Non-Cancer Effects following Ionizing Irradiation Involving the Eye and Orbit

Prospective Study of Corneal Sensitivity in Patients Treated With Proton Therapy for Extraocular Tumors

INTRODUCTION

Several cases of radio-induced neurotrophic keratitis had been observed after proton therapy delivering a mean corneal dose of ≥50 GyRBE. We conducted a prospective exploratory study to assess corneal sensitivity in subsequent patients undergoing proton therapy for cephalic extraocular tumors.

MATERIAL AND METHODS

Forty-three patients (85 eyes) treated with high-energy proton therapy were included in this prospective, single-center, observational cohort study. All patients had their corneal sensitivity measured using Cochet-Bonnet esthesiometer, before and average 6 months after irradiation. Ocular surface was clinically assessed for stromal opacity, corneal thinning, corneal perforation, superficial punctate keratitis graded according to Oxford classification, and tear break-up time. Cornea and extraocular sensitive innervation structures of cornea were contoured and their dose metrics assessed.

RESULTS

No severe corneal damage was detected. Corneal sensitivity, superficial punctate keratitis according to Oxford classification, and tear break-up time did not vary significantly after irradiation. The mean value of maximal dose to cornea and extraocular sensory innervation of cornea were 10.7 GyRBE and 42.0 GyRBE, respectively. Doses to cornea and its innervation structures were not associated with significant changes in corneal sensitivity (P = 0.423 and P = 0.614). A dose per fraction greater than 2 GyRBE was significantly associated (P = 0.033) with a decrease of corneal sensitivity after proton therapy.

CONCLUSIONS

This pilot study showed no excess risk of damage to corneal sensitivity 6 months after proton therapy, as doses to the cornea could be minimized. However, based on prior neurotrophic keratitis cases for corneal doses above 50 GyRBE, further investigation is needed to establish the impact of high-dose proton therapy on corneal sensitivity.

Optimizing early phase clinical trial washout periods: a report from the Therapeutic Advances in Childhood Leukemia and Lymphoma consortium

BACKGROUND

The National Cancer Institute (NCI) issued a 2021 memorandum adopting the American Society of Clinical Oncology (ASCO) and Friends of Cancer Research (Friends) task force recommendations to broaden clinical study eligibility criteria. They recommended that washout periods be eliminated for most prior cancer therapy and when required to utilize evidence- and/or rationale-based criteria. The Therapeutic Advances in Childhood Leukemia and Lymphoma (TACL) consortium responded to this guidance.

METHODS

A TACL task force reviewed the consortium's research portfolio, the relevant literature and guidance documents from ASCO-Friends, NCI, and US Food and Drug Administration to make expert consensus and evidence-based recommendations for modernizing, broadening, and codifying TACL-study washout periods while ensuring consistency with pediatric ethics, and federal regulations. TACL's screening log was reviewed to estimate the impact that updated washout periods would have on patient inclusivity and recruitment.

RESULTS

Over a 19-year period, 42 (14.6% of all screened ineligible patients [n = 287]) patients were identified as excluded from TACL early phase studies exclusively because of not meeting washout criteria. An additional 6 (2.1%) did not meet washout and at least 1 other exclusion criterion. A new TACL washout guidance document was developed and then adopted for use. Where washout criteria were not eliminated, rationale- and/or evidenced-based criteria were established with citation.

CONCLUSION

In an effort to reduce unnecessary exclusion from clinical trials, TACL created rationale- and/or evidenced-based washout period standards largely following guidance from the NCI and ASCO-Friends recommendations. These new, expanded eligibility criteria are expected to increase access to TACL clinical trials while maintaining safety and scientific excellence.

Prospective assessment of peripapillary microvasculature using optical coherence tomography angiography in para-optic intracranial and sinonasal tumors treated with proton therapy

PURPOSE

Radiation-induced optic neuropathy (RION) is rare but may lead to blindness. The mechanisms by which this occurs include endothelial and neuronal damage, but RION has been assessed very little in the case of extraocular tumors treated with high-energy proton therapy, the use of which is expanding worldwide. We assessed peripapillary microvascular changes by optical coherence tomography angiography (OCT-A) in patients undergoing high-energy proton therapy for para-optic intracranial or head and neck tumors.

