Influence of implant distribution on the biomechanical behaviors of mandibular implant-retained overdentures: a three-dimensional finite element analysis

OBJECTIVE

To assess stress distribution in peri-implant bone and attachments of mandibular overdentures retained by small diameter implants, and to explore the impact of implant distribution on denture stability.

METHODS

Through three-dimensional Finite Element Analysis (3D FEA), four models were established: three models of a two mandibular implants retained overdenture (IOD) and one model of a conventional complete denture (CD). The three IOD models consisted of one with two implants in the bilateral canine area, another with implants in the bilateral lateral incisor area, and the third with one implant in the canine area, and another in the lateral incisor area. Three types of loads were applied on the overdenture for each model: a 100 N vertical load and a inclined load on the left first molar, and a100N vertical load on the lower incisors. The stress distribution in the peri-implant bone, attachments, and the biomechanical behaviors of the overdentures were analyzed.

RESULTS

Despite different distribution of implants, the maximum stress values in peri-implant bone remained within the physiological threshold for all models across three loading conditions. The dispersed implant distribution design (implant in the canine area) exhibited the highest maximum stress in peri-implant bone (822.8 µe) and the attachments (275 MPa) among the three IOD models. The CD model demonstrated highest peak pressure on mucosa under three loading conditions (0.8188 Mpa). The contact area between the denture and mucosa of the CD model was smaller than that in the IOD models under molar loading, yet it was larger in the CD model compared to the IOD model under anterior loading. However, the contact area between the denture and mucosa under anterior loading in all models was significantly smaller than those under molar loading. The IOD in all three models exhibited significantly less rotational movement than the complete denture. Different implant positions had minimal impact on the rotational movement of the IOD.

CONCLUSION

IOD with implants in canine area exhibited the highest maximum stress in the peri-implant bone and attachments, and demonstrated increased rotational movement. The maximum principal stress was concentrated around the neck of the small diameter one-piece implant, rather than in the abutment. An overdenture retained by two implants showed better stability than a complete denture.

Immune dysregulation and macrophage polarization in peri-implantitis

The term "peri-implantitis" (peri-implantitis) refers to an inflammatory lesion of the mucosa surrounding an endosseous implant and a progressive loss of the peri-implant bone that supports the implant. Recently, it has been suggested that the increased sensitivity of implants to infection and the quick elimination of supporting tissue after infection may be caused by a dysregulated peri-implant mucosal immune response. Macrophages are polarized in response to environmental signals and play multiple roles in peri-implantitis. In peri-implantitis lesion samples, recent investigations have discovered a considerable increase in M1 type macrophages, with M1 type macrophages contributing to the pro-inflammatory response brought on by bacteria, whereas M2 type macrophages contribute to inflammation remission and tissue repair. In an effort to better understand the pathogenesis of peri-implantitis and suggest potential immunomodulatory treatments for peri-implantitis in the direction of macrophage polarization patterns, this review summarizes the research findings related to macrophage polarization in peri-implantitis and compares them with periodontitis.

Factors influencing the detection rate of fumarate peak in 1H MR spectroscopy of fumarate hydratase-deficient renal cell carcinoma at 3 T MRI

AIM

To identify factors that may be associated with fumarate detection rate in 1H-magnetic resonance spectroscopy (MRS) in fumarate hydratase-deficient renal cell carcinoma (FH-RCC).

MATERIALS AND MEHODS

Between February 2018 and March 2022, 16 FH-RCC patients with 30 lesions underwent 1H-MRS. Detection results were classified as having a detected fumarate peak (n=12), undetected peak (n=10), or technical failure (n=8). Factors including tumour size, tumour location, treatment history, and metastasis status were collected and analysed. A Bayesian logistic regression model was applied to evaluate the association between these factors and the detection result.

RESULTS

Bayesian analysis demonstrated significant associations between fumarate detection results and the following factors: long-axis diameter (odds ratio [OR] of 1.64; 95% confidence interval [CI] of 1.07-2.53), short-axis diameter (OR of 1.90; 95% CI of 1.19-3.06), voxel size (OR of 2.85; 95% CI of 1.70-4.75), treatment history (OR of 0.35; 95% CI of 0.21-0.58), non-metastatic state (OR of 2.45; 95% CI of 1.48-4.06), and lymph node metastasis (OR of 0.35; 95% CI of 0.21-0.58). Technical failure results were associated with factors such as treatment history (OR of 2.59; 95% CI of 1.37-4.66), non-metastatic state (OR of 0.36; 95% CI of 0.19-0.66), and lymph node metastasis (OR of 2.61; 95% CI of 1.39-4.74).

CONCLUSION

Tumour size, treatment history, and metastasis character were associated with the detection of abnormal fumarate accumulation. This finding will serve as a reference for interpreting 1H-MRS results and for selecting suitable scenarios to evaluate FH-RCC.

A double-blind randomized within-subject study to evaluate clinical applicability of four digital workflows for the fabrication of posterior single implant crown

OBJECTIVE

To compare efficiency and clinical efficacy of posterior single implant crowns (PSIC) fabricated using four digital workflows.

MATERIALS AND METHODS

Twenty-two patients with one missing first molar were included. Each patient received four screw-retained implant crowns fabricated through four different workflows including a fully digital workflow with immediate digital impression (Group i-IOS), a fully digital workflow with digital impression after implant osseointegration (Group d-IOS), a model-based hybrid workflow using immediate analogue impression (Group i-AI), and a model-based hybrid workflow with conventional analogue impression after implant osseointegration (Group d-AI). The crown delivery sequence was randomized and blinded. The efficiency for each workflow and clinical outcome of each crown were recorded.

RESULTS

The average clinical working time in fully digital workflows (i-IOS 46.90 min, d-IOS 45.66 min) was significantly lower than that in the hybrid workflows (i-AI 54.59 min, d-AI 55.96 min; p < .001). Significantly more laboratory time was spent in hybrid workflows (i-AI 839.60 min, d-AI 811.73 min) as compared to fully digital workflows (i-IOS 606.25 min, d-IOS 607.83 min, p < .01). No significant differences in the chairside time at delivery were found. More crowns in Group i-AI (15%) needed additional laboratory interventions than in the other groups (p = .029).

CONCLUSION

Digital impression and model-free fully digital workflow improved prosthetic efficiency in the fabrication of PSIC. With the limitation that the results were only applicable to the implant system used and the digital technologies applied, findings suggested that workflows integrating immediate impression with implant surgery procedure was clinically applicable for restoration of PSIC.

The accuracy of dynamic computer assisted implant surgery in fully edentulous jaws: A retrospective case series

OBJECTIVES

To evaluate the accuracy of implant placement using a dynamic navigation system in fully edentulous jaws and to analyze the influence of implant distribution on implant position accuracy.

MATERIALS AND METHODS

Edentulous patients who received implant placement using a dynamic navigation system were included. Four to six mini screws were placed in the edentulous jaw under local anesthesia as fiducial markers. Then patients received CBCT scans. Virtual implant positions were designed in the planning software based on CBCT data. Under local anesthesia, implants were inserted under the guidance of the dynamic navigation system. CBCTs were taken following implant placement. The deviation between the actual and planned implant positions was measured by comparing the pre- and postsurgery CBCT.

