Frameless Linear Accelerator (LINAC) Based Radiosurgery (SRS) vs. Framed Gamma Knife SRS for Idiopathic Trigeminal Neuralgia (TN)

PURPOSE/OBJECTIVE(S)

Stereotactic radiosurgery (SRS) is an effective treatment for idiopathic trigeminal neuralgia (TN). Conventional treatment is done through frame-based solution due to small target and high radiation dose. More recently, LINAC based frameless SRS technique has been established as a patient friendly alternative. Herein we compared our single institution experience of LINAC based frameless SRS vs frame-based gamma knife SRS for TN. The hypothesis is LINAC based frameless SRS can provide equivalent dosimetric and clinical outcome as compared frame-based gamma knife treatment.

MATERIALS/METHODS

Patients with idiopathic TN who received SRS treatment (LINAC based frameless treatment or Gamma knife framed treatment) at our institution from 2015-2022 were included. A minimum follow up of 1 year was required. Patient data was extracted from electronic medical records and radiation treatment planning system. Pain intensity was evaluated utilizing a modified 0-4 Barrow Neurological Institute (BNI) pain intensity score, and then dichotomized where BNI score 0-2 represented response to treatment and BNI score 3-4 represented no response. Statistical analysis was conducted with a linear regression model accounting for race, gender, prior pain, pain distribution including laterality and branch involvement, medication regimen at time of treatment, previous radiation treatment, and prior procedures. Response was then compared between both modalities overall and within each sub-group with chi-square testing and linear regression.

RESULTS

A total of 81 patients were identified, 14 patients were excluded due to lack of adequate follow-up, leaving 67 for analysis. 12 (17.9%) were male and, 55 (82.1%) were female. All patients were managed with medication prior to SRS treatment. 5 (7.5%) had rhizotomy and 13 (19.4) had microvascular decompression, and 8 (11.9%) had previous gamma-knife radiosurgery prior to SRS treatment at our institution. Of the 67 patients, 23 (34.3%) received frame-based gamma knife SRS, 44(65.7%) received frameless LINAC treatment. 58 (86.6%) radiation naïve patients received 90 Gy in 1 fraction, while out of the 9 who had previously had intracranial radiation treatment 7 (10.4%) received 70 Gy and 2 (3%) received 80 Gy all prescribed to 100% isodose line. All patients were treated with 4 mm cone. There was no significant difference in brainstem dose between these two techniques. Between LINAC-based or Gamma Knife modalities rate of pain control (77.3 % vs 82.6 %, respectively, p = 0.61) as well as toxicity in facial numbness (31.8% vs 21.7%, respectively, p = 0.38) showed no statistical difference. There was no statistically significant signal (p > 0.05) detected within the subgroups analyzed. The linear regression model also showed no significant difference.

CONCLUSION

LINAC based frameless SRS provides comparable dosimetry and pain control for TN as compared to frame-based gamma knife treatment. It is a patient friendly solution for patients with TN.

Definitive radiotherapy for meningeal brainstem melanocytoma: a case report

Meningeal melanocytomas are rare, benign tumours of the central nervous system arising from the melanocytes of the leptomeninges. First-line treatment consists of either gross or subtotal resection with or without radiotherapy. However, given the sensitive locations of these tumours, alternative treatment options such as definitive radiotherapy may be warranted in patients deemed high-risk or without accessible tumours. A 67-year-old male presenting with spastic gait, frequent falls, and vertical gaze palsy was diagnosed with a 2.4 cm primary meningeal melanocytoma arising from the interpeduncular fossa. Given the critical tumour position within the brainstem, definitive radiotherapy was recommended. He received fractionated stereotactic radiotherapy (FSRT) to a total dose of 54 Gy in 27 fractions, resulting in a gradual improvement in gait and ocular range of motion. Follow-up imaging over the next three years revealed largely stable disease and an increase in edema with mild upper extremity weakness that improved with steroids. He was followed for three years and expired four years after treatment due to pneumonia. For patients unable to receive surgical resection, definitive RT may provide local control with minimal morbidity.

The IgG4 hinge with CD28 transmembrane domain improves VHH-based CAR T cells targeting a membrane-distal epitope of GPC1 in pancreatic cancer

Heterogeneous antigen expression is a key barrier influencing the activity of chimeric antigen receptor (CAR) T cells in solid tumors. Here, we develop CAR T cells targeting glypican-1 (GPC1), an oncofetal antigen expressed in pancreatic cancer. We report the generation of dromedary camel V_HH nanobody (D4)-based CAR T cells targeting GPC1 and the optimization of the hinge (H) and transmembrane domain (TM) to improve activity. We find that a structurally rigid IgG4H and CD28TM domain brings the two D4 fragments in proximity, driving CAR dimerization and leading to enhanced T-cell signaling and tumor regression in pancreatic cancer models with low antigen density in female mice. Furthermore, single-cell-based proteomic and transcriptomic analysis of D4-IgG4H-CD28TM CAR T cells reveals specific genes (e.g., HMGB1) associated with high T-cell polyfunctionality. This study demonstrates the potential of V_HH-based CAR T for pancreatic cancer therapy and provides an engineering strategy for developing potent CAR T cells targeting membrane-distal epitopes.

