Chemoradiation with Hypofractionated Proton Therapy in Stage II-III Non-Small Cell Lung Cancer: A Proton Collaborative Group Phase 2 Trial.

PURPOSE: Hypofractionated radiation therapy has been safely implemented in the treatment of early-stage non-small cell lung cancer (NSCLC) but not locally advanced NSCLC owing to prohibitive toxicities with photon therapy. Proton therapy, however, may allow for safe delivery of hypofractionated radiation therapy. We sought to determine whether hypofractionated proton therapy with concurrent chemotherapy improves overall survival. METHODS AND MATERIALS: The Proton Collaborative Group conducted a phase 1/2 single-arm nonrandomized prospective multicenter trial from 2013 through 2018. We received consent from 32 patients, of whom 28 were eligible for on-study treatment. Patients had stage II or III unresectable NSCLC (based on the 7th edition of the American Joint Committee on Cancer's staging manual) and received hypofractionated proton therapy at 2.5 to 4 Gy per fraction to a total 60 Gy with concurrent platin-based doublet chemotherapy. The primary outcome was 1-year overall survival comparable to the 62% reported for the Radiation Therapy Oncology Group (RTOG) 9410 trial. RESULTS: The trial closed early owing to slow accrual, in part, from a competing trial, RTOG 1308. Median patient age was 70 years (range, 50-86 years). Patients were predominantly male (n = 20), White (n = 23), and prior smokers (n = 27). Most had stage III NSCLC (n = 22), 50% of whom had adenocarcinoma. After a median follow-up of 31 months, the 1- and 3-year overall survival rates were 89% and 49%, respectively, and progression-free survival rates were 58% and 32%, respectively. No acute grade ≥3 esophagitis occurred. Only 14% developed a grade ≥3 radiation-related pulmonary toxic effect. CONCLUSIONS: Hypofractionated proton therapy delivered at 2.5 to 3.53 Gy per fraction to a total 60 Gy with concurrent chemotherapy provides promising survival, and additional examination through larger studies may be warranted.

Bilateral dysthyroid compressive optic neuropathy responsive to teprotumumab.

Thyroid eye disease is an auto-immune mediated orbitopathy which can cause dysthyroid compressive optic neuropathy. Traditional management of active thyroid eye disease includes temporizing high-dose steroids, orbital radiation and surgical decompression, which each possess significant limitations and/or side effects. Teprotumumab is an IGF-IR inhibitor recently FDA-approved for active thyroid eye disease. The authors report reversal of bilateral dysthyroid compressive optic neuropathy managed medically utilizing teprotumumab.

Treatment Options for Lower Eyelid Festoons.

Festoons represent a combination of fluid accumulation and soft tissue laxity in the superolateral cheek. They remain a difficult entity to treat. The ideal treatment for festoons would possess minimal invasiveness and recovery time, and predictably improve the condition. No nonsurgical treatment currently meets these criteria, and surgical treatments have significant limitations. Fortunately, a variety of treatment options exist that can benefit each patient and be tailored to their specific needs. Knowledge of the underlying anatomy, clinical characteristics, and clinical evaluation will better equip the treating physician to manage festoons.

Blindness After Filler Injection: Mechanism and Treatment.

Dermal fillers remain popular for facial rejuvenation but with its increasing use, the potential for more complications including blindness is present. This article focuses on the mechanism of filler-associated blindness, possible treatments, and future directions. Unfortunately, to date there is no proven treatment to reverse filler-induced blindness or visual compromise. It is essential for all injectors to discuss the potential ocular risks including blindness with their patients and obtain informed consent before filler injection.

Dimensions, Function and Applications of the Auricular Muscle in Facial Plastic Surgery.