RESULTS

A total of 13 edentulous patients with 13 edentulous maxillae and 7 edentulous mandibles were included, and 108 implants were placed. The average linear deviations at the implant entry point and apex were 1.08 ± 0.52 mm and 1.15 ± 0.60 mm, respectively. The average angular deviation was 2.85 ± 1.20°. No significant difference was detected in linear and angular deviations between the maxillary and mandibular implants, neither between the anterior and posterior implants.

CONCLUSIONS

The dynamic navigation system provides high accuracy for implant placement in fully edentulous jaws, while the distribution of the implants showed little impact on implant position accuracy.

Evaluation of Radiotherapy Dose and Survival Outcomes for Teenagers, and Young Adults with Nasopharyngeal Carcinoma in UK and Ireland

PURPOSE/OBJECTIVE(S)

Nasopharyngeal carcinoma (NPC) follows a bimodal distribution with a smaller incidence peak in teenagers and young adults (TYAs). In TYAs, an over-whelming proportion are associated with Epstein-Barr virus (EBV). We have evaluated the variation in TYA NPC practice patterns across the UK and Ireland, along with survival outcomes.

MATERIALS/METHODS

We performed a multicenter, observational cohort study, of patients aged 13-25 years, with histologically confirmed NPC, treated between the years 2002-2022. An initial expression of interest was sent to selected centers treating H&N patients in the UK and Ireland. For analysis, patients were assessed based on total prescribed dose, with a cut off for low dose (LD) (≤61.2Gy) versus a high dose (HD)(>61.2Gy).

RESULTS

Ninety-five patients, from 9 centers, were eligible for inclusion. Patient demographics are shown in table1. At a median follow up of 45 months (IQR 23-111), 3-year overall survival (OS) was 98% (95% CI 93%-100%) with LD versus 91% (95% CI 83%-99%) with HD (Hazard ratio (HR) = 3.0; 95% CI 0.3-27, p = 0.3). 3-year progression free survival (PFS) was 84% (95% CI 71%-97%) with LD versus 83% (95% CI 72%-94%) with HD (HR 1.3; 95% CI 0.4-4.0, p = 0.6), and 5-year PFS was 84% (95% CI 71%-97%) with LD versus 83% (95% CI 72%-94%) with HD (HR 1.3; 95% CI 0.4-4.0, p = 0.6). Incidence of distant metastasis (DM) was 9.9%. 2 patients (6%) with T3-T4 tumors, treated with LD, had locoregional failure (LRF) compared to 1 patient (3%) treated with HD.

CONCLUSION

We have demonstrated excellent survival outcomes for the UK & Ireland TYA NPC patients. As the majority of cases in this age group have EBV+ NPC, with survival similar between LD and HD protocols, we propose that pediatric protocols, with lower radiotherapy doses should be considered for all TYA NPC, with the aim of reducing late effects. Additional analysis to better understand the impact of heterogeneity between both groups, including choice of protocol, induction and adjuvant treatment will follow this study. Prospective evaluation, as part of an international collaboration, is required to optimize the management strategy for this rare cohort of patients.

Rapid Unpaired CBCT-Based Synthetic CT for CBCT-Guided Adaptive Radiotherapy

PURPOSE/OBJECTIVE(S)

Quantitative cone beam CT (CBCT) is the foundation for image-guided radiation therapy, improving treatment setup, tumor delineation and dose calculation. However, CBCT images suffer from severe artifacts, limiting clinical utility. Deep learning can overcome these limitations, boosting radiographic and dosimetric quality critical for online adaptive radiotherapy (ART). We hypothesize adapted contrastive unpaired translation (CUT), a recent method for image-to-image translation of photographic images, can improve CBCT quality while reducing compute time, demonstrating utility for ART.

MATERIALS/METHODS

Same-day CBCT and quality assurance CT (QACT) images acquired from 79 patients receiving proton therapy for prostate cancer between 2019 and 2020 at a single institution were retrospectively collected. QACT images were acquired for quality assurance in accordance with institutional policy. Seventy-nine patients yielded 102 non-contrast CBCT-QACT image sets. Each QACT image was rigidly registered to the corresponding CBCT and resampled to 1 × 1 × 2 mm to establish uniform voxel size and spacing. CBCT images were randomly shuffled prior to input to the CUT model for unsupervised training and QACT-quality synthetic CT images were generated as outputs. We compared mean absolute error (MAE), structural similarity index measure (SSIM), and Fréchet inception distance (FID) against same-day QACT.

RESULTS

MAE, SSIM, and FID were compared for the CycleGAN and CUT data relative to input QACT and are reported as the mean across five-fold cross-validation ± standard error. CUT achieved superior performance in MAE (19.5 ± 3.9 HU vs. cycleGAN 47.1 ± 25.4) and FID (31.5 ± 6.6 vs cycleGAN 75.9 ± 41.3). MAE indicates pixel-level correspondence to QACT HU intensity values, making the synthetic outputs of CUT useful for dose calculations during ART. FID further demonstrates perceptual visual similarity. SSIM for CycleGAN (0.7 ± 0.2) and CUT (0.8 ± 0.0) were similar, indicating acceptable reproducibility of global structure. CUT was faster and lighter than CycleGAN. CycleGAN contained a total of 28,286,000 parameters; CUT contained 14,703,000, approximately half that of CycleGAN. As a result, CycleGAN computes on a single CT image slice over 0.33s while CUT requires just 0.18s.

CONCLUSION

The contrastive method investigated here was demonstrated to be faster and more accurate than CycleGAN, requiring fewer networks and parameters to achieve superior performance. We demonstrated anatomic boundary preservation and HU fidelity superior to cycleGAN while significantly reducing compute time. We plan to investigate the use of these synthetic CT images in automated segmentation prior to exploration of CUT in a prospective setting.

Equity of Access to Proton Beam Therapy in England: A National NHS analysis

PURPOSE/OBJECTIVE(S)

Policies to improve population health have often focused on equitable access to health services. While new technologies have an enormous potential in improving health outcomes, they may not always be equally accessible across diverse geographical areas and socio-economic backgrounds. Between 2008 and 2018, 1352 patients with eligible indications for Proton Beam Therapy (PBT) were treated overseas within the NHS Proton Overseas Programme (POP) and 947 patients have been treated at the Christie since the National NHS PBT service started in December 2018. The 8 most common PBT cancer indications cover more than 80% of the referrals and referral rates depend on several factors. Aim of this study is to evaluate equity of access to PBT throughout the country and how this has changed since the national PBT service inception.

MATERIALS/METHODS

Incidence data were available for 7/8 of the most common PBT cancer indications. These data were provided by the National Disease Registration Service (NDRS) by diagnosis, age group and by the 7 NHS regions in England. The incidence data referred to the time period 2013-2019. The first national NHS PBT center started accepting referrals in October 2018, therefore this time period was split in pre-NHS PBT (1/1/13-30/9/18) and post-NHS PBT (1/10/18-31/12/19). Demographics and clinical characteristics of patients referred for PBT were extracted from the national NHS PBT registry for matching clinical diagnoses and time period. The ratio between the referred (observed) and newly diagnosed (expected) patients is the Proton Utilization Proportion (PUP), which tracks the proportion of eligible patients using the technology.

