Mean Prescription Research Articles

SP2.6 - Improvements in patient discharge efficiency and safety: the impact of a dedicated Clinical Pharmacist in an Emergency General Surgery team

Abstract Introduction Efficiency in management of acute surgical admissions is related to safe clinical practice combined with good patient flow, optimising use of limited capacity. Preventable morbidity and discharge delays may significantly compromise outcomes for Emergency General Surgery (EGS) teams managing increasing numbers of admissions. Aim To investigate the effectiveness of a prescribing pharmacist employed within an EGS team in a DGH, with specific focus on patient discharge times by facilitating discharge prescription efficiency, including venous thromboembolism (VTE) prophylaxis. Methods Data was collected for two separate 1-month time periods in 2021 (Period A), before the appointment of a pharmacist and in 2023 (Period B), after pharmacist appointment. Data was analysed for (i) differences in times related to ‘to take home’ (TTH) medication prescription and (ii) prescribing of post-operative extended enoxaparin prophylaxis (EEP) following discharge. Results Mean time for prescription of TTH medications during working hours in Period A was 100 minutes (n=133, range 0-433 minutes) compared with 67 minutes (n=120, range 0-416 minutes) in Period B. Pharmacist prescribing accounted for 51.6% of TTH prescriptions with a mean prescription time of 18.6 minutes (range 0-389 minutes). During Period A, 36% of patients (n=48) who had a VTE assessment mandating EEP received this on discharge compared to 100% in Period B (n=31). Conclusions This data highlights an improvement in prescribing of TTH medications since appointment of a dedicated EGS pharmacist. The consequences of such improvements include more rapid patient flow, better patient experience and heightened patient safety by prevention of post-operative VTE through EEP.

Practice patterns in pediatric myopia management: Insights from a 2023 survey among Indian ophthalmologists.

This study investigates the practice patterns related to paediatric myopia among Paediatric Ophthalmologists in India, based on a 2023 survey conducted via Google Forms. The survey aimed to gather insights into physicians' perceptions and experiences concerning the clinical and treatment aspects of myopia in children. The survey reveals several key insights into current practice patterns among Paediatric Ophthalmologists in India regarding paediatric myopia management. The recommended mean age for a child's first eye checkup is 3 years, underscoring the importance of early detection. Refractive error thresholds for prescribing spectacles are set at 3.0 D for infants, 2.0 D for preschool children, and 1.0 D for school-going children older than 3 years. There is a growing trend in using 0.01% Atropine eye drops for myopia management, with a mean prescription age of 4.83 years. Notably, 80.11% of respondents prioritize documenting myopia progression regardless of the child's age. Orthokeratology and Peripheral Defocus spectacle lenses are gaining recognition, and lifestyle modifications such as increasing outdoor activities and reducing near activities are widely acknowledged as effective. While most respondents do not use progressive lenses for myopia, there is significant emphasis on axial length measurements and considering the lag of accommodation. Additionally, under-correction of myopia is favored by a notable proportion of practitioners. These findings indicate a shift towards early intervention and evidence-based strategies in myopia control. The survey highlights a shift towards early intervention and evidence-based myopia control strategies among practitioners. There is, however, room for improvement in standardizing approaches and considering additional factors like axial length and lag of accommodation. Collaborative efforts among policymakers, health regulatory bodies, and industry stakeholders are essential to enhance the accessibility and affordability of myopia control treatments and address the growing health burden associated with paediatric myopia.

Improvement of medication adherence for desmopressin by adjusting the prescription dosage in male patients with overactive bladder: A claims database analysis.

Desmopressin is widely used for nocturia in patients with nocturnal polyuria. We investigated the continuation rate and adherence for desmopressin in patients with overactive bladder and nocturia using a claims database and evaluated factors that improved adherence. Patients with nocturia in a Japanese claims database who started desmopressin between September 2019 and July 2021 were evaluated. Drug persistence was assessed using the Kaplan-Meier method for initial prescription of desmopressin. The proportion of days covered (PDC) was also evaluated among patients with prescription persistence. Multivariate analysis was performed using logistic regression analysis to identify factors predicting adherence to desmopressin. The study included 72,888 patients entered into Japan Medical Data Center (JMDC) database between September 2019 and July 2021. For the 236 patients prescribed desmopressin formulations, mean prescription duration was 114 days. Among the total cases, 90 (38.1%) cases were prescribed only once, mean PDC was 0.60, and the number of high-adherence patients (PDC ≥ 0.80) was 108 (45.8%). Desmopressin prescription doses were fixed in 216 patients and adjusted in 20 patients. Multivariate analysis identified prescription dose adjustment for desmopressin as significantly associated with high PDC. Desmopressin showed a 38% dropout rate after the first dose. However, high medication continuation and high medication adherence rates (PDC) could be maintained with prescription adjustments. Careful patient monitoring and appropriate adjustment of the desmopressin dosage appear to be important factors in improving nocturia.