PURPOSE: To determine the dimensions and function of the auricular muscle and to consider applications of this muscle in facial plastic surgery. METHODS: Nonpreserved fresh frozen human cadaver dissections from the (HOSPITAL-Blinded) Body Donation program were dissected. The length and width of the superior auricular muscle were measured. One surgeon performed all dissections and measurements. RESULTS: A total of seven left and five right hemifaces were studied. The average central height of the superior auricular muscle was 4.7 cm, and an average width was 5.0 cm. There was no significant difference between the average values of the left versus the right hemiface measurements. The muscle originated in the fibers of the galea and temporal fascia and inserted into the conchal cartilage in each specimen. Engaging the muscle in its line of action yielded slight elevation of the forehead and prevented movement of the galea along the vertex of the scalp. CONCLUSIONS: The auricular muscle acts as an occipitofrontalis stabilizer and a weak brow elevator. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors - www.springer.com/00266 .

Unilateral Ptosis, Proptosis, and Orbital Myositis After Shingles Vaccination.

Vaccinations for shingles are recommended for most adults over 60 years of age and are typically well tolerated. The present case describes acute onset of unilateral ptosis, proptosis, and orbital myositis developing within days after administration of shingles vaccination. The episode resolved to baseline after 1 week of treatment with steroids. To the authors' knowledge, this is first reported case of orbital inflammation following shingles vaccination. Given the temporal relationship and rapid response to treatment, this may represent an autoimmune reaction to the shingles vaccine.

Long-Term Patient Experience with Tetracycline Injections for Festoons.

BACKGROUND: The purpose of this study was to evaluate the long-term patient experience with tetracycline injections for treatment of festoons. METHODS: Charts of all patients undergoing tetracycline injection for treatment of lower eyelid festoons at the Cole Eye Institute, Cleveland Clinic, between 2008 and 2018 were identified using billing records. Patients were invited to participate in a questionnaire based on the FACE-Q checklist, a previously validated questionnaire for studying cosmetic procedure outcomes. Data from the questionnaire were summarized with size, mean, and frequency. RESULTS: One hundred two patients who received tetracycline injection during the study period were identified and 61 responses were obtained. The average follow-up time after injection was 3.6 years. Of 61 respondents, 36 (59 percent) noted improvement in their festoons after treatment, and 27 of 33 (82 percent) noted that improvement occurred within 2 months of treatment. Overall, 40 of 60 respondents (67 percent) would consider repeating tetracycline treatment. The most common adverse effects included discomfort (18 percent), swelling (15 percent), and bruising (13 percent). There was no statistically significant difference in questionnaire responses between men and women, except that men were more likely to consider repeated injection (92 percent versus 58 percent; p = 0.005). CONCLUSION: Tetracycline injection appears to improve festoons in a majority of patients, with an acceptable side-effect profile, although more data are needed to determine the optimal dose and frequency and to identify possible rare and/or significant side effects.

Development of a Comprehensive, Contour-Based, Peer Review Workflow at a Community Proton Center.

PURPOSE: Quality assurance and continuing quality improvement are integral parts of any radiation oncology practice. With increasingly conformal radiation treatments, it has become critical to focus on every slice of the target contour to ensure adequate tumor coverage and optimal normal tissue sparing. Proton therapy centers open internationally with increasing frequency, and radiation oncologists with varying degrees of subspecialization apply proton therapy in daily practice. Precise treatment with proton therapy allows us to limit toxicity but requires in-depth knowledge of the unique properties of proton beam delivery. To address this need at our proton therapy center, we developed a comprehensive peer review program to help improve the quality of care that we were providing for our patients. MATERIALS AND METHODS: We implemented a policy of comprehensive peer review for all patients treated at our community proton facility starting in January 2013. Peer review begins at the time of referral with prospective cases being reviewed for appropriateness for proton therapy at daily rounds. There is then biweekly review of target contouring and treatment plans. RESULTS: During a 6-month period from June 2013 to November 2013, a total of 223 new patients were treated. Documentation of peer review at chart rounds was completed for 222 of the 223 patients (99.6%). An average of 10.7 cases were reviewed in each biweekly chart rounds session, with a total of 560 case presentations. The average time required for contour review was 145 seconds (±71 seconds) and plan review was 120 seconds (±64 seconds). Modifications were suggested for 21 patients (7.9%) during contour review and for 19 patients (6.4%) during treatment plan review. An average of 4 physicians were present at each session. CONCLUSIONS: We demonstrated that the implementation of a comprehensive, prospective peer review program is feasible in the community setting. This article can serve as a framework for future quality assurance programs.