RESULTS

For the 7 common PBT indications examined, the total number of newly diagnosed patients was 2134 in the pre-NHS PBT period and 461 in the post-NHS PBT period. The (accepted) referrals were 587 and 300 in the pre-and post-NHS PBT period, respectively. An increase in the PUP between the pre-NHS PBT and the post-NHS PBT is noted for any diagnostic category, age group and NHS region. The most noticeable increase is noticed for Medulloblastoma, which became a commissioned indication for PBT only in 2016.The PUP in England increased post-NHS PBT by 137% overall. Of note, post-NHS PBT, 99% of the patients aged 0-15 with these 7 common indications for PBT were referred and treated with PBT.

CONCLUSION

Promoting equality of access to cutting-edge radiotherapy technologies is at the heart of NHS England's values. Throughout the development of the policies and processes related to PBT access in the UK, the NHS has given regard to the need to reduce geographical variation which may contribute to health inequalities. The PUP has increased since the opening of a National PBT service in England, which uses a central web-based Proton Referral Pathway managed by a National Proton Office. Further analysis will follow to examine whether socio-economic or geographical barriers exist within each region.

Proton Beam Therapy in the Reirradiation Setting of Brain and Base of Skull Tumour Recurrences

The therapeutic management of local tumour recurrence after a first course of radical radiotherapy is always complex. Surgery and reirradiation carry increased morbidity due to radiation-induced tissue changes. Proton beam therapy (PBT) might be advantageous in the reirradiation setting, thanks to its distinct physical characteristics. Here we systematically reviewed the use of PBT in the management of recurrent central nervous system (CNS) and base of skull (BoS) tumours, as published in the literature. The research question was framed following the Population, Intervention, Comparison and Outcomes (PICO) criteria: the population of the study was cancer patients with local disease recurrence in the CNS or BoS; the intervention was radiation treatment with PBT; the outcomes of the study focused on the clinical outcomes of PBT in the reirradiation setting of local tumour recurrences of the CNS or BoS. The identification stage resulted in 222 records in Embase and 79 in Medline as of March 2023. Sixty-eight duplicates were excluded at this stage and 56 were excluded after screening as not relevant, not in English or not full-text articles. Twelve full-text articles were included in the review and are presented according to the site of disease, namely BoS, brain or both brain and BoS. This review showed that reirradiation of brain/BoS tumour recurrences with PBT can provide good local control with acceptable toxicity rates. However, reirradiation of tumour recurrences in the CNS or BoS setting needs to consider several factors that can increase the risk of toxicities. Therefore, patient selection is crucial. Randomised evidence is needed to select the best radiation modality in this group of patients.

Dose Volume Thresholds Associated with Acute Skin Toxicities in Proton Beam Therapy

PURPOSE/OBJECTIVE(S)

The depth-dose characteristics of proton beam therapy (PBT) mean that the skin-sparing effect is reduced with PBT, potentially leading to an increased incidence and severity of acute radiotherapy induced skin toxicities (RIST). Predictive factors of acute RIST in patients treated with PBT remain largely undefined. In this study, we retrospectively reviewed the acute RIST of patients treated with pencil beam scanning (PBS) PBT to identify dose-volume thresholds which are predictive of acute RIST.

MATERIALS/METHODS

All patients treated with PBS-PBT at a single institution between December 2018-October 2022 were included in this study. Acute RIST were recorded as per RTOG grading scale and dichotomized to Grade (G) <2 vs ≥2. Anonymized demographics, clinical and dosimetric data were extracted from electronic patient records and a treatment planning system. Skin structure is defined as 5mm rind grown as an inner margin from the patient contour. The following skin dose-volume statistics were collected: Dmax (maximum dose to any pixel inside the skin contour) and dose to skin volumes in 5Gy increments (V5Gy, V10Gy etc.). Preliminary analyses of dosimetric data of patients with G0, G1 vs ≥G2 acute RIST are presented, with significance assessed at the 5% level using t-tests and univariate logistic regression models, and risk thresholds determined using receiver operating characteristic (ROC) curves.

RESULTS

We report the data for 582 patients with extracted dosimetric data. The pediatric, teenage and young adult (TYA) and adult populations were 38%, 19% and 43% respectively. The three most common indications for PBT were head and neck cancers (HNC) (23%), sarcoma (21%), and chordoma (15%). Increasing age, HNC and sarcoma were associated with an increased risk of grade 2+ acute RIST. For patients who developed acute RIST of G2+, the median volume receiving 10Gy, 20Gy, 30Gy, 40Gy and 50Gy were significantly higher (P<0.0001) than patients with G0 and G1. The dose volume effect of acute RIST is greater at 30Gy and above. Similarly, median Dmax was significantly higher in the G2+ acute RIST group compared to G0 and G1 (P<0.0001) for all age groups. Using the ROC curve, we observed threshold volumes (in cm3) for V10Gy, V20Gy, V30Gy, V40Gy and V50Gy (Table 1).

CONCLUSION

The volume of irradiated skin and Dmax are associated with the risk of developing acute RIST in patients treated with PBS PBT. Further work is being done to develop a model predictive of acute RIST in clinical setting.

Assessing Equity of Access to Proton Beam Therapy: A Literature Review

Proton beam therapy (PBT) is one of the most advanced radiotherapy technologies, with growing evidence to support its use in specific clinical scenarios and exponential growth of demand and capacity worldwide over the past few decades. However, geographical inequalities persist in the distribution of PBT centres, which translate into variations in access and use of this technology. The aim of this work was to look at the factors that contribute to these inequalities, to help raise awareness among stakeholders, governments and policy makers. A literature search was conducted using the Population, Intervention, Comparison, Outcomes (PICO) criteria. The same search strategy was run in Embase and Medline and identified 242 records, which were screened for manual review. Of these, 24 were deemed relevant and were included in this analysis. Most of the 24 publications included in this review originated from the USA (22/24) and involved paediatric patients, teenagers and young adults (61% for children and/or teenagers and young adults versus 39% for adults). The most reported indicator of disparity was socioeconomic status (16/24), followed by geographical location (13/24). All the studies evaluated in this review showed disparities in the access to PBT. As paediatric patients make up a significant proportion of the PBT-eligible patients, equity of access to PBT also raises ethical considerations. Therefore, further research is needed into the equity of access to PBT to reduce the care gap.

