Impaired electrical activity of the brain explains the onset of dementia in aging people.

Aging brains that share many cognitive deficits with the early stages of Alzheimer's-type dementias are not caused by toxic protein deposits but by somatic mutations that impair synaptic signaling. These mutant proteins that contribute to neuronal action potentials could be biomarkers of functional defects that offer new approaches to diagnosis and treatment.

Efficacy of extracranial stereotactic body radiation therapy (SBRT) added to standard treatment in patients with solid tumors (breast, prostate and non-small cell lung cancer) with up to 3 bone-only metastases: study protocol for a randomised phase III trial (STEREO-OS).

BACKGROUND: Stereotactic Body Radiation Therapy (SBRT) is an innovative modality based on high precision planning and delivery. Cancer with bone metastases and oligometastases are associated with an intermediate or good prognosis. We assume that prolonged survival rates would be achieved if both the primary tumor and metastases are controlled by local treatment. Our purpose is to demonstrate, via a multicenter randomized phase III trial, that local treatment of metastatic sites with curative intent with SBRT associated of systemic standard of care treatment would improve the progression-free survival in patients with solid tumor (breast, prostate and non-small cell lung cancer) with up to 3 bone-only metastases compared to patients who received systemic standard of care treatment alone. METHODS: This is an open-labeled randomized superiority multicenter phase III trial. Patients with up to 3 bone-only metastases will be randomized in a 1:1 ratio.between Arm A (Experimental group): Standard care of treatment & SBRT to all bone metastases, and Arm B (Control group): standard care of treatment. For patients receiving SBRT, radiotherapy dose and fractionation depends on the site of the bone metastasis and the proximity to critical normal structures. This study aims to accrue a total of 196 patients within 4 years. The primary endpoint is progression-free survival at 1 year, and secondary endpoints include Bone progression-free survival; Local control; Cancer-specific survival; Overall survival; Toxicity; Quality of life; Pain score analysis, Cost-utility analysis; Cost-effectiveness analysis and Budget impact analysis. DISCUSSION: The expected benefit for the patient in the experimental arm is a longer expectancy of life without skeletal recurrence and the discomfort, pain and drastic reduction of mobility and handicap that the lack of local control of bone metastases eventually inflicts. TRIALS REGISTRATION: ClinicalTrials.gov NCT03143322 Registered on May 8th 2017. Ongoing study.

De novo digenic mutations of telomere-associated proteins and inflammasomes initiate many chronic human diseases: a hypothesis.

Many age-related human diseases have inflammatory components of uncertain causes. It has been proposed that some may be initiated or sustained by doubly mutated immune cells that have both inappropriately activated inflammasomes and enhanced replicative potential. Genes of cells that express mutant TERT and NLRP3 proteins are presumed to be at increased risk for mutagenesis because they reside in subtelomeric regions of chromatin that are deficient in DNA repair mechanisms. Expanded clones of proinflammatory cells can occur throughout one's lifetime and could represent an alternative explanation for some forms of pathologic scarring that are now attributed to truncated telomeres.-Marchesi, V. T. De novo digenic mutations of telomere-associated proteins and inflammasomes initiate many chronic human diseases: a hypothesis.

Gain-of-function somatic mutations contribute to inflammation and blood vessel damage that lead to Alzheimer dementia: a hypothesis.

Amyloid deposits are a characteristic feature of advanced Alzheimer dementia (AD), but whether they initiate the disease or are a consequence of it remains an unsettled question. To explore an alternative pathogenic mechanism, I propose that the triggering events that begin the pathogenic cascade are not amyloid deposits but damaged blood vessels caused by inflammatory reactions that lead to ischemia, amyloid accumulation, axonal degeneration, synaptic loss, and eventually irreversible neuronal cell death. Inflammation and blood vessel damage are well recognized complications of AD, but what causes them and why the cerebral microvasculature is affected have never been adequately addressed. Because heritable autosomal dominant mutations of NLRP3, APP, TREX1, NOTCH3, and Col4A1 are known to provoke inflammatory reactions and damage the brain in a wide variety of diseases, I propose that one or more low abundant, gain-of-function somatic mutations of the same 5 gene families damage the microvasculature of the brain that leads to dementia. This implies that the pathogenic triggers that lead to AD are derived not from external invaders or amyloid but from oxidative damage of our own genes.

