Prospective Evaluation of the Clinical Benefits of a Novel Tattoo-less Workflow for Nonspine Bone Stereotactic Body Radiation Therapy: Integrating Surface-Guidance With Triggered Imaging Reduces Treatment Time and Eliminates the Need for Tattoos

PURPOSE

Oligometastatic disease has expanded the indications for nonspine bone stereotactic body radiation therapy (NSB SBRT). We investigated whether optical surface monitoring systems (OSMS) could enable tattoo-less setup and substitute for 2-dimensional/3-dimensional or cone beam computed tomography (CBCT)-based mid-imaging in NSB SBRT.

METHODS AND MATERIALS

OSMS was incorporated in parallel with an existing workflow using pretreatment CBCT and 2-dimensional/3-dimensional kV/kV mid-imaging beginning November 2019. The ability of OSMS to detect out-of-tolerance (>2 mm/>2°) and commanded couch shifts was analyzed. A workflow incorporating OSMS reference captures, CBCT for pretreatment verification, and OSMS/triggered imaging (TI) for intrafraction monitoring was developed for rib/sternum SBRT beginning November 2021 and all NSB SBRT beginning February 2022. Treatment time and CBCT-related radiation dose between the OSMS and the non-OSMS intrafraction monitoring group was analyzed pre- and post-OSMS/TI workflow adoption. All fractions were analyzed through statistical process control with use of an XmR chart of treatment time per quarter from February 2019 to February 2023. Special cause rules were based on Institute for Healthcare Improvement criteria.

RESULTS

From February 2019 to February 2023, 1993 NSB SBRT fractions were delivered, including 234 rib, 109 sternum, 214 ilium, and 682 multisite. Over 20 commanded shifts, OSMS could detect 2-mm shifts to within 0.4 mm 67% of the time and 0.8 mm 95% of the time. All NSB SBRT sites showed significant reductions in treatment time, including the greatest improvement in rib total treatment (21.6-13.4 minutes; P = 1.16 × 10-17) and beam time (7.9-3.2 minutes; P = 7.32 × 10-27). Significant reductions in CBCT-related radiation were also observed for several NSB sites. These process improvements were associated with OSMS adoption.

CONCLUSIONS

Adoption of a novel NSB SBRT workflow incorporating OSMS/TI for bone intrafraction motion monitoring reduced treatment time and CBCT-related radiation exposure while also allowing for more continuous intrafraction motion monitoring for NSB SBRT. OSMS/TI enabled the transition to a tattoo-less workflow.

Multimodality planning of stereotactic radio-ablation for ventricular tachycardia. Results from the international MUSIC consortium

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Research Council

Background

Optimal SBRT planning methods for VT ablation are yet to be defined.

Purpose

To evaluate a multimodal approach for SBRT planning.

Methods

30 pts (age 70±10, 90% men, LVEF 26±9%, 67% ICM, 47% NICM or mixed, 1.7±1.2 prior catheter ablations) with drug-refractory VT underwent imaging prior to SBRT. The inHEART technology was used to create image-based 3D models of substrate, cardiac anatomy, and organs at risk (coronaries, phrenic nerve, GI tract, AV node). In MUSIC software (IHU Liryc-Inria), 3D models were fused with prior EP maps, and SBRT targets were interactively drawn in 3D by the referring EP cardiologist. Transmural target volumes and organs at risk were fused with a 4D planning CT and used to plan SBRT in Eclipse (Varian).

Results

SBRT was delivered on median PTVs of 96[63-149] mL (total dose 25 Gy) with either Truebeam or Edge systems (Varian). Over a median FU of 4[2-8] months, death occurred in 11(37%) pts, due to arrhythmia recurrence in 4(13%). FU at 6 months was available in 14 pts. In these, the median numbers of VT episodes and ICD shocks over the 6 months preceding SBRT were 20[9-27] and 8[5-15], respectively. In the 6 months following SBRT, these decreased to 0[0-30] and 0[0-0], respectively (P<0.001 for both). 8/14(57%) pts were free from any VT recurrence, and 11/14(79%) were free from any ICD shock. In the total cohort, complications attributed to SBRT were observed in 2/30 (7%), none of which were fatal (heart failure and pneumonitis, both managed with steroids).