Characterizing the treatment patterns, medication burden, and patient demographics of older adults with major depressive disorder treated with antidepressants with or without selected comorbidities

Objective Evaluate clinical characteristics, comorbidity burden, major depressive disorder (MDD)-related healthcare resource utilization (HCRU), medication burden, and antidepressant treatment (ADT) patterns among older adults with MDD with and without selected comorbidities. Methods Using Komodo’s Healthcare Map claims data (1/1/2016-9/30/2022), patients with MDD (≥65 years) treated with ADTs were assessed 24 months preceding (baseline) and 12 months following (follow-up) first observed ADT prescription fill (index). Patients were separated into cohorts of those with ≥1 of 5 selected comorbidities and those without. Clinical characteristics, comorbidities, and MDD-related HCRU were assessed during baseline; treatment patterns were assessed during follow-up. Baseline and follow-up all-cause and comorbidity-specific medication burdens (mean prescription claims/month) were determined. Results Among the total cohort (N = 417,643), 97.1% had ≥1 of 5 selected comorbidities: hypertension (80.3%), hyperlipidemia (75.4%), diabetes (54.2%), anxiety disorder (39.0%), and chronic obstructive pulmonary disorder (19.5%). Baseline and follow-up all-cause medication burdens per month were 3.8 and 4.5 for patients with selected comorbidities and 1.7 and 2.3 for those without. During baseline, most patients (96.0% with selected comorbidities, 96.2% without) had ≥1 outpatient visit, and a numerically higher percentage of those with vs. without selected comorbidities had MDD-related emergency room (13.9% vs. 6.0%) and inpatient (13.5% vs. 4.1%) visits. The majority of both cohorts (61.0% with selected comorbidities, 59.5% without) underwent treatment pattern changes. Conclusion This study highlights the medication burden and ADT patterns in older adults with MDD, assessing these outcomes among patients with and without comorbidities. Numerically higher medication burdens among those with selected comorbidities suggests future studies could investigate the impact of comorbidities on MDD-related care.

On the need of in vivo verifications as quality control for intraoperative electron radiotherapy in breast cancer.

Intraoperative electron radiotherapy (IOERT) is a technique aiming to deliver radiotherapy during oncological surgery. In breast IOERT, the applicator and shielding disc placement are correlated with organs at risk (OAR) irradiation, in vivo verification of these parameters is scarcely reported. The aim of our study is to report and analyze possible causes of the misalignment using radiochromic films and compare our results to others reported in the bibliography. From November 2019 to April 2023, in vivo verifications were performed for 33 patients. IOERT was performed using a LIAC 10MeV (Sordina, Italy) electron accelerator. We attached a radiochromic film to the upper side of the polytetrafluoroethylene cover of the shielding disc. The percentage of the irradiation area outside the disc was recorded and various parameters (applicator angulations, prescription depth, tumor location and breast size) were analyzed to find possible correlations. For 29 patients, 20Gy were prescribed while 10Gy were prescribed to 4 patients. The average irradiated area outside the disc was 19% (0-56%) corresponding to a surface of 4.5 cm2 (0-17.4 cm2). The applicator of 5cm was used for most of the patients. The mean prescription depth was 1.4cm (0.5-2.5cm). We found no correlation between the analyzed parameters and misalignment. This study confirms the presence and magnitude of the misalignments. We strongly recommend in vivo verifications as a quality check during IOERT procedures. The misalignment has no correlation with tumor localization parameters, so the solution could be based on technical improvements of the applicator.

Healthcare Resource Use and Costs Among Individuals with Vitiligo and Psychosocial Comorbidities: Retrospective Analysis of an Insured US Population.