MATERIALS AND METHODS

In this prospective institutional review board approved study, patients receiving>40Gy_RBE maximal PBT dose to their optic nerve between 2018 and 2020 underwent quantitative OCT-A analyses. ImageJ software was used to assess changes in the peripapillary superficial vascular complex (SVC) using vascular area density (VAD), vessel length density (VLD) and fractal dimension (FDsk). Uni- and multivariate analyses were performed.

RESULTS

Of 47 patients (78 eyes) with 29±6 months of follow-up (range 18-42), 29 patients (61.7%) had previously undergone surgery and 18 (32.1%) had microvascular abnormalities prior to proton therapy. Total radiotherapy dose was the most relevant factor in decreased peripapillary microvasculature. Duration of follow-up was associated with lower VAD (P=0.005) and mean retinal nerve fiber layer (RNFLm) thickness also decreased. There was no significant correlation between OCT-A changes and mean visual defect.

CONCLUSION

Peripapillary microvasculature changes may occur from tumor compression or surgery and proton therapy for extraocular tumors. OCT-A may provide quantitative and mechanistic insights into RION before the occurrence of clinical symptoms.

Dexamethasone Implant under a Proactive Treatment Regimen in a Clinical Setting: The ProDEX Study

PURPOSE

To assess the effectiveness of switching intravitreal dexamethasone implants (DEX-implant) from pro re nata (PRN) treatment regimen to a proactive regimen in patients with macular edema of diverse etiologies.

DESIGN

An observational, retrospective, uncontrolled, multicenter, national case series.

PARTICIPANTS

Eighty-one eyes from 68 patients treated between October 2015 and June 2023 were included.

METHODS

This study included consecutive eyes treated with DEX-implant who were switched from a PRN regimen to a proactive regimen for diabetic macular edema (DME), retinal vein occlusion (RVO), noninfectious uveitis macular edema (UME; including postsurgical macular edema), and radiation maculopathy (RM).

MAIN OUTCOME MEASURES

The main outcome measures were change in the best-corrected visual acuity (BCVA), central macular thickness (CMT), and intraocular pressure (IOP) at each visit.

RESULTS

According to the etiology, DME represented 49.4% of eyes, UME 24.3%, RVO 21.0%, and RM 6.2%. The mean (standard deviation [SD]) duration of follow-up under the PRN and proactive regimens was 20.6 (13.3) and 14.2 (10.3) months, respectively. Switching from a PRN to a proactive regimen significantly improved mean (SD) BCVA by 3.7 (12.9) ETDRS letters (P = 0.01) with a mean (SD) decrease in CMT of 108.0 (151.4) μm (P < 0.001). The proportion of visits with significant anatomic recurrence (> 50 μm) also decreased from 40.1% to 6.0% after switching to a proactive regimen (P < 0.001). The number of DEX-implant injections significantly increased during the proactive treatment period (P < 0.001), but the change in the number of visits was not significantly different (P = 0.2). The proactive treatment period was not associated with a significant increase in IOP (P = 0.6).

CONCLUSIONS

Switching to a proactive regimen in patients already treated with DEX-implant seems to significantly improve BCVA and CMT while maintaining stable IOP.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Assessment of gaze direction during head and neck irradiation and dosimetric impact on the retina, macula and papilla in a cohort of 240 patients with paraoptic tumors

In a prospective cohort of 240 paraoptic tumors patients treated with protons, there was 10° inter-individual gaze angle variability (up to 30°). In a random 21-patient subset with initial CTs versus and adaptive CTs, 6 (28.57 %) patients had at least twice a 10°-difference in their gaze angle, with > 5 Gy difference on the retina/macula or papilla in 2/21 (9.52 %) and 1/21 (4.76 %) based on cumulative dose from rescans, respectively.

Comparison of stereotactic radiotherapy and protons for uveal melanoma patients

Background and purpose

Uveal melanoma (UM) is the most common primary ocular malignancy. We compared fractionated stereotactic radiotherapy (SRT) with proton therapy, including toxicity risks for UM patients.

