ABSTRACT
The prognosis for locked-in syndrome after acquired brainstem injury is unfavourable. However, partial recovery of motor function occurs in many patients and benefits from intensive rehabilitation. Here we evaluate two patient cases and results of a questionnaire among medical doctors specialised in rehabilitation. We define bottlenecks in the treatment of acute locked-in syndrome in the ICU. Locked-in patients have a years-long life expectancy once they have survived the acute phase. There is no validated prognostic instrument to predict recovery, but even small neurological recovery can have large functional benefits. Recovery may take place over an extended period of time, up to years after onset. To unlock the potential to recover we recommend to start with early rehabilitation while the patient is still in the ICU on life sustaining treatment This may set the patient off along the road from locked-in to unlocked.
Subject(s)
Locked-In Syndrome , Recovery of Function , Humans , Male , Prognosis , Middle Aged , Adult , Treatment Outcome , Quadriplegia/rehabilitation , FemaleABSTRACT
BACKGROUND: Distinguishing postoperative fibrosis from isolated local recurrence (ILR) after resection of pancreatic ductal adenocarcinoma (PDAC) is challenging. A prognostic model that helps to identify patients at risk of ILR can assist clinicians when evaluating patients' postoperative imaging. This nationwide study aimed to develop a clinically applicable prognostic model for ILR after PDAC resection. PATIENTS AND METHODS: An observational cohort study was performed, including all patients who underwent PDAC resection in the Netherlands (2014-2019; NCT04605237). On the basis of recurrence location (ILR, systemic, or both), multivariable cause-specific Cox-proportional hazard analysis was conducted to identify predictors for ILR and presented as hazard ratios (HRs) with 95% confidence intervals (CIs). A predictive model was developed using Akaike's Information Criterion, and bootstrapped discrimination and calibration indices were assessed. RESULTS: Among 1194/1693 patients (71%) with recurrence, 252 patients (21%) developed ILR. Independent predictors for ILR were resectability status (borderline versus resectable, HR 1.42; 95% CI 1.03-1.96; P = 0.03, and locally advanced versus resectable, HR 1.11; 95% CI 0.68-1.82; P = 0.66), tumor location (head versus body/tail, HR 1.50; 95% CI 1.00-2.25; P = 0.05), vascular resection (HR 1.86; 95% CI 1.41-2.45; P < 0.001), perineural invasion (HR 1.47; 95% CI 1.01-2.13; P = 0.02), number of positive lymph nodes (HR 1.04; 95% CI 1.01-1.08; P = 0.02), and resection margin status (R1 < 1 mm versus R0 ≥ 1 mm, HR 1.64; 95% CI 1.25-2.14; P < 0.001). Moderate performance (concordance index 0.66) with adequate calibration (slope 0.99) was achieved. CONCLUSIONS: This nationwide study identified factors predictive of ILR after PDAC resection. Our prognostic model, available through www.pancreascalculator.com , can be utilized to identify patients with a higher a priori risk of developing ILR, providing important information in patient evaluation and prognostication.