This study aimed to describe healthcare resource utilization and costs among individuals with vitiligo who were diagnosed with ≥1 psychosocial comorbidity, using data from US claims databases. A retrospective, observational cohort analysis of the IBM MarketScan Commercial and Medicare supplemental claims databases for US individuals with vitiligo aged ≥12 years and a first vitiligo claim between January 1 and December 31, 2018, was undertaken to assess psychosocial burden, including mental and behavioral health comorbidities. Of the 12,427 individuals included in the analysis, nearly 1 in 4 (23.5%) who had vitiligo were also diagnosed with ≥1 psychosocial comorbidity. A greater percentage of these individuals versus those who were not diagnosed with a psychosocial comorbidity had a vitiligo-related prescription claim (50.2% vs 45.4%; P<0.0001), especially for oral corticosteroids (25.4% vs 16.6%; P<0.0001) and low-potency topical corticosteroids (9.0% vs 7.6%; P<0.05). Total vitiligo-related healthcare resource utilization and costs were consistent among individuals with and without psychosocial comorbidity despite significantly (P<0.05) higher vitiligo-related ER visit utilization and expenditure among those with psychosocial comorbidity. Furthermore, individuals diagnosed with vitiligo and ≥1 psychosocial comorbidity had significantly (P<0.0001) greater utilization of all-cause mean prescription claims (25.0 vs 12.8), outpatient services (other than physician and ER visits: 19.5 vs 11.3), outpatient physician visits (10.1 vs 6.4), inpatient stays (0.6 vs 0.1), and ER visits (0.4 vs 0.2) and incurred significantly higher mean (SD) direct medical expenditures ($18,804 [$46,621] vs $9833 [$29,094] per patient per year; P<0.0001). Individuals with vitiligo who were diagnosed with ≥1 psychosocial comorbidity incurred greater total all-cause but not vitiligo-related healthcare resource utilization and expenditures than those without diagnosis of psychosocial comorbidities. Identification of psychosocial comorbidities in individuals with vitiligo may be important for multidisciplinary management of vitiligo to reduce overall burden for individuals with vitiligo.

Evaluation of longer- vs short-term use of patiromer on health care resource utilization in the patiromer longer-term use evaluation (VALUE) study.

Studies suggest that continuous long-term use of patiromer by patients with hyperkalemia is associated with less health care resource utilization compared with not using potassium binders. To retrospectively evaluate health care resource utilization and costs with longer-term adherent vs short-term use of patiromer. Time-restricted extracts from Optum's de-identified Clinformatics® Data Mart Database (CDM; January 2016-May 2019) and Symphony Health (SHA; January 2016-September 2018) deidentified databases were analyzed. Both include participants enrolled in commercial and privatized public insurance programs (SHA includes some government programs). Both integrate health care claims data from medical and pharmacy claims. Patients aged 18 years or older with hyperkalemia and an index patiromer prescription were selected. Patiromer use was identified as short-term (<2 months) and any fill quantity or adherent longer-term with claims for at least 2 consecutive months and fill quantities of at least 80% of the total days. Groups were matched on multiple categorical covariates to control for demographic variables, baseline characteristics, and markers of disease severity. Random sampling without replacement was performed 50 times to identify 50 sets of patients matched from the short-term cohort to the longer-term cohort. Health care costs/charges and encounters were compared for a 6-month post-index period using t-tests. Of the CDM patients, 1,267 (40.2%) vs 1,887 (59.8%) and of the SHA patients, 2,234 (35.1%) vs 4,132 (64.9%) experienced longer-term vs short-term patiromer use, respectively. Patient sampling selected 242 and 485 patient-matched pairs from CDM and SHA databases, respectively. At 6 months post-index in longer-term vs short-term patiromer groups (P < 0.0001 for all differences shown), respective mean medical and prescription costs/charges were $42,000 vs $54,311 (-$12,311) and $6,816 vs $4,786 (+$2,030), respectively, for CDM patients and $75,147 vs $84,414 (-$9,267) and $4,689 vs $3,736 (+$953) for SHA patients. In the CDM database, medical costs were lower for longer-term vs short-term cohorts for end-stage renal disease services charges ($10,342 vs $14,976 [-$4,634]), inpatient charges ($15,789 vs $21,473 [-$5,684]), and office visit charges ($10,152 vs $13,152 [-$3,000]). Patient out-of-pocket costs ($658 vs $420 [+$238]) and total prescription charges ($6,158 vs $4,366 [+$1,792]) were higher for the longer-term cohort of CDM patients, with similar findings in the SHA dataset. Adherent, longer-term use of patiromer is associated with significantly lower medical costs offsetting higher prescription costs, driven by the largest changes in inpatient and clinic services at CDM and SHA, respectively. This illustrates an economic value of longer-term adherence to patiromer.

A multi-center prospective study of plant-based nutritional support in adult community-based patients at risk of disease-related malnutrition.