Alzheimer's disease and CADASIL are heritable, adult-onset dementias that both involve damaged small blood vessels.

This essay explores an alternative pathway to Alzheimer's dementia that focuses on damage to small blood vessels rather than late-stage toxic amyloid deposits as the primary pathogenic mechanism that leads to irreversible dementia. While the end-stage pathology of AD is well known, the pathogenic processes that lead to disease are often assumed to be due to toxic amyloid peptides that act on neurons, leading to neuronal dysfunction and eventually neuronal cell death. Speculations as to what initiates the pathogenic cascade have included toxic abeta peptide aggregates, oxidative damage, and inflammation, but none explain why neurons die. Recent high-resolution NMR studies of living patients show that lesions in white matter regions of the brain precede the appearance of amyloid deposits and are correlated with damaged small blood vessels. To appreciate the pathogenic potential of damaged small blood vessels in the brain, it is useful to consider the clinical course and the pathogenesis of CADASIL, a heritable arteriopathy that leads to damaged small blood vessels and irreversible dementia. CADASIL is strikingly similar to early onset AD in that it is caused by germ line mutations in NOTCH 3 that generate toxic protein aggregates similar to those attributed to mutant forms of the amyloid precursor protein and presenilin genes. Since NOTCH 3 mutants clearly damage small blood vessels of white matter regions of the brain that lead to dementia, we speculate that both forms of dementia may have a similar pathogenesis, which is to cause ischemic damage by blocking blood flow or by impeding the removal of toxic protein aggregates by retrograde vascular clearance mechanisms.

Adjuvant pulse-dose-rate brachytherapy for oral cavity and oropharynx carcinoma: Outcome and toxicity assessment of 66 patients.

Purpose: Brachytherapy (BT) is a validated radiation technique for treatment of early stage tumors of oral cavity and oropharynx. This study aimed to analyze the results of our institute's patients after replacing low-dose-rate (LDR) with pulse-dose-rate (PDR) brachytherapy. Material and methods: We retrospectively collected data from all patients treated between 2009 and 2020 for squamous cell carcinoma (floor of the mouth, tongue, and oropharynx) using adjuvant interstitial BT with or without external RT. Primary outcome was local control. Secondary outcomes were regional control rate and toxicity. Statistical analysis of local and regional recurrences were described using Kaplan-Meier method. Prognostic value of each factor for recurrence or toxicity was evaluated with bivariate Fine-Gray model. Results: Data from 66 patients were analyzed. Local and regional recurrences were reported in 11% and 20% of the patients, respectively. No significant factors were identified in the present study. Grade 2 and 3 acute mucositis were reported in 21% of patients, and were more frequent in the BT only group. Almost half (47%) of the patients described acute pain following BT, and 26% required stage 2 or 3 analgesics. Trophic disorders were observed in 16 patients. Five patients presented with soft tissue necrosis (STN) and required medical treatment, of whom one subsequently required hyperbaric oxygen therapy. No predictive factors were identified for STN risk. Two patients developed osteoradionecrosis. Conclusions: Oral and oropharyngeal PDR-BT as adjuvant treatment is safe and effective for well-defined indications.

Alzheimer's disease 2012: the great amyloid gamble.

Alzheimer's disease threatens to become the scourge of the 21st century. Hundreds of millions of aging people throughout the world are at risk, but it is clear that the disease encompasses more than just the natural aging process. Deposits of amyloid ß peptides in the brains of demented individuals are a defining feature of the disease, yet two decades of intensive investigation, focusing on reducing or removing amyloid deposits, have failed to produce any meaningful therapeutic interventions. Some researchers question whether amyloid is the appropriate target. Others maintain that early, presymptomatic intervention would be a more informative test, and propose large-scale clinical trials in patients who are believed to be in the earliest, and potentially reversible, stages of the disease. This review explores the wisdom of that approach.

