Melanoma endoresection: a perspective

Local Resection in Choroidal Melanoma: A Review

Surgical resection is widely used to treat small tumours located in the iris and the ciliary body, due to the accessibility of these sites. By contrast, surgical removal of choroidal tumours is substantially more challenging, which is why this procedure is performed only at specialised centres. In the present article, we review the literature on surgical resection of choroidal tumours, which can be performed as endoresection (ab interno) or transscleral resection (ab externo). An important aim of this review is to describe and compare the two approaches in terms of visual outcomes, survival rates, and complications. Both approaches are indicated for the removal of large tumours (thickness > 8 mm) with small base diameters. Surgical resection of the tumour allows clinicians to obtain valuable histopathologic and cytogenetic data from the specimen and eliminates the risks associated with radiotherapy. However, both of these surgical approaches are technically challenging procedures involving the risk of severe early and late postoperative complications.

Quantitative analysis of Gamma Knife stereotactic radiosurgery for uveal melanoma

The purpose of the study was to analyze single fraction Gamma Knife stereotactic radiosurgery (SRS) for uveal melanoma (UM). In the treatment of UMs, the dose distribution exhibited by an irregular eye surface has more calculation uncertainty. A tissue-equivalent bolus was placed on the left eye surface of a human head-shaped phantom. It was assumed that the treated eye is fixed using retrobulbar anesthesia and suture on extraocular muscles for phantom study. Leksell stereotactic frame was fixed around phantom’s head and the stereotactic computed tomography (CT) was performed. Two sets of scans were acquired (a) without bolus and (b) with a bolus of 1.0 cm thickness. These scans were transferred into a treatment planning system (TPS). The skull contouring was performed using stereotactic CT images. The target, visual pathways, and eye lens were delineated in stereotactic CT space created on TPS. A clinical relevant plan was designed on the CT study set “a” to deliver a radiation dose of 30Gy at tumor margin. The plan superimposed over CT study set “b” and compiled for convincing treatment strategy. The tumor coverage was 95% at 50% prescription isodose line. The conformity index, selectivity and the gradient index were 1.27, 0.80 and 3.28 respectively. The left optic nerve and eye lens received a maximum dose of 11.1 Gy and 11.0 Gy respectively. The treatment plan overlay showed similar planning indices and critical organ doses. The plan comparison showed: an irradiated volume received the radiation dose > 15 Gy varies < 1.0% whereas the volume received < 15 Gy were larger (> 1.0%) in the study set “b”. The distant lateral points from the target volume which describe the phantom’s eyelid showed a radiation dose of 3.2 Gy - 2.5 Gy. The doses to these points were misled and ignored in the CT study set “a”. The eye bolus provides better dosimetric information in the estimation of low dose areas which is commonly misled on TPS in SRS planning for UMs.

Endoresection with adjuvant ruthenium brachytherapy for selected uveal melanoma patients - the Tuebingen experience

PURPOSE

To evaluate the treatment of selected patients with uveal melanoma with endoresection and adjuvant ruthenium brachytherapy.

METHODS

Thirty-five patients with uveal melanoma not suitable for ruthenium plaque monotherapy were treated with endoresection and adjuvant ruthenium brachytherapy between January 2001 and October 2013. Recurrence-free survival, globe retention, course of visual acuity (VA), occurrence of therapy-related complications and metastasis-free and overall survival were analysed retrospectively.

RESULTS

Eight patients (22.9%) had a tumour recurrence after a median follow-up of 49.5 months (range: 21-134 months). Enucleation was necessary in eight patients. Thirty-two patients (91%) had a loss of VA with a median loss of nine lines (range: 0 to -39 lines); VA was stable in three patients and no patients had a gain in VA. Four patients (11.4%) developed radiation retinopathy. Metastases were detected in seven patients (20.0%) during follow-up. The occurrence of metastasis was significantly associated with monosomy 3 (p < 0.0001). Twenty-four patients (68.6%) were alive at the end of follow-up. Five patients (14.3%) died because of uveal melanoma (UM) metastasis.

CONCLUSIONS

Endoresection with adjuvant ruthenium brachytherapy is an option for selected patients with UM who cannot be treated with brachytherapy as monotherapy. About two-thirds of eyes can be retained long term without recurrences. Visual acuity cannot be maintained in most cases, and may even decrease considerably. Radiation complications are comparatively rare and not a significant problem.

Long-term outcome of primary endoresection of choroidal melanoma

BACKGROUND

Endoresection of choroidal melanoma may offer the best hope of conserving vision in some patients but is controversial because of concerns regarding iatrogenic tumour dissemination.