Conclusion

In patients with severe drug- and catheter ablation-refractory VT, SBRT planning based on 3D image-based models fused with prior EP maps is feasible, and associated with favorable efficacy and safety profiles.

Radiation Dose to the Intraprostatic Urethra Correlates Strongly With Urinary Toxicity After Prostate Stereotactic Body Radiation Therapy: A Combined Analysis of 23 Prospective Clinical Trials

PURPOSE

Clinical trials assessing evaluation prostate stereotactic body radiation therapy (SBRT) have used a wide range of allowed doses to the intraprostatic urethra, but the relationship between urethral dose and urinary toxicity has not been thoroughly evaluated. The goal of this study was to characterize urinary toxicity outcomes according to urethral dose administered during prostate SBRT.

METHODS AND MATERIALS

The MEDLINE (PubMed) database was searched for published prospective studies of prostate SBRT through August 2020 that documented a maximum urethral dose metric (MUDM). Reported acute and late urinary toxicity rates were collected. Logistic regression and weighted Pearson correlation models were used to assess associations between urinary toxicity rates and MUDM.

RESULTS

Twenty-three unique studies (n = 2232 patients) met the inclusion criteria and included a wide range of MUDMs (equivalent dose in 2 Gy fractions [EQD₂]: 69-141.75 Gy; α/β = 3 Gy). The median follow-up ranged from 3 to 67 months (median, 32 months). On logistic regression analysis, the MUDM EQD₂ was significantly associated with multiple urinary toxicity endpoints, including acute grade (G) 2+ (odds ratio [OR], 1.02; P < .001), late G2+ (OR, 1.03; P < .0001), and late G3+ (OR, 1.04; P = .003) urinary toxicity. On weighted Pearson correlation analysis, the MUDM was more closely associated with all evaluated urinary toxicity endpoints than prescription dose, including acute G2+ (r = 0.51; P = .02), late G2+ (r = 0.9; P < .0001), and late G3+ toxicity (r = 0.7; P = .003). Multivariate analysis accounting for age, prostate size, bladder dosimetry, and baseline urinary function confirmed associations between urinary outcomes and MUDM. Within the studied dose range, each increase of 1 Gy to the MUDM corresponded to a 0.8% and 1.0% increase in acute G2+ and late G2+ toxicity, respectively.

CONCLUSIONS

Radiation dose to the urethra correlates closely with urinary toxicity in patients with prostate cancer treated with SBRT. Attention should be paid to the urethral dose when delivering prostate SBRT to high doses, and approaches for urethral dose reduction warrant further investigation.

Dosimetric Planning Tradeoffs to Reduce Heart Dose Using Machine Learning-Guided Decision Support Software in Patients with Lung Cancer

BACKGROUND AND PURPOSE

Cardiac toxicity is a well-recognized risk following radiotherapy (RT) in patients with non-small cell lung cancer (NSCLC). However, the extent to which treatment planning optimization can reduce mean heart dose (MHD) without untoward increases in lung dose is unknown.

MATERIALS AND METHODS

Retrospective analysis of RT plans from 353 consecutive patients with locally advanced NSCLC treated with intensity-modulated RT (IMRT) or 3-dimensional conformal RT (3D-CRT). Commercially available machine learning-guided clinical decision support software was utilized to match RT plans. A leave-one-out predictive model was used to examine lung dosimetric tradeoffs necessary to achieve a MHD reduction.

RESULTS

Thirty-nine percent (91/232) of patients had RT plan matches showing potential MHD reductions of >4 to 8 Gy, without violating the upper limit of lung dose constraints (lung volume [V] receiving 20 Gy (V20Gy)<37%, V5Gy<70%, and mean lung dose [MLD]<20Gy). When switching to IMRT, 72.8% (75/103) had plan matches demonstrating improved MHD (average 2.0 Gy reduction, P<.0001) without violation of lung constraints. Examining specific lung dose tradeoffs, a mean ≥3.7 Gy MHD reduction was achieved with corresponding absolute increases in lung V20Gy, V5Gy, and MLD of 3.3%, 5.0%, and 1.0 Gy, respectively.

CONCLUSION

Nearly 40% of RT plans overall, and 73% when switched to IMRT, were predicted to have reductions in MHD >4 Gy with potentially clinically acceptable tradeoffs in lung dose. These observations demonstrate that decision support software for optimizing heart-lung dosimetric tradeoffs is feasible and may identify patients who might benefit most from more advanced RT technologies.