Dosimetric predictive factors for facial nerve paralysis after cyberknife® stereotactic radiotherapy for vestibular schwannomas: A single institution experience of 88 patients.

PURPOSE: To identify dosimetric predictive factors of facial nerve paralysis for patients with vestibular schwannomas (VS) treated in a single institution with Cyberknife® (CK) hypofractionated stereotactic radiotherapy (SRT). METHODS AND MATERIALS: Eighty-eight patients were treated from 2010 to 2020. Different treatment schedules were used over that period, some prescribed to the 80% isodose line (4 × 5 Gy, 3 × 7 Gy, 3 × 8 Gy and 5 × 5 Gy) and one to the 70% isodose line (3 × 7.7 Gy). Local control tumor and facial nerve toxicity were recorded, as well as various dosimetric indicators. RESULTS: Median follow-up 37 months (range, 7-96). Of the 88 stereotactic treatments, 20 patients (23%) developed objectively diagnosed radiation-induced facial nerve paralysis. The 2-year and 5-year local tumor control were respectively 95% and 88%, and the overall 2-year facial nerve preservation was 76%. Prescriptions with a maximum dose point (Dmax) of 33 Gy were at a substantially higher risk of facial paralysis than prescriptions with a Dmax less than or equal to 30 Gy (HR = 4.51, 95% CI = [1.04;19.6], p = 0.045). The 2-years cumulative incidences of facial paralysis were 32% [20%;44%] in the case of a 33 Gy Dmax, against 7% [1%;21%] otherwise. We identified four significative dosimetric predictive factors for radiation-induced facial nerve dysfunction: a GTV minimal dose over 22 Gy (EQD2 = 45.5 Gy, p = 0.019), a GTV mean dose over 29 Gy (EQD2 = 73.5 Gy, HR = 2.84, 95% CI = [1.10;7.36], p = 0.024), a PTV mean dose over 27 Gy (EQD2 = 64.8 Gy, HR = 10.52, 95% CI = [1.39;79.76], p = 0.002) and a PTV maximal dose of 32 Gy (EQD2 = 87.5 Gy,HR = 5.09, 95% CI = [1.17;22.15], p = 0.013). CONCLUSION: We identified four dosimetric predictive factors for post-treatment facial paralysis. Increasing the doses of hypofractionated stereotactic radiotherapy for vestibular schwannomas leads to higher facial nerve toxicity and may lead to lower local control rates than other published series. Our three-hypofractionated regimens may have also played a role in these results.

CyberKnife® stereotactic radiation therapy for stage I lung cancer and pulmonary oligometastases: is fiducial implantation still relevant?-a cohort study.