Remote Activity Monitoring and Electronic Patient-Reported Outcomes Collection During Radiotherapy for Head and Neck Cancer: A Pilot Study

PURPOSE

Modern wearable devices provide objective and continuous activity data that could be leveraged to enhance cancer care. We prospectively studied the feasibility of monitoring physical activity using a commercial wearable device and collecting electronic patient-reported outcomes (ePROs) during radiotherapy (RT) for head and neck cancer (HNC).

METHODS

Patients planned for a course of external beam RT with curative intent for HNC were instructed to use a commercial fitness tracker throughout the RT course. During weekly clinic visits, physician-scored adverse events were recorded during using Common Terminology Criteria for Adverse Events version 4.0, and patients completed ePRO surveys using a clinic tablet or computer. Feasibility of activity monitoring was defined as collection of step data for at least 80% of the RT course for at least 80% of patients. Exploratory analyses described associations between step counts, ePROs, and clinical events.

RESULTS

Twenty-nine patients with HNC were enrolled and had analyzable data. Overall, step data were recorded on 70% of the days during patients' RT courses, and there were only 11 patients (38%) for whom step data were collected on at least 80% of days during RT. Mixed effects linear regression models demonstrated declines in daily step counts and worsening of most PROs during RT. Cox proportional hazards models revealed a potential association between high daily step counts and both reduced risk of feeding tube placement (hazard ratio [HR], 0.87 per 1,000 steps, P < .001) and reduced risk of hospitalization (HR, 0.60 per 1,000 steps, P < .001).

CONCLUSION

We did not achieve our feasibility end point, suggesting that rigorous workflows are required to achieve continuous activity monitoring during RT. Although limited by a modest sample size, our findings are consistent with previous reports indicating that wearable device data can help identify patients who are at risk for unplanned hospitalization.

Bariatric Surgery for Congestive Heart Failure Patients Improves Access to Transplantation and Long-term Survival

INTRODUCTION

Obese patients with congestive heart failure (CHF) are often denied access to heart transplantation until they obtain significant weight loss to achieve a certain BMI threshold, often less than 35 kg/m². It is unknown whether the rapid weight loss associated with bariatric surgery leads to improved waitlist placement, and as such improved survival for morbidly obese patients with CHF.

METHODS

A decision analytic Markov state transition model was created to simulate the life of morbidly obese patients with CHF who were deemed ineligible to be waitlisted for heart transplantation unless they achieved a BMI less than 35 kg/m². Life expectancy following medical weight management (MWM), Roux-en-Y gastric bypass (RYGB), and sleeve gastrectomy (SG) was estimated. Base case patients were defined as having a pre-intervention BMI of 45 kg/m². Sensitivity analysis of initial BMI was performed. Markov parameters were extracted from literature review.

RESULTS

RYGB improved survival compared with both SG and MWM. RYGB patients had higher rates of transplantation, leading to improved mean long-term survival. Base case patients who underwent RYGB gained 2.1 additional years of life compared with patient's who underwent SG and 7.4 additional years of life compared with MWM. SG patients gained 5.3 years of life compared with MWM.

CONCLUSIONS

When strict waitlist criteria were applied, bariatric surgery improved access to heart transplantation and thereby increased long-term survival compared with MWM. Morbidly obese CHF patients who anticipate need for heart transplantation should be encouraged to pursue surgical weight management strategies, necessitating discussion between bariatric surgeons, cardiologists, and cardiac surgeons for appropriate perioperative risk management.

Comparison of nontechnical skills grading rubrics for OR in situ simulation for general surgery and Obstetrician/Gynecologist residents

BACKGROUND

This study utilized the Team Strategies and Tools to Enhance Performance and Patient Safety and the Nontechnical Skills for Surgeons grading systems to evaluate the nontechnical skills of general surgery and obstetrician/gynecologist residents to see if these grading systems were concordant. These simulations were also intended to teach about crisis resources available at our institution.

METHODS

Nineteen teams were created consisting of either one general surgery resident or 2 Obstetrician/Gynecologist residents plus 2 Anesthesia residents and 2 to 4 nurses. Each team was given a short briefing on Team Strategies and Tools to Enhance Performance and Patient Safety, then performed 2 simulated operating room crises. All exercises were graded by 2 independent observers with experience in the operating room and in using the Team Strategies and Tools to Enhance Performance and Patient Safety and Nontechnical Skills for Surgeons grading systems.