Hypofractionated Proton Therapy with Concurrent Chemotherapy for Locally Advanced Non-Small Cell Lung Cancer: A Phase 1 Trial from the University of Florida and Proton Collaborative Group.

PURPOSE: We report the safety data from the first multicenter phase 1 trial investigating the use of hypofractionated proton therapy with concurrent chemotherapy for patients with stage II or III non-small cell lung cancer. METHODS AND MATERIALS: From 2013 through 2018, patients with newly diagnosed stage II or III non-small cell lung cancer were enrolled in a multicenter phase 1 clinical trial evaluating concurrent chemotherapy with increasing dose-per-fraction proton therapy. This was a stepwise 5 + 2 dose-intensification protocol with the following dose arms: (1) 2.5 GyRBE per fraction to 60 GyRBE; (2) 3.0 GyRBE per fraction to 60 GyRBE; (3) 3.53 GyRBE per fraction to 60.01 GyRBE; and (4) 4.0 GyRBE per fraction to 60 GyRBE. A dose arm was considered tolerable if no radiation therapy-attributable severe adverse event (SAE) occurred within 90 days of treatment among 5 patients enrolled on the arm or if 1 SAE occurred among 7 patients enrolled. Dose constraints to the heart, brachial plexus, and spinal cord were more conservative at higher doses per fraction. RESULTS: The study closed early because of slow accrual and competing enrollment in NRG 1308 before accrual was met, with no maximum tolerated dose identified. Eighteen patients were treated, including 5 patients on arms 1 and 2, 7 patients on arm 3, and 1 patient on arm 4. Two SAEs occurred among 7 patients treated at 3.53 GyRBE per fraction; however, per outside expert review, both were attributed to chemotherapy and unrelated to radiation therapy. CONCLUSIONS: Hypofractionated proton therapy delivered at 2.5 to 3.53 GyRBE per fraction to a dose of 60 GyRBE with concurrent chemotherapy has an acceptable toxicity profile. Further exploration of this regimen is warranted on a phase 2 clinical trial.

Longitudinal Changes in Adult Bony Orbital Volume.

PURPOSE: To our knowledge, no prior study has measured bony orbital volume in a group of subjects over time. This study evaluates longitudinal changes in bony orbital volume with age. METHODS: A search was created for patients with digitized CT imaging studies of the orbit at least 8 years apart. Charts with a history of prior head trauma, head and neck tumors, sinus disease, head surgery, elevated intracranial pressure, thyroid eye disease, or conditions that could affect bone metabolism were excluded. Three outcome measures were used: orbital volume, medial orbital wall length, and lateral orbital wall length. Categorical data were summarized with frequency (%); normally distributed continuous data are summarized with mean (standard deviation), and non-normally distributed data were summarized with median. Normality was verified with Shapiro-Wilk Test. Paired t-tests were used to analyze the differences in the 3 outcome variables. RESULTS: One hundred and eighty-two subjects, 91 males and 91 females, were included. The median time between CT scans was 9.4 years. Orbital volume was significantly larger at the second scan than the first (p < 0.001). The average difference in orbital volume was 0.91 ml, an increase of 4.1%. Lateral orbital length was significantly shorter in the second scan than in the first (p = 0.046) though the difference was only 0.4 mm. There was no statistically significant change in medial orbital wall length. CONCLUSIONS: Bony orbital volume increases in individuals with age. This increase in orbital volume occurs in the context of soft tissue changes to contribute to the aging appearance of the periorbital region.

Temporal Fat Pad Volume in Patients With Thyroid Eye Disease.

