The efficacy and safety of low-dose rituximab in the treatment of pemphigus vulgaris: a cohort study

BACKGROUND

Rituximab (RTX) is considered the first-line treatment for pemphigus vulgaris (PV), which is a B-cell-mediated acquired autoimmune disease. However, no consensus on the optimum dosage has been achieved.

OBJECTIVES

To investigate the efficacy and safety of low-dose RTX (a single infusion of 500 mg) for the treatment of PV, a cohort study was conducted for patients with PV, along with a 12-month follow-up following the administration of RTX.

METHODS

Patients with moderate or severe PV were divided into group A (low-dose RTX combined with corticosteroids) and group B (corticosteroids alone). Data on complete remission (CR) rates, doses of corticosteroids, cumulative doses of corticosteroids at the third, sixth, and twelfth months, pemphigus disease area index and adverse effects (AEs) were collected.

RESULTS

Forty-four patients with moderate or severe PV were enrolled in this study (19 in group A and 25 in group B). Patients treated with low-dose RTX had higher CR rates, lower doses of corticosteroids at the third, sixth, and twelfth months, lower cumulative doses of corticosteroids at the sixth and twelfth months, and fewer AEs than those who received corticosteroids alone.

CONCLUSIONS

This study indicated that low-dose RTX may be a beneficial and secure therapy option for patients with moderate to severe PV.

Low and very low lithium levels: Thyroid effects are small but still require monitoring

AIM

Low doses of lithium, as might be used for mood or dementia prevention, do not carry the same renal, toxicity, and tolerability problems of doses used for prophylaxis or treatment of mania. However, thyroid effects of low doses have not been investigated. Our goal in this study was to assess the changes in thyroid-stimulating hormone (TSH) associated with a broad range of lithium levels, including those well below the therapeutic range for bipolar disorders.

METHODS

This study was conducted in a small healthcare system with 19 associated primary care clinics served by a Collaborative Care program of psychiatric consultation. In this retrospective review of electronic records, we searched for patients who had received a lithium prescription and both pre- and post-lithium thyroid-stimulating hormone (TSH) levels.

RESULTS

Patients with low lithium levels (<0.5 mEq/L, N = 197) had a mean thyroid-stimulating hormone (TSH) increase of 0.52 mIU/L. Patients with maintenance lithium levels (0.5-0.8 mEq/L; N = 123) had a mean TSH increase of 1.01 mIU/L; and patients with antimanic lithium levels (>0.8 mEq/L; N = 79) had a mean TSH increase of 2.16 mIU/L. The probability of TSH exceeding the upper limit of normal in our laboratory (>4.2 mIU/L) was positively associated with pre-lithium TSH.

CONCLUSION

These results suggest that the risk of lithium-induced hypothyroidism is dose-related, and relatively small with very low doses, but thyroid monitoring, including a pre-lithium TSH, is still warranted.

[A low- dose CT reconstruction algorithm across different scanners based on federated feature learning]

OBJECTIVE

To propose a low-dose CT reconstruction algorithm across different scanners based on federated feature learning (FedCT) to improve the generalization of deep learning models for multiple CT scanners and protect data privacy.

METHODS

In the proposed FedCT framework, each client is assigned an inverse Radon transform-based reconstruction model to serve as a local network model that participates in federated learning. A projection- domain specific learning strategy is adopted to preserve the geometry specificity in the local projection domain. Federated feature learning is introduced in the model, which utilizes conditional parameters to mark the local data and feed the conditional parameters into the network for encoding to enhance the generalization of the model in the image domain.

RESULTS

In the cross-client, multi-scanner, and multi-protocol low-dose CT reconstruction experiments, FedCT achieved the highest PSNR (+2.8048, +2.7301, and +2.7263 compared to the second best federated learning method), the highest SSIM (+0.0009, +0.0165, and +0.0131 in the same comparison), and the lowest RMSE (- 0.6687, - 1.5956, and - 0.9962). In the ablation experiment, compared with the general federated learning strategy, the model with projection-specific learning strategy showed an average improvement by 1.18 on Q1 of the PSNR and an average decrease by 1.36 on Q3 of the RMSE on the test set. The introduction of federated feature learning in FedCT further improved the Q1 of the PSNR on the test set by 3.56 and reduced the Q3 of the RMSE by 1.80.

CONCLUSION

FedCT provides an effective solution for collaborative construction of CT reconstruction models, which can enhance model generalization and further improve the reconstruction performance on global data while protecting data privacy.

M3S-Net: multi-modality multi-branch multi-self-attention network with structure-promoting loss for low-dose PET/CT enhancement

Objective.PET (Positron Emission Tomography) inherently involves radiotracer injections and long scanning time, which raises concerns about the risk of radiation exposure and patient comfort. Reductions in radiotracer dosage and acquisition time can lower the potential risk and improve patient comfort, respectively, but both will also reduce photon counts and hence degrade the image quality. Therefore, it is of interest to improve the quality of low-dose PET images.Approach.A supervised multi-modality deep learning model, named M3S-Net, was proposed to generate standard-dose PET images (60 s per bed position) from low-dose ones (10 s per bed position) and the corresponding CT images. Specifically, we designed a multi-branch convolutional neural network with multi-self-attention mechanisms, which first extracted features from PET and CT images in two separate branches and then fused the features to generate the final generated PET images. Moreover, a novel multi-modality structure-promoting term was proposed in the loss function to learn the anatomical information contained in CT images.Main results.We conducted extensive numerical experiments on real clinical data collected from local hospitals. Compared with state-of-the-art methods, the proposed M3S-Net not only achieved higher objective metrics and better generated tumors, but also performed better in preserving edges and suppressing noise and artifacts.Significance.The experimental results of quantitative metrics and qualitative displays demonstrate that the proposed M3S-Net can generate high-quality PET images from low-dose ones, which are competable to standard-dose PET images. This is valuable in reducing PET acquisition time and has potential applications in dynamic PET imaging.

Deep learning-based projection synthesis for low-dose cone-beam computed tomography imaging in image-guided radiotherapy

Background

The imaging dose of cone-beam computed tomography (CBCT) in image-guided radiotherapy (IGRT) poses adverse effects on patient health. To improve the quality of sparse-view low-dose CBCT images, a projection synthesis convolutional neural network (SynCNN) model is proposed.

Methods

Included in this retrospective, single-center study were 223 patients diagnosed with brain tumours from Beijing Cancer Hospital. The proposed SynCNN model estimated two pairs of orthogonally direction-separable spatial kernels to synthesize the missing projection in between the input neighboring sparse-view projections via local convolution operations. The SynCNN model was trained on 150 real patients to learn patterns for inter-view projection synthesis. CBCT data from 30 real patients were used to validate the SynCNN, while data from a phantom and 43 real patients were used to test the SynCNN externally. Sparse-view projection datasets with 1/2, 1/4, and 1/8 of the original sampling rate were simulated, and the corresponding full-view projection datasets were restored using the SynCNN model. The tomographic images were then reconstructed with the Feldkamp-Davis-Kress algorithm. The root-mean-square error (RMSE), peak signal-to-noise ratio (PSNR), and structural similarity (SSIM) metrics were measured in both the projection and image domains. Five experts were invited to grade the image quality blindly for 40 randomly selected evaluation groups with a four-level rubric, where a score greater than or equal to 2 was considered acceptable image quality. The running time of the SynCNN model was recorded. The SynCNN model was directly compared with the three other methods on 1/4 sparse-view reconstructions.

Results

The phantom and patient studies showed that the missing projections were accurately synthesized. In the image domain, for the phantom study, compared with images reconstructed from sparse-view projections, images with SynCNN synthesis exhibited significantly improved qualities with decreased values in RMSE and increased values in PSNR and SSIM. For the patient study, between the results with and without the SynCNN synthesis, the averaged RMSE decreased by 3.4×10-4, 10.3×10-4, and 21.7×10-4, the averaged PSNR increased by 3.4, 6.6, and 9.4 dB, and the averaged SSIM increased by 5.2×10-2, 18.9×10-2 and 33.9×10-2, for the 1/2, 1/4, and 1/8 sparse-view reconstructions, respectively. In expert subjective evaluation, both the median scores and acceptance rates of the images with SynCNN synthesis were higher than those reconstructed from sparse-view projections. It took the model less than 0.01 s to synthesize an inter-view projection. Compared with the three other methods, the SynCNN model obtained the best scores in terms of the three metrics in both domains.

Conclusions

The proposed SynCNN model effectively improves the quality of sparse-view CBCT images at a low time cost. With the SynCNN model, the CBCT imaging dose in IGRT could be reduced potentially.

Sex and individual differences in the effect of chronic low-dose ethanol on behavioral strategy selection

BACKGROUND

The development of an alcohol use disorder (AUD) involves impaired behavioral control and flexibility. Behavioral inflexibility includes an inability to shift behavior in response to changes in behavioral outcomes. Low levels of ethanol drinking may promote the formation of inflexible, habitual reward seeking, but this may depend on the timing of ethanol exposure in relation to learning. The goal of this study was to determine whether a history of low-dose ethanol exposure promoted contingency-insensitive sucrose seeking and altered behavioral strategy selection.

METHODS

Male and female C57BL/6J mice were trained to perform a response (lever press) for sucrose on two different reinforcement schedules: one that is thought to promote inflexible responding (random interval) and one that maintains flexible responding (variable ratio [VR]). Following instrumental training each day, mice were exposed to saline or low-dose ethanol (0.5 g/kg; i.p.) either proximal (1 h after) or distal (4 h after) to learning. Mice were then tested for sensitivity to changes in contingency in a contingency degradation test.

RESULTS

A history of low-dose ethanol exposure shifted behavioral strategy selection, as measured by reward tracking behavior, but this depended on sex and reinforcement schedule history. Both male and female mice used different strategies depending on the reinforcement schedule, but only males exhibited ethanol-induced shifts in strategy selection. A history of low-dose ethanol exposure did not impact contingency sensitivity in males but promoted insensitivity in females specifically on the VR lever.