RESULTS

Averaged general surgery Team Strategies and Tools To Enhance Performance and Patient Safety score increased between scenarios (14.3-17; P ≤ .01), as did obstetrician/gynecologist Team Strategies and Tools to Enhance Performance and Patient Safety score (14.9-19.2; P ≤ .01). Averaged general surgery Nontechnical Skills for Surgeons score increased between scenarios (10.3-12.2; P ≤ .02), as did obstetrician/gynecologist Nontechnical Skills for Surgeons score (10.2-14.3; P ≤ .01). Surgery Team Strategies and Tools to Enhance Performance and Patient Safety scores demonstrated a strong correlation of movement with Nontechnical Skills for Surgeons scores (r = 0.83), as did obstetrician/gynecologist (r = 0.91). On average both general surgery (11%-100%; P ≤ .01) and obstetrician/gynecologist (50%-90%; P ≤ .01) saw a statistically significant increase in their awareness of the crisis checklist.

CONCLUSION

Team Strategies and Tools to Enhance and Patient Safety scores and Nontechnical Skills for Surgeons are effective and concordant tools for gauging general surgery and obstetrician/gynecologist resident nontechnical skills. In situ simulations are an effective way to teach general surgery and obstetrician/gynecologist residents about available crisis resources.

STEP improves long-term survival for pediatric short bowel syndrome patients: A Markov decision analysis

INTRODUCTION

Increasingly, for pediatric patients with short bowel syndrome (SBS), intestinal lengthening procedures such as serial transverse enteroplasty (STEP) are being offered with the hope of improving patients' chances for achieving enteral autonomy. However, it remains unclear to what extent STEP reduces the long-term need for intestinal transplant or improves survival.

METHODS

Based on existing literature, a decision analytic Markov state transition model was created to simulate the life of 1,000 pediatric SBS patients. Two simulations were modeled: 1) No STEP: patients were listed for transplant once medical management failed and 2) STEP: patients underwent STEP therapy and subsequent transplant listing if enteral autonomy was not achieved. Sensitivity analysis of small bowel length and anatomy was completed. Base case patients were defined as neonates with a small bowel length of 30cm.

RESULTS

For base case patients with an ostomy and a NEC SBS etiology, STEP was associated with increased rates of enteral autonomy after 10 years for patients with an ICV (53.9% [STEP] vs. 51.1% [No STEP]) and without an ICV (43.4% [STEP] vs. 36.3% [No STEP]). Transplantation rates were also reduced following STEP therapy for both ICV (17.5% [STEP] vs. 18.2% [No STEP]) and non-ICV patients (20.2% [STEP] vs. 22.1% [No STEP]). 10-year survival was the highest in the (+) STEP and (+) ICV group (85.4%) and lowest in the (-) STEP and (-) ICV group (83.3%).

CONCLUSIONS

For SBS patients, according to our model, STEP increases rates of enteral autonomy, reduces need for intestinal transplantation, and improves long-term survival.

TYPE OF STUDY

Economic/Decision Analysis or Modeling Studies LEVEL OF EVIDENCE: Level III.

Sleeve Gastrectomy Compared with Gastric Bypass for Morbidly Obese Patients with End Stage Renal Disease: a Decision Analysis

INTRODUCTION

The use of bariatric surgery has increased for morbidly obese patients with end stage renal disease (ESRD) for whom listing on the waitlist is often restricted until a certain BMI threshold is achieved. Effective weight loss for this population improves access to life-saving renal transplantation. However, it is unclear whether sleeve gastrectomy (SG) vs Roux-en-Y gastric bypass (RYGB) is a more effective therapy for these patients.

METHODS

A decision analytic Markov state transition model was created to simulate the life of morbidly obese patients with ESRD who were deemed ineligible to be waitlisted for renal transplantation unless they achieved a BMI less than 35 kg/m². Life expectancy following weight management (MWM), RYGB, and SG were estimated. Base case patients were defined as having a pre-intervention BMI of 45 kg/m². Sensitivity analysis of initial BMI was performed. Markov parameters were extracted from literature review.

RESULTS

RYGB improved survival compared with SG and MWM. RYGB patients had higher rates of transplantation, leading to improved mean long-term survival. Base case patients who underwent RYGB gained 1.3 additional years of life compared with patient's who underwent SG and 2.6 additional years of life compared with MWM.

CONCLUSIONS

RYGB improves access to renal transplantation and thereby increases long-term survival compared with SG and MWM. The use of SG may be incongruent with the goal of improving access to renal transplantation for morbidly obese patients.