PURPOSE: To determine whether thyroid eye disease (TED) is associated with a change in temporal fossa soft tissue volume. METHODS: CT imaging studies were selected from patients with TED considering orbital decompression surgery and from an age-matched group of controls presenting to the Emergency Department for nontraumatic conditions requiring CT imaging. Measurements of the temporal fossa fat pad and soft tissue thickness were used as a proxy for volume and were performed using the zygomaticotemporal suture as a reference point. Categorical variables were described using frequencies and percentages, while continuous variables were described using medians and standard deviations. Chi-square tests were used to assess the relationship between gender and age group, while t-tests were used to examine the relationship between continuous variables and age group. RESULTS: A total of 56 CT scans were evaluated, including scans from 28 patients with TED and 28 controls. The following measurements were found to be significantly larger in the TED population: left fat pad measured 5 mm above the zygomaticotemporal suture (p = 0.012), right fat pad measured 15 mm above the suture (p = 0.005), right soft tissue measured 15 mm above the suture (p = 0.026), left fat pad measured 15 mm above the suture (p = 0.006), and the left soft tissue measure 15 mm above the suture (p = 0.032). CONCLUSIONS: Thyroid eye disease is associated with an increase in temporal fossa fat pad and soft tissue volume. These findings suggest that TED disease may produce pan-facial changes rather than changes confined to the peri-orbital region.

Retrospective analysis of reduced energy switching and room switching times on throughput efficiency of a multi-room proton therapy center.

OBJECTIVE: To quantify how a control software upgrade changed beam delivery times and impacted efficiency and capacity of a multiroom proton therapy center. METHODS: A four-room center treating approximately 90 patients/day, treating for approximately 7 years with optimized operations, underwent a software upgrade which reduced room and energy switching times from approximately 30 to 20 s and approximately 4 s to ~0.5 s, respectively. The center uses radio-frequency identification data to track patient treatments and has software which links this to beam delivery data extracted from the treatment log server. Two 4-month periods, with comparable patient volume, representing periods before and after the software change, were retrospectively analyzed. RESULTS: A total of 16,168 and 17,102 fields were analyzed. For bilateral head and neck and prostate patients, the beam waiting time was reduced by nearly a factor of 3 and the beam delivery times were reduced by nearly a factor of 2.5. Room switching times were reduced more modestly. Gantry capacity has increased from approximately 30 patients to 40-45 patients in a 16-h daily operation. CONCLUSIONS: Many proton centers are striving for increased efficiencies. We demonstrated that reductions in energy and room switching time can significantly increase center capacity. Greater potential for further gains would come from improvements in setup and imaging efficiency. ADVANCES IN KNOWLEDGE: This paper provides detailed measured data on the effect on treatment times resulting from reducing energy and room switching times under controlled conditions. It helps validate the models of previous investigations to establish treatment capacity of a proton therapy center.

Comparison of Orbital Volume in Young Versus Senescent Human Skulls.

PURPOSE: To compare bony orbital volumes in young skulls with those of older skulls to elucidate aging-associated changes of the orbit. METHODS: One hundred Caucasian male skulls from the Hamann-Todd collection of the Cleveland Museum of Natural History were studied. There were 50 young skulls (age range, 19-33 years) and 50 senescent skulls (age range, 79-96 years). Volcanic sand was used to fill each orbit in an identical fashion and weighed as a proxy for volume. Digital calipers were used to perform linear measurements of the orbit. The relationship between orbit measures and skull size was assessed using Pearson's correlations and 95% CI, and statistical models to compare age groups adjusted for skull size. RESULTS: The volume of the orbits (P < 0.001), the horizontal diameter of the orbit (P = 0.015), and the orbital depth (P < 0.001) were significantly larger in the senescent group of skulls after adjusting for skull surface area. No significant differences were found in the vertical diameters of the orbit between the 2 groups. Skull size did not statistically differ between the age groups. CONCLUSIONS: Increases in the depth and horizontal dimensions of the orbit lead to increasing bony orbital volume with increasing age. These changes in size and shape of the orbit with age may contribute to phenotypic changes of aging and may affect disease processes and management.