There is an emerging need for plant-based, vegan options for patients requiring nutritional support. Twenty-four adults at risk of malnutrition (age: 59 years (SD 18); Sex: 18 female, 6 male; BMI: 19.0 kg/m2 (SD 3.3); multiple diagnoses) requiring plant-based nutritional support participated in a multi-center, prospective study of a (vegan suitable) multi-nutrient, ready-to-drink, oral nutritional supplement (ONS) [1.5 kcal/mL; 300 kcal, 12 g protein/200 mL bottle, mean prescription 275 mL/day (SD 115)] alongside dietary advice for 28 days. Compliance, anthropometry, malnutrition risk, dietary intake, appetite, acceptability, gastrointestinal (GI) tolerance, nutritional goal(s), and safety were assessed. Patients required a plant-based ONS due to personal preference/variety (33%), religious/cultural reasons (28%), veganism/reduce animal-derived consumption (17%), environmental/sustainability reasons (17%), and health reasons (5%). Compliance was 94% (SD 16). High risk of malnutrition ('MUST' score ≥ 2) reduced from 20 to 16 patients (p = 0.046). Body weight (+0.6 kg (SD 1.2), p = 0.02), BMI (+0.2 kg/m2 (SD 0.5), p = 0.03), total mean energy (+387 kcal/day (SD 416), p < 0.0001) and protein intake (+14 g/day (SD 39), p = 0.03), and the number of micronutrients meeting the UK reference nutrient intake (RNI) (7 vs. 14, p = 0.008) significantly increased. Appetite (Simplified Nutritional Appetite Questionnaire (SNAQ) score; p = 0.13) was maintained. Most GI symptoms were stable throughout the study (p > 0.06) with no serious adverse events related. This study highlights that plant-based nutrition support using a vegan-suitable plant-based ONS is highly complied with, improving the nutritional outcomes of patients at risk of malnutrition.

Association of arbitrary prescribing behavior to costly drug expenditures: a pharmacoeconomic study in primary care.

We aimed to examine the cost-related prescribing performance of primary care physicians who had a higher versus lower tendency of arbitrary prescribing. In this cross-sectional study, we evaluated the prescriptions of primary care physicians in Istanbul, collected with 3:1 systematic sampling. We determined higher versus lower arbitrary prescribing by the physician's degree of writing the solo diagnosis of "Z00- General examination without diagnosis/complaint": those for whom such prescriptions constituted >5% were classified as Group A and those with them at <0.5% as Group B. We compared these two groups by the total and disease-specific drug costs per prescription they produced for 10 frequently encountered indications. The median cost of disease-specific medication for all diagnoses in Group A and Group B, except anemia, was equal. In upper respiratory tract infections (URTIs), hypertension, anemia, diabetes, and conjunctivitis, the mean prescription costs of Group A were significantly higher than those of Group B (P < .001, P < .001, P = .009, P = .007, and P < .001, respectively), whereas disease-specific drug costs per prescription were similar (P > .05 in all diagnoses). In myalgia, Group A had lower cost per prescription (P < .001) and higher analgesic costs per prescription (P < .001) compared to those in Group B. We found significantly higher disease-specific drug cost share in Group B for URTIs (antibiotic), gastroesophageal reflux disease (gastric acid-suppressant), hypertension (antihypertensive), anemia (iron preparations), diabetes (antidiabetic), depression (antidepressant), and conjunctivitis (corticosteroid) than those in Group A (P < .001 for each). Our study showed that physicians who had a higher tendency of prescribing for no clear indication are also more likely to produce costly prescriptions.

A Point Prevalence Survey of Antimicrobial Use at Geita Regional Referral Hospital in North-Western Tanzania.

We conducted a point prevalence survey (PPS) to determine the prevalence of antibiotic use at Geita Regional Referral Hospital (GRRH) located along the shores of Lake Victoria in north-western Tanzania. This has led to the identification of gaps for improvement. This PPS study was conducted on 9-10 March 2023. Patient-related information, including sociodemographic and clinical data, was collected from medical records. STATA software version 15.0 was used to perform descriptive data analysis. About 94.8% (55/58) patients were on antibiotics with a mean (±SD) prescription of 2 (±0.5) antibiotic agents ranging from 1 to 4 different agents. The commonest indications of the antibiotic prescription were medical prophylaxis 47.3% (26/55) followed by empiric treatment 41.8% (23/55). In total, 110 prescriptions were made, of which metronidazole (25.5%; n = 28), ceftriaxone (23.6%; n = 26), and ampicillin-cloxacillin (23.6%; n = 26) were frequently observed. Only 67.3% (n = 74) of prescriptions complied with Tanzania Standard Treatment Guidelines. Moreover, according to the WHO-AWaRe classification, 50.9%, 23.6%, and 25.5% were under the Access category, Watch category, and Not Recommended category, respectively. The prevalence of antibiotic use among patients admitted to GRRH was high, whereby medical prophylaxis and empiric treatment were the commonest indications for antibiotic prescription. To support rational therapy and antimicrobial stewardship initiatives, we recommend that laboratories in regional hospitals be equipped to conduct sustained routine culture and antimicrobial susceptibility testing.