ABSTRACT
BACKGROUND: Disease recurrence remains one of the biggest concerns in patients after resection of pancreatic ductal adenocarcinoma (PDAC). Despite (neo)adjuvant systemic therapy, most patients experience local and/or distant PDAC recurrence within 2 years. High-level evidence regarding the benefits of recurrence-focused surveillance after PDAC resection is missing, and the impact of early detection and treatment of recurrence on survival and quality of life is unknown. In most European countries, recurrence-focused follow-up after surgery for PDAC is currently lacking. Consequently, guidelines regarding postoperative surveillance are based on expert opinion and other low-level evidence. The recent emergence of more potent local and systemic treatment options for PDAC recurrence has increased interest in early diagnosis. To determine whether early detection and treatment of recurrence can lead to improved survival and quality of life, we designed an international randomized trial. METHODS: This randomized controlled trial is nested within an existing prospective cohort in pancreatic cancer centers in the Netherlands (Dutch Pancreatic Cancer Project; PACAP) and the United Kingdom (UK) (Pancreas Cancer: Observations of Practice and survival; PACOPS) according to the "Trials within Cohorts" (TwiCs) design. All PACAP/PACOPS participants with a macroscopically radical resection (R0-R1) of histologically confirmed PDAC, who provided informed consent for TwiCs and participation in quality of life questionnaires, are included. Participants randomized to the intervention arm are offered recurrence-focused surveillance, existing of clinical evaluation, serum cancer antigen (CA) 19-9 testing, and contrast-enhanced computed tomography (CT) of chest and abdomen every three months during the first 2 years after surgery. Participants in the control arm of the study will undergo non-standardized clinical follow-up, generally consisting of clinical follow-up with imaging and serum tumor marker testing only in case of onset of symptoms, according to local practice in the participating hospital. The primary endpoint is overall survival. Secondary endpoints include quality of life, patterns of recurrence, compliance to and costs of recurrence-focused follow-up, and the impact on recurrence-focused treatment. DISCUSSION: The RADAR-PANC trial will be the first randomized controlled trial to generate high level evidence for the current clinical equipoise regarding the value of recurrence-focused postoperative surveillance with serial tumor marker testing and routine imaging in patients after PDAC resection. The Trials within Cohort design allows us to study the acceptability of recurrence-focused surveillance among cohort participants and increases the generalizability of findings to the general population. While it is strongly encouraged to offer all trial participants treatment at time of recurrence diagnosis, type and timing of treatment will be determined through shared decision-making. This might reduce the potential survival benefits of recurrence-focused surveillance, although insights into the impact on patients' quality of life will be obtained. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04875325 . Registered on May 6, 2021.
Subject(s)
Carcinoma, Pancreatic Ductal , Neoplasm Recurrence, Local , Pancreatectomy , Pancreatic Neoplasms , Quality of Life , Randomized Controlled Trials as Topic , Humans , Carcinoma, Pancreatic Ductal/surgery , Carcinoma, Pancreatic Ductal/mortality , Carcinoma, Pancreatic Ductal/diagnostic imaging , Carcinoma, Pancreatic Ductal/pathology , Carcinoma, Pancreatic Ductal/blood , Pancreatic Neoplasms/surgery , Pancreatic Neoplasms/pathology , Pancreatectomy/adverse effects , Time Factors , Prospective Studies , Multicenter Studies as Topic , Treatment Outcome , Predictive Value of Tests , Netherlands , United Kingdom , Research Design , Early Detection of Cancer/methodsABSTRACT
Aluminum monofluoride (AlF) is a suitable molecule for laser cooling and trapping. Such experiments require extensive spectroscopic characterization of the electronic structure. Two of the theoretically predicted higher-lying triplet states of AlF, the counterparts of the well-characterized D1Δ and E1Π states, had not been experimentally identified yet. We here report on the characterization of the d3Π (v = 0-6) and e3Δ (v = 0-2) states, confirming the predicted energetic ordering of these states (J. Chem. Phys. 1988, 88, 5715-5725), as well as of the f3Σ+ (v = 0-2) state. The transition intensity of the d3Π, v = 3 - a3Π, v = 3 band is negligibly small. This band gets its weak, unexpected rotational structure via intensity borrowing from the nearby e3Δ, v = 2 - a3Π, v = 3 band, made possible via spin-orbit and spin-rotation interaction between the d3Π and e3Δ states. This interaction affects the equilibrium rotational constants in both states; their deperturbed values yield equilibrium internuclear distances that are consistent with the observations. We determined the ionization potential of AlF to be 78,492(1) cm-1 by ionization from the d3Π state.