Clinical Outcomes of Recurrent Intracranial Meningiomas Treated with Proton Beam Reirradiation.

PURPOSE: Recurrent meningiomas remain therapeutically challenging, often progressive despite multimodality salvage. There are limited data guiding reirradiation (reRT), and proton beam radiation therapy (PBRT) offers a potential advantage owing to lower integral brain dose. PATIENTS AND METHODS: We retrospectively conducted a review of 16 patients who received PBRT reRT for recurrent meningiomas. Kaplan-Meier and proportional hazards were used to determine post-PBRT progression-free survival (PFS) and overall survival (OS) and to evaluate clinical predictors. RESULTS: At diagnosis, 7 (44%), 8 (50%), and 1 (6%) patient had World Health Organization (WHO) grade I, II and III tumors, respectively. All received prior radiation therapy (RT) to a median of 54 Gy (range 13-65.5). Median time to PBRT reRT after prior RT was 5.8 years (range 0.7-18.7). Median PBRT dose was 60 Gy(RBE) (range 30-66.6), and median planning tumor volume (PTV) was 76 cm3 (range 8-249). Median follow-up was 18.8 months. At last follow-up, 7 intracranial recurrences (44%) and 3 disease-related deaths (19%) were found. Median cohort PFS was 22.6 months, with 1- and 2-year PFS of 80% and 43%, respectively. Median OS was not achieved, with 1- and 2-year OS of 94% and 73%; all deaths were felt to be related to meningioma. Patients with initially grade I tumors had improved PFS versus higher grade (Hazard Ratio, HR = 0.23, P = .03) with 1- and 2-year PFS estimates of 100% versus 71% and 75% versus 29%, respectively. Longer interval between prior RT and PBRT also predicted improved PFS (P = .03) and OS (P = .049). Overall late grade 3+ toxicity rate was 31%. Two patients (13%) developed radionecrosis at 6 and 16 months after PBRT; only 1 was symptomatic. CONCLUSIONS: This is the first series specifically analyzing PBRT alone as a reRT strategy for recurrent meningioma. We report fair intracranial control with low rates of radionecrosis at 1 year after reRT. However, strategies to achieve durable outcomes are needed, particularly for high-grade tumors.

Early outcomes of breast cancer patients treated with post-mastectomy uniform scanning proton therapy.

BACKGROUND: Postmastectomy proton radiotherapy improves normal tissue sparing in comparison to photon-based approaches. Several studies have reported dosimetry comparison and tolerable acute toxicity profile with limited follow-up. We report our institutional experience of postmastectomy proton radiation including clinical efficacy and toxicities. METHODS: From December 2013 to February 2015, 42 consecutive patients who received mastectomy for non-metastatic breast cancer were treated with adjuvant chest wall and regional nodal proton therapy at a single proton center. 3D conformal uniform scanning with en face matching fields was used. RESULTS: The median follow-up among patients was 35 months (range 1-55 months). There was one local failure, zero regional nodal failure, and six distant failures. The 3-year rate of locoregional disease-free survival was 96.3%, metastasis-free survival was 84.1%, and overall survival was 97.2%. The only local failure event occurred on the chest wall within the radiation field, approximately 2.5 years after the completion of radiation. Skin dermatitis, fatigue, and esophagitis were the most common acute toxicity. All patients developed grade 1 or 2 acute skin toxicity and there was no grade 3 or 4 acute skin toxicity. Proton radiation is able to achieve excellent target coverage with median PTV V95 over 95% and heart sparing with median mean heart dose less than 1 Gy (RBE). CONCLUSION: With close to three years of median follow-up, post-mastectomy proton radiation has shown excellent locoregional control rates and favorable toxicity profile. Long-term adverse effect of heart-sparing radiation will require longer follow-up time and randomized clinical trials.