Cesium-131 Low-Dose Rate Interstitial Brachytherapy as a Salvage Re-Irradiation Technique in Treating Cervical and Uterine Cancer Pelvic Recurrence with Prior History of Pelvic Radiation

Pelvic recurrence among cervical and uterine cancer patients with prior history of pelvic radiation is a poor prognostic factor and remains challenging. The standard of care is pelvic exenteration, which is a highly morbid surgical procedure. The purpose of this study is to report local control rate and toxicity profile of Cesium-131 low-dose rate interstitial brachytherapy (LDR) as a salvage re-irradiation technique in managing pelvic relapse. We reviewed procedures and outcomes from patients with previously irradiated uterine corpus or cervix neoplasms, who subsequently relapsed and then underwent cesium-131 LDR implants between January 2016 and December 2022. Patient demographics, treatment planning variables, and disease response were reviewed. Acute toxicities, late toxicities, and local control rate were compiled for this study. A total of 12 eligible patients (6 cervical and 6 uterine cancer) with 16 cesium-131 LDR implants were included in this study. The majority (75%) of pelvic relapses occurred at the exocervix (cervix-intact) or vaginal cuff (post-hysterectomy). Median time from disease relapse to cesium implant was 32 days. The average area of implementation was 9 cm2 and average number of seeds implanted was 16. The mean prescription dose was 50 Gy. Six patients also received high-dose rate vaginal intracavitary brachytherapy in addition to cesium-131 LDR. Median follow up was 12 months. 81% of cesium implants achieved complete response at first post-treatment follow-up, while the remaining 19% demonstrated partial response. The 6-months local control rate was 79%. After cesium implant, 25% patients had local recurrence and 33% with distal metastasis. The most reported acute toxicities included vaginal mucositis (63%), dysuria (50%) and pain (19%). All patients had various degrees of vaginal stenosis and strictures long-term. Only 1 (8%) out of 12 patients, with 4 repeated cesium-131 LDR implants, developed a rectovaginal fistula and chronic pain. Cesium-131 LDR interstitial brachytherapy is a safe and feasible salvage re-irradiation technique in treating pelvic relapse among uterine corpus or cervix cancer patients with prior history of pelvic radiation. Local control rate at 6-months was acceptable with minimum toxicity. Long-term follow up is warranted to validate the efficacy of cesium-131 LDR. We conclude that cesium-131 LDR interstitial brachytherapy is a promising alternative to pelvic exenteration in selective patient population. Future prospective study is warranted.

Plan Assessment Metrics for Dose Painting in Stereotactic Radiosurgery

As radiation therapy treatment precision increases with advancements in imaging and radiation delivery, dose painting treatment becomes increasingly feasible, where targets receive a nonuniform radiation dose. The high precision of stereotactic radiosurgery (SRS) makes it a good candidate for dose painting treatments, but no suitable metrics to assess dose painting SRS plans exist. Existing dose painting assessment metrics weigh target overdose and underdose equally but are unsuited for SRS plans, which typically avoid target underdose more. Current SRS metrics also prioritize reducing healthy tissue dose through selectivity and dose fall-off, and these metrics assume single prescriptions. We propose a set of metrics for dose painting SRS that would meet clinical needs and are calculated with nonuniform dose painting prescriptions. Sample dose painting SRS prescriptions are first created from Gamma Knife SRS cases, apparent diffusion coefficient magnetic resonance images, and various image-to-prescription functions. Treatment plans are found through semi-infinite linear programming optimization and using clinically determined isocenters, then assessed with existing and proposed metrics. Modified versions of SRS metrics are proposed, including coverage, selectivity, conformity, efficiency, and gradient indices. Quality factor, a current dose painting metric, is applied both without changes and with modifications. A new metric, integral dose ratio, is proposed as a measure of target overdose. The merits of existing and modified metrics are demonstrated and discussed. A modified conformity index using mean or minimum prescription dose would be suitable for dose painting SRS with integral or maximum boost methods, respectively. Either modified efficiency index is a suitable replacement for the existing gradient index. The proposed modified SRS metrics are appropriate measures of plan quality for dose painting SRS plans and have the advantage of giving equal values as the original SRS metrics when applied to single-prescription plans.

Feasibility and Safety of Diffusing Alpha-Emitter Radiation Therapy for Recurrent or Unresectable Skin Cancers