Substrate Stiffness of Bone Microenvironment Controls Functions of Pre-Osteoblasts and Fibroblasts In Vitro

The formation of bone in a bone defect is accomplished by osteoblasts, while the over activation of fibroblasts promotes fibrosis. However, it is not clear how the extracellular matrix stiffness of the bone-regeneration microenvironment affects the function of osteoblasts and fibroblasts. This study aim to investigate the effect of bone-regeneration microenvironment stiffness on cell adhesion, cell proliferation, cell differentiation, synthesizing matrix ability and its potential mechanisms in mechanotransduction, in pre-osteoblasts and fibroblasts. Polyacrylamide substrates mimicking the matrix stiffness of different stages of the bone-healing process (15 kPa, mimic granulation tissue; 35 kPa, mimic osteoid; 150 kPa, mimic calcified bone matrix) were prepared. Mouse pre-osteoblasts MC3T3-E1 and mouse fibroblasts NIH3T3 were plated on three types of substrates, respectively. There were significant differences in the adhesion of pre-osteoblasts and fibroblasts on different polyacrylamide substrates. Runx2 expression increased with increasing substrate stiffness in pre-osteoblasts, while no statistical differences were found in the Acta2 expression in fibroblasts on three substrates. OPN expression in pre-osteoblasts, as well as Fn1 and Col1a1 expression in fibroblasts, decreased with increasing stiffness. The difference between the cell traction force generated by pre-osteoblasts and fibroblasts on substrates was also found. Our results indicated that substrate stiffness is a potent regulator of pre-osteoblasts and fibroblasts with the ability of promoting osteogenic differentiation of pre-osteoblasts, while having no effect on myofibroblast differentiation of fibroblasts.

An investigation of the PM2.5 concentrations and cumulative inhaled dose during subway commutes in Changchun, China

Air quality in subway systems is crucial as it affects the health of passengers and staff. Although most tests of PM2.5 concentrations in subway stations have taken place in public areas, PM2.5 is less understood in workplaces. Few studies have estimated the cumulative inhaled dose of passengers based on real-time changes in PM2.5 concentrations as they commute. To clarify the above issues, this study first measured PM2.5 concentrations in four subway stations in Changchun, China, where measuring points included five workrooms. Then, passengers' exposure to PM2.5 during the whole subway commute (20-30 min) was measured and segmented inhalation was calculated. The results showed that PM2.5 concentration in public places ranged from 50 to 180 μg/m3, and was strongly correlated with outdoors. While the PM2.5 average concentration in workplaces was 60 µg/m3, and it was less affected by outdoor PM2.5 concentration. Passenger's cumulative inhalations in single commuting were about 42 μg and 100 μg when the outdoor PM2.5 concentrations were 20-30 μg/m3 and 120-180 μg/m3, respectively. The PM2.5 inhalation in carriages accounted for the largest proportion of the entire commuting, about 25-40%, because of the longer exposure time and higher PM2.5 concentrations. It is recommended to improve the tightness of the carriage and filter the fresh air to improve the air quality inside. The average daily PM2.5 inhaled by staff was 513.53 μg, which was 5-12 times higher than that of passengers. Installing air purification devices in workplaces and reminding staff to take personal protection can positively protect their health.

A Salivary Gland Resident Macrophage Subset Regulating Radiation Responses

Radiotherapy of head and neck cancers frequently leads to irreversible hypofunction of salivary glands, which severely compromises the quality of life and is extremely difficult to treat. We found recently that salivary gland resident macrophages are sensitive to radiation and interact with epithelial progenitors and endothelial cells through homeostatic paracrine factors. Heterogeneous subpopulations of resident macrophages are present in other organs with distinct functions, whereas subpopulations of salivary gland resident macrophages with distinct functions or transcriptional profiles have not been reported yet. Using single-cell RNA sequencing, we found that mouse submandibular glands (SMGs) contain 2 distinct self-renewing resident macrophage subsets, an MHC-IIhi subset present in many other organs and an uncommon Csf2r+ subset. The main source of Csf2 in SMGs are innate lymphoid cells (ILCs) that rely on IL15 for maintenance, while the main source of IL15 protein is Csf2r+ resident macrophages, indicating a homeostatic paracrine interaction between these cells. Csf2r+ resident macrophages are the major source of hepatocyte growth factor (Hgf) that regulates homeostasis of SMG epithelial progenitors. Meanwhile, Csf2r+ resident macrophages are responsive to Hedgehog signaling that can rescue salivary function impaired by radiation. Consistently, irradiation persistently decreased numbers of ILCs and levels of IL15 and Csf2 in SMGs, which were all recovered by transient activation of Hedgehog signaling after radiation. Csf2r+ resident macrophages and MHC-IIhi resident macrophages share transcriptome profiles of perivascular macrophages and macrophages associated with nerves and/or epithelial cells in other organs, respectively, and such niche preferences were supported by lineage tracing and immunofluorescent staining. These findings reveal an uncommon resident macrophage subset that regulates the homeostasis of the salivary gland and is promising as the target to restore salivary gland function impaired by radiation.

Chimeric Antigen Receptor-Natural Killer Cells: A New Breakthrough in the Treatment of Solid Tumours

Natural killer (NK) cells can quickly and directly eradicate tumour cells without recognising tumour-specific antigens. NK cells also participate in immune surveillance, which arouses great interest in the development of novel cancer therapies. The chimeric antigen receptor (CAR) family is composed of receptor proteins that give immune cells extra capabilities to target specific antigen proteins or enhance their killing effects. CAR-T cell therapy has achieved initial success in haematological tumours, but is prone to adverse reactions, especially with cytokine release syndrome in clinical applications. Currently, CAR-NK cell therapy has been shown to successfully kill haematological tumour cells with allogeneic NK cells in clinical trials without adverse reactions, proving its potential to become an off-the-shelf product with broad clinical application prospects. Meanwhile, clinical trials of CAR-NK cells for solid tumours are currently underway. Here we will focus on the latest advances in CAR-NK cells, including preclinical and clinical trials in solid tumours, the advantages and challenges of CAR-NK cell therapy and new strategies to improve the safety and efficacy of CAR-NK cell therapy.

Transcriptome analysis of the binucleate ciliate Tetrahymena thermophila with asynchronous nuclear cell cycles

Tetrahymena thermophila harbors two functionally and physically distinct nuclei within a shared cytoplasm. During vegetative growth, the "cell cycles" of the diploid micronucleus and polyploid macronucleus are offset. Micronuclear S phase initiates just before cytokinesis and is completed in daughter cells before onset of macronuclear DNA replication. Mitotic micronuclear division occurs mid-cell cycle, while macronuclear amitosis is coupled to cell division. Here we report the first RNA-seq cell cycle analysis of a binucleated ciliated protozoan. RNA was isolated across 1.5 vegetative cell cycles, starting with a macronuclear G1 population synchronized by centrifugal elutriation. Using MetaCycle, 3244 of the 26,000+ predicted genes were shown to be cell cycle regulated. Proteins present in both nuclei exhibit a single mRNA peak that always precedes their macronuclear function. Nucleus-limited genes, including nucleoporins and importins, are expressed before their respective nucleus-specific role. Cyclin D and A/B gene family members exhibit different expression patterns that suggest nucleus-restricted roles. Periodically expressed genes cluster into seven cyclic patterns. Four clusters have known PANTHER gene ontology terms associated with G1/S and G2/M phase. We propose that these clusters encode known and novel factors that coordinate micro- and macronuclear-specific events such as mitosis, amitosis, DNA replication, and cell division.

Survival and renal outcomes of direct heart transplant from veno-arterial extracorporeal membrane oxygenation support

Backgrounds

Patients on veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support are given the highest priority for cardiac transplantation (OHT) in the new UNOS heart allocation policy adopted in October 2018. Although patients may receive an organ quicker there may not be enough time to recover end-organ function. To date, little is known about survival and renal outcomes of direct OHT in patients that have been supported with VA-ECMO as a bridge to transplant due to limited experience in most transplant centers.