CONCLUSIONS

Female mice show distinct behavioral effects of repeated, low-dose ethanol exposure as compared to males, with sex differences in the use of reward tracking strategies to guide behavior. Future studies should investigate sex differences in the neural consequences of chronic low-dose ethanol exposure that may underlie behavioral changes.

Multicenter phase II study of moderate low-dose radiotherapy in indolent non-Hodgkin lymphoma: CLCG-iNHL-01 protocol

Background: Radiotherapy is an effective treatment for indolent non-Hodgkin lymphoma (iNHL); however, the optimal radiotherapy dose remains to be determined. We hypothesize that a suitable dose may exist between 4 and 24 Gy. Methods: This prospective multicenter phase II trial intends to recruit 73 sites of iNHL patients, who will receive involved-site radiotherapy of 12 Gy in four fractions. The primary objective is the 6-month clinical complete response rate. Tumor tissue, blood and conjunctival specimens will be collected to identify potential predictive biomarkers. Discussion: The CLCG-iNHL-01 trial will evaluate the efficacy and toxicity of 12 Gy in patients with iNHL and provide information on a novel hypofractionation regimen of low-dose radiotherapy. Clinical Trial Registration: NCT05543070 (ClinicalTrials.gov).

The impact of radiation dose on the efficacy of definitive chemoradiotherapy in patients with locally advanced esophageal carcinoma: a systematic review and meta-analysis

To investigate the impact of radiation dose on the efficacy of definitive chemoradiotherapy(dCCRT) in patients with locally advanced esophageal carcinoma. PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Wanfang, and Chinese National Knowledge Infrastructure(CNKI) were searched for eligible studies. Studies that compared high-dose radiation(HD-RT) group with low-dose radiation(LD-RT) group using modern radiotherapy techniques for locally advanced esophageal carcinoma patients in dCCRT were identified. The hazard ratios (HR) for overall survival (OS), progression-free survival (PFS), and the odds ratios (OR) for clinical complete response (cCR), local-regional failure (LRF), distant metastasis (DM), and grade≥3 AEs. Meta-analysis was performed when relevant data were available. Eleven studies involving 1943 patients were included for analyses. The results showed that the HD-RT group had better OS (pooled HR 0.78 [0.70, 0.87], p < .00001), PFS (pooled HR 0.72 [0.55, 0.94], p = .01), cCR (OR 1.52 [1.13, 2.05], p = .005), and LRF (OR 0.60 [0.45, 0.80], p = .0004). In addition, there were no significant differences between the two groups in terms of DM (OR 1.43 [1.00, 2.04], p = .05), grade 3-5 radiation pneumonitis (OR 1.38 [0.71, 2.68], p = .35), grade 3-5 radiation esophagitis (OR 1.36 [0.88, 2.10], p = .17), grade 3-5 other esophageal toxicities(stenosis/fistula/hemorrhage) (OR 1.22 [0.75, 2.00], p = .43), and treatment-related death (OR 1.40 [0.73, 2.68], p = .31). High-dose radiotherapy in definitive CCRT for patients with locally advanced esophageal carcinoma is associated with improved PFS, OS, cCR, and LC with no increase of grade≥3AEs. Simultaneously, we await the preliminary and final results of several ongoing dose-escalation randomized trials. Furthermore, future studies should provide personalized radiotherapy doses for these patients.

Systematic review and meta-analysis of low-dose CT-driven biopsy for pulmonary nodules

Introduction

The diagnosis of pulmonary nodules (PNs) has traditionally relied on computed tomography (CT)-guided biopsy. To reduce radiation exposure, low-dose CT-guided PN biopsy has been employed.

Aim

This meta-analysis aimed at evaluating the efficacy and safety of low-dose CT-guided biopsy in the diagnosis of PNs.

Material and methods

PubMed, Web of Science, and Wanfang were searched for relevant articles until June 2023. Comparing low-dose CT to normal-dose CT, we considered factors such as diagnostic yield, diagnostic accuracy, biopsy process time, dose-length product (DLP) value, the frequency of pneumothorax and pulmonary bleeding, and the frequency with which complications necessitated the placement of a chest tube.

Results

This meta-analysis included data from a total of 6 investigations. There was a total of 459 patients who had a CT-guided PN biopsy performed at a low dosage, and 384 patients who had a normal-dose CT-guided PN biopsy. There were no statistically significant differences between the low-dose CT and normal-dose CT groups in terms of diagnostic accuracy (p = 0.08), diagnostic yield (p = 0.55), biopsy procedure duration (p = 0.30), pneumothorax (p = 0.61), pulmonary hemorrhage (p = 0.29), or complications requiring a chest tube (p = 0.48). Low-dose CT patients obtained a DLP that was 91% lower than those in the standard-dose CT group (p = 0.01). According to Egger's test, there is a significant possibility of publication bias in DLP (p = 0.034).

Conclusions

The diagnostic and safety results of low-dose CT-driven PN biopsy are equivalent to those of the standard one, although patients are much less exposed to radiation.

Safety, feasibility, and effectiveness of a CT-guided transthoracic lung and pleural biopsy - a single-centre experience with own low-dose protocol

Purpose

To assess the efficacy and safety of a low-dose, computed tomography (CT)-guided transthoracic biopsy of lung and pleural lesions.

Material and methods

A total of 135 low-dose, CT-guided transthoracic lung and pleural lesions biopsies were performed. A cutting needle was utilized in 124 cases, and fine needle aspiration biopsy was performed in 14 cases. In all cases, 14- to 22-gauge biopsy needles were used.

Results

Diagnostic material was obtained in 111 (82.2%) patients. In 97 (71.8%) cases neoplastic lesions were found, predominantly adenocarcinoma and non-small cell carcinoma. In 14 (12.6%) cases non atypical cells were reported. Biopsy failed to obtain material suitable for histopathological examination in 24 (17.7%) cases. Complications occurred in 31 patients, including pneumothorax in 28 patients and haematoma in 3 cases.

Conclusions

Based on the obtained results, it can be stated that low-dose, CT-guided transthoracic biopsy of lung and pleural tissues is an accurate and safe procedure. Also, it is linked to a low risk of complications such as a small pneumothorax.

[Evaluation of Low-dose Whole-body FDG PET with SiPM-based PET/CT Scanner: Visual and Semi-quantitative Analyses Using Random Sampling from Full-dose Scan Data]

PURPOSE

Sensitivity and count rate performance of the latest PET/CT scanners with a silicon photomultiplier (SiPM) have been substantially improved compared to scanners with a photomultiplier tube (PMT), thereby promising a low-dose whole-body PET scan with maintaining image quality. However, it is ethically difficult to verify the low-dose protocol in actual clinical settings. In this study, we investigated the effect of dose reduction on reconstructed images by using a low-dose simulation technique, i.e., reducing the number of events from the acquired data.

METHOD

For 21 subjects who underwent whole-body 18F-FDG PET examination with an SiPM-based PET/CT scanner, Biograph Vision (Siemens Healthineers, Erlangen, Germany), at a dosage of 3.5 MBq/kg and a continuous bed motion speed of 1.1 mm/sec (the standard protocol in our hospital), the number of events in acquired list data (100%; "full-dose") was reduced to 50%, 25%, 12.5%, and 6.25% ("low-dose"). The low-dose reconstructed images were evaluated visually and physically with reference to the full-dose images. The physical evaluation was performed by calculating differences in SUVmax at abnormal uptake (n=54) between the full-dose and low-dose images.

RESULT

The 25% data images were visually acceptable, and the difference in SUVmax between the 100% and 25% data images was 9.8±13.5%.

CONCLUSION

Our results suggest that Biograph Vision is a feasible method to reduce conventional dose with the potential use of 25% data images.

Rituximab at lower dose for neuromyelitis optica spectrum disorder: a multicenter, open-label, self-controlled, prospective follow-up study

Objective

To address a novel lower-dose rituximab (RTX) therapy strategy based on our clinical experience and assess its efficacy and safety in neuromyelitis optica spectrum disorder (NMOSD).

Methods

A multicenter, open-label, self-controlled, prospective follow-up study. Totally, 108 NMOSD patients were enrolled and a lower-dose RTX strategy was applied including 100 mg weekly for 3 weeks and then reinfusions every 6 months. Annualized relapse rate (ARR), the expanded disability status scale (EDSS) score and length of spinal cord lesions were included to evaluate the efficacy. Side effects were recorded to assess the safety profile.

Results

Of 108 patients, 80 (74.1%) initiated low-dose RTX therapy immediately after acute attack treatment and 33 (30.6%) initiated it after the first attack. During a median treatment period of 35.5 (22.0-48.8) months, significant decreases were observed in median ARR (1.1 [0.8-2.0] versus 0 [0-0.2], p < 0.001), EDSS score (3.5 [2.5-4.0] versus 2.0 [1.0-3.0], p < 0.001) and spinal cord lesion segments (5.0 [4.0-8.0] versus 3.0 [1.0-6.0], p < 0.001). The cumulative risk of relapses significantly decreased during the post- versus pre-RTX period (HR 0.238, 95%CI 0.160-0.356, p < 0.001) and on early therapy initiated within 24 months after disease onset versus delayed therapy (HR 0.506, 95%CI 0.258-0.994, p = 0.041). No serious side effects were recorded and all the subjects did not discontinue treatment due to RTX-related side effects.

Conclusion

Our research provided evidence supporting the lower-dose RTX strategy in treating NMOSD and reopened the issues of optimal dosage and therapy initiation timing.