Background: Few studies have investigated whether there is a difference in local control or overall survival rates following treatment with robotic stereotactic body radiation therapy (SBRT) with or without prior fiducial marker implantation. Our study aimed to investigate this in patients with primary or secondary lung tumors. Methods: A retrospective study was conducted at the Institut de Cancérologie de Lorraine of patients treated for primary lung cancer or pulmonary oligometastases with SBRT from January 2013 to July 2016. We included patients at least 18 years old who had stage I non-small cell lung cancer (NSCLC) or lung metastases and a follow-up of at least 1 month. Results: A total of 294 patients were included. Tumors included 122 lung metastases, 89 stage I NSCLC, and 83 non-histologically confirmed lung lesions. The tracking methods were Synchrony® in 191 cases (119 gold seeds and 72 coils) and Xsight® Spine with 4D computed tomography in 103 cases. Median follow-up was 31.6 months [interquartile range (IQR), 18.1-50.2 months]. The two- and five-year probability of local control were respectively 92.22% [95% confidence interval (CI): 0.89-0.95] and 85.35% (95% CI: 0.79-0.99). The two- and five-year probability of overall survival were respectively 87.46% and 72.77% (P=0.586). Local control rates did not significantly differ between techniques at 2 and 5 years (P=0.685) (gold seeds, coils or Xsight® Spine) within tumors grouped by location, gross tumor volume (GTV) (respectively P=0.9, P=0.7, and P=0.4), planning target volume (PTV) (respectively P=0.4, P=0.9, and P=0.7), or PTV/GTV ratio (respectively P=0.6, P=0.6, and P=0.5). Metastasis-free survival and Overall survival rates did not significantly differ between techniques at 2 and 5 years (P=0.664 and P=0.586, respectively). There were no grade 4 or 5 toxicities and only one grade 3 pneumonitis and one grade 3 pneumothorax. Conclusions: Fiducial-less SBRT using Xsight® Spine is a safe alternative to Synchrony® using gold seeds or coils, with comparable local control and overall survival rates and a similar toxicity profile.

Alzheimer's dementia begins as a disease of small blood vessels, damaged by oxidative-induced inflammation and dysregulated amyloid metabolism: implications for early detection and therapy.

There is a widely shared view among Alzheimer's disease (AD) investigators that the amyloid hypothesis best describes the pathogenic cascade that leads, ultimately, to neuronal degeneration and irreversible dementia. The most persuasive evidence comes from studies of damaged brains of patients in the late stages of AD and from animal studies that attempt to mimic the hereditary forms of early-onset dementia. Despite this impressive body of knowledge, we still lack the means to either arrest or prevent this horrible contagion. This essay attempts to describe what we know, and do not know, about the earliest stages of the disease, focusing on the possibility that the initial pathological changes involve oxidative-induced inflammatory damage to small blood vessels. The resulting ischemia activates amyloid-processing enzymes and other proinflammatory factors that eventually compromise neuronal functions, leading, over time, to the complex lesions that characterize advanced disease. The idea that blood vessel damage is primary has a long history and many prior advocates. The novel addition offered here is the speculation that low-abundance, gain-of-function somatic mutations of the amyloid precursor protein may be part of the triggering mechanism.

Requirement for AHNAK1-mediated calcium signaling during T lymphocyte cytolysis.

Cytolytic CD8(+) T cells (CTLs) kill virally infected cells, tumor cells, or other potentially autoreactive T cells in a calcium-dependent manner. To date, the molecular mechanism that leads to calcium intake during CTL differentiation and function has remained unresolved. We demonstrate that desmoyokin (AHNAK1) is expressed in mature CTLs, but not in naive CD8(+) T cells, and is critical for calcium entry required for their proper function during immune response. We show that mature AHNAK1-deficient CTLs exhibit reduced Ca(v)1.1 alpha1 subunit expression (also referred to as L-type calcium channels or alpha1S pore-forming subunits), which recently were suggested to play a role in calcium entry into CD4(+) T cells. AHNAK1-deficient CTLs show marked reduction in granzyme-B production, cytolytic activity, and IFN-gamma secretion after T cell receptor stimulation. Our results demonstrate an AHNAK1-dependent mechanism controlling calcium entry during CTL effector function.

High-dose-rate brachytherapy for facial skin cancer: Outcome and toxicity assessment for 71 cases.