Purpose

The aim of this study was to investigate survival and renal outcomes of direct OHT in patients supported with VA-ECMO prior to transplant.

Methods

From January 2010 to February 2022, 23 patients who received single organ OHT alone directly from VA-ECMO support were retrospectively analyzed (16 patients after the new allocation policy). Kaplan-Meier analysis was used to estimate event-free survival.

Results

The median age of recipients was 48 years. The median length of pre-transplant VA-ECMO support was 5 days. Additional pre-transplant support with intra-aortic balloon pump or Impella was utilized in 15 patients (65.2%) and 2 patients (9%) respectively. There was a trend toward improvement of serum creatinine after initiation of VA-ECMO support (Pre-ECMO: 1.66±1.22 mg/dl vs. Pre-OHT: 1.20±0.74 mg/dl, P=0.084). Four patients required preoperative renal replacement therapy (RRT); three were on RRT at the time of OHT. The median ischemic time of donor hearts was 168 minutes. VA-ECMO support was continued in 10 patients (43.5%) after OHT.

Hospital mortality was 8.7% (2 patients). Post-transplant RRT was required in 9 patients (39.1%), and, of these, 5 patients were transitioned to permanent dialysis. Among the 14 patients who did not require post-transplant RRT, none required RRT during the follow-up period (median, 21.5 months). Kaplan-Meier survival analysis showed that estimated survival at 1 year and 3 years were 86.1%, and 77.5%, respectively (Figure 1A). The freedom from dialysis rate was 82.4% at 1 year, and 74.9% at 3 years (Figure 2A). Both survival (100% vs. 66.7%, P=0.008, Fig.1B) and dialysis free rate (100% vs. 55.6%, P=0.002, Figure 2B) at one-year were significantly worse in patients who required postoperative RRT.

Conclusions

To our knowledge this is the largest single center study of OHT in patients that were supported with VA-ECMO. VA-ECMO as a bridge to end-organ recovery and OHT resulted in excellent outcomes. Patients who required post-transplant RRT more likely to require long-term dialysis, while those that did not receive RRT showed favorable outcomes. Overall survival in this patient population is comparable to patients that were not on VA-ECMO prior to transplant.

Funding Acknowledgement

Type of funding sources: None.

P01.07.A Neurocognitive outcomes after proton beam therapy for skull base tumours

Background

Evidence suggests that Proton Beam Therapy (PBT) may lessen the risk of neurocognitive decline (NCD) by reducing the dose to the normal brain as compared to conventional photon radiotherapy (XRT). We report the incidence of moderate-severe (Grade ≥3) NCD in adults treated for skull base chordomas and chondrosarcomas within the United Kingdom’s Proton Overseas Programme (POP).

Material and Methods

Baseline (pre-PBT) and follow-up clinical outcomes data were prospectively collected as part of a national PBT-outcomes registry, which started in 2008 . This registry is curated by a dedicated Proton Clinical Outcomes Unit. Specifically, late toxicities ≥G3 as per CTCAE (Common Terminology Criteria for Adverse Events) v4.0 definition, occurring later than 90 days after treatment completion, were recorded. This study focuses on the incidence of memory impairment (MI) in the adult (≥25 y) cohort.

Results

Between 2008-2018, 141 adult patients were treated for skull base chordomas (77 patients, 54.6%) and chondrosarcomas (64 patients, 45.4%) via the POP (the majority -62.8%- treated at the University of Florida PBT Institute). Median age at treatment was 51 years (range 26-77). Median prescription dose was 73.8 GyRBE (70-75.6), with a median dose per fraction of 1.8 Gy (1.2-2.1). Of note, the median dose for chondrosarcomas was 70.2 GyRBE (70-75.6), whereas the median dose for chordomas was 73.8 GyRBE (72-75.6). Median follow up was 39 months (0-138). On clinical assessment, 4 patients (2 chordomas, 2 chondrosarcomas) were reported with G3 MI after a median time of 43 months (27-49). None of them had impaired memory at baseline, nor relevant neurological comorbidities. Median age of those who developed G3 MI was 63 y (39-70). Median prescription dose was 72.9 GyRBE (70-73.8). Plans were available for 3 of these 4 patients. Relevant dose statistics to hippocampi and temporal lobes were extracted. Dmean to the omo- and contralateral hippocampi in these 3 patient plans were: patient 1) 33.7 and 11.6 GyRBE; patient 2) 28.1 and 24.4 Gy; patient 3) 8.7 and 8.2 GyRBE, respectively. V20 to the omo- and contralateral temporal lobes in the same patients were: patient 1) 47% and 10%; patient 2) 29% and 28.7%; patient 3) 30% and 28%, respectively. Suggested constraints for these structures are: Dmean &lt; 20 Gy to the hippocampi and V20Gy &lt;10% to the temporal lobes.

Conclusion

Our results indicate that adult patients undergoing high dose radiation for radioresistant tumours may experience detrimental effects on memory. Neurocognitive baseline and follow-up assessment is not routinely performed in this age group but might be appropriate to explore which domains of cognitive function are mainly affected. Larger cohorts are warranted to establish predictive factors and better understand dose volume effect of brain structures and neurocognitive sequelae.

[Value of purple sign for predicting rebleeding events in cirrhotic patients following endoscopic selective varices devascularization]

OBJECTIVE

To assess the value of the purple sign for predicting long-term rebleeding events in cirrhotic patients following endoscopic selective varices devascularization.

METHODS

We retrospectively analyzed the clinical data of 97 patients with liver cirrhosis, who had a history of gastroesophageal variceal bleeding and underwent endoscopic selective varices devascularization. Thirty-two of the patients showed purple sign after endoscopic treatment. We used propensity score matching (PSM) to minimize the selection bias of the patients (purple sign vs no purple sign) and reduce the intergroup differences of clinical characteristics. The primary outcome measure of this study was cumulative rebleeding events after endoscopic selective varices devascularization.

RESULTS

The 1-year rebleeding rate (27.0% vs 36.7%) or 6-month rebleeding rate (10.9% vs 26.9%) following endoscopic treatment was not significantly different between the purple sign group and no purple sign group before PSM (P=0.2385). But after PSM, the 1-year rebleeding rate (28.2% vs 56.4%) and 6-month rebleeding rate (5.0% vs 37.0%) were significantly lower in the purple sign group than in the no purple sign group (P=0.0304).

CONCLUSIONS

The presence of purple sign indicates a lower risk of rebleeding after endoscopic treatment of cirrhotic gastroesophageal varices and a potentially favorable treatment response after endoscopic therapy, thus providing a clinical indicator for stratification of the patients for sequential endoscopic sessions.