Patients with recurrent or unresectable skin cancers have limited treatment options. Diffusing alpha-emitter radiation therapy (DaRT), a novel solid tumor management strategy using alpha-particle interstitial brachytherapy, may address this challenge. To evaluate the feasibility and safety of using DaRT to manage recurrent or unresectable skin cancers. This prospective cohort study of patients who received a 2-week to 3-week treatment course and were followed up for 24 weeks after treatment during 2021 and 2022 at 2 sites in the US. Patients with malignant skin tumors or soft tissue tumors were recruited if they had limited treatment options for tumors recurrent after prior surgery or external beam radiotherapy or unresectable tumors. Patients underwent DaRT to deliver a physical dose of 10 Gy (equivalent weighted dose of 200 CGE) to the tumor. Feasibility of the DaRT procedure was evaluated based on the ability of investigators to successfully deliver radiation to the tumor. Patients were followed up for adverse events (AEs) for 24 weeks and for tumor response by physicians' physical examination and imaging 12 weeks after device removal. This study included 10 participants with recurrent or unresectable skin cancer (median [IQR] age, 72 [68-75] years; 6 males [60%]; 4 females [40%]). Six patients (60%) had recurrent disease, and 4 (40%) had tumors that were deemed unresectable. Tumors were located on the nose, chin, eyelid, scalp, neck, trunk, and extremities. Median (range) tumor volume before treatment was 2.1 cm3 (0.65-12.65 cm3). The mean (SD) prescription dose coverage of the gross tumor volume was 91% (2.8%) with all tumors having coverage of 85% or more. No device-related grade 3 AEs were noted. Common AEs were grade 1 to 2 erythema, edema, and pruritus. At 12 weeks following treatment, there was a 100% complete response rate. Nine of 10 complete responses (90%) were confirmed by CT imaging. This cohort study suggests the feasibility and preliminary safety of DaRT in the management of recurrent or unresectable skin cancers. The favorable safety profile and high response rates are promising. A US trial for marketing approval based on this pilot study is under way. ClinicalTrials.gov Identifier: NCT04377360.

Impact of chronic potassium binder treatment on the clinical outcomes in patients with hyperkalemia: Results of a nationwide hospital-based cohort study.

Introduction: Hyperkalemia (HK) is a common disorder in patients with heart failure or chronic kidney disease, and potassium binders (PBs) are recommended to control serum potassium (S-K) levels. Although HK is often a chronic condition, short-term and intermittent PBs treatment has been largely applied to control S-K levels, and little is known about the impact of long-term and chronic PBs treatment on clinical outcomes. Method: This retrospective cohort study was conducted using a Japanese claims database (April 2008-September 2018). HK was defined as at least two S-K ≥5.1mmol/L within a 12-month(M) interval. The index date was defined as the initial PB prescription date, and the S-K values were examined at 3M, 6M, and 12M after the index. The medication possession ratio (MPR) was used to evaluate the length of the prescribed period of PB, as prescription refill was not allowed in Japan. Clinical outcomes were analyzed by comparing MPR <80% to MPR ≥80% using Cox proportional hazards regression. Results: We found 4,321 patients with HK and were on initial PB treatments, and 993 and 3,328 patients were categorized in the MPR <80% and MPR ≥80% groups, respectively. The mean prescription days ±SD in the MPR <80% and MPR ≥80% groups were 114.7 ± 9.1 and 1151.2 ± 22.5, respectively. S-K value with adjustment by covariates in MPR <80% and MPR ≥80% groups were 5.62 (95% CI: 5.57-5.68) and 5.72 (95% CI: 5.68-5.76) at index followed by 4.65 (95% CI: 4.58-4.71) and 4.57 (95% CI: 4.51-4.62) at 3M, respectively. The hazard ratios of incidence rates in hospitalization was 1.41 (p < 0.001), introduction of renal replacement therapy was 1.25 (p < 0.003), recurrent HK was 1.67 (p < 0.001), and decreased eGFR was 1.41 (p < 0.001), respectively. Conclusion: These results indicate a higher risk of adverse outcomes when PBs were not prescribed chronically, whereas S-K levels were similarly controlled. Chronic control with continued PBs rather than temporary treatment may be associated with the reduction of adverse clinical outcomes in patients with HK.

Phase II Trial of LINAC-Based STereotactic Arrhythmia Radioablation (STAR) for Paroxysmal Atrial Fibrillation in Elderly: Planning and Dosimetric Point of View.

Purpose: Approaching treatment for elderly patients with atrial fibrillation is difficult. A prospective phase II trial evaluating LINAC-based stereotactic arrhythmia radioablation (STAR) safety in this population started in 2021. Dosimetric and planning data were reported. Materials and Methods: A vac-lock bag was used for immobilization in the supine position and a computed tomography (CT, 1 mm) was performed. The clinical target volume (CTV) was defined as the area around the pulmonary veins. An internal target volume (ITV) was added to the CTV to compensate heart and respiratory movement. The planning target volume (PTV) was defined by adding 0-3 mm to the ITV. STAR was performed during free-breathing with a PTV prescription total dose (Dp) of 25 Gy/1 fraction. Flattening filter-free volumetric-modulated arc therapy plans were generated, optimized, and delivered by TrueBeamTM. Image-guided radiotherapy with cone-beam CT and surface-guided radiotherapy with Align-RT (Vision RT) were employed. Results: From May 2021 to March 2022, 10 elderly patients were treated. Mean CTVs, ITVs, and PTVs were 23.6 cc, 44.32 cc, and 62.9 cc, respectively; the mean prescription isodose level and D2% were 76.5% and 31.2 Gy, respectively. The average heart and left anterior descending artery (LAD) Dmean were 3.9 and 6.3 Gy, respectively; the mean Dmax for LAD, spinal cord, left and right bronchus, and esophagus were 11.2, 7.5, 14.3, 12.4, and 13.6 Gy, respectively. The overall treatment time (OTT) was 3 min. Conclusions: The data showed an optimal target coverage, sparing surrounding tissue, in 3 min of OTT. LINAC-based STAR for AF could represent a valid non-invasive alternative for elderly patients who were excluded from catheter ablation.