Substrate Modification Using Stereotactic Radioablation to Treat Refractory Ventricular Tachycardia in Patients With Ischemic Cardiomyopathy

OBJECTIVES

This study aimed to determine the feasibility of using radioablation for arrhythmogenic a substrate modification.

BACKGROUND

Stereotactic body radiation therapy (SBRT) is a promising therapy for ventricular tachycardia (VT) refractory to catheter ablation.

METHODS

A total of 6 male patients (median age 72 years) with ischemic cardiomyopathy (left ventricular ejection fraction 20% [interquartile range (IQR): 16%-25%]) and VT refractory to antiarrhythmic medications and catheter ablations underwent SBRT to extensive scar substrate. In addition to electroanatomical mapping, 5 of 6 patients had computed tomography segmentation using MUSIC (Institut Hospitalo-Universitaire l'Institut de Rythmologie et Modélisation Cardiaque, Bordeaux, France). Regions of wall thinning <5 mm, calcification, and intramyocardial fat were targeted for radioablation at 25 Gy.

RESULTS

The median planning target volume was 319 (IQR: 280-330) mL. Device-treated or sustained VT episodes were not significantly reduced by radioablation (median 42 [IQR: 19-269] to 29 [IQR: 0-81]; P = 0.438). However, a reduction in device shocks was observed from 12 (IQR: 3-19) to 0 (IQR: 0-1) (P = 0.046). Over a follow-up period of 231 (IQR: 212-311) days, 3 patients died of end-stage heart failure and 3 of 6 patients had possible adverse events (heart failure exacerbation, pneumonia, and an asymptomatic pericardial effusion).

CONCLUSIONS

Substrate modification using SBRT assisted by computed tomography segmentation is feasible for treatment of VT in patients with ischemic cardiomyopathy. Although a significant reduction in device shocks was observed, suboptimal VT burden reduction and significant mortality rate in this cohort of patients with advanced cardiomyopathy underscore the need to improve mechanistic understanding for antiarrhythmic effects to guide dosing and targeting of scar substrates.

Deep-learning system to improve the quality and efficiency of volumetric heart segmentation for breast cancer

Although artificial intelligence algorithms are often developed and applied for narrow tasks, their implementation in other medical settings could help to improve patient care. Here we assess whether a deep-learning system for volumetric heart segmentation on computed tomography (CT) scans developed in cardiovascular radiology can optimize treatment planning in radiation oncology. The system was trained using multi-center data (n = 858) with manual heart segmentations provided by cardiovascular radiologists. Validation of the system was performed in an independent real-world dataset of 5677 breast cancer patients treated with radiation therapy at the Dana-Farber/Brigham and Women’s Cancer Center between 2008–2018. In a subset of 20 patients, the performance of the system was compared to eight radiation oncology experts by assessing segmentation time, agreement between experts, and accuracy with and without deep-learning assistance. To compare the performance to segmentations used in the clinic, concordance and failures (defined as Dice < 0.85) of the system were evaluated in the entire dataset. The system was successfully applied without retraining. With deep-learning assistance, segmentation time significantly decreased (4.0 min [IQR 3.1–5.0] vs. 2.0 min [IQR 1.3–3.5]; p < 0.001), and agreement increased (Dice 0.95 [IQR = 0.02]; vs. 0.97 [IQR = 0.02], p < 0.001). Expert accuracy was similar with and without deep-learning assistance (Dice 0.92 [IQR = 0.02] vs. 0.92 [IQR = 0.02]; p = 0.48), and not significantly different from deep-learning-only segmentations (Dice 0.92 [IQR = 0.02]; p ≥ 0.1). In comparison to real-world data, the system showed high concordance (Dice 0.89 [IQR = 0.06]) across 5677 patients and a significantly lower failure rate (p < 0.001). These results suggest that deep-learning algorithms can successfully be applied across medical specialties and improve clinical care beyond the original field of interest.

Association of Left Anterior Descending Coronary Artery Radiation Dose With Major Adverse Cardiac Events and Mortality in Patients With Non-Small Cell Lung Cancer

IMPORTANCE

Radiotherapy accelerates coronary heart disease (CHD), but the dose to critical cardiac substructures has not been systematically studied in lung cancer.