Comparative immunogenicity of outer membrane protein K and whole-cell antigens of Vibrio parahaemolyticus for diagnosis

The immunogenicity of soluble outer membrane protein K (OmpK)- small ubiquitin-like modifier, OmpK inclusion bodies, formalin, and heat-killed Vibrio parahaemolyticus cells were prepared and studied in a mouse model. The results of whole-cell ELISA and Western blot (WB) revealed that the serum against soluble OmpK and OmpK inclusion bodies reacted only with homologous V. parahaemolyticus. Furthermore, recombinant OmpK proteins were not recognized by the serum against whole-cell V. parahaemolyticus antigens. Unexpectedly, the serum against formalin and heat-killed V. parahaemolyticus reacted broadly with homologous (an immunization strain) and heterologous (non-immunization strains) V. parahaemolyticus and Vibrio species. The WB results revealed that the serum against the two V. parahaemolyticus whole-cell antigens primarily reacted with proteins that were approximately 100, 70, 36, 28, and 22 kDa in the cell lysates from different Vibrio strains, rather than the recombinant OmpK. The 70 and 28 kDa proteins exhibited specificity to Vibrio species, while the 22 kDa protein was more specific to V. parahaemolyticus. This study showed the limitation of recombinant OmpK to prepare diagnostic antibodies and revealed several specific Omps of Vibrio sp. and V. parahaemolyticus that were promising in diagnosis and vaccine development.

Three-dimensional vectorcardiographic characteristics of breast cancer patients treated with chemotherapy

Funding Acknowledgements

Type of funding sources: None.

Background

 Patients receiving chemotherapy for breast cancer (BC) may develop cardiac electrophysiological abnormalities. The aim of this study is to examined possible alterations in cardiac electrophysiological parameters detected by three-dimensional vectorcardiograms (3D-VCGs) in BC patients who received chemotherapy.

Methods

This was a prospective single-center cohort study conducted. Patients with BC referred for chemotherapy from May 1, 2019, to October 1, 2019 were invited to participate in the study. 3D-VCG and echocardiography were recorded at rest four times (baseline, after the first cycle, after third cycles and at the end of the regimen, respectively). 

Results

 A total of 63 patients were included. Compared with baseline, decreases in 3-dimensional maximum T vector magnitude (TVM) (0.29 ± 0.10 vs. 0.25 ± 0.10mV; p &lt; 0.05) and 3-dimensional T/QRS ratio (0.26 ± 0.11 vs. 0.21 ± 0.11; p &lt; 0.05) were observed by the end of chemotherapy regimen, while echocardiographic parameters showed no significant variation before and after chemotherapy (all P &gt; 0.05). Maximum TVM showed a significant positive correlation with left ventricular ejection fraction (LVEF) (all p &lt; 0.05). Furthermore, the cut-off value with 0.23 of 3-dimensional T/QRS ratio (the area under the curve [AUC] 0.725) for differentiating LVEF reduction ≥10% following initiation of chemotherapy. The AUC of the front plane T/QRS ratio and horizontal plane T/QRS ratio for the detection of an LVEF reduction ≥10% was 0.725 and 0.763, respectively.

Conclusions

 3D-VCGs can be used to detect electrophysiological abnormalities in BC patients receiving chemotherapy. Subclinical cardiac dysfunction can be revealed by 3D-VCGs before alterations in traditional echocardiographic parameters.

The migration of neighboring and antagonist teeth three months after implant placement in healed single tooth-missing sites

OBJECTIVES

To quantify the neighboring and antagonist teeth migration of a single posterior tooth-missing site within 3 months using digital scanning and measuring techniques.

MATERIALS AND METHODS

Intraoral scans (IOS) were made in 40 patients presenting a single posterior tooth-missing gap and receiving implant therapy. IOS were obtained at the day of and three months after implant surgery rendering a digital baseline model (BM) and a digital follow-up model (FM). Digital models were superimposed using the implant scan body as reference. Antagonist models were processed by the best fit alignment. Dimensional change between anatomical landmarks on neighboring teeth and that of featuring points on antagonistic teeth were measured using a three-dimensional analysis software. The Mann-Whitney U test was applied to compare the tooth-moving distance between the mesial and distal neighboring teeth. The Kruskal-Wallis one-way ANOVA was used to test the difference in dimensional change in tooth-missing site among age subgroups.

RESULTS

The mean dimensional change in the tooth-missing site was -37.62 ± 106.36 μm (median: -28.33 μm, Q₂₅ -72.65/Q₇₅ 38.97) mesial-distally and -67.91 ± 42.37 μm (median: -61.50 μm, Q₂₅ -88.25/Q₇₅ -36.75) occlusal-gingivally. Eighteen out of 40 mesial neighboring teeth and 24 out of 40 distal neighboring teeth showed migration towards the implants. When patients were grouped according to age, the mesial-distal reduction in the tooth-missing site was significantly larger in patients younger than 30 years compared with those older than 50 years (p < .05).

CONCLUSIONS

The dimensions of posterior tooth-missing sites decreased over an observation period of 3 months.

Accuracy of a milled digital implant surgical guide: An in vitro study

STATEMENT OF PROBLEM

An accurate surgical template for guided implant surgery is essential for the success of an implant restoration. However, reports on the accuracy of digitally designed and computer numeric controlled (CNC) machine-milled surgical templates are sparse.

PURPOSE

The purpose of this in vitro study was to investigate the accuracy of an implant surgical guide digitally designed by using data from cone beam computed tomography (CBCT) scans and milled with a 5-axis CNC machine.

MATERIAL AND METHODS

Six representative radiographic templates were prepared from radiopaque resin plates. For each guide, a CBCT scan was made, and the extracted Digital Imaging and Communications in Medicine (DICOM) data were imported into a planning software program (ORGANICAL Dental Implant). Nine implants were virtually designed for each guide. The design data were imported into a 5-axis CNC machine, and the radiographic guides were fixed onto the CNC machine (Organical Multi S). Bore holes for surgical guide sleeves were milled directly in the radiographic template, which was converted into a surgical template. After the milling process, the surgical guides were scanned by using a laboratory cast scanner. The deviation between the position of the sleeve bore hole in the milled template and that in the virtual implant planning was digitally calculated.

RESULTS

The mean global deviation of the surgical guide was 0.16 ±0.06 mm in the circle center of the sleeve top, and the mean angular deviation was 0.61 ±0.40 degrees. The sleeve-implant distance and the sleeve axis angle showed no significant influence on the in vitro accuracy of the implant surgical guide.

CONCLUSIONS

The mean deviation of the surgical guide prepared by using the virtual planning software and 5-axis CNC milling procedure in this study was 0.16 ±0.06 mm in the center of the sleeve top. Thus, the guide had acceptable precision.

The Effectiveness of Waist-Shaped and Straight-Shaped Interdental Brushes in Cleaning Implant Overdenture Attachments: A Self-Controlled Clinical Trial

Elderly patients often find it challenging to remove plaque accumulated on the attachments of implant overdentures (IODs) using conventional cleaning instruments. Further, excessive plaque accumulation can lead to peri-implant diseases and occasionally to respiratory diseases. Therefore, here, we aimed to compare the effectiveness of waist-shaped interdental brushes (WIBs) with that of straight-shaped interdental brushes (SIBs) in plaque removal from the locator attachments of IODs. Twenty participants with 2 locator attachments retaining mandibular IODs participated in this study. After the baseline cleaning, the participants refrained from oral hygiene maintenance for 3 days. A dentist cleaned 1 of the attachments using the WIB and the other attachment using the SIB. The pre- and post-cleaning modified plaque index (mPLI) scores were recorded. After another 3 days free from oral hygiene maintenance, the trained participants repeated the same cleaning procedure using the WIB and SIB. Pre- and post-cleaning mPLI scores were recorded. Regardless of the type of brush used, the post-cleaning mPLI scores were lower than the pre-cleaning scores. After the cleaning procedure, the overall mean mPLI score was lower in the WIB group than in the SIB group. The post-cleaning mPLI scores at the line angles and on the axial surfaces of the attachments were also lower in the WIB group than in the SIB group. There was no difference in the cleaning effectiveness between the dentist and participants when they used the same type of interdental brush. The WIB was significantly more efficient in plaque removal than the SIB, especially at the line-angle sites.