ABSTRACT
Osseointegrated dental implants in the vicinity of oral squamous cell carcinoma (OSCC) will become more common given the increasing popularity of dental implants. Reports and studies of OSCC around dental implants are rare, as is the topic of how to handle OSCC surgically when implants are in contact with the tumour. In view of this uncertainty, a histological study was performed to assess tumour behaviour around implants. The aim was to determine whether an implant facilitates inward growth of the tumour and how this should be taken into account during staging and treatment planning. A total of 20 specimens were collected. The implants were macroscopically in contact with OSCC in 13 of the 20 specimens. Histologically, tumour tissue near the implant was indeed confirmed in nine of these cases. In seven cases, tumour invasion had led to resorption of the underlying jaw bone; tumour between the bone-implant interface was identified in only two of these cases, but without downward growth along the implant. In conclusion, no proof was found to confirm that the bone-implant interface is a preferred route for invasion. Therefore, dental implants in the vicinity of OSCC should not influence staging and treatment planning in this regard.
Subject(s)
Alveolar Bone Loss , Carcinoma, Squamous Cell , Dental Implants , Head and Neck Neoplasms , Mouth Neoplasms , Humans , Squamous Cell Carcinoma of Head and Neck , Dental Implantation, EndosseousABSTRACT
BACKGROUND: Many screening programs for colorectal cancer (CRC) use the fecal immunochemical test (FIT) to triage individuals for colonoscopy. Although these programs reduce CRC incidence and CRC-related mortality, the detection of advanced precursor lesions (advanced adenomas and advanced serrated polyps) by FIT could be improved. As an alternative for FIT, the antibody-based multitargetFIT (mtFIT) has been proposed. The mtFIT measures three protein markers: hemoglobin, calprotectin, and serpin family F member 2. In a retrospective diagnostic accuracy study in a large colonoscopy-controlled series (n = 1284), mtFIT showed increased sensitivity for advanced neoplasia (AN), at equal specificity, compared to FIT (42.9% versus 37.3%; p = 0.025). This increase was mainly due to a higher sensitivity of mtFIT for advanced adenomas (37.8% versus 28.1% for FIT; p = 0.006). The present mtFIT study aims to prospectively validate these findings in the context of the Dutch national CRC screening program. METHOD: The mtFIT study is a cross-sectional intervention study with a paired design. Eligible subjects for the Dutch FIT-based national CRC screening program are invited to perform mtFIT in addition to FIT. Samples are collected at home, from the same bowel movement, and are shipped to a central laboratory by postal mail. If either one or both tests are positive, participants are referred for colonoscopy. Detailed colonoscopy and pathology data are centrally stored in a national screening database (ScreenIT; Topicus, Deventer, the Netherlands) that is managed by the screening organization, and will be retrieved for this study. We aim to determine the relative sensitivity for AN, comprising of CRC, advanced adenomas and advanced serrated polyps, of mtFIT compared to FIT at an equal positivity rate. Additionally, we will use the Adenoma and Serrated Pathway to Colorectal CAncer model to predict lifetime health effects and costs for programmatic mtFIT- versus FIT-based screening. The target sample size is 13,131 participants. DISCUSSION: The outcome of this study will inform on the comparative clinical utility of mtFIT versus FIT in the Dutch national CRC screening program and is an important step forward in the development of a new non-invasive stool test for CRC screening. TRIAL REGISTRATION: Clinicaltrials.gov ; NCT05314309, registered April 6th 2022, first inclusions March 25th 2022 https://clinicaltrials.gov/ct2/results?cond=&term=NCT05314309&cntry=&state=&city=&dist =.
