Optimal minimum MU for intensity-modulated proton therapy with pencil-beam scanning proton beams.

PURPOSE: A higher minimum monitor unit (minMU) for pencil-beam scanning proton beams in intensity-modulated proton therapy is preferred for more efficient delivery. However, plan quality may be compromised when the minMU is too large. This study aimed to identify the optimal minMU (OminMU) to improve plan delivery efficiency while maintaining high plan quality. METHODS: We utilized clinical plans including six anatomic sites (brain, head and neck, breast, lung, abdomen, and prostate) from 23 patients previously treated with the Varian ProBeam system. The minMU of each plan was increased from the current clinical minMU of 1.1 to 3-24 MU depending on the daily prescribed dose (DPD). The dosimetric parameters of the plans were evaluated for consistency against a 1.1-minMU plan for target coverage as well as organs-at-risk dose sparing. DPD/minMU was defined as the ratio of DPD to minMU (cGy/MU) to find the OminMU by ensuring that dosimetric parameters did not differ by >1% compared to those of the 1.1-minMU plan. RESULTS: All plans up to 5 minMU showed no significant dose differences compared to the 1.1-minMU plan. Plan qualities remained acceptable when DPD/minMU ≥35 cGy/MU. This suggests that the 35 cGy/MU criterion can be used as the OminMU, which implies that 5 MU is the OminMU for a conventional fraction dose of 180 cGy. Treatment times were decreased by an average of 32% (max 56%, min 7%) and by an average of 1.6 min when the minMU was increased from 1.1 to OminMU. CONCLUSION: A clinical guideline for OminMU has been established. The minMU can be increased by 1 MU for every 35 cGy of DPD without compromising plan quality for most cases analyzed in this study. Significant treatment time reduction of up to 56% was observed when the suggested OminMU is used.

Injection Laryngoplasty for Children with Dysphagia after Cardiac Surgery.

Objective: To determine whether injection laryngoplasty (IL) resolves thin liquid aspiration among children with unilateral vocal cord paralysis (UVCP) after cardiac surgery. Study Design: Retrospective case-control. Setting: Tertiary children's hospital. Methods: Consecutive children (<5 years) between 2012 and 2022 with UVCP after cardiac surgery were included. Resolution of thin liquid aspiration after IL versus observation was determined for children obtaining videofluoroscopic swallow studies (VFSS). Results: A total of 32 children with left UVCP after cardiac surgery met inclusion. Initial surgeries were N = 9 (28%) patent ductus arteriosus ligations, N = 7 (22%) aortic arch surgeries, N = 9 (28%) surgeries for hypoplastic left heart syndrome, and N = 7 (22%) other cardiac surgeries. The mean age at initial surgery was 1.8 months (SD: 3.7). All children had a VFSS obtained after surgery that confirmed aspiration. There were 17 children that obtained an IL at 33.6 months (SD: 20.9) after cardiac surgery and 15 children observed without IL procedure. No surgical complications after IL were noted. The rate of aspiration resolution based on postoperative VFSS was N = 14 (82%) for the IL group and N = 9 (60%) for the control group P = .24. Documented VFSS aspiration resolution after cardiac surgery occurred by 9.6 months (SD: 10.0) in the observation group and 47.4 months (SD: 24.1) in the IL group (P < .001). Conclusion: IL can help treat aspiration in children with UVCP after cardiac surgery but the benefit beyond observation remains unclear. Future studies should continue to explore the utility for IL in managing dysphagia in this pediatric population.

Laryngopharyngeal Reflux: Effect of Race and Insurance Status on Symptomology.

OBJECTIVES: Laryngopharyngeal reflux (LPR) is an extraesophageal variant of gastroesophageal reflux disease associated with intermittent dysphonia, throat-clearing, and chronic cough. This study aims to evaluate the impact of race and insurance status on symptoms often attributable to LPR. METHODS: Retrospective review of all patients with suspected LPR from 2017 to 2019 was performed at a tertiary care center. The diagnostic criteria comprised evaluation by a fellowship trained laryngologist and Reflux Symptom Index (RSI) scores. Demographics, patient history, and insurance status were recorded. Descriptive statistics were calculated for each parameter using SPSS version 22. RESULTS: A total of 170 patients (96 White, 44 Black, 26 Latinx, 4 Asian) were included in this study. About 57.1% had private insurance, 30.6% had Medicare, and 11.8% had Medicaid. Black and Latinx patients demonstrated higher RSI scores (26.67 ± 8.61, P = .017) when compared to their White and Asian counterparts. RSI scores between all 3 insurance types also varied significantly (P = .035). Medicaid patients reported higher RSI scores (28.65 ± 10.09, P = .028), while private insurance patients reported significantly lower scores (23.75 ± 7.88, P = .03). Controlling for insurance type eliminates the statistically significant association between RSI scores and Black and Latinx patients. Particularly, within the Medicaid group, Black, Latinx, and White patients did not have statistically different RSI scores. CONCLUSIONS: Black and Latinx patients presented with higher RSI scores than White and Asian patients. Similarly, Medicaid patients reported higher RSI scores than the Non-Medicaid cohort. These findings suggest that access to appropriate healthcare, due to varied insurance coverage and socioeconomic, may potentially influence symptoms attributed to LPR.