Clinical outcomes and lung toxicities after lung SABR using dynamic conformal arc therapy: a single-institution cohort study

BackgroundStereotactic ablative radiotherapy (SABR) is a validated treatment for early stage lung cancer and pulmonary metastases. It provides a high local control rate with low symptomatic toxicities. Recently, Dynamic Conformal Arc Therapy (DCAT), a delivery option that differs from conventional DCA, has been implemented in the Monaco Treatment Planning System for SABR. The aim of the study was to report clinical outcomes and toxicities for patients treated for lung SABR with this new technique.MethodsWe retrospectively identified adult patients treated for primary or secondary lung tumors with DCAT-SABR and reported their clinical, radiological, histological characteristics and dosimetric parameters. Total dose was delivered in 3 or 5 fractions for 95% of patients and prescribed on the 80% isodose line to the PTV periphery.Results145 patients met inclusion criteria for a total of 152 lesions with a median follow up of 12 months. Local control for the irradiated site was 96.7% at 1 year. Overall survival was 93.1% at 1 year. Mean prescription dose in BED10 was 110 Gy. 92% of patients had a prescribed dose superior to 100 Gy BED10. Mean PTV coverage was 95.1%. There were 66 cases of grade 1 radiation pneumonitis (RP) (43%) and only 7 cases of symptomatic grade 2 RP (4.6%).ConclusionLung SABR for primary or metastatic lung tumors using dynamic conformal arc therapy provides efficient results of local control and low lung toxicities, similar to other SABR techniques. Advances in knowledge: SABR using DCAT is a safe technique to treat lung lesions, allowing intra-fraction motion limitation, potentially higher OARs protection and a shortened beam delivery.

Pseudo-siamese network combined with dosimetric and clinical factors, radiomics features, CT images and 3D dose distribution for the prediction of radiation pneumonitis: A feasibility study

PurposeRadiation pneumonitis (RP)(grade ≥ 2) can have a considerable impact on patient quality-of life. In previous studies, the traditional method commonly used radiomics and clinical factors for RP prediction. This study aims to develop and evaluate a novel pseudo-siamese network (PSN) to assist radiologists predict RP before radiotherapy based on combination of dosimetric and clinical factors, radiomics features, CT (computed tomography) images, and dose distribution (hybrid model). MethodOne hundred and ten patients with lung cancer (19 RP ≥ 2) who received radiotherapy between 2016 and 2020 were retrospectively enrolled in this study. Dosimetric factors were calculated from DVH (dose-volume histogram), such as lung mean dose, lung V5, and prescription dose. Clinical characteristics were recorded, such as age, sex, smoking status, TN stage, and overall stage. A total of 1419 radiomics features were extracted. Cluster analysis was used for detecting radiomics features that associated with RP. Patients were randomly split into a training set (90 %, 85 non-RP, and 14 RP) and a validation set (10 %, 6 non-RP, and 5 RP). A PSN architecture was designed for combining 1D (dosimetric and clinical factors, radiomics) and 3D (CT images, 3D dose distribution) features. 5-fold cross-validation procedure for estimating the skill of the model on new data. ResultsFor cluster analysis, totally of 106 radiomics features with high correlation were selected. The accuracy was 0.727, 0.636, 0.545, and 0.727 for input dosimetric and clinical factors, dose distribution, CT images, and radiomics features, respectively. The accuracy of hybrid model was 0.818. The sensitivity of hybrid model was 0.800 (95 % confidence interval (CI) [0.299, 0.989]), and specificity was 0.833(95 % CI [0.364, 0.991]). The areas under the receiver operating characteristic curves (AUCs) result in 5-fold cross-validation was 0.77–0.90(mean AUC ± std was 0.85 ± 0.05). ConclusionThis study firstly propose method that the combination of high dimensional and low dimensional features for RP prediction. The results confirm the feasibility of multi-dimensional features predict RP.