Subject(s)
Adenoma , Colorectal Neoplasms , Polyps , Humans , Adenoma/diagnosis , Adenoma/pathology , Colonoscopy , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/pathology , Cross-Sectional Studies , Early Detection of Cancer/methods , Feces/chemistry , Hemoglobins/analysis , Mass Screening/methods , Occult Blood , Retrospective StudiesABSTRACT
BACKGROUND: In â¼3%-5% of patients with metastatic disease, tumor origin remains unknown despite modern imaging techniques and extensive pathology work-up. With long diagnostic delays and limited and ineffective therapy options, the clinical outcome of patients with cancer of unknown primary (CUP) remains poor. Large-scale genome sequencing studies have revealed that tumor types can be predicted based on distinct patterns of somatic variants and other genomic characteristics. Moreover, actionable genomic events are present in almost half of CUP patients. This study investigated the clinical value of whole genome sequencing (WGS) in terms of primary tumor identification and detection of actionable events, in the routine diagnostic work-up of CUP patients. PATIENTS AND METHODS: A WGS-based tumor type 'cancer of unknown primary prediction algorithm' (CUPPA) was developed based on previously described principles and validated on a large pan-cancer WGS database of metastatic cancer patients (>4000 samples) and 254 independent patients, respectively. We assessed the clinical value of this prediction algorithm as part of routine WGS-based diagnostic work-up for 72 CUP patients. RESULTS: CUPPA correctly predicted the primary tumor type in 78% of samples in the independent validation cohort (194/254 patients). High-confidence predictions (>95% precision) were obtained for 162/254 patients (64%). When integrated in the diagnostic work-up of CUP patients, CUPPA could identify a primary tumor type for 49/72 patients (68%). Most common diagnoses included non-small-cell lung (n = 7), gastroesophageal (n = 4), pancreatic (n = 4), and colorectal cancer (n = 3). Actionable events with matched therapy options in clinical trials were identified in 47% of patients. CONCLUSIONS: Genome-based tumor type prediction can predict cancer diagnoses with high accuracy when integrated in the routine diagnostic work-up of patients with metastatic cancer. With identification of the primary tumor type in the majority of patients and detection of actionable events, WGS is a valuable diagnostic tool for patients with CUP.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Neoplasms, Unknown Primary , Humans , Neoplasms, Unknown Primary/diagnosis , Neoplasms, Unknown Primary/genetics , Neoplasms, Unknown Primary/drug therapy , Genomics , Whole Genome SequencingABSTRACT
BACKGROUND: Disease recurrence is the main cause of mortality after resection of pancreatic ductal adenocarcinoma (PDAC). In 20-30% of resected patients, isolated local PDAC recurrence occurs. Retrospective studies have suggested that stereotactic body radiation therapy (SBRT) might lead to improved local control in these patients, potentially having a beneficial effect on both survival and quality of life. The "nationwide randomized controlled trial on additional treatment for isolated local pancreatic cancer recurrence using stereotactic body radiation therapy" (ARCADE) will investigate the value of SBRT in addition to standard of care in patients with isolated local PDAC recurrence compared to standard of care alone, regarding both survival and quality of life outcomes. METHODS: The ARCADE trial is nested within a prospective cohort (Dutch Pancreatic Cancer Project; PACAP) according to the 'Trials within Cohorts' design. All PACAP participants with isolated local PDAC recurrence after primary resection who provided informed consent for being randomized in future studies are eligible. Patients will be randomized for local therapy (5 fractions of 8 Gy SBRT) in addition to standard of care or standard of care alone. In total, 174 patients will be included. The main study endpoint is survival after recurrence. The most important secondary endpoint is quality of life. DISCUSSION: It is hypothesized that additional SBRT, compared to standard of care alone, improves survival and quality of life in patients with isolated local recurrence after PDAC resection. TRIAL REGISTRATION: ClinicalTrials.gov registration NCT04881487 . Registered on May 11, 2021.
Subject(s)
Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Radiosurgery , Humans , Radiosurgery/adverse effects , Retrospective Studies , Prospective Studies , Quality of Life , Pituitary Adenylate Cyclase-Activating Polypeptide , Neoplasm Recurrence, Local/pathology , Pancreatic Neoplasms/radiotherapy , Pancreatic Neoplasms/surgery , Carcinoma, Pancreatic Ductal/radiotherapy , Carcinoma, Pancreatic Ductal/surgery , Pancreatic NeoplasmsABSTRACT
In this work, we explore the role of chemical reactions on the properties of buffer gas cooled molecular beams. In particular, we focus on scenarios relevant to the formation of AlF and CaF via chemical reactions between the Ca and Al atoms ablated from a solid target in an atmosphere of a fluorine-containing gas, in this case, SF6 and NF3. Reactions are studied following an ab initio molecular dynamics approach, and the results are rationalized following a tree-shaped reaction model based on Bayesian inference. We find that NF3 reacts more efficiently with hot metal atoms to form monofluoride molecules than SF6. In addition, when using NF3, the reaction products have lower kinetic energy, requiring fewer collisions to thermalize with the cryogenic helium. Furthermore, we find that the reaction probability for AlF formation is much higher than for CaF across a broad range of kinetic temperatures.
