Iris melanomas: are they more frequent in New Zealand?

An optimized 3T MRI scan protocol to assess iris melanoma with subsequent histopathological verification - A prospective study

INTRODUCTION

Magnetic resonance imaging (MRI) has demonstrated high levels of tissue contrast, accuracy and reproducibility in evaluating posterior uveal melanoma. Owing to smaller size, the role of MRI in detecting and characterising iris melanoma has not yet been explored.

AIMS

To develop a protocol to image iris melanoma and describe the MRI characteristics of histopathological-confirmed iris melanoma.

MATERIALS AND METHODS

An optimised MRI protocol, using a 3T MRI scanner and a 32-channel head coil, was developed to image iris tumours. A prospective, single-centre, 12-month study was conducted on all patients with lesions suspicious for iris melanoma. All patients were offered an MRI scan in addition to the standardised clinical procedures. Image quality comparison was made with existing clinical investigations. Iris melanoma characteristics on MRI are described.

RESULTS

A successful optimised MRI scan protocol was developed that was able to detect and characterise iris melanoma. One normal participant and five patients with subsequent histopathological-confirmed iris melanoma (n = 6) were recruited. Four patients completed the full MRI sequence. All iris melanoma were detected on at least one T1- or T2-weighted images. When compared to the vitreous, all iris melanomas demonstrated hyper-intensity on T1-weighted images and hypo-intensity on T2-weighted images. On T1-mapping, T1-values of iris melanoma demonstrated an inverse relationship with the degree of tumour pigmentation.

CONCLUSIONS

This study highlights an optimised, easily reproducible MRI scan protocol to image iris melanoma. Numerous MR imaging characteristics of iris melanoma are reported for the first time and a potential non-invasive tumour biomarker is described.

Iris melanoma: Review of clinical features, risks, management, and outcomes

Primary uveal melanoma is rare and affects approximately 8,000 persons per year worldwide. This malignancy can involve the iris, ciliary body, and choroid. Of these three structures, the iris is the least commonly affected site, representing only 4% of all uveal melanomas. Iris melanoma can arise from iris melanocytic nevus, iris melanocytosis, or de novo. In a longitudinal study of 1,611 patients with iris nevus, transformation into melanoma, using Kaplan-Meier estimates, was found in 2.6% by five years and in 4.1% by 10 years. The factors that predicted growth of iris melanocytic nevus into melanoma are denoted by a letter (ABCDEF) guide: A for age ≤40 years old at presentation (hazard ratio [HR] = 3, P = .01), B for blood (hyphema) (HR = 9, P < .0004), C for clock hour of tumor inferiorly (tumor location) (HR = 9, P = .03), D for diffuse flat tumor configuration (HR = 14, P = .02), E for ectropion uveae (HR = 4, P = .002), and F for feathery ill-defined margins (HR = 3, P = .02). At diagnosis, iris melanoma has a mean cross-sectional diameter of 5.5 mm and thickness of 2.1 mm, often with tumor seeding (28%) and secondary glaucoma (35%). We provide a comprehensive review of iris nevus and melanoma to explore relevant demographic and clinical data, risk factors for tumor growth, management, and prognosis, with the hope that clinicians will be more comfortable in understanding this rare malignant condition.

The Burden of Histologically Confirmed Uveal Melanoma in Aotearoa-New Zealand: A 21-year Review of the National Cancer Registry

PURPOSE

The burden of uveal melanoma (UM) in Aotearoa-New Zealand (NZ), a country with the highest global burden of cutaneous melanoma, is unknown. This first, large-scale study of UM in NZ investigates survival and risks of mortality in histologically confirmed UM.

METHODS

Deidentified epidemiological data on histologically confirmed UM between January 1, 2000, and December 31, 2020, were extracted from the NZ Cancer Registry. The main outcome measures were patient demographics, tumor characteristics, all-cause versus disease-specific survival, and risks of mortality.

RESULTS

Histologically confirmed UM constituted 1.5% (n=703) of all-body site melanomas in NZ (n=47,997). UM predominantly affected Europeans (95%), followed by NZ indigenous Māori (4%), Asians (<1%), and Pacific Peoples (<1%), with no eye or sex predilection. Three hundred eighteen (45%) were deceased at follow-up. Of the deceased, 50% died from UM. The 1-, 5-, and 10-year survival from all-cause mortality was 94%, 68%, and 51%, and disease-specific survival was 97%, 79%, and 71%, respectively. Increasing age at UM diagnosis (>60 y), UM arising from nonspecified sites, and mixed cell UM were associated with an increased risk of disease-specific mortality. No difference in disease-specific mortality was found between sex and ethnicity on multivariate and competing risks analysis.