Influence of the Hypersensitivity to Low Dose Phenomenon on the Tumor Response to Hypofractionated Stereotactic Body Radiation Therapy

Stereotactic body radiation therapy (SBRT) has made the hypofractionation of high doses delivered in a few sessions more acceptable. While the benefits of hypofractionated SBRT have been attributed to additional vascular, immune effects, or specific cell deaths, a radiobiological and mechanistic model is still needed. By considering each session of SBRT, the dose is divided into hundreds of minibeams delivering some fractions of Gy. In such a dose range, the hypersensitivity to low dose (HRS) phenomenon can occur. HRS produces a biological effect equivalent to that produced by a dose 5-to-10 times higher. To examine whether HRS could contribute to enhancing radiation effects under SBRT conditions, we exposed tumor cells of different HRS statuses to SBRT. Four human HRS-positive and two HRS-negative tumor cell lines were exposed to different dose delivery modes: a single dose of 0.2 Gy, 2 Gy, 10 × 0.2 Gy, and a single dose of 2 Gy using a non-coplanar isocentric minibeams irradiation mode were delivered. Anti-γH2AX immunofluorescence, assessing DNA double-strand breaks (DSB), was applied. In the HRS-positive cells, the DSB produced by 10 × 0.2 Gy and 2 Gy, delivered by tens of minibeams, appeared to be more severe, and they provided more highly damaged cells than in the HRS-negative cells, suggesting that more severe DSB are induced in the "SBRT modes" conditions when HRS occurs in tumor. Each SBRT session can be viewed as hyperfractionated dose delivery by means of hundreds of low dose minibeams. Under current SBRT conditions (i.e., low dose per minibeam and not using ultra-high dose-rate), the response of HRS-positive tumors to SBRT may be enhanced significantly. Interestingly, similar conclusions were reached with HRS-positive and HRS-negative untransformed fibroblast cell lines, suggesting that the HRS phenomenon may also impact the risk of post-RT tissue overreactions.

Topical proactive therapy in dermatology. A scoping review

The term 'proactive therapy' refers to a long-term management of clinically intact skin in previously disease-affected areas. This method was initially implemented in atopic dermatitis to maintain the remission and decrease the risk of exacerbations. Proactive therapy aims to limit the need for reactive treatment and improve the patients' quality of life. A proactive approach is likely to be adopted for other relapsing and inflammatory skin conditions in the future. This scoping review aims to identify dermatological conditions to be treated with the proactive approach, evaluate the available evidence for its efficacy and safety, as well as highlight the research gaps.

Low-dose Ketamine-Induced Deficits in Arbitrary Visuomotor Mapping in Monkeys

Ketamine, an NMDA antagonist, is widely used in clinical settings, particularly for its promising role as a rapid antidepressant. Recently, low-dose ketamine has gained attention due to its potential therapeutic benefits. However, the effects of low-dose ketamine on brain function, particularly higher cognitive functions of primate brains, are not fully understood. In this study, we used two macaque monkeys as subjects and found that acute low-dose ketamine administration significantly impairs the ability for arbitrary visuomotor mapping, a form of associative learning essential for flexible behaviors, including executions of learned stimuli-response contingency or learning of new contingencies. We conducted in-depth analyses and identified intrinsic characteristics of these ketamine-induced functional deficits, including lowered accuracy, prolonged time for planning and movement execution, increased tendency to make errors when visual cues are changed from trial to trial, and stronger impact on the associative learning and another key higher cognitive function, working memory. Our results shed new light on how associative learning relies on the NMDA-mediated synaptic transmission of the brain and contribute to a better understanding of the potential acute side effects of low-dose ketamine on cognition, which can help facilitate its safe usage in medical practice.Significance StatementThis study found that acute low-dose ketamine significantly impairs the ability of arbitrary visual motor mapping, a critical form of associative learning for flexible behavior, including stimulus-response contingency learning or learning of new contingencies. We conducted a thorough analysis and identified intrinsic features of ketamine-induced functional deficits, including decreased accuracy, prolonged planning and motor execution time, increased error tendency when visual cues changed from trial to trial, and stronger impact on associative learning and another key higher-order cognitive function, working memory. These findings contribute to a better understanding of the potential acute cognitive side effects of low-dose ketamine and promote its safe use in medical practice.

Comparison of low-dose (162 mg) and high-dose (650 mg) Aspirin prophylaxis following total joint arthroplasty: a prospective cohort study

Since Aspirin's adverse effects are dose-dependent, and evidence supporting the use of low-dose (LD) Aspirin in preventing venous thromboembolism (VTE) after total hip arthroplasty (THA) is weak, the authors do not know what the minimal effective dosage of Aspirin is to prevent VTE. This study aimed to compare the rates of 90-day symptomatic VTE following THA and total knee arthroplasty in healthy patients taking LD Aspirin vs. high-dose (HD) Aspirin for 6 weeks postoperatively.

Materials and methods

A prospective cohort of patients with THA and total knee arthroplasty was conducted at two tertiary centres. Symptomatic VTE within 90 days of index arthroplasty was the primary outcome; gastrointestinal bleeding (GIB) and mortality were secondary outcomes.

Results

The final analysis included 312 consecutive patients: 158 in the LD group and 154 in the HD group. Two groups were similar regarding preoperative data, including sex, age, BMI, smoking, diabetes mellitus, Hgb and platelet count, and type of surgery. The LD group had one deep vein thrombosis (0.6%), and the HD group had two (1.3%) (P=0.62). Neither group had PTE. Therefore, VTE rates are the same as deep vein thrombosis rates and similar between the groups (0.6% vs. 1.3%, P=0.62)Regarding GIB due to anticoagulant therapy, no patient in the LD group reported GIB, whereas two (1.3%) patients in the HD group reported GIB within 90 days of arthroplasty. GIB rates did not differ significantly between groups (P=0.24). Considering VTE + GIB combined, the HD groups showed a higher rate of complications (N=4, 2.6%) than the LD groups (N=1, 0.6%) but not statistically significant (P=0.21).

Conclusions

Prophylactic administration of Aspirin with low doses (81 mg BID) and high doses (325 mg BID) for six weeks is equally effective at reducing VTE in total joint arthroplasty patients and had similar adverse effects.

Level of Evidence

Therapeutic Level II.

Comparison of efficacy and safety between third-dose triple and third-dose dual antihypertensive combination therapies in patients with hypertension

We compared the efficacy and safety of third-standard-dose triple and third-standard-dose dual antihypertensive combination therapies in patients with mild to moderate hypertension. This was a phase II multicenter, randomized, double-blind, parallel-group trial. After a 4-week placebo run-in period, 245 participants were randomized to the third-dose triple combination (ALC group; amlodipine 1.67 mg + losartan potassium 16.67 mg + chlorthalidone 4.17 mg) or third-dose dual combination (AL group; amlodipine 1.67 mg + losartan potassium 16.67 mg, LC group; losartan potassium 16.67 mg + chlorthalidone 4.17 mg, AC group; amlodipine 1.67 mg + chlorthalidone 4.17 mg) therapy groups and followed up for 8 weeks. The mean systolic blood pressure (BP) reduction was -18.3 ± 13.2, -13.0 ± 13.3, -16.3 ± 12.4, and -13.8 ± 13.2 mmHg in the ALC, AL, LC, and AC groups, respectively. The ALC group showed significant systolic BP reduction compared to the AL and AC groups at weeks 4 (P = .010 and P = .018, respectively) and 8 (P = .017 and P = .036, respectively). At week 4, the proportion of systolic BP responders was significantly higher in the ALC group (42.6%) than in the AL (22.0%), LC (23.3%), and AC (27.1%) groups (P = .013, P = .021, and P = .045, respectively). At week 8, the proportion of systolic and diastolic BP responders was significantly higher in the ALC group (59.7%) than in the AL (39.3%) and AC (42.4%) groups (P = .022 and P = .049, respectively) at week 8. Third-standard-dose triple antihypertensive combination therapy demonstrated early effective BP control compared to third-standard-dose dual combination therapies, without increasing adverse drug reactions in patients with mild-to-moderate hypertension.

Determination of lower radiation dose limit for automatic measurement of adipose tissue

The purpose of this study was to determine the lower limit of radiation dose required to measure visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) volumes when a fat quantification and noise reduction techniques (NRTs) are combined. For this purpose, we utilized CT colonography (CTC) images taken at low doses and manually segmented VAT and SAT fat volumes as ground truth. In order to derive the acceptable precision of the measurements needed to estimate the lower limit of radiation dose, we estimated the effect of different positioning during CT scanning on fat measurements using manually segmented VAT and SAT against normal dose. As a result, the acceptable accuracy of SAT and VAT was found to be 94.5% and 85.2%, respectively. Using these thresholds, the lower radiation dose limit required to accurately measure SAT using 5.25-mm slice-thick images was 1.5 mGy of size-specific dose estimates (SSDE), while the lower radiation dose limit required to accurately measure VAT was 0.4 mGy of SSDE. The lower dose limit for SAT and VAT combined was 1.5 mGy, which was equivalent to an estimated effective dose of 0.38 mSv. Alternatively, without noise reduction, SAT could not achieve acceptable accuracy even for images with a slice thickness of 5.25 mm, while VAT required noise reduction for images with a slice thickness of 1.25 mm, but could achieve acceptable accuracy without noise reduction for images with a slice thickness of 5.25 mm.

Photon-counting computed tomography in the assessment of rheumatoid arthritis-associated interstitial lung disease: an initial experience

PURPOSE

Interstitial lung disease (ILD) accounts for a significant proportion of mortality and morbidity in patients with rheumatoid arthritis (RA). The aim of this cross-sectional study is to evaluate the performance of novel photon-counting detector computed tomography (PCD-CT) in the detection of pulmonary parenchymal involvement.

METHODS

Sixty-one patients with RA without a previous definitive diagnosis of ILD underwent high-resolution (HR) (0.4 mm slice thickness) and ultra-high-resolution (UHR) (0.2 mm slice thickness) PCDCT examination. The extent of interstitial abnormalities [ground-glass opacity (GGO), reticulation, bronchiectasis, and honeycombing] were scored in each lobe using a Likert-type scale. Total ILD scores were calculated as the sum of scores from all lobes.