ABSTRACT
Aluminum monofluoride (AlF) possesses highly favorable properties for laser cooling, both via the A1Π and a3Π states. Determining efficient pathways between the singlet and the triplet manifold of electronic states will be advantageous for future experiments at ultralow temperatures. The lowest rotational levels of the A1Π, v = 6 and b3Σ+, v = 5 states of AlF are nearly iso-energetic and interact via spin-orbit coupling. These levels thus have a strongly mixed spin-character and provide a singlet-triplet doorway. We here present a hyperfine resolved spectroscopic study of the A1Π, v = 6//b3Σ+, v = 5 perturbed system in a jet-cooled, pulsed molecular beam. From a fit to the observed energies of the hyperfine levels, the fine and hyperfine structure parameters of the coupled states and their relative energies as well as the spin-orbit interaction parameter are determined. The standard deviation of the fit is about 15 MHz. We experimentally determine the radiative lifetimes of selected hyperfine levels by time-delayed ionization, Lamb dip spectroscopy, and accurate measurements of the transition lineshapes. The measured lifetimes range between 2 and 200 ns, determined by the degree of singlet-triplet mixing for each level.
ABSTRACT
Spectroscopic studies of aluminum monofluoride (AlF) have revealed its highly favorable properties for direct laser cooling. All Q lines of the strong A1Π â X1Σ+ transition around 227 nm are rotationally closed and thereby suitable for the main cooling cycle. The same holds for the narrow, spin-forbidden a3Π â X1Σ+ transition around 367 nm, which has a recoil limit in the µK range. We here report on the spectroscopic characterization of the lowest rotational levels in the a3Π state of AlF for v = 0-8 using a jet-cooled, pulsed molecular beam. An accidental AC Stark shift is observed on the a3Π0, v = 4 â X1Σ+, v = 4 band. By using time-delayed ionization for state-selective detection of the molecules in the metastable a3Π state at different points along the molecular beam, the radiative lifetime of the a3Π1, v = 0, J = 1 level is experimentally determined as τ = 1.89 ± 0.15 ms. A laser/radio frequency multiple resonance ionization scheme is employed to determine the hyperfine splittings in the a3Π1, v = 5 level. The experimentally derived hyperfine parameters are compared to the outcome of quantum chemistry calculations. A spectral line with a width of 1.27 kHz is recorded between hyperfine levels in the a3Π, v = 0 state. These measurements benchmark the electronic potential of the a3Π state and yield accurate values for the photon scattering rate and for the elements of the Franck-Condon matrix of the a3Π-X1Σ+ system.
ABSTRACT
Purpose: This R-Ideal stage 1b/2a study describes the workflow and feasibility of long-course fractionated online adaptive MR-guided chemoradiotherapy with reduced CTV-to-PTV margins on the 1.5T MR-Linac for patients with esophageal cancer. Methods: Patients with esophageal cancer scheduled to undergo chemoradiation were treated on a 1.5T MR-Linac. Daily MR-images were acquired for online contour adaptation and replanning. Contours were manually adapted to match the daily anatomy and an isotropic CTV-to-PTV margin of 6 mm was applied. Time was recorded for all individual steps in the workflow. Feasibility and patient tolerability were defined as on-table time of ≤60 min and completion of >95% of the fractions on the MR-Linac, respectively. Positioning verification and post-treatment MRIs were retrospectively analyzed and dosimetric parameters were compared to standard non-adaptive conventional treatment plans. Results: Nine patients with esophageal cancer were treated with chemoradiation; eight patients received 41.4 Gy in 23 fractions and one received 50.4 Gy in 28 fractions. Four patients received all planned fractions on the MR-Linac, whereas for two patients >5% of fractions were rescheduled to a conventional linac for reasons of discomfort. A total of 183 (86%) of 212 scheduled fractions were successfully delivered on the MR-Linac. Three fractions ended prematurely due to technical issues and 26 fractions were rescheduled on a conventional linac due to MR-Linac downtime (n = 10), logistical reasons (n = 3) or discomfort (n = 13).The median time per fraction was 53 min (IQR = 3 min). Daily adapted MR-Linac plans had similar target coverage, whereas dose to the organs-at-risk was significantly reduced compared to conventional treatment (26% and 12% reduction in mean lung and heart dose, respectively). Conclusion: Daily online adaptive fractionated chemoradiotherapy with reduced PTV margins is moderately feasible for esophageal cancer and results in better sparing of heart and lungs. Future studies should focus on further optimization and acceleration of the current workflow.
