c levels and outcomes, with values &lt;6.2% predicting significantly decreased all-cause and CV mortality.

Conclusions

The presence of DM on top of AF was associated with a 1.5-fold increased risk for all-cause or CV mortality and excess morbidity. HbA1c levels lower than 6.2% were independently related to better survival rates. Follow-up outcomes by presence of DMOutcomeDMNon-DMAdjusted HR(95% CI)p-valueAll-cause death171/373 (45.8%)243/736 (33%)1.44 (1.12-1.85)&lt;0.001CV-death130/373 (34.9%)173/736 (23.5%)1.44 (1.08-1.93)&lt;0.001Major bleeding18/340 (5.3%)29/644 (4.5%)1.53 (0.71-3.28)0.291Stroke24/340 (7.1%)28/645 (4.3%)2.62 (1.24-5.53)0.013AF-related hospitalization59/340 (17.4%)115/645 (17.8%)1.20 (0.78-1.85)0.281HF-related hospitalization35/333 (10.5%)46/640 (7.2%)1.34 (0.83-2.19)0.235Hospitalization or CV-death243/373 (65.1%)399/736(54.2%)1.28 (1.06-1.54)&lt;0.001*Adjusted for: age, gender, smoking, BMI, history of hypertension, eGFR (CKD-EPI) and use of statin, ACEI-ARB, OAC and rate control medication after discharge.DM, diabetes mellitus; HR, hazard ratio; AF, atrial fibrillation; CV, cardiovascular; HF, heart failure.Abstract Figure. Visual overview of the study

Polypharmacy and major adverse events in atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Background

Polypharmacy has been defined as the daily use of more than 4 drugs, by an individual, regardless of the condition(s) they have been prescribed for and their efficacy. The burden of polypharmacy pertains to adverse drug reactions, disability, frequent and longtime hospitalization and long-term mortality. The prevalence of polypharmacy exceeds 10% in most adult age groups and particularly in the elderly. At the same time, atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia, afflicting more than 8% of the elderly and those with multiple comorbidities.

Purpose

The purpose of this study was to examine the association between the presence of polypharmacy and outcomes among AF patients.

Methods

This is a retrospective analysis among 1140 patients enrolled in the MISOAC-AF trial. All cause- and cardiovascular- mortality have been defined as primary endpoints. Independent clinical predictors of polypharmacy and of major adverse outcomes were identified via bootstrapped multivariate logistic and Cox regression analysis, respectively.

Results

The mean number of prescribed medications at patients’ discharge was 3.9 ± 1.6 and polypharmacy (use of more than 4 medications daily) was found in 36.9% of the patients. Smoking (p = 0.036), dyslipidemia (p &lt; 0.001), coronary artery disease (p &lt; 0.001), heart failure (HF; p = 0.003) and chronic kidney disease (p &lt; 0.001) were independent predictors of polypharmacy among AF paients. Kaplan–Meier survival analysis showed that AF patients with polypharmacy have significantly greater risk of CV death (p = 0.040), while Cox regression analysis indicated polypharmacy as an independent predictor for all-cause and CV- mortality [adjusted hazard ratios: 1.31(1.03 - 1.67) and 1.39(1.05 - 1.84), respectively] and for the composite outcome of AF- or HF- related hospitalization or CV death [adjusted hazard ratio: 1.31 (1.05 - 1.63)].

Conclusion

This study highlights the implications of polypharmacy in the context of AF, a prevalent, chronic, life-threatening condition. Investigating polypharmacy is quite relevant in the era of pharmacovigilance, contributing to rational pharmacotherapy with regard to cardiovascular conditions and beyond. Abstract Figure. Mortality rates by polypharmacy presence

Digoxin and association with mortality in patients discharged from hospital with atrial fibrillation, with or without heart failure

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

MISOAC- AF study group

BACKGROUND

Digoxin is widely used in atrial fibrillation (AF) and heart failure (AF). However, established evidence is conflicting regarding its association with clinical outcomes.