RESULTS

Reticulation and bronchiectasis scores were higher in the UHR measurements taken compared with the HR protocol [median (quartile 1, quartile 3): 2 (0, 3.5) vs. 0 (0, 3), P < 0.001 and 2 (0, 2) vs. 0 (0, 2), P < 0.001, respectively]; however, GGO and honeycombing scores did not differ [2 (2, 4) vs. 2 (2, 4), P = 0.944 and 0 (0, 0) vs. 0 (0, 0), P = 0.641, respectively]. Total ILD scores from both HR and UHR scans showed a mild negative correlation in diffusion capacity for carbon monoxide (HR: r = -0.297, P = 0.034; UHR: r = -0.294, P = 0.036). The pattern of lung parenchymal involvement did not differ significantly between the two protocols. The HR protocol had significantly lower volume CT dose index [0.67 (0.69, 1.06) mGy], total dose length product [29 (24.48, 33.2) mGy*cm] compared with UHR scans [8.18 (6.80, 9.23) mGy, P < 0.001 and 250 (218, 305) mGy*cm, P < 0.001].

CONCLUSION

UHR PCD-CT provides more detailed information on ILD in patients with RA than low-dose HR PCDCT. HR PCD-CT image acquisition with a low effective radiation dose may serve as a valuable, low-radiation screening tool in the selection of patients for further, higher-dose UHR PCD-CT screening.

Learning CT projection denoising from adjacent views

BACKGROUND

Many learning-based low-dose (LD) computed tomography (CT) imaging methods require large paired full- and low-dose datasets for training, which are usually unavailable in clinic. Whereas models trained on simulated data often face the generalization problem on real clinical data.

PURPOSE

To develop an unsupervised learning technique to acquire clean CT projection from its adjacent LD projections.

METHODS

Given a sequential LD projection set, the method extracts out the middle projection as the target and treats the rest ones as the input. The model is trained with the mean absolute error with proposed inter-view gradient constraint term, which helps to suppress outliers and preserve edges in the denoised projection. The simulated low-dose CT grand challenge dataset and a real physical torso phantom dataset were employed for experiment. The peak signal to noise ratio (PSNR) and structural similarity index measure (SSIM) were calculated for quantitative evaluation.

RESULTS

In experiments with both the simulated and real datasets, visual comparisons reveal that the proposed method obtained images superior to unsupervised and supervised methods working in both image and projection domain. For numerical comparison, our method obtains larger SSIMs than other unsupervised methods at quarter and eighth dose levels. As for PSNR, our method obtains larger value at eighth dose whereas smaller value at quarter dose. The supervised models obtain better numerical results than all unsupervised models on simulated datasets.

CONCLUSION

The proposed method can reduce the noise in CT projections effectively, making it an attractive tool for practical LDCT pre-processing.

Low-Dose Radiation Therapy (LDRT) against Cancer and Inflammatory or Degenerative Diseases: Three Parallel Stories with a Common Molecular Mechanism Involving the Nucleoshuttling of the ATM Protein?

Very early after their discovery, X-rays were used in multiple medical applications, such as treatments against cancer, inflammation and pain. Because of technological constraints, such applications involved X-ray doses lower than 1 Gy per session. Progressively, notably in oncology, the dose per session increased. However, the approach of delivering less than 1 Gy per session, now called low-dose radiation therapy (LDRT), was preserved and is still applied in very specific cases. More recently, LDRT has also been applied in some trials to protect against lung inflammation after COVID-19 infection or to treat degenerative syndromes such as Alzheimer's disease. LDRT illustrates well the discontinuity of the dose-response curve and the counterintuitive observation that a low dose may produce a biological effect higher than a certain higher dose. Even if further investigations are needed to document and optimize LDRT, the apparent paradox of some radiobiological effects specific to low dose may be explained by the same mechanistic model based on the radiation-induced nucleoshuttling of the ATM kinase, a protein involved in various stress response pathways.

Low- dose Apatinib promotes vascular normalization and hypoxia reduction and sensitizes radiotherapy in lung cancer

BACKGROUND AND PURPOSE

Abnormal vascular network of tumor can create a hypoxic microenvironment, and reduce radiotherapy sensitivity. Normalization of tumor vasculature can be a new therapeutic strategy for sensitizing radiotherapy. This study aimed to explore the effect of apatinib on vascular normalization, as well as the syngeneic effect with radiotherapy on lung cancer.

MATERIALS AND METHODS

Lewis lung carcinoma (LLC) xenograft-bearing female C57BL/6 mice were treated with different doses of apatinib (30, 60, and 120 mg/kg per day) and/or radiation therapy (8 Gy/1F) and then sacrificed to harvest tumor tissue for immunohistochemical test. Further ¹⁸ F-FMISO micro- PET in vivo explored the degree of hypoxia.

RESULTS

Immunohistochemistry of CD31 and alpha-smooth muscle actin (α-SMA) proved that low-dose apatinib can normalize vasculature in tumor, especially on Day 10. Tissue staining of hypoxyprobe-1 and ¹⁸ F-FMISO micro- PET in vivo showed that 60 mg/kg/day of apatinib significantly alleviates hypoxia. Moreover, this study further proved that low-dose apatinib (60 mg/kg/day) can enhance the radio-response of LLC xenograft mice.

CONCLUSION

Our data suggested that low- dose apatinib can successfully induce a vascular normalization window and function as a radio- sensitizer in the lung cancer xenografts model.

Deep learning-based attenuation map generation with simultaneously reconstructed PET activity and attenuation and low-dose application

Objective. In PET/CT imaging, CT is used for positron emission tomography (PET) attenuation correction (AC). CT artifacts or misalignment between PET and CT can cause AC artifacts and quantification errors in PET. Simultaneous reconstruction (MLAA) of PET activity (λ-MLAA) and attenuation (μ-MLAA) maps was proposed to solve those issues using the time-of-flight PET raw data only. However,λ-MLAA still suffers from quantification error as compared to reconstruction using the gold-standard CT-based attenuation map (μ-CT). Recently, a deep learning (DL)-based framework was proposed to improve MLAA by predictingμ-DL fromλ-MLAA andμ-MLAA using an image domain loss function (IM-loss). However, IM-loss does not directly measure the AC errors according to the PET attenuation physics. Our preliminary studies showed that an additional physics-based loss function can lead to more accurate PET AC. The main objective of this study is to optimize the attenuation map generation framework for clinical full-dose¹⁸F-FDG studies. We also investigate the effectiveness of the optimized network on predicting attenuation maps for synthetic low-dose oncological PET studies.Approach. We optimized the proposed DL framework by applying different preprocessing steps and hyperparameter optimization, including patch size, weights of the loss terms and number of angles in the projection-domain loss term. The optimization was performed based on 100 skull-to-toe¹⁸F-FDG PET/CT scans with minimal misalignment. The optimized framework was further evaluated on 85 clinical full-dose neck-to-thigh¹⁸F-FDG cancer datasets as well as synthetic low-dose studies with only 10% of the full-dose raw data.Main results. Clinical evaluation of tumor quantification as well as physics-based figure-of-merit metric evaluation validated the promising performance of our proposed method. For both full-dose and low-dose studies, the proposed framework achieved <1% error in tumor standardized uptake value measures.Significance. It is of great clinical interest to achieve CT-less PET reconstruction, especially for low-dose PET studies.

Application of low dose aspirin in pre-eclampsia

Aspirin is widely used in the primary and secondary prevention of cardiovascular and cerebrovascular diseases. Low-dose aspirin is also widely used to prevent pre-eclampsia and fetal growth retardation in utero. However, the use of aspirin during pregnancy is controversial. Since 1985, when aspirin was reported to be effective in obstetrics, numerous studies have attempted to determine the effect of low-dose aspirin on the morbidity of pre-eclampsia but have remained inconclusive. Guidelines for aspirin in preventing pre-eclampsia are different in different countries and regions. This article summarizes the research progress, mechanism, and application prospect of aspirin in preventing pre-eclampsia, providing a theoretical basis for the rational use of aspirin in pregnancy.

Marine Bacteria under Low-Intensity Radioactive Exposure: Model Experiments

Radioactive contaminants create problems all over world, involving marine ecosystems, with their ecological importance increasing in the future. The review focuses on bioeffects of a series of alpha and beta emitting radioisotopes (americium-241, uranium-(235 + 238), thorium-232, and tritium) and gamma radiation. Low-intensity exposures are under special consideration. Great attention has been paid to luminous marine bacteria as representatives of marine microorganisms and a conventional bioassay system. This bioassay uses bacterial bioluminescence intensity as the main testing physiological parameter; currently, it is widely applied due to its simplicity and sensitivity. Dependences of the bacterial luminescence response on the exposure time and irradiation intensity were reviewed, and applicability of hormetic or threshold models was discussed. A number of aspects of molecular intracellular processes under exposure to low-intensity radiation were analyzed: (a) changes in the rates of enzymatic processes in bacteria with the bioluminescent system of coupled enzymatic reactions of NADH:FMN-oxidoreductase and bacterial luciferase taken as an example; (b) consumption of an intracellular reducer, NADH; (c) active role of reactive oxygen species; (d) repairing of the DNA damage. The results presented confirm the function of humic substances as natural radioprotectors.

Diagnostic Validity and Reliability of Low-Dose Prospective ECG-Triggering Cardiac CT in Preoperative Assessment of Complex Congenital Heart Diseases (CHDs)

For the precise preoperative evaluation of complex congenital heart diseases (CHDs) with reduced radiation dose exposure, we assessed the diagnostic validity and reliability of low-dose prospective ECG-gated cardiac CT (CCT). Forty-two individuals with complex CHDs who underwent preoperative CCT as part of a prospective study were included. Each CCT image was examined independently by two radiologists. The primary reference for assessing the diagnostic validity of the CCT was the post-operative data. Infants and neonates were the most common age group suffering from complex CHDs. The mean volume of the CT dose index was 1.44 ± 0.47 mGy, the mean value of the dose-length product was 14.13 ± 5.4 mGy*cm, and the mean value of the effective radiation dose was 0.58 ± 0.13 mSv. The sensitivity, specificity, PPV, NPV, and accuracy of the low-dose prospective ECG-gated CCT for identifying complex CHDs were 95.6%, 98%, 97%, 97%, and 97% for reader 1 and 92.6%, 97%, 95.5%, 95.1%, and 95.2% for reader 2, respectively. The overall inter-reader agreement for interpreting the cardiac CCTs was good (κ = 0.74). According to the results of our investigation, low-dose prospective ECG-gated CCT is a useful and trustworthy method for assessing coronary arteries and making a precise preoperative diagnosis of complex CHDs.