ABSTRACT
While abroad, a healthy 36-year-old woman slammed head-on into a rock wall at high speed, resulting in significant facial trauma. The initial trauma care and first aid took place abroad. In the Netherlands, the woman was referred to the Department of Oral and Maxillofacial Surgery (OMFS) for reconstruction of her face and alveolar processes, gingiva and dentition. In view of the seriousness of the injuries, a 3D treatment plan was drawn up in a multidisciplinary collaboration with an OMF surgeon, an implantologist, dentist and dental technician. By making a digital setup of both the top and bottom front in advance, it was possible to work predictably. The first step consisted of bone augmentation by means of an iliac crest graft to reconstruct the major bone defects of the superior and inferior alveolar processes. Implants were then placed in the upper and lower jaws in the ideal position for the suprastructure by means of drill jigs. Within 10 months after the trauma, the implant bridges could be placed on individual zirconia frameworks to optimally restore oral function and aesthetics, completing the reconstruction.
Subject(s)
Dental Implants , Adult , Alveolar Process , Bone Transplantation/methods , Dental Implantation, Endosseous/methods , Female , Gingiva/surgery , Humans , Mandible/surgeryABSTRACT
We report on hyperfine-resolved laser spectroscopy of the A2Π â X2Σ+ transition of magnesium monofluoride (MgF), relevant for laser cooling. We recorded 25 rotational transitions with an absolute accuracy of better than 20 MHz, assigned 56 hyperfine lines, and determined precise rotational, fine, and hyperfine structure parameters for the A2Π state. The radiative lifetime of the A2Π state was determined to be 7.2(3) ns, in good agreement with ab initio calculations. The transition isotope shift between bosonic isotopologues of the molecule is recorded and compared to predicted values within the Born-Oppenheimer approximation. We measured the Stark effect of selected rotational lines of the A2Π â X2Σ+ transition by applying electric fields of up to 10.6 kV cm-1 and determined the permanent electric dipole moments of 24MgF in its ground X2Σ+ and first excited A2Π states to be µX = 2.88(20) D and µA = 3.20(22) D, respectively. Based on these measurements, we caution for potential losses from the optical cycling transition due to electric field induced parity mixing in the excited state. In order to scatter 104 photons, the electric field must be controlled to below 1 V cm-1.
ABSTRACT
The aim of this study was to evaluate a novel soft tissue-based method to register an intraoral scan (IOS) with a cone beam computed tomography (CBCT) scan. IOS and CBCT data were obtained from eight dentate patients (mean age 21±2 years; three male, five female) and 14 fully edentulous patients (mean age 56±9 years; eight male, six female). An algorithm was developed to create a soft tissue model of the CBCT scan, which allowed a soft tissue-based registration to be performed with the IOS. First, validation was performed on dentate jaws with registration of the palatal mucosal surface and accuracy evaluation at the level of the teeth. Second, fully edentulous jaws were registered using both the palatal and alveolar crest mucosal surfaces. Distance maps were created to measure the method accuracy. The mean registration error was 0.49±0.26mm for the dentate jaws. Registration of the fully edentulous jaws had a mean error of 0.16±0.08mm at the palate and 0.16±0.05mm at the alveolar crest. In conclusion, the high accuracy of this registration method may allow the digital workflow to be optimized when no teeth are available to perform a regular registration procedure.