PURPOSE: In France, the reference technique for skin cancer was low-dose-rate brachytherapy (BT) delivered via iridium wire. At the end of their commercialization in 2015 we have replaced them by high-dose-rate (HDR) BT via interstitial catheters. We assessed efficacy and tolerance as soon as this technique was implemented. METHODS AND MATERIALS: Patients received 7 Gy on the first day, followed by 8 × 4 Gy over the next 4 days for exclusive BT and 9 × 4 Gy over 5 days for post-operative BT. RESULTS: Sixty-six patients of median age 81 years received a total of 58 primary BT and 13 post-operative BT for non-melanoma facial skin cancers. Implantation was without difficulty. Median follow up was 15.3 months. Two patients died of intercurrent diseases before first follow up. For the others, 98.5% showed complete response and 3% local recurrence after a median of 20.5 months. Four patients had grade 3 acute dermatitis and three patients had grade 3 mucositis. All the Grade 3 toxicities were resolved within 3 months. A late significant hypopigmentation occurred in 4 patients. CONCLUSIONS: HDR BT is efficient and well-tolerated with good cosmetic results. HDR catheters are similar with iridium wires in terms of technical difficulty.

A comprehensive analysis of the IMRT dose delivery process using statistical process control (SPC).

The aim of this study is to introduce tools to improve the security of each IMRT patient treatment by determining action levels for the dose delivery process. To achieve this, the patient-specific quality control results performed with an ionization chamber--and which characterize the dose delivery process--have been retrospectively analyzed using a method borrowed from industry: Statistical process control (SPC). The latter consisted in fulfilling four principal well-structured steps. The authors first quantified the short-term variability of ionization chamber measurements regarding the clinical tolerances used in the cancer center (+/- 4% of deviation between the calculated and measured doses) by calculating a control process capability (C(pc)) index. The C(pc) index was found superior to 4, which implies that the observed variability of the dose delivery process is not biased by the short-term variability of the measurement. Then, the authors demonstrated using a normality test that the quality control results could be approximated by a normal distribution with two parameters (mean and standard deviation). Finally, the authors used two complementary tools--control charts and performance indices--to thoroughly analyze the IMRT dose delivery process. Control charts aim at monitoring the process over time using statistical control limits to distinguish random (natural) variations from significant changes in the process, whereas performance indices aim at quantifying the ability of the process to produce data that are within the clinical tolerances, at a precise moment. The authors retrospectively showed that the analysis of three selected control charts (individual value, moving-range, and EWMA control charts) allowed efficient drift detection of the dose delivery process for prostate and head-and-neck treatments before the quality controls were outside the clinical tolerances. Therefore, when analyzed in real time, during quality controls, they should improve the security of treatments. They also showed that the dose delivery processes in the cancer center were in control for prostate and head-and-neck treatments. In parallel, long-term process performance indices (P(p), P(pk), and P(pm)) have been analyzed. Their analysis helped defining which actions should be undertaken in order to improve the performance of the process. The prostate dose delivery process has been shown statistically capable (0.08% of the results is expected to be outside the clinical tolerances) contrary to the head-and-neck dose delivery process (5.76% of the results are expected to be outside the clinical tolerances).

Intensity-modulated radiation therapy of anal squamous cell carcinoma: Relationship between delineation quality and regional recurrence.

BACKGROUND AND PURPOSE: Intensity-modulated radiation therapy (IMRT) is currently indicated to treat anal squamous cell carcinoma (ASCC). Conformal dose delivery and steep dose gradients may cause marginal misses. We analyzed patterns of locoregional recurrences (LRR) and delineation quality to determine IMRT-specific predictive factors. MATERIAL AND METHODS: Lymph node area delineation was classified as "compliant" or "non-compliant" according to experts' workgroup recommendations. The recurrence volume (Vrecur) was delineated on initial planning-CT by recurrence imaging registration. The Vrecur was determined to be "in-field" (IF), "marginal" (ML), or "out-of-field" (OF) in regard to the 95% isodose coverage. RESULTS: Out of 165 patients, 30 had LRR. Among the 27 local recurrences (LR), 20 (74%) were IF, 4 (15%) ML, and 2 (7%) OF. Fourteen patients had regional recurrence (RR), amounted to 33 separate recurrence sites (RS). RS were mostly localized in inguinal (n = 12;36,4%), external iliac (n = 7;21.1%), presacral (n = 4;12.1%) and common iliac (n = 3;9.1%) nodes. Eighteen (54.5%) RS were IF, 6 (18.2%) ML, and 9 (27.3%) OF. Performance status ≥2 (p = 0.007) and active smoking (p = 0.025) were predictors of LR. Immunodepression (p = 0.012), external iliac involvement (p < 0.001), and non-compliant delineation for ≥10 areas (p = 0.005) were predictors of RR. CONCLUSIONS: New predictive factors for recurrences of ASSC treated with IMRT have been found, suggesting that the delineation accuracy is essential for regional control.