AIM

To investigate the relation between digoxin and adverse outcomes in patients with AF, with or without HF, in a contemporary AF cohort.

METHODS

We performed a retrospective analysis of data from 698 patients, originating from the MISOAC- AF (Motivational Interviewing to Support Oral AntiCoagulation Adherence in patients with non-valvular Atrial Fibrillation) trial, and followed over a median of 2.5 years. HF was denoted at baseline. The primary outcome was all-cause mortality and the secondary outcome was all-cause hospitalization, in a time-to-event analysis. Propensity scores were used to derive matched populations, balanced on key baseline covariates. To limit potential confounding, we also implemented inverse probability of treatment weighting (IPTW) analysis.

RESULTS

Among patients with HF, 10.5% (n = 39) were administered digoxin at baseline, whereas 89.5% (n = 331) were not. Digoxin administration was not associated with an increased risk of death (hazard ratio (HR) in the digoxin group, 1.21; 95% Confidence Interval (CI), 0.69 to 2.13, p = 0.5) or hospitalization of any cause (HR 1.15; 95% CI, 0.67 to 1.96; p = 0.6). Among patients without HF, 3.5% (n = 11) were administered digoxin, with neutral effects on all-cause mortality (HR: 3.25; 95% CI, 0.98 to 10.70), p = 0.06) and all-cause hospitalization (HR, 1.15; 95% CI, 0.67 to 1.96, p = 0.60). Consistent qualitatively results were observed using IPTW.

CONCLUSIONS

Among patients with AF, digoxin administration was not associated with an increased risk of death and hospitalization of any cause, irrespective of HF status. Abstract Figure.

Mortality in patients with atrial fibrillation with or without heart failure following hospital discharge

Background

The association of heart failure (HF) with the prognosis of atrial fibrillation (AF) remains unclear.

OBJECTIVES

To assess all-cause mortality in patients following hospitalization with comorbid AF in relation to the presence of HF.

Methods

We performed a cross-sectional analysis of data from 977 patients discharged from the cardiology ward of a single tertiary center between 2015 and 2018 and followed for a median of 2 years. The association between HF and the primary endpoint of death from any cause was assessed using multivariable Cox regression.

Results

HF was documented in 505 (51.7%) of AF cases at discharge, including HFrEF (17.9%), HFmrEF (16.5%) and HFpEF (25.2%). A primary endpoint event occurred in 212 patients (42%) in the AF-HF group and in 86 patients (18.2%) in the AF-no HF group (adjusted hazard ratio [aHR] 2.27; 95% confidence interval [CI], 1.65 to 3.13; P&lt;0.001). HF was associated with a higher risk of the composite secondary endpoint of death from any cause, AF or HF-specific hospitalization (aHR 1.69; 95% CI 1.32 to 2.16 p&lt;0.001). The associations of HF with the primary and secondary endpoints were significant and similar for AF-HFrEF, AF-HFmrEF, AF-HFpEF.

Conclusions

HF was present in half of the patients discharged from the hospital with comorbid AF. The presence of HF on top of AF was independently associated with a significantly higher risk of all-cause mortality than did absence of HF, irrespective of HF subtype.

Funding Acknowledgement

Type of funding source: None

Motivational Interviewing to Support Oral AntiCoagulation adherence in patients with non-valvular Atrial Fibrillation (MISOAC-AF): a randomised clinical trial

Background

Oral anticoagulation (OAC) is paramount to effective thromboprophylaxis; yet adherence to OAC remains largely suboptimal in patients with atrial fibrillation (AF).

Purpose

We aimed to assess the impact of an educational, motivational intervention on the adherence to OAC in patients with non-valvular AF.