The acquisition of Mycobacterium tuberculosis infection in village doctors in China: a prospective study

BACKGROUND: Occupational exposure-related risk of Mycobacterium tuberculosis infection has been reported for village doctors in China. This prospective study aims to estimate the infection acquisition in this key population.METHODS: At baseline, all village doctors registered in Zhongmu County were tested by QuantiFERON^®-TB Gold In-Tube (QFT) and QuantiFERON^®-TB Gold Plus (QFT-Plus) in parallel. Those negatives for either of the tests were retested to identify conversions at the 2-year follow-up investigation.RESULTS: A total of 367 eligible participants completed the 2-year follow-up survey with frequency of conversion of 5.0% (18/361) for QFT and 6.1% (21/343) for QFT-Plus. The agreement of follow-up results between the tests was 93.2% with a κ coefficient of 0.43 (95%CI 0.20-0.65). Among QFT-Plus convertors, the difference between TB1 and TB2 tubes (TB2-TB1) was significantly increased as compared with baseline results (P = 0.039). Participants from the villages with occurrence of microbiologically confirmed pulmonary TB showed higher frequency of QFT conversions (11.0% vs. 3.2%, P = 0.011) and QFT-Plus conversions (12.3% vs. 4.4%, P = 0.027) than those from the villages without occurrence.CONCLUSION: Our results consistently suggest that capability on occupational protection and M. tuberculosis infection control should be improved in village doctors in China.

Large-for-gestational age diagnosed during second-trimester anatomy ultrasound and association with gestational diabetes and large-for-gestational age at birth

OBJECTIVES

To determine if large-for-gestational age (LGA) diagnosed during second-trimester ultrasound examination is associated with the development of gestational diabetes mellitus (GDM) and LGA at birth.

METHODS

This was a retrospective cohort study of all pregnant women who underwent a second-trimester anatomy ultrasound examination between 18 and 22 weeks at our institution from 2012 to 2017. Patients were included in the LGA group if estimated fetal weight and/or fetal abdominal circumference was ≥ 90^th percentile for gestational age. Patients with a history of pre-GDM, multiple gestation, preterm delivery, use of betamethasone or fetal anomaly were excluded. The control group consisted of appropriate-for-gestational-age (AGA) pregnancies that were scanned at 18-22 weeks during the study period. AGA was defined as EFW > 10^th percentile and ≤ 89^th percentile. Prenatal and delivery records were reviewed and demographic and outcome variables were collected. Multivariable logistic regression models were applied to assess the impact of LGA diagnosed in the second trimester on the development of GDM and LGA at birth (birth weight ≥ 90^th percentile).

RESULTS

The study population included 756 patients with a LGA fetus and 756 with an AGA fetus on second-trimester ultrasound examination. In patients with a LGA fetus diagnosed during the second-trimester ultrasound examination, the incidence of GDM was 6.0% and the incidence of LGA at birth was 14.9%. Among patients with a LGA fetus in the second trimester, those who developed GDM or LGA at birth were significantly older and were more likely to be obese. Moreover, parity was associated with neonatal LGA (P = 0.0003) but not with GDM (P = 0.82). On multivariable logistic regression analysis with adjustment for age, parity, change in gestational body mass index, obesity, ethnicity and neonatal sex, LGA diagnosed during the second trimester was associated significantly with GDM (adjusted odds ratio (aOR), 2.54; 95% CI, 1.29-5.03; P = 0.007) and LGA at birth (aOR, 6.85; 95% CI, 3.60-13.05; P < 0.0001).

CONCLUSIONS

LGA diagnosed during second-trimester ultrasound examination is associated with the development of GDM and LGA at birth, independent of known risk factors, and could be used to identify these women earlier for intervention. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Accuracy of implant surgical guides fabricated using computer numerical control milling for edentulous jaws: a pilot clinical trial

Background

To evaluate the accuracy of a computer numerical control (CNC) milled surgical guide for implant placement in edentulous jaws.

Methods

Edentulous patients seeking implants treatment were recruited in this prospective cohort study. Radiographic guides with diagnostic templates were fabricated from wax-up dentures. Patients took cone-beam computed tomography (CBCT) wearing the radiopaque radiographic guides. Implant positions were virtually designed in the planning software based on the CBCT data, and the radiographic templates were converted into surgical guides using CNC milling technique. Forty-four implants were placed into 12 edentulous jaws following guided implant surgery protocol. Post-surgery CBCT scans were made for each jaw, and the deviations between the planned and actual implant positions were measured. Deviation of implant position was compared between maxilla and mandible, and between cases with and without anchor pins using independent t-test.

Results

Nine patients (3 males and 6 females) with 12 edentulous jaws were recruited. The mean age of patients was 59.2 ± 13.9 years old. All 44 implants was placed without complication and survived, the mean three dimensional linear deviation of implant position between virtual planning and actual placement was 1.53 ± 0.48 mm at the implant neck and 1.58 ± 0.49 mm at the apex. The angular deviation was 3.96 ± 3.05 degrees. No significant difference was found in the deviation of implant position between maxilla and mandible (P = 0.28 at neck, 0.08 at apex), nor between cases with and without anchor pins (P = 0.87 at neck, 0.06 at apex).

Conclusions

The guides fabricated using the CNC milling technique provided comparable accuracy as those fabricated by Stereolithography. The displacement of the guides on edentulous arch might be the main contributing factor of deviation.

Trial registration: Chinese Clinical Trial Registry, ChiCTR-ONC-17014159 (July 26, 2017).

Identification of novel monoclonal antibodies targeting the outer membrane protein C and lipopolysaccharides for Escherichia coli O157:H7 detection

AIMS

To identify and evaluate the application of two novel monoclonal antibody (mAb) 2G12 against outer membrane protein (Omp) C and mAb 12B1 targeting the O chain of the lipopolysaccharides (LPS) of Escherichia coli O157:H7 (ECO157).

METHODS AND RESULTS

The sensitivity and specificity of these two antibodies were evaluated with eight ECO157 strains and 68 untargeted strains. mAb 2G12 and 12B1 had no detectable binding with any of the non-O157 strains at 6·0 log₁₀ CFU per ml, while its high specificity and affinity remained with all ECO157 strains. When a higher level (8·0 log₁₀ CFU per ml) was tested, 2G12 and 12B1 did not react with 82·35 and 97·06% of the non-O157 strains respectively. Based on the pair of two antibodies, the sandwich enzyme-linked immunosorbent assay detected 100% (8/8) of ECO157 strains and none of the non-ECO157 strains. The detection limit of ECO157 strains in pure culture were 4·2 ± 0·2 log₁₀ CFU per ml. When the developed test was applied to artificially inoculated beef samples, the detection limit was 6·0 log₁₀ CFU per gram without enrichment and 1·0 log₁₀ CFU per gram after 12 h of enrichment.