Patterns of proton therapy use in pediatric cancer management in 2016: An international survey.

PURPOSE: To facilitate the initiation of observational studies on late effects of proton therapy in pediatric patients, we report on current patterns of proton therapy use worldwide in patients aged less than 22 years. MATERIALS & METHODS: Fifty-four proton centers treating pediatric patients in 2016 in 11 countries were invited to respond to a survey about the number of patients treated during that year by age group, intent of treatment, delivery technique and tumor types. RESULTS: Among the 40 participating centers (participation rate: 74%), a total of 1,860 patients were treated in 2016 (North America: 1205, Europe: 432, Asia: 223). The numbers of patients per center ranged from 1 to 206 (median: 29). Twenty-four percent of the patients were <5 years of age, and 50% <10 years. More than 30 pediatric tumor types were identified, mainly treated with curative intent: 48% were CNS, 25% extra-cranial sarcomas, 7% neuroblastoma, and 5% hematopoietic tumors. About half of the patients were treated with pencil beam scanning. Treatment patterns were broadly similar across the three continents. CONCLUSION: To our knowledge, this survey provides the first worldwide assessment of proton therapy use for pediatric cancer management. Since previous estimates in the United States and Europe, CNS tumors remain the cancer types most commonly treated with protons in 2016. However, the proportion of extra-cranial tumors is growing worldwide. The typically low numbers of patients treated in each center indicate the need for international research collaborations to assess long-term outcomes of proton therapy in pediatric patients.

Patient-reported Quality of Life After Proton Beam Therapy for Prostate Cancer: The Effect of Prostate Size.

BACKGROUND: In the present study, we assessed the effect of prostate gland size on patient-assessed genitourinary and gastrointestinal (GI) quality of life (QOL) after definitive treatment of prostate adenocarcinoma with proton beam therapy. PATIENTS AND METHODS: As a part of a prospective outcome tracking protocol, 81 patients treated at a single center between with proton beam therapy completed the Expanded Prostate Cancer Index Composite (EPIC) questionnaire before treatment and at the follow-up examinations. We reviewed the dosimetric data, reported as Vx (volume of organ receiving x Gy), and patient-reported QOL at 6 months. Genitourinary QOL was assessed using the American Urological Association symptom score and EPIC urinary domain score. GI QOL was assessed using the EPIC GI domain score. RESULTS: Larger prostate glands were associated with greater bladder V70 (P < .01) and rectal V70 (P < .01). The rectal V70 was < 15% for all patients (range, 4%-13.8%) with the planned treatment volume coverage (percentage of the prescription dose covering 95% of the volume > 95%) maintained. Patients with larger prostates did not have a greater change in their American Urological Association symptom index scores (< 30 cm3, +2.3; 30-49 cm3, +3.2; ≥ 50 cm3, 0.2; P = .06) or urinary domain score (< 30 cm3, -3.6; 30-49 cm3, -3.1; ≥ 50 cm3, +3.8; P = .76) at 6 months after treatment. Also, prostate size was not associated with a change in the EPIC GI domain score at 6 months after treatment (< 30 cm3, -3.7; 30-49 cm3, -1.1; ≥ 50 cm3, -0.55; P = .67). CONCLUSION: Definitive proton beam therapy for prostate cancer to a dose of 79.2 Gy resulted in excellent patient-reported urinary and GI QOL, independently of the baseline prostate size. This single-institution finding should be tested further in a multi-institutional study to confirm the potential limited role of androgen deprivation therapy.

Bloody Epiphora (Hemolacria) Years After Repair of Orbital Floor Fracture.

Surgical repair of orbital fractures with implants is a widely used treatment modality. While a variety of established complications are associated with this technique, most are directly understood and treated. Bloody epiphora is a finding with potentially ominous causes. The authors present a unique case of bloody epiphora, accompanied by orbital hemorrhage arising several years after orbital floor fracture repair, due to erosion of the nasolacrimal drainage system by a displaced implant combined with anticoagulation. The collection and evaluation of all protected patient health information was compliant with the regulations and conditions set forth in the Health Insurance Portability and Availability Act of 1996.