Cyberknife® stereotactic radiation therapy for stage I lung cancer and pulmonary metastases: evaluation of local control at 24 months.

BACKGROUND: CyberKnife® stereotactic radiotherapy allows for minimally invasive treatment with satisfactory results in patients with inoperable primary or metastatic lung cancer. The objective of this study was to identify factors influencing the probability of local control. METHODS: Ninety-five patients (100 lung tumors) treated between January and December 2013 at our department by SBRT (stereotactic body radiation therapy) using CyberKnife® were included in the study. There were 71 stage T1 or T2 primary tumors and 29 secondary tumors. The tracking methods were as follow: fiducial markers with Synchrony® in 50 cases (gold seeds in 35, coils in 15 cases), spine with 4D-CT and Xsight® Spine in 43 cases, and direct viewing by Xsight® Lung in 7 cases. The methods were allocated according to the characteristics of each target. RESULTS: With a median follow-up of 24 months, the probability of local control at 24 months was 88%. The probability of local control differed according to the size of the target (92% for tumors ≤35 mm and 54% for tumors >35 mm: P=0.013) and according to the distance of the fiducial markers in relation to the target (95% when <50 mm and 69% when ≥50 mm: P=0.011). CONCLUSIONS: The best results were obtained with small lesions. With Synchrony®, the distance of the target relative to the fiducial markers should be less than 50 mm. Gold seeds are recommended, although coils may be used instead of gold seeds. The number of fiducial markers did not have a significant impact on the probability of local control. With an appropriate tracking method, stereotactic radiotherapy is an efficient treatment for stage I lung cancer and lung oligometastases.

Impact of intensity-modulated radiotherapy on health-related quality of life for head and neck cancer patients: matched-pair comparison with conventional radiotherapy.

PURPOSE: To assess the benefit of intensity-modulated radiotherapy (IMRT) compared with conventional RT for the quality of life (QOL) of head and neck cancer survivors. METHODS AND MATERIALS: Cross-sectional QOL measures (European Organization for Research and Treatment of Cancer QOL questionnaire C30 and head and neck cancer module) were used with a French multicenter cohort of patients cured of head and neck cancer (follow-up > or = 1 year) who had received bilateral neck RT (> or = 45 Gy) as a part of their initial treatment. We compared the QOL mean scores regarding RT modality (conventional RT vs. IMRT). The patients of the two groups were matched (one to one) according to the delay between the end of RT and the timing of the QOL evaluation and the T stage. Each QOL item was divided into two relevant levels of severity: "not severe" (responses, "not at all" and "a little") vs. "severe" (responses "quite a bit" and "very much"). The association between the type of RT and the prevalence of severe symptoms was approximated, through multivariate analysis using the prevalence odds ratio. RESULTS: Two comparable groups (67 pairs) were available. Better scores were observed on the head and neck cancer module QOL questionnaire for the IMRT group, especially for dry mouth and sticky saliva (p < 0.0001). Severe symptoms were more frequent with conventional RT concerning saliva modifications and oral discomfort. The adjusted prevalence odds ratios were 3.17 (p = 0.04) for dry mouth, 3.16 (p = 0.02) for sticky saliva, 3.58 (p = 0.02) for pain in the mouth, 3.35 (p = 0.04) for pain in the jaw, 2.60 (p = 0.02) for difficulties opening the mouth, 2.76 (p = 0.02) for difficulties with swallowing, and 2.68 (p = 0.03) for trouble with eating. CONCLUSION: The QOL assessment of head and neck cancer survivors demonstrated the benefit of IMRT, particularly in the areas of salivary dysfunction and oral discomfort.