CONCLUSIONS

Despite the government-funded public eye care and increasing research and awareness on UM globally, the burden of UM in the 21st century in NZ remains comparable to global studies. We continue to observe an earlier presentation of UM in non-European cohorts, particularly in our Māori population, and further studies on UM in NZ are warranted.

Iris melanocytic tumours in New Zealand/Aotearoa: presentation, management and outcome in a high UV exposure environment

BACKGROUND/OBJECTIVES

Iris melanoma, a rare intraocular malignancy, represents the smallest subgroup of uveal melanoma. This first, comprehensive study of iris melanocytic lesions in the high ultraviolet environment in New Zealand/ Aotearoa (NZ) examines diagnosis, management and outcomes.

SUBJECTS/METHODS

Retrospective study of iris melanocytic tumours referred to tertiary referral centres in Auckland, NZ, over 20 years (1999-2018). Data analysed include demographics, tumour characteristics, histology, genetic analyses, treatment modalities, recurrence, metastasis, 5-year and overall survival.

RESULTS

Cohort (N = 51) was predominantly NZ European (98.0%) with no indigenous Māori, or Pasifika. Median age at presentation was 58 years. Tumours involved a median of two clock hours of iris. The posterior tumour margin extended to the anterior chamber angle in 22 patients (45.8%). Management included initial observation 54.9%, iridectomy/excision biopsy 29.4%, irido-cyclectomy 7.8%, plaque radiotherapy 7.8%, proton beam radiotherapy 7.8%, and ultimately enucleation 17.6%. Histology was performed in 19 cases (37%) with 16 confirmed melanomas (84%). Mean follow-up 4.2 years with median visual acuity of 6/7.5 two years post intervention. Melanoma-related metastasis and mortality occurred in two cases with five-year melanoma-related mortality of 2.0%.

CONCLUSION

In a climate with high ultraviolet exposure iris melanocytic tumours occurred almost exclusively in NZ Europeans, however, the majority of cases were category T1, possibly reflecting early diagnosis in the NZ health system. Nonetheless, >50% underwent surgery or radiotherapy, often utilising more than one modality. A high index of suspicion and early referral of iris melanocytic lesions should be considered in regions with high UV exposure.

Topography and clinical features of iris melanoma

Background

To characterise the topographical and clinical features of primary iris melanoma and to visualise the patterns of tumour extent in the iris.

Methods

Clinical characteristics of iris melanomas were analysed, and data on their size, shape, and location were converted into a database of two-dimensional iris charts by means of computer-drawing software. The geometric centre of each tumour was entered into corresponding sectors of the chart. The extent of the melanomas was computationally visualised by merging the iris drawings and displaying the number of overlapping tumours on colour-coded iris maps.

Results

Twenty-nine patients (18 females and 11 males) with a mean age of 52 years met the inclusion criteria. The mean largest tumour diameter was 6.1 mm (range, 1.8–11.0 mm). Five tumours (17%) involved the pupillary margin, 10 (34%) involved the iris root, and 10 (34%) involved both sites. The hemispheric location of the tumour centroid was superior in 3 eyes (11%) and inferior in 25 (89%) (p < 0.0001), and the distribution between the temporal and nasal hemispheres was 17 (61%) and 11 (39%), respectively (p = 0.26). In females, the iris melanomas were located more temporally (p  =  0.02) and had more often originated from a pre-existing naevus (p = 0.03), than in males. There was also shift towards more temporally located melanomas in younger patients.

Conclusions

The lower temporal iris quadrant is the preferential area of melanoma occurrence and growth. Iris melanoma tends to be more temporally located in females, who compared with males also have a higher proportion of melanomas arising from a pre-existing naevus.

Iris Melanoma: Management and Prognosis

Iris melanomas represent 2–5% of uveal melanomas. Iris melanomas vary in their size, shape, degree of pigmentation and clinical behavior. The main local clinical complications of iris melanomas are tumor vascularization, ectropion uvea, pupillary distortion, pigment dispersion, sector cataract, chronic uveitis, hyphema and glaucoma with irreversible optic nerve damage. The most effective treatment for iris nevus and melanoma remains debatable; treatment modalities have been proposed depending on the local status as well as the age and general condition of the patient. A melanocytic iris nevus is usually observed until documented progression is identified. In this case, radiotherapy or surgical resection is generally performed. Cataract, glaucoma and limbal stem cell deficiency are usually secondary to radiotherapy, while incomplete tumor excisions, which could lead to recurrence, hemorrhage, vitreous loss, dislocated lens, iridocyclitis, macular edema, retinal detachment, glaucoma and cataract, are related to surgical resection. In some cases, a combination of radiotherapy and surgery is used. Conservative treatment is an efficient alternative to enucleation and allows good local tumor control.