Safety and Efficacy of MR-Guided Re-Irradiation in Patients with GI Malignancies

<h3>Purpose/Objective(s)</h3> This study aimed to assess the safety of administering re-irradiation in the abdomen or pelvis with MR-guided radiation therapy to patients with primary gastrointestinal (GI) malignancies. <h3>Materials/Methods</h3> A retrospective analysis was performed on a total of 9 patients that received MR-guided re-irradiation from March 2018 to February 2022 at a single institution. Patients were re-irradiated with 5 fractions using a dose constraint to re-irradiated mucosal structures of V 20 Gy <1cc. Treatment and clinical parameters including staging, histology, prescription radiation dose, and time interval between radiation treatments were collected. Patients were monitored for acute and late toxicity. <h3>Results</h3> Majority of the patients had pancreatic adenocarcinoma (n=6; 66%) and localized disease (n=6; 66%). The median age at the time of re-irradiation was 58 years (range 36-84 years) and median follow-up was 16 months (range 0.4- 39 months). 8 patients had surgery following the first dose of radiation. The median time between radiation treatments was 11.6 months (range 6.8 -87.9 months). The mean prescription was slightly higher at the time of re-irradiation compared to the initial prescription dose). The mean total prescription was 158.0 Gy EQD2 equivalent dose (range 99.4 Gy – 200 Gy). Majority of the patients experienced no acute toxicity or grade 1 toxicity, including fatigue and abdominal pain. One patient experienced grade 2 abdominal cramping. Dose constraints were met in all patients. No patients had recurrence in the re-irradiated field. Two patients experienced additional recurrences in their initially radiated fields after re-irradiation. No patients experienced late toxicity. <h3>Conclusion</h3> MR-guided re-irradiation in patients with GI malignancies may be a safe alternative in select patients. Further studies are needed to optimize patient selection and safe dose constraints.

Efficacy and Toxicity of Stereotactic Body Radiation Therapy Treatment of Multiple Lung Lesions

<h3>Purpose/Objective(s)</h3> As the role of SBRT in caring for patients with complex cancer presentations continues to expand, it is paramount to elucidate how many courses of lung SBRT are safe and what factors predict toxicity. Our study seeks to evaluate the dose-volume factors and associated toxicities for treatment of multiple lung tumors with SBRT. <h3>Materials/Methods</h3> This retrospective IRB approved study was conducted using our institutional database of patients who underwent SBRT for multiple lung lesions between 2012 to 2020. 64 patients underwent SBRT for multiple tumors for a total of 137 tumors treated. We compared dosimetry and clinical outcome parameters of these patients to a paired set of 50 randomly selected patients who received SBRT for a solitary lung lesion. Variables collected include patient age, gender, cancer stage, tumor histology, SBRT dose, dosimetric parameters, toxicities from SBRT, and progression-free survival (PFS). Acute toxicity was defined as any toxicity related to lung SBRT occurring <90 days from the start of SBRT and late toxicity was beyond 90 days from the end of SBRT. Statistical analysis was performed using statistical software. <h3>Results</h3> 137 pulmonary lesions in 64 patients (2+ lesions in every patient) were treated using SBRT at our institution. Of these 137 lesions, 122/137 (89.1%) were primary lung tumors and 15/137 (10.9%) were metastatic lesions. Out of the 137 lesions, 9.5% were classified as SCLC, 43.1% as adenocarcinoma, 36.5% as squamous cell carcinoma, and 10.9% as distant metastases. The mean prescription dose for multi-lesion patients was 50 Gy delivered in 3-5 fractions versus 50 Gy in 5 fractions in the single lesion group. The mean V5 (47.3% vs. 25.7%, p<0.05), V10 (26.8.3% vs. 15.4%, p<0.05), V20 (10.2% vs. 4.5%, p<0.05), and mean lung dose (10.05 Gy vs. 5.29 Gy, p<0.05) were significantly greater in multi-lesion patients compared to single lesion patients, respectively. Fatigue and dyspnea were the most commonly reported acute toxicities; 56.2% multi-lesion patients experienced fatigue and 18.8% experienced dyspnea while 22.0% of single lesion patients experienced fatigue and 12.0% experienced dyspnea (p=0.315). No late toxicities were documented. 126/137 (92.0%) of the lung lesions treated with multiple SBRT treatments demonstrated local control, while 11/137 (8.0%) had local recurrence. 1-year PFS was 92.2% in the multi-lesion group versus 84.0% in the single lesion group. There was no significant correlation between pulmonary toxicity and histology in the single lesion and multi-lesion groups. <h3>Conclusion</h3> Our results suggest that SBRT treatment of multiple pulmonary tumors is safe and feasible without increasing in acute or late pulmonary toxicity. While there is significant difference in all lung parameters between these two groups, it did not translate into increasing toxicity. Further studies are needed to understand the relation between radiation dose parameters and incidence of pulmonary toxicity.

Risk of Radiation Pneumonitis in Patients Receiving Osimertinib and Thoracic Radiotherapy

Risk of Radiation Pneumonitis in Patients Receiving Osimertinib and Thoracic Radiotherapy