Materials and methods

For a total of 66 UM patients from a single center, SRT dose distributions were compared to protons using the same planning CT. Fourteen dose-volume parameters were compared in 2-Gy equivalent dose per fraction (EQD2). Four toxicity profiles were evaluated: maculopathy, optic-neuropathy, visual acuity impairment (Profile I); neovascular glaucoma (Profile II); radiation-induced retinopathy (Profile III); and dry-eye syndrome (Profile IV). For Profile III, retina Mercator maps were generated to visualize the geographical location of dose differences.

Results

In 9/66 cases, (14 %) proton plans were superior for all dose-volume parameters. Higher T stages benefited more from protons in Profile I, especially tumors located within 3 mm or less from the optic nerve. In Profile II, only 9/66 cases resulted in a better proton plan. In Profile III, better retina volume sparing was always achievable with protons, with a larger gain for T3 tumors. In Profile IV, protons always reduced the risk of toxicity with a median RBE-weighted EQD2 reduction of 15.3 Gy.

Conclusions

This study reports the first side-by-side imaging-based planning comparison between protons and SRT for UM patients. Globally, while protons appear almost always better regarding the risk of optic-neuropathy, retinopathy and dry-eye syndrome, for other toxicity like neovascular glaucoma, a plan comparison is warranted. Choice would depend on the prioritization of risks.

Radiation effects on retinal layers revealed by OCT, OCT-A, and perimetry as a function of dose and time from treatment

Optical coherence tomography (OCT) has become a key method for diagnosing and staging radiation retinopathy, based mainly on the presence of fluid in the central macula. A robust retinal layer segmentation method is required for identification of the specific layers involved in radiation-induced pathology in individual eyes over time, in order to determine damage driven by radiation injury to the microvessels and to the inner retinal neurons. Here, we utilized OCT, OCT-angiography, visual field testing, and patient-specific dosimetry models to analyze abnormal retinal layer thickening and thinning relative to microvessel density, visual function, radiation dose, and time from radiotherapy in a cross-sectional cohort of uveal melanoma patients treated with 125I-plaque brachytherapy. Within the first 24 months of radiotherapy, we show differential thickening and thinning of the two inner retinal layers, suggestive of microvessel leakage and neurodegeneration, mostly favoring thickening. Four out of 13 eyes showed decreased inner retinal capillary density associated with a corresponding normal inner retinal thickness, indicating early microvascular pathology. Two eyes showed the opposite: significant inner retinal layer thinning and normal capillary density, indicating early neuronal damage preceding a decrease in capillary density. At later time points, inner retinal thinning becomes the dominant pathology and correlates significantly with decreased vascularity, vision loss, and dose to the optic nerve. Stable multiple retinal layer segmentation provided by 3D graph-based methods aids in assessing the microvascular and neuronal response to radiation, information needed to target therapeutics for radiation retinopathy and vision loss.

[High energy proton therapy for extraocular tumors, neurotrophic keratitis and functional consequence: A series of 3 cases]

INTRODUCTION

High energy proton therapy (HEP) is a form of radiation therapy using protons for extraocular tumors. Its ballistic properties are theoretically advantageous, but the real impact on the surrounding ocular tissues during cerebral and ENT irradiation is poorly documented. We describe three consecutive patients with corneal damage following such irradiation.

MATERIALS/METHODS

Post-proton therapy neurotrophic keratitis (NK) is defined as corneal hypo/anesthesia responsible for an alteration of corneal trophicity and graded according to the Mackie classification, in terms of a prospective ophthalmological follow-up protocol for all patients with extraocular tumors treated with HEP.

RESULTS

Among 193 patients treated with HEP between 2018 and 2021 for extraocular tumors, three patients developed severe neurotrophic keratitis, i.e. 1.6% of treated patients. According to the Mackie classification, the three patients showed grade 3 NK less than one year after the conclusion of their HEP. These three patients underwent amniotic membrane grafting. They were placed on autologous serum eye drops. Two of the three patients had to be eviscerated. The dose to the cornea was greater than 50 Gray (Gy)_Relative biological effectiveness (RBE) in the three cases.