Uveal melanoma: progress in molecular biology and therapeutics

Uveal melanoma (UM) is the most common intraocular malignancy in adults. So far, no systemic therapy or standard treatment exists to reduce the risk of metastasis and improve overall survival of patients. With the increased knowledge regarding the molecular pathways that underlie the oncogenesis of UM, it is expected that novel therapeutic approaches will be available to conquer this disease. This review provides a summary of the current knowledge of, and progress made in understanding, the pathogenesis, genetic mutations, epigenetics, and immunology of UM. With the advent of the omics era, multi-dimensional big data are publicly available, providing an innovation platform to develop effective targeted and personalized therapeutics for UM patients. Indeed, recently, a great number of therapies have been reported specifically for UM caused by oncogenic mutations, as well as other etiologies. In this review, special attention is directed to advancements in targeted therapies. In particular, we discuss the possibilities of targeting: GNAQ/GNA11, PLCβ, and CYSLTR2 mutants; regulators of G-protein signaling; the secondary messenger adenosine diphosphate (ADP)-ribosylation factor 6 (ARF6); downstream pathways, such as those involving mitogen-activated protein kinase/MEK/extracellular signal-related kinase, protein kinase C (PKC), phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (mTOR), Trio/Rho/Rac/Yes-associated protein, and inactivated BAP1; and immune-checkpoint proteins cytotoxic T-lymphocyte antigen 4 and programmed cell-death protein 1/programmed cell-death ligand 1. Furthermore, we conducted a survey of completed and ongoing clinical trials applying targeted and immune therapies for UM. Although drug combination therapy based on the signaling pathways involved in UM has made great progress, targeted therapy is still an unmet medical need.

Uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UMs are usually initiated by a mutation in GNAQ or GNA11, unlike cutaneous melanomas, which usually harbour a BRAF or NRAS mutation. The annual incidence in Europe and the USA is ~6 per million population per year. Risk factors include fair skin, light-coloured eyes, congenital ocular melanocytosis, ocular melanocytoma and the BAP1-tumour predisposition syndrome. Ocular treatment aims at preserving the eye and useful vision and, if possible, preventing metastases. Enucleation has largely been superseded by various forms of radiotherapy, phototherapy and local tumour resection, often administered in combination. Ocular outcomes are best with small tumours not extending close to the optic disc and/or fovea. Almost 50% of patients develop metastatic disease, which usually involves the liver, and is usually fatal within 1 year. Although UM metastases are less responsive than cutaneous melanoma to chemotherapy or immune checkpoint inhibitors, encouraging results have been reported with partial hepatectomy for solitary metastases, with percutaneous hepatic perfusion with melphalan or with tebentafusp. Better insight into tumour immunology and metabolism may lead to new treatments.

Iris nevus growth into melanoma: analysis of 1611 consecutive eyes: the ABCDEF guide

PURPOSE

To determine clinical features predictive of growth of iris nevus into melanoma.

DESIGN

Retrospective, comparative case series.

PARTICIPANTS

A total of 1611 consecutive patients referred to an ocular oncology center with iris nevus.

INTERVENTION

Observation and photographic documentation.

MAIN OUTCOME MEASURES

Growth into melanoma.

RESULTS

The mean age at referral for iris nevus was 51 years (median, 54; range, <1-94 years). At presentation, the mean tumor basal diameter was 3 mm (median, 3 mm; range, <1-12 mm) and mean tumor thickness was 0.8 mm (median, 0.5 mm; range, 0-5 mm). All patients were initially diagnosed with benign iris nevus. Growth of iris nevus to melanoma was confirmed in 2% of eyes (n = 27) over a mean follow-up of 68 months (median, 46 months; range, 3-465 months). By Kaplan-Meier estimates, iris nevus growth to melanoma occurred in <1%, 3%, 4%, 8%, and 11% at 1, 5, 10, 15, and 20 years, respectively. Factors predictive of iris nevus growth to melanoma by multivariable analysis included age ≤ 40 years at presentation (hazard ratio [HR], 3), episode of hyphema (HR, 9), 4:00 to 9:00 clock hour location of tumor (HR, 9), diffuse tumor (involving entire iris surface) (HR, 14), ectropion uveae (HR, 4), and feathery tumor margins (HR, 3). Additional important factors by univariable analysis included tumor seeding on the iris or in the anterior chamber angle, feeder vessels, and nodule formation. These factors can be remembered using the mnemonic ABCDEF, representing A = age young, B = blood, C = clock hour inferior, D = diffuse, E = ectropion, and F = feathery margin.

CONCLUSIONS

In an analysis of 1611 cases of iris nevus referred for evaluation at an ocular oncology center, growth into melanoma occurred in 8% by 15 years. Risk factors for growth, identified by ABCDEF included Age young, Blood (hyphema), Clock hour inferior, Diffuse configuration, Ectropion uveae, and Feathery tumor margin.