Adjuvant Proton Beam Therapy in the Management of Thymoma: A Dosimetric Comparison and Acute Toxicities.

BACKGROUND: We evaluated the dosimetric differences between proton beam therapy (PBT) and intensity modulated radiation therapy (IMRT) for resected thymoma. We simultaneously report our early clinical experience with PBT in this cohort. PATIENTS AND METHODS: We identified 4 patients with thymoma or thymic carcinoma treated at our center from 2012 to 2014 who completed adjuvant PBT to a median dose of 57.0 cobalt Gy equivalents (CGE; range, 50.4-66.6 CGE) after definitive resection. Adjuvant radiation was indicated for positive (n = 3) or close margin (n = 1). Median age was 45 (range, 32-70) years. Stages included II (n = 2), III (n = 1), and IVA (n = 1). Analogous IMRT plans were generated for each patient for comparison, and preset dosimetric endpoints were evaluated. Early toxicities were assessed according to retrospective chart review. RESULTS: Compared with IMRT, PBT was associated with lower mean doses to the lung (4.6 vs. 8.1 Gy; P = .02), esophagus (5.4 vs. 20.6 Gy; P = .003), and heart (6.0 vs. 10.4 Gy; P = .007). Percentages of lung, esophagus, and heart receiving radiation were consistently lower in the PBT plans over a wide range of radiation doses. There was no difference in mean breast dose (2.68 vs. 3.01 Gy; P = .37). Of the 4 patients treated with PBT, 3 patients experienced Grade 1 radiation dermatitis, and 1 patient experienced Grade 2 dermatitis, which resolved after treatment. With a median follow-up of 5.5 months, there were no additional Grade ≥ 2 acute or subacute toxicities, including radiation pneumonitis. CONCLUSION: PBT is clinically well tolerated after surgical resection of thymoma, and is associated with a significant reduction in dose to critical structures without compromising coverage of the target volume. Prospective evaluation and longer follow-up is needed to assess clinical outcomes and late toxicities.

Association of ocular conditions with narrow angles in different ethnicities.

PURPOSE: To quantify the predictive strength of anterior chamber area (ACA), anterior chamber volume (ACV), anterior chamber width (ACW), lens vault (LV), iris thickness (IT), and iris area (IArea) for 2 angle width parameters, trabecular-iris space area (TISA750) and angle opening distance (AOD750) at 750 µm from the scleral spur, in different ethnicities. DESIGN: Prospective, cross-sectional study. METHODS: Anterior segment optical coherence tomography images for 166 white, 90 African, 75 Hispanic, and 132 Chinese subjects were analyzed. First, ACA, ACV, ACW, LV, IT, and IArea were compared among ethnic groups. Second, associations of TISA750 and AOD750 with ACA, ACV, ACW, LV, IT, and IArea were investigated within each ethnic group using multivariable linear regression models, standardized regression coefficients (ß), and coefficients of determination (R(2)). RESULTS: Significant ethnic differences were observed in ACA, ACV, ACW, LV, IT, and IArea (all P < .05). ACA, ACV, and LV were significant predictors of TISA750 and AOD750 in all ethnic groups (all P < .001). ACW and IT were significant predictors of AOD750 in white and African subjects (all P < .05). ACW and IT were significant predictors of TISA750 in white subjects (all P < .05). IArea was a significant predictor of AOD750 in Chinese (P < .05). ACA, ACV, and LV had the highest predictive strength for both TISA750 and AOD750 in all ethnic groups based on ß and R(2). CONCLUSIONS: Despite ethnic differences in ACA, ACV, ACW, LV, IT, and IArea, the same 3 anterior segment parameters (ACA, ACV, and LV) were the strongest predictors of angle width (TISA750 and AOD750) in all 4 ethnic groups.