DISCUSSION

The diagnosis and etiological origin of neurotrophic keratitis are often difficult to establish. In these cases, the imputability of radiation therapy, proton therapy in our cases, in the development of neurotrophic keratitis was plausible based on the dosimetry of the patients, all of whom had anterior tumors with a poor prognosis requiring high tumoricidal doses.

CONCLUSION

Further studies to establish the impact of proton therapy on corneal sensitivity are necessary. However, this feedback and the multidisciplinary management of tumors can help to limit the risk of some complications of radiation therapy. Early diagnosis allows for appropriate management and could possibly minimize the anatomical and functional ocular complications of neurotrophic keratitis.

Need for a Dedicated Ophthalmic Malignancy Clinico-Biological Biobank: The Nice Ocular MAlignancy (NOMA) Biobank

Ophthalmic malignancies include various rare neoplasms involving the conjunctiva, the uvea, or the periocular area. These tumors are characterized by their scarcity as well as their histological, and sometimes genetic, diversity. Uveal melanoma (UM) is the most common primary intraocular malignancy. UM raises three main challenges highlighting the specificity of ophthalmic malignancies. First, UM is a very rare malignancy with an estimated incidence of 6 cases per million inhabitants. Second, tissue biopsy is not routinely recommended due to the risk of extraocular dissemination. Third, UM is an aggressive cancer because it is estimated that about 50% of patients will experience metastatic spread without any curative treatment available at this stage. These challenges better explain the two main objectives in the creation of a dedicated UM biobank. First, collecting UM samples is essential due to tissue scarcity. Second, large-scale translational research programs based on stored human samples will help to better determine UM pathogenesis with the aim of identifying new biomarkers, allowing for early diagnosis and new targeted treatment modalities. Other periocular malignancies, such as conjunctival melanomas or orbital malignancies, also raise specific concerns. In this context, the number of biobanks worldwide dedicated to ocular malignancies is very limited. The aims of this article were (i) to describe the specific challenges raised by a dedicated ocular malignancy biobank, (ii) to report our experience in setting up such a biobank, and (iii) to discuss future perspectives in this field.

Melphalan intra-arterial chemotherapy for choroidal melanoma chemoreduction

Background

Intra-arterial chemotherapy (IAC) has been used to treat multiple cancers including liver metastasis from uveal and cutaneous melanoma but not as primary tumor treatment. We report the compassionate use of chemoreduction with intra-arterial melphalan before ruthenium brachytherapy to salvage an eye with choroidal melanoma.

Case presentation

A 61-year-old female patient complained of decreased vision and central-temporal scotoma in OS (left eye) for 1 month. Visual acuity was 20/20 in right eye (OD) and 20/125 OS. Anterior segment examination and intraocular pressure were unremarkable in both eyes, as was fundus examination of the OD. Fundus examination of OS revealed a brown, solid tumor partially obscuring the temporal optic disc margin and extending to the equatorial fundus midzone. Serous retinal detachment was present over the lesion and around it. Ultrasonography revealed a solid choroidal tumor with a largest basal diameter (LBD) of 13.0 mm and thickness of 10.4 mm. The tumor presented acoustic hollowness and a superimposing retinal detachment. After metastatic screening was negative, the patient underwent intra-arterial chemotherapy with melphalan. Three weeks later, her visual acuity was 20/200 and there was noticeable tumor regression to 11.9 mm (LBD) by 7.9 mm (thickness) allowing brachytherapy to be performed. Ten weeks after brachytherapy (13 weeks after IAC), visual acuity was HM due to biopsy-related vitreous hemorrhage (VH). Tumor dimensions were 9.9 (LBD) mm and 6.5 mm (thickness) and PPV was performed to remove VH. Six weeks after PPV (20 weeks after IAC), her visual acuity was 20/200 and further reduction of tumor dimensions was observed: largest basal diameter was 8.9 mm and thickness was 4.9 mm.

Conclusion

This case illustrates the feasibility of combining induction IAC prior to ruthenium brachytherapy for large choroidal melanoma. More studies are warranted to confirm these early preliminary findings.