Intensity-modulated radiation therapy from 70Gy to 80Gy in prostate cancer: six- year outcomes and predictors of late toxicity.

OBJECTIVE: To report grade ≥2 overall late rectal and urinary toxicities in patients (pts) with prostate cancer treated by intensity-modulated radiotherapy (IMRT) at 3 dose-levels. Identify predictors of radiation toxicity and report biochemical progression free survival (bPFS). METHODS: A total of 277 pts were treated with 70Gy (10.8%), 74Gy (63.9%) and 80 Gy (25.3%) using IMRT without pelvic irradiation were analyzed. Short or long-course androgen deprivation therapy (ADT) was allowed in 46.1% of pts. The toxicity was described using the Common Terminology Criteria for Adverse Events (CTCAE) v4.0 scale. Cox regression models addressed demographics, disease and dosimetry characteristics as potential predictors of late grade ≥2 toxicity after adjusting for other modifying factors. RESULTS: The median follow-up was 77 months (range 15; 150). There was no grade ≥4 toxicity. The 5-year cumulative rate of grade ≥2 late rectal and urinary toxicities was 6.3% (95% CI = 3.8%; 10.3%) and 25.3% (95% CI = 19.8%; 31.8%) respectively. In multivariate analysis, only the dose (80Gy vs 74 and 70Gy) was found to increase the risk of rectal toxicity (HR = 2.96 [1.07; 8.20]). For pts receiving 74 Gy, International Prostate Symptom Score (IPSS) at baseline ≥8 (HR = 2.40 [1.08; 5.35]) and dose ≥73Gy delivered in more than 2% of bladder (D2%) were found to be predictors of bladder toxicity (HR = 3.29 [1.36; 7.98]). The 5-year biochemical relapse free survival was 81.0% [74.5%; 86.0%] in the entire population, 97.5% [83.5%; 99.6%] in the low risk group, 84.9% [76.7%; 90.3%] in the intermediate risk group and 66.4% [51.8%; 77.4%] in the high-risk group. D'Amico low (HR = 0.09 [0.01; 0.69]) and intermediate risk groups (HR = 0.50 [0.28; 0.88]) as well as PSA nadir ≥0.2 ng/ml (HR = 1.79 [1.01; 3.21]) were predictive of biochemical relapse. CONCLUSIONS: The rate of late rectal toxicity increased with higher doses, while Dmax ≥74Gy, D2% ≥ 73Gy for bladder wall and baseline IPSS ≥8 increased late urinary toxicity.

Qualitative estimation of pelvic organ interactions and their consequences on prostate motion: study on a deceased person.

In an attempt to have better targeting of the prostate during radiotherapy it is necessary to understand the mechanical interactions between bladder, rectum, and prostate and estimate their consequences on prostate motion. For this, the volumes of bladder, rectum, and lungs were modified concomitantly on a deceased person. A CT acquisition was performed for each of these different pelvic configurations (36 acquisitions). An increase in the volume of the bladder or lungs induces a compression of tissues of the pelvic area from its supero-anterior (S-A) to infero-posterior (I-P) side. Conversely, an increase of rectum volume induces a compression from the I-P to the S-A side of the pelvic region. These compressive actions can be added or subtracted from each other, depending on their amplitudes and directions. Prostate motion occurs when a movement of the rectum is observed (this movement depends, itself, on lungs and bladder volume). The maximum movement of prostate is 9 mm considering maximal bladder or rectal action, and 11 mm considering maximum lung action. In some other cases, opposition of compressive effects can lead to stasis of the prostate. Based on the volumes of bladder, rectum, and lungs, it is possible to qualitatively estimate the movement of organs of the pelvic area. The best way to reduce prostate movement is to recommend the patient to have an empty rectum, with either full bladder and/or full lungs.