Methods

Hospitalised patients with non-valvular AF who received OAC were randomly assigned to usual medical care or a proactive intervention, comprising motivational interviewing and tailored counseling on medication adherence. The primary study outcome was adherence to OAC at 1-year, evaluated as Proportion of Days Covered (PDC) by OAC regimens and assessed through nationwide prescription registers. Secondary outcomes included the rate of persistence to OAC, gaps in treatment, proportion of VKA-takers with labile INR (defined as time to therapeutic range&lt;70%) and clinical events.

Results

A total of 1009 patients were randomised, 500 in the intervention group and 509 in the control group. At 1-year follow-up, 77.2% (386/500) of patients in the intervention group had good adherence (PDC&gt;80%), compared with 55% (280/509) in the control group (adjusted odds ratio 2.84, 95% confidence interval 2.14–3.75; p&lt;0.001). Mean PDC±SD was 0.85±0.26 and 0.75±0.31, respectively (p&lt;0.001). Patients that received the intervention were more likely to persist in their OAC therapy at 1 year, while usual medical care was associated with more major (≥3 months) treatment gaps [Figure]. Among 212 VKA-takers, patients in the intervention group were less likely to have labile INR compared with those in the control group [21/120 (17.1%) vs 34/92 (37.1%), OR 0.33 95% CI 1.15–0.72, p=0.005]. Clinical events over a median follow-up period of 2 years occurred at a numerically lower, yet non-significant, rate in the intervention group [Table].

Conclusions

In patients receiving OAC therapy for non-valvular AF, a motivational intervention significantly improved patterns of medication adherence, without significantly affecting clinical outcomes.

Primary and secondary outcomes

Funding Acknowledgement

Type of funding source: None

P1869A novel risk score to predict mortality in patients with atrial fibrillation: the BLACCK (AF) death risk score

Background

Prior risk stratification schemes for atrial fibrillation (AF) have extensively focused on stroke as the principal outcome. However, an accurate estimation of the risk of death in patients with AF has received disproportional attention.

Purpose

The aim of this study was to develop and validate a risk score for predicting mortality in patients with AF who underwent a hospitalization for cardiac reasons.

Methods

The new risk score was developed and internally validated in 887 patients with AF, who were followed up for a median of 2 years. The outcome measure was all-cause mortality. Biomarker samples, echocardiographic data and renal function values were obtained at the date closest to hospital discharge. A Cox-model that determined the variables that significantly contributed to the prediction of all-cause mortality, was adapted to a risk points system through weighting of the model coefficients. The model was internally validated by bootstrapping, assessing both discrimination and calibration.

Results

311 all-cause deaths were reported during 1755 person-years of follow-up (incidence rate 17.7 events per 100 person-years). The most important predictors of death were N-terminal pro B-type natriuretic peptide (NT-proBNP), high-sensitivity troponin-T (hs-TnT), left atrial area indexed to body surface area (LAAi), prior cardiac arrest, kidney impairment, congestive heart failure and age, and were included in the BLACCK (AF) death risk score. The score was well-calibrated (observed probabilities adjusted to predicted probabilities) and showed good discriminative ability [c-index 0.87 (95% CI 0.85–0.90)]. The internal validation of the score reported minimal over-fitting (optimism-corrected c-index of 0.85). The 1, 2 and 3-year risk of death derived by the score's total points may be calculated immediately through the nomogram (Figure 1).

BLACCK (AF) risk score nomogram

Conclusions

We developed a simple, well-calibrated and internally validated novel risk score for predicting 1, 2 and 3-year risk of death in patients with AF after a hospitalization for cardiac reasons. The BLACCK (AF) death risk score included both cardiac biomarkers and clinical information, performed well and may assist physicians in decision-making when treating patients with AF.