OBJECTIVE

To examine independent cardiac substructure radiotherapy factors for major adverse cardiac events (MACE) and all-cause mortality in patients with locally advanced non-small cell lung cancer (NSCLC).

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort analysis of 701 patients with locally advanced NSCLC treated with thoracic radiotherapy at Harvard University-affiliated hospitals between December 1, 2003, and January 27, 2014, was performed. Data analysis was conducted between January 12, 2019, and July 22, 2020. Cardiac substructures were manually delineated. Radiotherapy dose parameters (mean, maximum, and the volume [V, percentage] receiving a specific Gray [Gy] dose in 5-Gy increments) were calculated. Receiver operating curve and cut-point analyses estimating MACE (unstable angina, heart failure hospitalization or urgent visit, myocardial infarction, coronary revascularization, and cardiac death) were performed. Fine and Gray and Cox regressions were adjusted for preexisting CHD and other prognostic factors.

MAIN OUTCOMES AND MEASURES

MACE and all-cause mortality.

RESULTS

Of the 701 patients included in the analysis, 356 were men (50.8%). The median age was 65 years (interquartile range, 57-73 years). The optimal cut points for substructure and radiotherapy doses (highest C-index value) were left anterior descending (LAD) coronary artery V15 Gy greater than or equal to 10% (0.64), left circumflex coronary artery V15 Gy greater than or equal to 14% (0.64), left ventricle V15 Gy greater than or equal to 1% (0.64), and mean total coronary artery dose greater than or equal to 7 Gy (0.62). Adjusting for baseline CHD status and other prognostic factors, an LAD coronary artery V15 Gy greater than or equal to 10% was associated with increased risk of MACE (adjusted hazard ratio, 13.90; 95% CI, 1.23-157.21; P = .03) and all-cause mortality (adjusted hazard ratio, 1.58; 95% CI, 1.09-2.29; P = .02). Among patients without CHD, associations with increased 1-year MACE were noted for LAD coronary artery V15 Gy greater than or equal to 10% (4.9% vs 0%), left circumflex coronary artery V15 Gy greater than or equal to 14% (5.2% vs 0.7%), left ventricle V15 Gy greater than or equal to 1% (5.0% vs 0.4%), and mean total coronary artery dose greater than or equal to 7 Gy (4.8% vs 0%) (all P ≤ .001), but only a left ventricle V15 Gy greater than or equal to 1% increased the risk among patients with CHD (8.4% vs 4.1%; P = .046). Among patients without CHD, 2-year all-cause mortality was increased with an LAD coronary artery V15 Gy greater than or equal to 10% (51.2% vs 42.2%; P = .009) and mean total coronary artery dose greater than or equal to 7 Gy (53.2% vs 40.0%; P = .01).

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that optimal cardiac dose constraints may differ based on preexisting CHD. Although the LAD coronary artery V15 Gy greater than or equal to 10% appeared to be an independent estimator of the probability of MACE and all-cause mortality, particularly in patients without CHD, left ventricle V15 Gy greater than or equal to 1% appeared to confer an increased risk of MACE among patients with CHD. These constraints are worthy of further study because there is a need for improved cardiac risk stratification and aggressive risk mitigation strategies.

Treating the SARS-CoV-2-positive patient with cancer: A proposal for a pragmatic and transparent ethical process

The treatment of patients with cancer who test positive for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) poses unique challenges. In this commentary, the authors describe the ethical rationale and implementation details for the creation of a novel, multidisciplinary treatment prioritization committee, including physicians, frontline staff, an ethicist, and an infectious disease expert. Organizational obligations to health care workers also are discussed. The treatment prioritization committee sets a threshold of acceptable harm to patients from decreased cancer control that is justified to reduce risk to staff. The creation of an ethical, consistent, and transparent decision‐making process involving such frontline stakeholders is essential as departments across the country are faced with decisions regarding the treatment of SARS‐CoV‐2–positive patients with cancer.

This commentary describes the ethical rationale and implementation details for a novel, multidisciplinary, treatment prioritization committee that makes treatment decisions regarding patients with cancer who are positive for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). This consistent, ethical, and transparent process could be adapted to any oncology department in which there is risk disparity between physician decision makers and the frontline staff who are implementing these decisions.