Fatal low-dose methotrexate toxicity: A case report and literature review

Methotrexate (MTX) is a chemotherapeutic agent that acts primarily by inhibiting the folic acid cycle. In addition to its application for treating malignancies, MTX is also used to treat chronic inflammatory diseases including psoriasis. Adverse effects have been reported even at low doses (up to 25 mg/week), and there is risk of toxicity in the form of myelosuppression, hepatotoxicity, or pulmonary fibrosis. Here, we report a case of a 67-year-old male with a past medical history of end stage renal disease on peritoneal dialysis and moderate-to-severe psoriasis with psoriatic arthritis presented with abdominal pain, diarrhea, rash, mucositis, and mucocutaneous ulcers and erosions. The patient was taking methotrexate 10 mg weekly without folic acid supplementation and was found to be pancytopenic. Despite treatment, the patient developed multiorgan failure and passed away after 16 days of hospitalization. Myelosuppression is considered the most serious side effect with the highest risk of mortality. Risk factors for toxicity include renal insufficiency, advanced age, lack of folate supplementation, drug interactions, and medication errors. Importantly, serum levels of MTX do not correlate with toxicity; therefore, folinic acid rescue therapy should be started as soon as MTX toxicity is suspected. MTX toxicity is rare with low dose, proper dose scheduling, and adherence to the recommended guidelines. It is imperative that physicians considering therapy with low dose MTX for dermatologic indications take into consideration a patient's risk factors for toxicity and monitor appropriately.

Investigation of small lung lesion detection for lung cancer screening in low dose FDG PET imaging by deep neural networks

Purpose

FDG PET imaging is often recommended for the diagnosis of pulmonary nodules after indeterminate low dose CT lung cancer screening. Lowering FDG injecting is desirable for PET imaging. In this work, we aimed to investigate the performance of a deep learning framework in the automatic diagnoses of pulmonary nodules at different count levels of PET imaging.

Materials and methods

Twenty patients with 18F-FDG-avid pulmonary nodules were included and divided into independent training (60%), validation (20%), and test (20%) subsets. We trained a convolutional neural network (ResNet-50) on original DICOM images and used ImageNet pre-trained weight to fine-tune the model. Simulated low-dose PET images at the 9 count levels (20 × 10⁶, 15 × 10⁶, 10 × 10⁶, 7.5 × 10⁶, 5 × 10⁶, 2 × 10⁶, 1 × 10⁶, 0.5 × 10⁶, and 0.25 × 10⁶ counts) were obtained by randomly discarding events in the PET list mode data for each subject. For the test dataset with 4 patients at the 9 count levels, 3,307 and 3,384 image patches were produced for lesion and background, respectively. The receiver-operator characteristic (ROC) curve of the proposed model under the different count levels with different lesion size groups were assessed and the areas under the ROC curve (AUC) were compared.

Results

The AUC values were >0.98 for all count levels except for 0.5 and 0.25 million true counts (0.975 (CL 95%, 0.953-0.992) and 0.963 (CL 95%, 0.941-0.982), respectively). The AUC values were 0.941(CL 95%, 0.923-0.956), 0.993(CL 95%, 0.990-0.996) and 0.998(CL 95%, 0.996-0.999) for different groups of lesion size with effective diameter (R) <10 mm, 10-20 mm, and >20 mm, respectively. The count limit for achieving high AUC (≥0.96) for lesions with size R < 10 mm and R > 10 mm were 2 million (equivalent to an effective dose of 0.08 mSv) and 0.25 million true counts (equivalent to an effective dose of 0.01 mSv), respectively.

Conclusion

All of the above results suggest that the proposed deep learning based method may detect small lesions <10 mm at an effective radiation dose <0.1 mSv.

Advances in knowledge

We investigated the advantages and limitations of a fully automated lung cancer detection method based on deep learning models for data with different lesion sizes and different count levels, and gave guidance for clinical application.

Low-Dose Linezolid for Treatment of Patients With Multidrug-Resistant Tuberculosis

Background

Linezolid has been prioritized for treating multidrug-resistant tuberculosis (MDR TB), but toxicity limits its use. We report treatment outcomes for MDR TB patients in California who received standard-dose linezolid vs those who switched to low-dose.

Methods

We include culture-positive MDR TB cases treated with linezolid and receiving California MDR TB Service consultation during 2009-2016. Demographic, clinical, and laboratory data are analyzed using univariate analysis to compare patients who received linezolid of different dosing strategies. Analysis end points are linezolid treatment duration (measure of tolerability), treatment success (completion or cure), and adverse events (AEs).

Results

Sixty-nine of 194 (36%) MDR TB patients met inclusion criteria. While all patients began linezolid treatment at 600 mg daily, 39 (57%) continued at this dosage (standard-dose), and 30 (43%) switched to 300 mg daily (29%) or intermittent dosing (14%) (low dose). Patients on standard-dose linezolid were treated for 240 days, compared with 535 for those on low-dose (P < .0001). Sixty-three patients (91%) achieved treatment success, 2 (2.9%) died, 1 (1.5%) failed treatment, 1 (1.5%) stopped treatment due to side effects, and 2 (2.9%) were lost or moved. Treatment success was higher (P = .03) in the low-dose group. Sixty-two patients experienced ≥1 hematologic (71%) or neurologic (65%) AE. Those on low-dose linezolid experienced significantly (P = .03) fewer AEs per linezolid-month after switching (0.32 vs 0.10).

Conclusions

Patients who switched to low dose tolerated linezolid longer with better treatment outcomes and fewer recurring AEs.

Low-Dose Olanzapine in the Treatment of Adolescents with Anorexia Nervosa: An Observational Naturalistic Case-Control Study

Background: Although recent articles have investigated the use of low-dose olanzapine in different psychiatric conditions, only one study so far has assessed this treatment in 13 girls with anorexia nervosa (AN). Methods: Observational naturalistic case-control study aimed at reporting the use and tolerability of low-dose olanzapine in the context of a multidisciplinary hospital intervention for adolescents with AN. Three groups with AN were compared: group 1 was treated with low-dose olanzapine (≤5 mg/day), group 2 with full-dose olanzapine (>5 mg/day), and group 3 (control group) was treated without antipsychotics. Psychopathology was assessed at admission (T0) and discharge (T1) with Eating Disorders Inventory-3 Eating Disorders Risk, Body Uneasiness Test Global Severity Index (BUT-GSI), Beck's Depression Inventory-II (BDI-II), and Self-administered Psychiatric Scales for Children and Adolescents, Depression subtest (SAFA-D). Possible differences among the three groups, concerning clinical and treatment variables, were screened. Then, potential differences of T0-T1 modifications in psychopathological variables among the three treatment groups were assessed with analyses of covariance, corrected for baseline psychopathology and potential confounders, including possible concurrent antidepressants. Results: A total of 118 patients were enrolled (F = 94.1%; mean age = 15.4 ± 1.7 years), including 52 controls, 37 treated with low-dose olanzapine, and 29 with full-dose olanzapine. Low-dose olanzapine was well tolerated and used for a mean of 132.1 (±98.6) days, starting with a dosage of 3.4 (±1.2) mg/day and increasing to a maximum dose of 4.4 (±1.1) mg/day. The multidisciplinary intervention resulted in an improvement of BUT-GSI (p < 0.001), BDI-II (p < 0.001), and SAFA-D (p < 0.001) for the entire sample. Individuals treated with full-dose olanzapine experienced a significantly lower improvement in depressive measures: BDI-II (F[2,61] = 12.653, p < 0.001, η² = 0.269) and SAFA-D (F[2,57] = 7.413, p = 0.001, η² = 0.170), than the other groups. Discussion: This naturalistic controlled study expands the existing evidence on the use and tolerability of low-dose olanzapine in adolescents with AN. These results should be assessed in wider and prospective samples.

Evaluation of Hospitalized Patients Receiving High versus Low-Dose Opioids for Non-Cancer Pain

Limited studies suggest that opioid-related adverse effects (ORAEs) may worsen hospitalized patient outcomes, but there is insufficient data related to the impact of high-dose opioids compared to low-dose on adverse patient events. Given the paucity of data, our study aims to evaluate these ORAEs in the general hospitalized patient with non-cancer pain. A retrospective study of adult patients receiving opioids with a primary diagnoses of myocardial infarction, chronic obstructive pulmonary disease, heart failure, pneumonia, sepsis, or diabetes was conducted. Average oral morphine milligram equivalents (MMEs) administered over the entire LOS was collected, and patients were categorized as high-dose (≥50 MMEs/day) or low-dose (<50 MMEs/day). The primary composite endpoint was the incidence of ORAEs (naloxone use, decreased oxygen saturations, nausea/vomiting). Secondary outcomes included LOS, 30-day readmission, ORAEs with >100 MMEs/day. A total of 100 patients were included (n = 58 low-dose group; n = 42 high-dose group). For the primary outcome, more patients in the high-dose group experienced ORAEs (50% high-dose vs. 22.4% low-dose; p < 0.006). No statistically significant differences in LOS or 30-day readmission rates were identified between the groups. For patients receiving >100 MMEs/day, ORAEs occurred in 61% of patients. Hospitalized patients receiving high-dose opioids for non-cancer pain may have an increased incidence of ORAEs.