Radiobiological Evaluation of Breast Cancer Radiotherapy Accounting for the Effects of Patient Positioning and Breathing in Dose Delivery. A Meta Analysis

In breast cancer radiotherapy, significant discrepancies in dose delivery can contribute to underdosage of the tumor or overdosage of normal tissue, which is potentially related to a reduction of local tumor control and an increase of side effects. To study the impact of these factors in breast cancer radiotherapy, a meta analysis of the clinical data reported by Mavroidis et al. (2002) in Acta Oncol (41:471–85), showing the patient setup and breathing uncertainties characterizing three different irradiation techniques, were employed. The uncertainties in dose delivery are simulated based on fifteen breast cancer patients (5 mastectomized, 5 resected with negative node involvement (R-) and 5 resected with positive node involvement (R+)), who were treated by three different irradiation techniques, respectively. The positioning and breathing effects were taken into consideration in the determination of the real dose distributions delivered to the CTV and lung in each patient. The combined frequency distributions of the positioning and breathing distributions were obtained by convolution. For each patient the effectiveness of the dose distribution applied is calculated by the Poisson and relative seriality models and a set of parameters that describe the dose-response relations of the target and lung. The three representative radiation techniques are compared based on radiobiological measures by using the complication-free tumor control probability, P+ and the biologically effective uniform dose, D̿ concepts. For the Mastectomy case, the average P+ values of the planned and delivered dose distributions are 93.8% for a D̿CTV of 51.8 Gy and 85.0% for a D̿CTV of 50.3 Gy, respectively. The respective total control probabilities, PB values are 94.8% and 92.5%, whereas the corresponding total complication probabilities, PI values are 0.9% and 7.4%. For the R- case, the average P+ values are 89.4% for a D̿CTV of 48.9 Gy and 88.6% for a D̿CTV of 49.0 Gy, respectively. The respective PB values are 89.8% and 89.9%, whereas the corresponding PI values are 0.4% and 1.2%. For the R+ case, the average P+ values are 86.1% for a D̿CTV of 49.2 Gy and 85.5% for a D̿CTV of 49.1 Gy, respectively. The respective PB values are 90.2% and 90.1%, whereas the corresponding PI values are 4.1% and 4.6%. The combined effects of positioning uncertainties and breathing can introduce a significant deviation between the planned and delivered dose distributions in lung in breast cancer radiotherapy. The positioning and breathing uncertainties do not affect much the dose distribution to the CTV. The simulated delivered dose distributions show larger lung complication probabilities than the treatment plans. This means that in clinical practice the true expected complications are underestimated. Radiation pneumonitis of Grade 1–2 is more frequent and any radiotherapy optimization should use this as a more clinically relevant endpoint.

Investigating the Clinical Aspects of Using CT vs. CT-MRI Images during Organ Delineation and Treatment Planning in Prostate Cancer Radiotherapy

In order to apply highly conformal dose distributions, which are characterized by steep dose fall-offs, it is necessary to know the exact target location and extension. This study aims at evaluating the impact of using combined CT-MRI images in organ delineation compared to using CT images alone, on the clinical results. For 10 prostate cancer patients, the respective CT and MRI images at treatment position were acquired. The CTV was delineated using the CT and MRI images, separately, whereas bladder and rectum were delineated using the CT images alone. Based on the CT and MRI images, two CTVs were produced for each patient. The mutual information algorithm was used in the fusion of the two image sets. In this way, the structures drawn on the MRI images were transferred to the CT images in order to produce the treatment plans. For each set of structures of each patient, IMRT and 3D-CRT treatment plans were produced. The individual treatment plans were compared using the biologically effective uniform dose ([Formula: see text]) and the complication-free tumor control probability ( P+) concepts together with the DVHs of the targets and organs at risk and common dosimetric criteria. For the IMRT treatment, at the optimum dose level of the average CT and CT-MRI delineated CTV dose distributions, the P+ values are 74.7% in both cases for a [Formula: see text] of 91.5 Gy and 92.1 Gy, respectively. The respective average total control probabilities, PB are 90.0% and 90.2%, whereas the corresponding average total complication probabilities, PI are 15.3% and 15.4%. Similarly, for the 3D-CRT treatment, the average P+ values are 42.5% and 46.7%, respectively for a [Formula: see text] of 86.4 Gy and 86.7 Gy, respectively. The respective average PB values are 80.0% and 80.6%, whereas the corresponding average PI values are 37.4% and 33.8%, respectively. For both radiation modalities, the improvement mainly stems from the better sparing of rectum. According to these results, the expected clinical effectiveness of IMRT can be increased by a maximum Δ P+ of around 0.9%, whereas of 3D-CRT by about 4.2% when combined CT-MRI delineation is performed instead of using CT images alone. It is apparent that in both IMRT and 3D-CRT radiation modalities, the better knowledge of the CTV extension improved the produced dose distribution. It is shown that the CTV is irradiated more effectively, while the complication probabilities of bladder and rectum, which is the principal organs at risk, are lower in the CT-MRI based treatment plans.