Nonlinear optical contrast enhancement for optical coherence tomography

We present a new interferometric technique for measuring Coherent Anti-Stokes Raman Scattering (CARS) and Second Harmonic Generation (SHG) signals. Heterodyne detection is employed to increase the sensitivity in both CARS and SHG signal detection, which can also be extended to different coherent processes. The exploitation of the mentioned optical nonlinearities for molecular contrast enhancement in Optical Coherence Tomography (OCT) is presented.

Cyclosporin use in the precolectomy chronic ulcerative colitis patient: a community experience and its relationship to prospective and controlled clinical trials. Pacific Northwest Gastroenterology Society

OBJECTIVE

To define what effect seminal and controlled clinical trials have on practice patterns within a gastroenterological community. To define whether these practice patterns reproduce reported treatment methods and whether results comparable with those reported in such trials are noted within a community practice setting.

METHODS

Mailed surveies, with telephone follow-up, were sent to all members of the Pacific Northwest Gastroenterology Society. Respondents were queried regarding cyclosporin use in the precolectomy chronic ulcerative colitis (CUC) patient. Data collected included patient demographics, disease duration and extent, pre-treatment use of steroids, method, dosage, and duration of cyclosporin therapy, side effects, and short-term and subsequent clinical results.

RESULTS

Twenty-one percent of 81 respondents had used cyclosporin for precolectomy CUC, approximately one-half using constant infusion and one-half using parenteral bolus therapy. Side effects attributed to the cyclosporin were noted in eight of 30 patients (27%), and acute colectomy was avoided in 17 patients (57%). Subsequent colectomy was required in an additional nine patients (73% total) within a 6-month follow-up period, a significantly higher colectomy rate than that reported in prospective trials.

CONCLUSIONS

Potential reasons precluding cyclosporin use within the gastroenterological community may include lack of knowledge about cyclosporin therapy for CUC, lack of opportunity, skepticism, fear of medication side effects, survey sampling error, or treatment philosophy. Potential reasons for failure to duplicate the results reported in controlled trials are more complex but may include inadequate treatment duration the learning curve associated with the use of a new medication, or acceptance of colectomy as the treatment of choice in patients with acutely or chronically debilitating disease.

Nitroglycerin improves the hemodynamic response to vasopressin in portal hypertension

This study was designed to investigate whether the addition of nitroglycerin to vasopressin infusion could avoid the deleterious systemic effects of vasopressin while maintaining or enhancing the therapeutic benefits of portal pressure reduction. The effect of nitroglycerin on splanchnic and systemic hemodynamics was studied in cirrhotic patients and portal hypertensive dogs receiving i.v. vasopressin. During i.v vasopressin infusion (0.4 units per min), the cardiac output decreased in patients by 14% from 7.6 +/- 0.9 (mean +/- S.E.) to 6.5 +/- 0.7 liters per min, p less than 0.01, the mean arterial pressure increased 21% from 87 +/- 2 to 105 +/- 4, p less than 0.01, and the heart rate decreased 11% from 79 +/- 3 to 71 +/- 3, p less than 0.01. The administration of sublingual nitroglycerin (0.4 mg) returned all the systemic hemodynamic parameters to baseline values. In dogs, vasopressin infusion significantly reduced portal pressure and flow while increasing portal venous resistance. Nitroglycerin when added to the vasopressin infusion reduced portal venous resistance and further decreased portal pressure in dogs. In patients, vasopressin reduced the hepatic blood flow (44%), wedged hepatic venous pressure (11%), and the gradient between wedged and free hepatic venous pressures (23%). Nitroglycerin administration caused a further reduction of the wedged hepatic venous pressure (23.6 +/- 2.3 to 21.1 +/- 2.0, 11%, p less than 0.01). There was a small but not significant further decline (7%) in the hepatic venous pressure gradient. These results provide evidence that the addition of nitroglycerin to an i.v. infusion of vasopressin reversed the detrimental effects of vasopressin while preserving the beneficial effects.

Arsenic in detergents: possible danger and pollution hazard

Arsenic at a concentration of 10 to 70 parts per million has been detected in several common presoaks and household detergents. Arsenic values of 2 to 8 parts per billion have been measured in the Kansas River. These concentrations are close to the amount (10 parts per billion) recommended by the United States Public Health Service as a drinking-water standard.