Modified-Dose Pembrolizumab and Prognostic Outcomes among Non-Small Cell Lung Cancer Patients: A Chart Review Study

The modified dose (MD) regimen of pembrolizumab (2 mg/kg or 100 mg every 3 weeks) is an alternative option to reduce the financial burden resulting from the extremely high cost of the standard dose (SD) regimen (200 mg every 3 weeks). However, the clinical effectiveness and prognostic outcomes have not been fully elucidated in real-word clinical practice. Sixty-four consecutive patients in Taiwan receiving pembrolizumab for advanced NSCLC between 2018 and 2020 were recruited in this study. Comparisons of overall survival (OS) and progression-free survival (PFS) were performed using Kaplan−Meier survival curves. Additionally, 12 predictors, including pembrolizumab regimen, dose, neutrophil-to-lymphocyte ratio (NLR), age, sex, histopathology, smoking history, ECOG PS, EGFR mutation, PD-L1 expression, distant metastases and treatment line, were analyzed in multivariable Cox models for predicting OS and PFS. The results showed that the MD group and the SD group had similar OS and PFS, especially in patients beyond first-line treatment or with a pretreatment NLR < 5. The NLR was the only independent factor associated with both OS (adjusted HR = 0.052; p = 0.010) and PFS (adjusted HR = 0.259; p = 0.021). The results of this study assure the clinical effectiveness of MD pembrolizumab and suggest that the pretreatment NLR could highlight patients who may benefit from MD pembrolizumab.

Eradication of FIX inhibitor in haemophilia B children using low-dose immune tolerance induction with rituximab-based immunosuppressive agent(s) in China

INTRODUCTION

Development of haemophilia B inhibitors (HBI) results in the ineffectiveness of FIX replacement therapy. Inhibitor eradication by immune tolerance induction (ITI) is therefore necessary. In HBI, ITI even at high FIX dose is less effective and has a higher risk of severe complications.

AIM

To characterize clinical features and outcome of ITI on HBI.

METHODS

This retrospective study was conducted in Haemophilia Paediatric Comprehensive Care Centre of China. We used low-dose ITI (25-50 FIX IU/kg/three-times-weekly to every-other-day) with domestic prothrombin complex concentrate (PCC), combined with two successive immunosuppressive (IS) regimens.

RESULTS

Sixteen HBI children, representing 5.7% of all and 14.4% of our severe registered HB patients, were enroled. Seven cases reported allergic reactions (ARs) proximal to inhibitor development. The historic peak inhibitor titre was median 54.2 (range 4.7-512) BU, and 15 (93.8%) had high-titre inhibitors. Twelve patients adherent to ITI were analysable. Of the nine ITI patients who received rituximab/prednisone (IS Regimen-1), four achieved tolerization in 1.4-43.3 months. Two subsequently relapsed but re-tolerized after a second course of IS Regimen-1. During ITI, the median treated bleed was .39/month (82.7% reduction from before ITI), and the incidence of AR and nephrotic syndrome (NS) complications was each at 22% (2/9). Three ITI patients received modified 'Beutel' protocol (IS Regimen-2) using multiple-IS-drugs, and two had rapid tolerization (.8 and 1.8 months).

CONCLUSIONS

Inhibitor eradication could be achieved by low-dose ITI protocol using PCC combined with IS. Larger studies are needed to confirm if ITI with IS Regimen-2 is more effective with less complications.

Efficacy and Safety of Low-Dose Nab-Paclitaxel Plus Tislelizumab in Elderly Patients With Previously Treated Metastatic Non-Small Cell Lung Cancer

The combination of immunotherapy and chemotherapy has a synergic effect in non-small cell lung cancer (NSCLC). However, the elderly are often excluded from clinical trails due to their poor health status and more comorbidities. We sought to assess the efficacy and safety of low-dose nanoparticle albumin-bound paclitaxel (nab-paclitaxel) plus tislelizumab (an anti-PD-1 antibody) in elderly patients with advanced NSCLC. In this phase 2 clinical trail, eligible patients were those aged ≥65 years with metastatic NSCLC who had disease progression after treatment with ≥1 line of chemotherapy or targeted therapy. Patients with epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) variations were eligible if they demonstrated disease progression after treatment with ≥1 corresponding inhibitor. Primary endpoints were progression-free survival and safety/tolerability. Secondary endpoints included objective response rate and overall survival. Among 29 patients enrolled from May 2019 through August 2020, 21 (72.4%) had adenocarcinoma, 17 (58.6%) had a performance status of 2, 8 (27.6%) had asymptomatic brain metastases, and 13 (44.8%) had EGFR/ALK variations. As of the data cutoff point on April 1, 2021, median progression-free survival and overall survival were 9.5 months and 16.5 months, respectively. Ten patients achieved a partial response (objective response rate of 34.5%). Seventeen (58.6%) patients had ≥1 treatment-related adverse event, with grade 3 events seen in 3 patients (10.3%). The most common adverse events were fatigue (20.7%), fever (17.2%), abnormal liver function (17.2%), and rash (17.2%). These results suggest that low-dose nab-paclitaxel plus tislelizumab is well tolerated and effective in elderly patients with advanced NSCLC, including those with EGFR/ALK variations.

Comparative Effectiveness and Safety of Standard-Dose and Low-Dose Pembrolizumab in Patients with Non-Small-Cell Lung Cancer: A Multi-Institutional Cohort Study in Taiwan

Fixed doses at 200 mg of pembrolizumab or 2 mg/kg every 3 weeks are the standard dosages for first- and second-line treatment of non-small-cell lung cancer (NSCLC); however, in clinical practice, patients with NSCLC may receive lower doses of pembrolizumab due to drug product availability or economic factors. To date, the comparative effectiveness and safety of the standard dose and lower doses of pembrolizumab in these patients still remains limited. We conducted a retrospective cohort study by analyzing electronic medical records data from the largest multi-institutional hospital system in Taiwan. Advanced NSCLC patients newly receiving pembrolizumab with or without chemotherapy were included. Patients were classified into: (1) the standard-dose group (≥2 mg/kg), and (2) the low-dose group (<2 mg/kg). We applied inverse probability of treatment weighting (IPTW) to compare the overall survival (OS) and immune-related adverse events (irAEs) between the two treatment groups, and to evaluate the minimum clinically effective dose of pembrolizumab. We included a total of 147 NSCLC patients receiving standard-dose pembrolizumab (mean [range] age: 63.7 [58.0−73.0] years; male: 62.6%; mean [range] body weight: 60.5 [58.0−73.0] kg) and 95 patients receiving low-dose pembrolizumab (mean [range] age: 62.0 [50.0−68.8] years; male: 64.2%; mean [range] body weight: 63.9 [55.0−73.8] kg). After IPTW adjustments, the median OS was similar for both the standard-dose and low-dose pembrolizumab groups (19.3 vs. 14.3 months, log-rank p = 0.15). Also, the rate for all classes of irAEs was similar for both groups. We found that patients with a pembrolizumab dose ≥1.8 mg/kg were associated with better OS than those receiving <1.8 mg/kg. Our findings suggested no significant difference in OS and irAEs between patients receiving pembrolizumab ≥2 mg/kg and <2 mg/kg in clinical practice. A pembrolizumab dose ≥1.8 mg/kg may be the clinically most efficient dose.

Efficacy and Safety of Low-Dose Rituximab in Anti-MuSK Myasthenia Gravis Patients: A Retrospective Study

PURPOSE

To evaluate the efficacy and safety of low dosages of rituximab (RTX) in the treatment of MuSK-antibody-positive MG patients.

PATIENTS AND METHODS

We retrospectively analyzed the data of MuSK-antibody-positive MG patients who were treated with low dosages of RTX from January 2018 to October 2021. The long-term treatment response to RTX was assessed by Myasthenia Gravis Foundation of America (MGFA) post-interventional status (PIS), Myasthenia Gravis Status and Treatment Intensity (MGSTI), dosage of steroid, MG-related activities of daily living (MG-ADL) and myasthenic muscle score (MMS) at the end of follow-up.

RESULTS

Clinical improvement was observed in all eight patients with follow-up for 8 to 29 months after treatment. At the last visit, complete stable remission had been achieved in one patient, pharmacologic remission in three patients, minimal manifestations status in three patients and improved in one patient based on the MGFA-PIS criteria. MGSTI level 2 or better had been reached in six (75%) patients at the last visit. The steroid dosage decreased from 60 mg at baseline to 15 mg at the last follow-up (p = 0.011). The average MG-ADL score decreased from 11 (range 7 to 15) to 0 (range 0 to 3; p = 0.011), and the MMS improved from 38.5 (range 24 to 60) to 100 (range 90 to 100; p = 0.012). These differences were all statistically significant. During RTX treatment and subsequent follow-up, 1 patient reported minor post-infusion malaise.

CONCLUSION

Low-dose RTX is effective and safe for treating anti-MuSK antibody positive MG patients. A long-term response is observed after treatment. Larger prospective studies are required to provide further evidence.

Determinants for a low dose of alteplase and its relationship to a lower intracerebral bleeding risk in acute ischemic stroke

Background: Factors for the utilization of intravenous thrombolysis with a low-dose of alteplase (0.6mg/kg) and whether the low-dose of alteplase could reduce the risk of intracerebral bleeding in acute ischemic stroke (AIS) remains uncertain. Aims: We aimed to investigate determinants for the utilization of intravenous thrombolysis with a low-dose of alteplase. We further assessed the association between the low-dose of alteplase and the intracerebral bleeding risk in AIS patients. Method: We included AIS patients who received intravenous thrombolysis using alteplase in this multicenter retrospective observational study. We investigated the association between baseline characteristics and the utilization of a low-dose of alteplase to identify determinants. We assessed the association of the low-dose of alteplase with the risk of symptomatic intracranial hemorrhage (sICH) using a multivariable logistic regression model. We further compared the rate of sICH and any ICH in patients in the low-dose group to those in the standard-dose group, using propensity score-matching data. Results: A total of 506 AIS patients were included in this study. The mean age was 67 (interquartile range [IQR] 59-75), and 178 (35.2%) were women. A total of 96 patients were treated with the low-dose. Age (adjusted odds ratio [OR] 1.02, 95% confidence interval [CI] 1.00 -1.04, p = 0.042), having a previous ischemic stroke (adjusted OR 2.01, 95%CI 1.11 - 3.64 p = 0.021) and increasing baseline systolic blood pressure (adjusted OR 1.12, 95%CI 1.00 - 1.26, p = 0.049) were determinants for the utilization of the low-dose. Multivariable logistic regression analysis showed that the low-dose was significantly associated with a reduced risk of sICH (adjusted OR 0.13, 95%CI 0.03 - 0.62, p = 0.01). Propensity score analysis showed that the rate of sICH was significantly lower in the low-dose group compared to standard-dose group (2 [2.3%] vs 10 [11.4%], p = 0.032). There was no significant difference in the rate of any ICH between two groups (14 [15.9%] vs 18 [20.5%], p = 0.434). Conclusions: Patients with increasing age, a higher baseline systolic blood pressure, and previous ischemic stroke were at a higher odd of receiving a low-dose of alteplase. The low-dose was associated with a lower risk of developing symptomatic intracranial hemorrhage.