Subject(s)
Jaw, Edentulous , Mouth, Edentulous , Adult , Aged , Algorithms , Cone-Beam Computed Tomography , Female , Humans , Imaging, Three-Dimensional , Jaw, Edentulous/diagnostic imaging , Male , Middle Aged , Young AdultABSTRACT
In publications, implant retained overdentures have frequently been suggested to be a cost-efficient treatment alternative to conventional dentures. But whether the additional health benefits of implant retained overdentures even out the higher costs is not answered unequivocally. The qualification of the improved quality of life and the valuation of costs are strongly determined by the decision maker (insurance and/or patient). Future research must be encouraged to further elucidate patient willingness to pay for implant retained overdentures and the societal return on investment herein more generally.
Subject(s)
Dental Implants , Denture, Overlay , Dental Prosthesis, Implant-Supported , Denture Retention , Humans , Mandible , Patient Satisfaction , Quality of LifeABSTRACT
PURPOSE: This study aimed to assess the smallest clinical target volume (CTV) to planned target volume (PTV) margins for esophageal cancer radiotherapy using daily online registration to the bony anatomy that yield full dosimetric coverage over the course of treatment. METHODS: 29 esophageal cancer patients underwent six T2-weighted MRI scans at weekly intervals. An online bone-match image-guided radiotherapy treatment of five fractions was simulated for each patient. Multiple conformal treatment plans with increasing margins around the CTV were created for each patient. Then, the dose was warped to obtain an accumulated dose per simulated fraction. Full target coverage by 95% of the prescribed dose was assessed as a function of margin expansion in six directions. If target coverage in a single direction was accomplished, then the respective margin remained fixed for the subsequent dose plans. Margins in uncovered directions were increased in a new dose plan until full target coverage was achieved. RESULTS: The smallest set of CTV-to-PTV margins that yielded full dosimetric CTV coverage was 8 mm in posterior and right direction, 9 mm in anterior and cranial direction and 10 mm in left and caudal direction for 27 out of 29 patients. In two patients the curvature of the esophagus considerably changed between fractions, which required a 17 and 23 mm margin in right direction. CONCLUSION: Accumulated dose analysis revealed that CTV-to-PTV treatment margins of 8, 9 and 10 mm in posterior & right, anterior & cranial and left & caudal direction, respectively, are sufficient to account for interfraction tumor variations over the course of treatment when applying a daily online bone match. However, two patients with extreme esophageal interfraction motion were insufficiently covered with these margins and were identified as patients requiring replanning to achieve full target coverage.
Subject(s)
Esophageal Neoplasms , Prostatic Neoplasms , Radiotherapy, Image-Guided , Radiotherapy, Intensity-Modulated , Esophageal Neoplasms/radiotherapy , Humans , Male , Radiometry , Radiotherapy Dosage , Radiotherapy Planning, Computer-AssistedABSTRACT
Although the functional benefits of implants in the rehabilitation of edentulous cancer patients are well-known, most studies report on postponed implant placement. The outcome of immediate implant placement regarding successful rehabilitation, implant loading and survival is unclear. Two hundred and seven edentulous oral cancer patients that received implants during ablative surgery at the Radboud University Medical Centre between 2000 and 2011 were included. Data regarding the oncological treatment, implant placement, follow-up and prosthodontic rehabilitation were recorded retrospectively with a follow-up period of 5-17 years. Functioning implant-retained dentures were made in 73.9% of the patients. Of the surviving patients, 81.9% had functioning dentures after 2 years and 86.3% after 10 years. Patients with ASA score 1 and younger patients were rehabilitated more frequently. The median time of functioning denture placement was 336 days after surgery, with a negative influence of postoperative radiotherapy. Implant survival was 90.7%, and was lower when the implant was placed in a jaw involved in the tumour. Immediate implant placement during oral cancer surgery led to a high number of edentulous patients rehabilitated with implant-retained dentures, which are placed at an early time.