CONCLUSIONS

The two novel antibodies identified in this study served as great candidates for the recovery, and detection of ECO157 from different environmental and food samples.

SIGNIFICANCE AND IMPACT OF THE STUDY

ECO157-specific detection was improved by a combination of the novel OmpC mAb and LPS mAb with defined target antigen and good specificity.

Impact of Peer Review in Reducing Uncertainty in the Definition of the Lung Target Volume Among Trainee Oncologists

AIMS

To evaluate the impact of peer review and contouring workshops on reducing uncertainty in target volume delineation for lung cancer radiotherapy.

MATERIALS AND METHODS

Data from two lung cancer target volume delineation courses were analysed. In total, 22 trainees in clinical oncology working across different UK centres attended these courses with priori experience in lung cancer radiotherapy. The courses were made up of short presentations and contouring practice sessions. The participants were divided into two groups and asked to first individually delineate (IND) and then individually peer review (IPR) the contours of another participant. The contours were discussed with an expert panel consisting of two consultant clinical oncologists and a consultant radiologist. Contours were analysed quantitatively by measuring the volume and local distance standard deviation (localSD) from the reference expert consensus contour and qualitatively through visual analysis. Feedback from the participants was obtained using a questionnaire.

RESULTS

All participants applied minor editing to the contours during IPR, leading to a non-statistically significant reduction in the mean delineated volume (IND = 140.92 cm3, IPR = 125.26 cm3, P = 0.211). The overall interobserver variation was similar, with a localSD of 0.33 cm and 0.38 cm for the IND and IPR, respectively (P = 0.848). Six participants (29%) carried out correct major changes by either including tumour or excluding healthy tissue. One participant (5%) carried out an incorrect edit by excluding parts of the tumour, while another observer failed to identify a major contour error. The participants' level of confidence in target volume delineation increased following the course and identified the discussions with the radiologist and colleagues as the most important highlights of the course.

CONCLUSION

IPR could improve target volume delineation quality among trainee oncologists by identifying most major contour errors. However, errors were also introduced after IPR, suggesting the need to further discuss major changes with a multidisciplinary team.

Dynamic changes of interferon gamma release assay results with latent tuberculosis infection treatment

OBJECTIVES

Using QuantiFERON-TB Gold In-Tube (QFT-GIT) for monitoring tuberculosis (TB) and latent TB infection treatment effect is controversial. The present study aimed to evaluate the dynamic changes of interferon gamma (IFN-γ) levels along with latent TB infection treatment via a randomized controlled study.

METHODS

A total of 910 participants treated with 8 weeks of once-weekly rifapentine plus isoniazid (group A), 890 treated with 6 weeks of twice-weekly rifapentine plus isoniazid (group B) and 818 untreated controls (group C) were followed for 2 years to track active TB development. QFT-GIT tests were repeated three times for all groups: before treatment (T0), at completion of treatment (T1) and 3 months after completion of treatment (T2).

RESULTS

Similar rates of persistent QFT-GIT reversion were observed in groups A (19.0%, 173/910), B (18.5%, 165/890) and C (20.7%, 169/818) (p 0.512). The dynamic changes of IFN-γ levels were not statistically significant among the three groups. In treated participants, individuals with higher baseline IFN-γ levels showed increased TB occurrence (1.0%, 9/896) compared to those with lower baseline levels (0.2%, 2/904) (p 0.037). A similar but statistically insignificant trend was also observed in untreated controls (1.8% (7/400) vs. 0.5% (2/418), p 0.100). When TB cases were matched with non-TB cases on baseline IFN-γ levels, no significant differences were found with respect to the dynamic changes in IFN-γ levels with time, regardless of whether they received treatment.

CONCLUSIONS

QFT-GIT reversion or decreased IFN-γ levels should not be used for monitoring host response to latent TB infection treatment.

Outcome of Weekly Carboplatin-Paclitaxel-based Definitive Chemoradiation in Oesophageal Cancer in Patients Not Considered to be Suitable for Platinum-Fluoropyrimidine-based Treatment: A Multicentre, Retrospective Review

AIMS

Although cisplatin-fluoropyrimidine-based definitive chemoradiotherapy (dCRT) is a standard of care for oesophageal cancer, toxicity is significant and limits its use in elderly and frail patients. Weekly carboplatin-paclitaxel-based dCRT provides a viable alternative, although prospective data are lacking in the dCRT setting. Here we report the results of a national, multicentre retrospective review of outcome in patients treated with weekly carboplatin-paclitaxel-based dCRT.

MATERIALS AND METHODS

In this multicentre retrospective study of nine radiotherapy centres across the UK we evaluated the outcome of patients who had non-metastatic, histologically confirmed carcinoma of the oesophagus (adenocarcinoma, squamous cell or undifferentiated; World Health Organization performance status 0-2; stage I-III disease) and had been selected to receive weekly carboplatin-paclitaxel-based dCRT as they were considered not suitable for cisplatin-fluoropyrimidine-based dCRT. dCRT consisted of carboplatin AUC 2 and paclitaxel 50 mg/m2 (days 1, 8, 15, 22, 29) and the recommended radiation dose was 50 Gy in 25 daily fractions. We assessed overall survival, progression-free survival (PFS; overall, local and distant), proportion of patients who were failure free at the response assessment (12 weeks after dCRT), treatment compliance and toxicity.

RESULTS

In total, 214 patients from nine UK centres were treated between 15 February 2013 and 19 March 2019: 39.7% of patients were ≥75 years; 18.7% ≥ 80 years. Indications for weekly carboplatin-paclitaxel-based dCRT were comorbidities (47.2%), clinician choice (36.4%) and poor tolerance/progression on cisplatin-fluoropyrimidine induction chemotherapy (15.8%). The median overall survival was 24.28 months (95% confidence interval 20.07-30.09) and the median PFS was 16.33 months (95% confidence interval 14.29-20.96). Following treatment, 69.1% (96/139) had a combined complete response on endoscopy with non-progression (complete response/partial response/stable disease) on imaging. The 1- and 2-year overall survival rates for this patient group were 81.9% (95% confidence interval 75.6-86.8%) and 50.6% (95% confidence interval 40.5-60.0%), respectively. Thirty-three per cent (n = 70) of patients experienced at least one grade 3 + acute toxicity (grade 3/4 haematological: 10%; grade 3/4 non-haematological: 32%) and there were no treatment-related deaths. 86.9% of patients completed at least four cycles of concomitant weekly carboplatin-paclitaxel-based chemotherapy and planned radiotherapy was completed in 97.7% (209/214).

CONCLUSION

Weekly carboplatin-paclitaxel-based CRT seems to be well tolerated in elderly patients and in those with comorbidities, where cisplatin-fluoropyrimidine-based dCRT is contraindicated. Survival outcomes are comparable with cisplatin-fluoropyrimidine-based dCRT.