Technical note: Partitioning of gated single photon emission computed tomography raw data for protocols optimization

PURPOSE

Methodologies for optimization of SPECT image acquisition can be challenging due to imaging throughput, physiological bias, and patient comfort constraints. We evaluated a vendor-independent method for simulating lower count image acquisitions.

METHODS

We developed an algorithm that recombines the ECG-gated raw data into reduced counting acquisitions. We then tested the algorithm to simulate reduction of counting statistics from phantom SPECT image acquisition, which was synchronized with an ECG simulator. The datasets were reconstructed with a resolution recovery algorithm and the summed stress score (SSS) was assessed by three readers (two experts and one automatic).

RESULTS

The algorithm generated varying counting levels, simulating multiple examinations at the same time. The error between the expected and the simulated countings ranged from approximately 5% to 10% for the ungated simulations and 0% for the gated simulations.

CONCLUSIONS

The vendor-independent algorithm successfully generated lower counting statistics datasets from single-gated SPECT raw data. This method can be readily implemented for optimal SPECT research aiming to lower the injected activity and/ or to shorten the acquisition time.

Aspirin in the prevention of preeclampsia: A protocol for systematic review and meta analysis

INTRODUCTION

Aspirin is widely used to prevent pregnancy related vascular disorders such as preeclampsia (PE), intrauterine growth restriction and maternal disorders. However, the indications for the use of aspirin during pregnancy is currently controversial because the dosage of aspirin used and the sample sizes in various studies differ considerably. Furthermore, women of African ancestry are more likely to have higher rates of PE and more severe cases than those of their Caucasian counterparts. Yet, there are very few studies in this population group. Therefore, the aim of this review will be to determine the effect of low-dose aspirin (LDA) for prevention of PE in women of African ancestry.

METHODS AND ANALYSIS

This is a protocol for a systematic review and meta-analysis of published studies on the effect of LDA for prevention of PE. Relevant information will be accessed from the following databases; PubMed, Cochrane Central Register of Controlled Trials, Google Scholar, Google, EBSCO Host, and the Web of Science. The studies will be mapped in 2 stages: stage 1 will map studies descriptively by focus and method; stage 2 will involve additional inclusion criteria, quality assessment and data extraction undertaken by 2 reviewers in parallel. Evidence will be synthesized using relevant systematic research tools. Meta-analysis and subgroup analysis will be conducted using RevMan whilst Stata 13 will be used for meta-regressions. We will follow recommendations described in the preferred reporting items for systematic reviews and meta-analyses statement and the Cochrane Handbook for Intervention Reviews.

DISCUSSION

The use of LDA as a prophylactic treatment has been considered for the prevention of PE. However, studies evaluating the use of LDA in women of African ancestry are few. Therefore, with the increase in the prevalence of PE in the African population, it is critical to further investigate the use of LDA in pregnant women of African ancestry.

ETHICS AND DISSEMINATION

The review and meta-analysis will not require ethical approval and the findings will be published in peer-reviewed journals and presented at local and international conferences. The findings of this review will inform all stakeholders on current and future guidelines on the use of aspirin in pregnancy, especially in populations of African ancestry.

SYSTEMATIC REVIEW REGISTRATION

International prospective Register of Systematic Reviews (PROSERO) number: (CRD42020213213).

Axitinib Reverses Resistance to Anti-Programmed Cell Death-1 Therapy in a Patient With Renal Cell Carcinoma

Owing to broad and notable clinical anti-tumor activity, anti-programmed cell death-1 (PD-1)/anti-programmed cell death-ligand 1 (PD-L1) antibodies have been indicated for almost all types of cancer, and form a part of the current standard of care. However, a large proportion of patients do not respond to anti-PD-1/PD-L1 therapy (primary resistance), and responders often develop progressive disease (acquired resistance). The mechanisms of resistance are complex and largely unknown; therefore, overcoming resistance remains clinically challenging, and data on reversing anti-PD-1 resistance are scarce. Herein, we report the case of a 58-year-old woman with renal cell carcinoma associated with Xp11.2 translocation/transcription factor E3 gene fusion, who had already showed resistance to both anti-PD-1 monotherapy and standard-dose axitinib. However, she finally achieved a partial response with a continuous combination therapy comprising low-dose axitinib and anti-PD-1. We speculate that axitinib played a key role in reversing the primary resistance to anti-PD-1 therapy. Interestingly, we observed that the number of peripheral regulatory T cells increased after the standard-dose axitinib therapy, with accompanied tumor enlargement; however, after the dose was reduced, the number of regulatory T cells decreased gradually, and the tumor regressed. We also reviewed relevant literature, which supported the fact that low-dose axitinib might be more beneficial than standard-dose axitinib in assisting immunotherapy. Given that this is a single-case report, the immunomodulatory effect of axitinib requires further investigation.

The clinical utility and safety of short-course immune checkpoint inhibitors in multiple tumours-A real-world multicentric study from India

The real-world data on short course of immune checkpoint inhibitor (ICI) use are sparse and merit exploration. A multicentric observational study on the safety and efficacy of ICI in oncology patients between August 2014 and October 2020 involves 1011 patients across 13 centers in India. The median age was 59 (min 16-max 98) years with male preponderance (77.9%). The predominant cohort received short-course ICI therapy; the median number of cycles was 5 (95% confidence interval [CI] 1-27), and the median duration of therapy was 3 (95% CI 0.5-13) months. ICIs were used commonly in the second and third line setting in our study (66.4%, n = 671). Objective response rate (complete or partial response) was documented in 254 (25.1%) of the patients, 202 (20.0%) had stable disease, and 374 (37.0%) had progressive disease. The clinical benefit rate was present in 456 (45.1%). Among the patients whom ICI was stopped (n = 906), the most common reason for cessation of ICI was disease progression (616, 68.0%) followed by logistic reasons like financial constraints (234, 25.82%). With a median follow-up of 14.1 (95% CI 12.9-15.3) months, there were 616 events of progression and 443 events of death, and the median progression free survival and overall survival were 6.4 (95% CI 5.5-7.3) and 13.6 (95% CI 11.6-15.7) months, respectively, in the overall cohort. Among the immune-related adverse events, autoimmune pneumonitis (29, 3.8%) and thyroiditis (24, 2.4%) were common. Real-world multicentric Indian data predominantly with short-course ICI therapy have comparable efficacy/safety to international literature with standard ICI therapy.

Low-dose lipopolysaccharide as an immune regulator for homeostasis maintenance in the central nervous system through transformation to neuroprotective microglia

Microglia, which are tissue-resident macrophages in the brain, play a central role in the brain innate immunity and contribute to the maintenance of brain homeostasis. Lipopolysaccharide is a component of the outer membrane of gram-negative bacteria, and activates immune cells including microglia via Toll-like receptor 4 signaling. Lipopolysaccharide is generally known as an endotoxin, as administration of high-dose lipopolysaccharide induces potent systemic inflammation. Also, it has long been recognized that lipopolysaccharide exacerbates neuroinflammation. In contrast, our study revealed that oral administration of lipopolysaccharide ameliorates Alzheimer's disease pathology and suggested that neuroprotective microglia are involved in this phenomenon. Additionally, other recent studies have accumulated evidence demonstrating that controlled immune training with low-dose lipopolysaccharide prevents neuronal damage by transforming the microglia into a neuroprotective phenotype. Therefore, lipopolysaccharide may not a mere inflammatory inducer, but an immunomodulator that can lead to neuroprotective effects in the brain. In this review, we summarized current studies regarding neuroprotective microglia transformed by immune training with lipopolysaccharide. We state that microglia transformed by lipopolysaccharide preconditioning cannot simply be characterized by their general suppression of proinflammatory mediators and general promotion of anti-inflammatory mediators, but instead must be described by their complex profile comprising various molecules related to inflammatory regulation, phagocytosis, neuroprotection, anti-apoptosis, and antioxidation. In addition, microglial transformation seems to depend on the dose of lipopolysaccharide used during immune training. Immune training of neuroprotective microglia using low-dose lipopolysaccharide, especially through oral lipopolysaccharide administration, may represent an innovative prevention or treatment for neurological diseases; however more vigorous studies are still required to properly modulate these treatments.

Direct Visualization of the Earliest Stages of Crystallization

Investigating the earliest stages of crystallization requires the transmission electron microscope (TEM) and is particularly challenging for materials which can be affected by the electron beam. Typically, when imaging at magnifications high enough to observe local crystallinity, the electron beam's current density must be high to produce adequate image contrast. Yet, minimizing the electron dose is necessary to reduce the changes caused by the beam. With the advent of a sensitive, high-speed, direct-detection camera for a TEM that is corrected for spherical aberration, it is possible to probe the early stages of crystallization at the atomic scale. High-quality images with low contrast can now be analyzed using new computing methods. In the present paper, this approach is illustrated for crystallization in a Ge2Sb2Te5 (GST-225) phase-change material which can undergo particularly rapid phase transformations and is sensitive to the electron beam. A thin (20 nm) film of GST-225 has been directly imaged in the TEM and the low-dose images processed using Python scripting to extract details of the nanoscale nuclei. Quantitative analysis of the processed images in a video sequence also allows the growth of such nuclei to be followed.