Toolkit for determination of dose-response relations, validation of radiobiological parameters and treatment plan optimization based on radiobiological measures

Accurately determined dose-response relations of the different tumors and normal tissues should be estimated and used in the clinic. The aim of this study is to demonstrate developed tools that are necessary for determining the dose-response parameters of tumors and normal tissues, for clinically verifying already published parameter sets using local patient materials and for making use of all this information in the optimization and comparison of different treatment plans and radiation techniques. One of the software modules (the Parameter Determination Module) is designed to determine the dose-response parameters of tumors and normal tissues. This is accomplished by performing a maximum likelihood fitting to calculate the best estimates and confidence intervals of the parameters used by different radiobiological models. Another module of this software (the Parameter Validation Module) concerns the validation and compatibility of external or reported dose-response parameters describing tumor control and normal tissue complications. This is accomplished by associating the expected response rates, which are calculated using different models and published parameter sets, with the clinical follow-up records of the local patient population. Finally, the last module of the software (the Radiobiological Plan Evaluation Module) is used for estimating and optimizing the effectiveness a treatment plan in terms of complication-free tumor control, P(+). The use of the Parameter Determination Module is demonstrated by deriving the dose-response relation of proximal esophagus from head and neck cancer radiotherapy. The application of the Parameter Validation Module is illustrated by verifying the clinical compatibility of those dose-response parameters with the examined treatment methodologies. The Radiobiological Plan Evaluation Module is demonstrated by evaluating and optimizing the effectiveness of head and neck cancer treatment plans. The results of the radiobiological evaluation are compared against dosimetric criteria. The presented toolkit appears to be very convenient and efficient for clinical implementation of radiobiological modeling. It can also be used for the development of a clinical data and health information database for assisting the performance of epidemiological studies and the collaboration between different institutions within research and clinical frameworks.

Multiple variations in the branching pattern of the abdominal aorta

We report on a unique clinically and surgically significant case of multiple abdominal aorta variations. Specifically, the left inferior phrenic, left gastric and splenic artery arose in common from the left aspect of the aorta constituting a common phrenogastrosplenic trunk, while the common hepatic artery originated separately from the midline of the anterior aspect of the aorta just inferiorly to the trunk. An accessory right hepatic artery arises from the right-anterior aspect of the abdominal aorta adjacent to superior mesenteric artery origin. On the left side, two renal arteries were observed. Moreover, the left gonadal artery exhibited a high origin, arising inferiorly to the upper left renal artery. We discuss about the embryological development of abdominal aorta arterial abnormalities and we attempt to sort the noticed variations according to existing classification in the literature. It is highlighted that the thorough knowledge of these arterial variations is important for the success of upper abdomen surgical operations such as liver and kidney transplantation, kidney preservation, abdominal aorta related vascular surgery, treatment of hepatocellular carcinoma by transcatheter arterial chemoembolizations as well as imaging interpretation of the region. Preoperative selective angiography or other abdominal aorta imaging studies are helpful for arterial variation demonstration and a precious tool for appropriate surgery planning.