Iris melanoma: features and prognosis in 317 children and adults

PURPOSE

To evaluate iris melanoma in children versus adults.

METHODS

Retrospective, nonrandomized clinical case series including all patients with a clinical diagnosis of iris melanoma managed at the Ocular Oncology Service at Wills Eye Institute over 40 years. Patients were divided into three age categories based on age at presentation: children (≤ 20 years), mid-adults (21-60 years), and older adults (>60 years). The clinical features, treatments, and outcomes were statistically analyzed based on patient age at presentation. The main outcome measures were melanoma features and related metastasis and death.

RESULTS

Of 8,101 eyes with uveal melanoma, there were 317 (4%) with iris melanoma, including 24 (8%) children (≤ 20 years), 187 (59%) mid-adults (21-60 years), and 106 (33%) older adults (>60 years). There was no age-related difference in race, sex, tumor quadrant, thickness, pigmentation, associated corectopia, ectropion uveae, hyphema, or extraocular extension. Significant age-related differences were found with mean tumor basal diameter, tapioca appearance, mean intraocular pressure, secondary glaucoma, tumor seeding in angle, and mean number of clock hours of angle seeding. Multivariate analysis of factors predictive of metastasis included extraocular extension and high intraocular pressure. Factors predictive of death included increased tumor thickness and high intraocular pressure. There was no difference in metastasis or death by age group.

CONCLUSIONS

Iris melanoma shows significant clinical differences in children versus adults, with smaller tumor size, less tumor seeding in angle, and lower incidence of secondary glaucoma. There was no significant difference in metastasis or death by age group.

Uveal and Conjunctival Malignant Melanoma in Denmark, 1943–97: Incidence and Validation Study

PURPOSE

To study the incidence of malignant melanoma in the ocular region in Denmark during the period 1943-97.

METHODS

The patients were mainly identified through the Danish Cancer Registry. Age-period-cohort modelling of the incidence rates was done based on age at diagnosis, calendar period and birth cohort in 5-year groups and for each gender.

RESULTS

The age-standardized incidence of malignant melanoma in the ocular region was 0.78 for men (N = 1327) and 0.65 for women (N = 1242) per 100,000 person-years. Calendar period and birth cohort had no effect on the incidence in the ocular region or in the topography subgroups choroid/ciliary body and conjunctiva. However, the incidence increased with birth cohort for iris melanomas.

CONCLUSIONS

The incidence of malignant melanoma in the ocular region was stable in contrast to a major increase in cutaneous melanoma in Denmark during the period 1943-97. The incidence of iris melanomas increased substantially, whereas the rate was stable for choroid/ciliary body and conjunctival melanomas.

Iris melanoma: a case report and review

Iris melanoma is a rare ocular tumour, which can be detected early in its development. This tumour is almost always unilateral and arises usually from a pre-existing naevus. Failure to detect it may be associated with morbid ocular and systemic complications, yet there are successful therapies to treat this condition, if detected early. The patient presented to the eye clinic with symptoms of occasional, brief loss of vision in his left eye for a few weeks prior to his visit. Slit-lamp examination revealed a mass on the inferior part of the iris of the left eye. Intra-ocular pressure measurements were RE 15 mmHg and LE 38 mmHg. It was found that a tumour had spread throughout the iris stroma and invaded the anterior chamber angle. Although enucleation would have been the treatment of choice in the past, the trend today in the treatment of a growing, large circumscribed iris tumour is to excise it. It was successfully excised by irido-cyclo-trabeculectomy.

Sunlight exposure and pathogenesis of uveal melanoma

Uveal melanoma is the most frequent primary malignant intraocular tumor of adults. Among various non-modifiable risk factors, Caucasian race seems to be the most significant with light skin color, blond hair, and blue eyes being specific risk factors. The racial predisposition to uveal melanoma have been explained on the basis of susceptibility of Caucasian race to oncogenic effects of sunlight. Although there is ample evidence in support of this hypothesis in regard to skin melanoma, the evidence in regard to uveal melanoma is insufficient and contradictory. In the following review, we examine physiologic, epidemiological, and genetic data in order to determine the role of sunlight exposure in the pathogenesis of uveal melanoma.

Iris melanoma: pathology, prognosis and surgical intervention

A case of an iris melanoma in a 58-year-old woman is described. The clinical and pathological findings are discussed, highlighting the correlations between histopathology and prognosis for iris melanoma, which differ markedly from choroidal melanoma. The mixed cellular pathology of this iris melanoma (containing both spindle B cells and epithelioid cells) carries a higher metastatic rate than tumours composed exclusively of either. This contrasts with choroidal melanoma, where the presence of epithelioid cells is the strongest pathological marker for a poor prognosis. The ocular outcome that can be achieved with local surgical excision of a well-delineated iris melanoma that does not involve the angle is discussed.