A systematic review on efficacy, safety, and treatment-durability of low-dose rituximab for the treatment of Pemphigus: special focus on COVID-19 pandemic concerns

BACKGROUND

Rituximab is a FDA-approved monoclonal antibody for adults with moderate to severe potentially life-threatening pemphigus vulgaris. Recent studies have focused on assessments of efficacy and safety of low-dose rituximab (<2 gram in each cycle).

METHOD

Databases were searched from 2010 to 2020 (last update: 1 June 2020).

RESULT

Nine studies were entered; including180 cases (92: women, 88: men, age range: 9-83 years). The dosages of each Rituximab cycle varied between ultra-low-dose (≤500 mg for a cycle, either multiple infusions or a single infusion), low-dose (2 × 375 mg/m² or 2 × 500 mg) and modified-dose (3 × 375 mg/m² or 3 × 500 mg). The efficacy and safety of Rituximab in the studies are known by the recovery time, relapse time, and side events. According to the studies, 2 × 500 can lead to complete remission in a broad range, from 35 to 82%. These differences might be explained by different end-points and variable cumulative corticosteroid dosage after RTX administration. Although the studies showed that low dose RTX is efficient, there are some controversies regarding the choosing low-dose for severe patients.

CONCLUSION

Considering the effectiveness of low-dose, intermediate dose, and ultra-low-dose protocols of Rituximab in inducing remission in pemphigus disease and considering factors such as cost of therapy, and the need to induce a minimum of immunosuppression for a minimum duration in the COVID-19 pandemic, suggested to use low-dose Rituximab protocol (2 infusions of 500 mg Rituximab: interval of 2 weeks) to induce the remission in mild-to-moderate pemphigus patients.

Combination of ultra-low dose rituximab and low dose tacrolimus versus tacrolimus alone in the treatment of non-responsive idiopathic membranous nephropathy: a Chinese retrospective cohort study

INTRODUCTION

Some patients with idiopathic membranous nephropathy (iMN) do not respond to cyclophosphamide plus steroids treatment, and we define them as non-responsive iMN. The combined regimen of rituximab (RTX) and tacrolimus (TAC) has an excellent effect on this kind of non-responsive iMN patients; however, the optimal dose is still unclear. In this retrospective study, we comapred the efficacy and safety of ultra-low dose RTX plus low-dose TAC therapy versus standard TAC monotherapy in patients with non-responsive iMN.

MATERIALS AND METHODS

Sixty-seven Chinese non-responsive iMN patients were included. There were 41 patients received standard tacrolimus monotherapy (TAC) and 26 patients received ultra-low dose rituximab plus low dose tacrolimus (RTX/TAC) combination therapy. All patients were observed for 12 months.

RESULTS

18 patients (18/26, 69.2%) in the RTX/TAC group and 17 patients (17/41, 41.5%) in the TAC group achieved clinical response after 12-month follow-up (P=0.044). The median time for achieving response in the two groups was 3.0 months. As indicated by Kaplan-Meier curve, the response rate in the RTX/TAC group was higher than that in the TAC group (P=0.015). 24-hour proteinuria, serum albumin, estimated glomerular filtration rate (eGFR) and serum creatinine in the two groups were comparable at baseline; howerver, after 12-month follow up, they were significantly improved in the RTX/TAC group compared with the TAC group (P<0.05). B-cell depletion was achieved in all patients in the RTX/TAC group during the whole follow-up period. Pneumonia, urinary tract infections and glucose intolerance were the major side effects observed in this study. All adverse events were mild, and the cumulative incidence was lower in the RTX/TAC group compared with that in the TAC group (9 (34.6%) vs 27 (65.9%), P=0.023).

CONCLUSION

The combination of ultra-low dose rituximab and low dose tacrolimus is more effective in inducing proteinuria response, improving eGFR and serum albumin in non-responsive iMN patients than standard tacrolimus monotherapy. The combined treatment also has higher safty.

De-Escalation of Dual Antiplatelet Therapy in Patients With Acute Coronary Syndromes

BACKGROUND

Balancing the effects of dual antiplatelet therapy (DAPT) in the era of potent P2Y₁₂ inhibitors has become a cornerstone of acute coronary syndrome (ACS) management. Recent randomized controlled trials (RCTs) have investigated DAPT de-escalation to decrease the risk of bleeding outcomes.

OBJECTIVES

The aim of this study was to compare the efficacy and safety outcomes of various DAPT strategies in patients with ACS, including de-escalation from a potent P2Y₁₂ inhibitor to clopidogrel or low-dose prasugrel.

METHODS

MEDLINE and EMBASE were searched through January 2021 for RCTs investigating the efficacy and safety of DAPT in patients with ACS, and a network meta-analysis was conducted. The primary efficacy outcome was a composite of cardiovascular death, myocardial infarction, and stroke. The primary bleeding outcome was trial-defined major or minor bleeding.

RESULTS

Our search identified 15 eligible RCTs, including 55,798 patients with ACS. De-escalation therapy was associated with reduced risk of primary bleeding outcomes (HR: 0.48 [95% CI: 0.30-0.77] vs clopidogrel; HR: 0.32 [95% CI: 0.20-0.52] vs ticagrelor; HR: 0.36 [95% CI: 0.24-0.55] vs standard-dose prasugrel; and HR: 0.40 [95% CI: 0.22-0.75] vs low-dose prasugrel) without negatively affecting primary efficacy outcomes. There were no significant differences in ischemic or bleeding outcomes between de-escalation to clopidogrel or low-dose prasugrel.

CONCLUSIONS

Compared with other established uses of DAPT, de-escalation was the most effective strategy for ACS treatment, resulting in fewer bleeding events without increasing ischemic events.

Low-Dose Radiotherapy Versus Moderate-Dose Radiotherapy for the Treatment of Indolent Orbital Adnexal Lymphomas

Purpose

Radiation therapy (RT) with doses ranging from 24 Gray (Gy) to 40 Gy is a proven treatment modality for indolent orbital adnexal lymphoma (IOAL), but recently the use of low dose RT (LDRT, defined as 2 Gy x 2 fractions) has become a notable alternative. However, limited data exists comparing outcomes following LDRT to moderate-dose RT (MDRT, RT dose 4 – 36 Gy). We present a single institution retrospective analysis comparing outcomes of patients with IOALs following LDRT or MDRT.

Methods

A total of 36 patients treated with 38 consecutive courses of RT were identified; LDRT was delivered for 14 courses and MDRT for 24 courses. Overall response rates (ORR) were recorded according to Deauville or RECIST criteria with a response characterized as a complete response (CR) or partial response. Local control (LC), orbital control (OC), and overall survival (OS) rates were estimated with the Kaplan-Meier method. RT toxicity was graded per CTCAEv5 and compared with the Fisher’s exact test.

Results

Median follow-up time was 29 months (m) (range, 4-129m), and median MDRT dose used was 24 Gy (range 21-36 Gy). Overall response rates (ORR) were 100% (CR 50%) and 87.5% (CR 58.3%) following LDRT and MDRT, respectively. OS at 2 years was 100% and 95% for the LDRT and MDRT groups, respectively (p=0.36). LC rates at 2 years was 100% for both LDRT and MDRT groups and at 4 years was 100% and 89% for the LDRT and MDRT groups, respectively (p=0.56). The 4-year OC rate (including both ipsilateral and contralateral relapses) was 80% and 85% for the LDRT and MDRT groups, respectively (p=0.79). No patient required treatment with RT to a previously irradiated orbit. Acute toxicities were reported following 6 LDRT courses compared to 20 MDRT courses (p=.014). No Grade 3 or higher acute toxicities occurred in either group. Late toxicities were reported following 2 LDRT courses compared to 10 MDRT courses (p=0.147).

Conclusions

LDRT produced similar ORR, LC, OC, and OS rates compared to MDRT with fewer acute and minimal late toxicities reported. Future multi-center studies with larger patient numbers are warranted to show significant associations.

Dose-Dependent Effects of Cold Atmospheric Argon Plasma on the Mesenchymal Stem and Osteosarcoma Cells In Vitro

The antimicrobial, anti-inflammatory and tissue-stimulating effects of cold argon atmospheric plasma (CAAP) accelerate its use in various fields of medicine. Here, we investigated the effects of CAAP at different radiation doses on mesenchymal stem cells (MSCs) and human osteosarcoma (MNNG/HOS) cells. We observed an increase in the growth rate of MSCs at sufficiently low irradiation doses (10–15 min) of CAAP, while the growth of MNNG/HOS cells was slowed down to 41% at the same irradiation doses. Using flow cytometry, we found that these effects are associated with cell cycle arrest and extended death of cancer cells by necrosis. Reactive oxygen species (ROS) formation was detected in both types of cells after 15 min of CAAP treatment. Evaluation of the genes’ transcriptional activity showed that exposure to low doses of CAAP activates the expression of genes responsible for proliferation, DNA replication, and transition between phases of the cell cycle in MSCs. There was a decrease in the transcriptional activity of most of the studied genes in MNNG/HOS osteosarcoma cancer cells. However, increased transcription of osteogenic differentiation genes was observed in normal and cancer cells. The selective effects of low and high doses of CAAP treatment on cancer and normal cells that we found can be considered in terms of hormesis. The low dose of cold argon plasma irradiation stimulated the vital processes in stem cells due to the slight generation of reactive oxygen species. In cancer cells, the same doses evidently lead to the formation of oxidative stress, which was accompanied by a proliferation inhibition and cell death. The differences in the cancer and normal cells’ responses are probably due to different sensitivity to exogenous oxidative stress. Such a selective effect of CAAP action can be used in the combined therapy of oncological diseases such as skin neoplasms, or for the removal of remaining cancer cells after surgical removal of a tumor.