Presence of CrkI-containing microvesicles in squamous cell carcinomas could have ramifications on tumor biology and cancer therapeutics.

Recently, we described a phenomenon whereby apoptotic cells generate and release CrkI-containing microvesicles, which stimulate proliferation in surrounding cells upon contact to compensate for their own demise. We termed these microvesicles "ACPSVs" for Apoptotic Compensatory Proliferation Signaling microvesicles. As immune cells and a majority of current cancer therapeutics destroy tumor cells primarily by apoptosis, we conducted a small pilot study to assess the possibility that ACPSVs may also be generated in squamous cell carcinomas. We first evaluated a primary and a metastatic squamous cell carcinoma cancer cell lines for their ability to produce ACPSVs under normal and apoptotic conditions. We next conducted a pilot study to assess the occurrence of ACPSVs in solid tumors extracted from 20 cancer patients with squamous cell carcinomas. Both cancer cell lines produced copious amounts of ACPSVs under apoptotic conditions. Interestingly, the metastatic squamous cell carcinoma cancer cell line also produced high levels of ACPSVs under healthy condition, suggesting that the ability to generate ACPSVs may be hijacked by these cells. Importantly, ACPSVs were also abundant in the solid tumors of all squamous cell carcinoma cancer patients. Detection of ACPSVs in cancer has potentially important ramifications in tumor biology and cancer therapeutics which warrants further investigation.

Effect of histopathological grade on treatment and survival in base of tongue adenocarcinoma.

OBJECTIVES: The purpose of this study was to investigate survival differences between low-grade and high-grade base of tongue (BOT) adenocarcinoma by examining demographics, tumor characteristics, and treatment modalities. METHODS: The National Cancer Database was queried for patients with BOT adenocarcinoma between 2004 and 2017. Univariate and multivariate analyses were performed for all cases of BOT adenocarcinoma. Subsequent analysis focused on low-grade (grade 1 and grade 2) and high-grade (grade 3 and grade 4) BOT adenocarcinoma. RESULTS: A total of 286 patients with BOT adenocarcinoma were included in the main cohort and divided into low grade (n = 137) and high grade (n = 66). The 5-year overall survival for all patients, low-grade, and high-grade was 67%, 85%, and 58%, respectively. Prognostic factors associated with decreased survival for the main cohort include advanced age (hazard ratio [HR]: 1.04; 95% confidence interval [CI]: 1.02-1.06), non-white race (HR: 1.79; 95% CI: 1.04-3.25), public insurance (HR: 1.79; 95% CI: 1.02-3.14) and high-grade 3,4 (HR: 2.63; 95% CI: 1.51-4.56). The prognostic factor associated with increased survival for the main cohort was surgery (HR: 0.59; 95% CI: 0.36-0.96). Radiotherapy was associated with improved overall survival for high-grade BOT adenocarcinoma (HR: 0.09; 95% CI: 0.02-0.49) but not for low-grade BOT adenocarcinoma (HR: 0.93; 95% CI: 0.38-2.32). CONCLUSIONS: This investigation is the largest to date analyzing the association of treatment modalities with overall survival in BOT adenocarcinoma. Surgery remains standard of treatment, particularly in low-grade cases, with radiotherapy offering additional survival benefit for high-grade BOT adenocarcinoma.

Plan quality effects of maximum monitor unit constraints in pencil beam scanning proton therapy for central nervous system and skull base tumors.

PURPOSE/OBJECTIVE(S): With reports of CNS toxicity in patients treated with proton therapy at doses lower than would be expected based on photon data, it has been proposed that heavy monitor unit (MU) weighting of pencil beam scanning (PBS) proton therapy spots may potentially increase the risk of toxicity. We evaluated the impact of maximum MU weighting per spot (maxMU/spot) restrictions on PBS plan quality, prior to implementing clinic-wide maxMU/spot restrictions. MATERIALS/METHODS: PBS plans of 11 patients, of which 3 plans included boosts, for a total of 14 PBS sample cases were included. Per sample case, a single dosimetrist created 4 test plans, gradually reducing the maxMU/spot in the plan. Test Plan 1, unrestricted in maxMU/spot, was the reference for all restricted plan comparisons (comparison sets 2 vs. 1; 3 vs. 1; and 4 vs. 1). The impact of MU/spot restrictions on plan quality metrics were analyzed with Wilcoxon signed rank test analyses. Treatment delivery time was modeled for a representative case. RESULTS: A total of 14 PBS sample cases, 7 (50%) single-field optimized, 7 (50%) multi-field optimized, 9 (64%) delivering > 3500 cGy, 9 (64%) with 3 beams, and 7 (50%) without a range shifter were included. There were no differences in plan quality metrics of target coverage (V95% and V100% prescription), conformality and gradient indices, hot spot volume (V105% prescription), and dose to normal brain (V10%/30%/50%/70%/90%/100% prescription) with reductions of allowable maxMU/spot across all comparison sets (p > 0.05). Max MU/spot restrictions did not increase treatment delivery time when analyzed for a representative case. CONCLUSION: MaxMU/spot restrictions within the thresholds evaluated in this study did not degrade overall plan quality metrics. Future studies should evaluate spot weighting with linear energy transfer/relative biologic effectiveness-informed planning to determine if spot weighting manipulation impacts clinical outcomes and mitigates toxicity.