METHODS

Retrospective, non-randomised study of consecutive patients who underwent endoresection for choroidal melanoma at the Liverpool Ocular Oncology Centre between 1996 and 2010.

RESULTS

The study included 71 patients with a mean age of 58.7 years. The tumour extended within 2 disc diameters of the optic disc in 46 (65%) eyes, involving the disc in 24 (34%) eyes. The mean largest basal tumour diameter and tumour thickness were 9.5 mm and 4.4 mm, respectively. The median follow-up was 4.1 years. The visual acuity at the latest follow-up was better than 6/30 in 31% eyes. The main causes of visual loss were foveal excision, rhegmatogenous retinal detachment (RD) and proliferative vitreo-retinopathy (PVR). Local recurrence developed in two patients (3%), who were treated by enucleation and proton beam radiotherapy, respectively. RD occurred in 16 cases (22%). Three (4%) eyes were enucleated, two because of PVR and one because of local tumour recurrence. Five patients died of metastatic disease.

CONCLUSIONS

Endoresection achieved high rates of local tumour control. This operation would seem to be a useful alternative to radiotherapy as a means of conserving vision in eyes with juxtapapillary melanoma.

Endoresection versus iodine-125 plaque brachytherapy for the treatment of choroidal melanoma

PURPOSE

To compare the effectiveness of pars plana vitrectomy endoresection with iodine-125 brachytherapy in the treatment of choroidal melanoma.

DESIGN

A nested case-control study (1:2) from a surgical cohort.

METHODS

The study comprised 81 choroidal melanoma patients treated with either endoresection or iodine-125 brachytherapy. Twenty-seven patients who had undergone endoresection were matched according to tumor height and postequatorial tumor location with 54 cases treated with iodine-125 brachytherapy. Metastatic disease, overall survival, local tumor recurrence, visual acuity, and secondary enucleation rates were analyzed and compared between groups.

RESULTS

Metastatic spread was observed in 11 patients in the iodine-125 brachytherapy group vs only 1 patient in the endoresection group (20.4% and 3.7%, respectively, P = .053). Fourteen patients died during follow-up: 11 in the brachytherapy arm vs 3 in the endoresection arm (20.4% and 11.1%, respectively, P = .238). For the iodine-125 brachytherapy and endoresection groups, respectively, the 5-year Kaplan-Meier estimates were as follows: overall survival, 81.5% vs 89.2% (log-rank test, P = .429;); relapse-free survival, 96.6% vs 92.4% (P = .2); visual acuity retention equal or superior to 20/200, 66.4% vs 59.9% (P = .083), and eye retention, 85.7% vs 87.8% (P = .942).

CONCLUSIONS

Endoresection for choroidal melanoma is an effective treatment modality in selected cases of posterior choroidal melanomas, with outcomes similar to those obtained with iodine-125 brachytherapy.

Changing concepts in the management of choroidal melanoma

PURPOSE

To review emerging information related to changing concepts in the management of choroidal melanoma.

DESIGN AND METHODS

This perspective reviews and discusses selected studies from the past two decades that have influenced management strategies for large, medium, and small-size choroidal melanomas.

RESULTS

Large choroidal tumors continue to be managed primarily by enucleation. The large tumor trial of the Collaborative Ocular Melanoma Study (COMS) demonstrated neither a positive nor negative effect on 5- and 8-year mortality rates among more than 1000 patients whose eyes containing large choroidal melanomas were randomized to treatment between enucleation alone or enucleation preceded by external radiation. The medium-size tumor trial of the COMS randomized more than 1300 patients between iodine-125 brachytherapy and enucleation. Mortality rates following brachytherapy did not differ from mortality rates following enucleation for up to 12 years after treatment. Iodine-125 has become the most commonly used isotope for brachytherapy in North America. Ten-year follow-up of eyes treated with helium ion and 20 years of experience with proton beam confirm the relative safety and efficacy of these modalities for treatment of choroidal melanoma. Although there is a trend toward earlier treatment of small melanomas, controversy exists regarding the indications for treatment as well as the choice of specific therapy. Recurrences of melanoma after eye-sparing treatment appear to be associated with an increased rate of metastatic disease. Effective adjunctive therapy to prevent or treat melanoma metastasis is lacking.

CONCLUSIONS

Choroidal melanoma is a lethal tumor. Although evidence suggests that patients with untreated choroidal melanomas have a poorer prognosis than patients who receive treatment, our current treatments are unable to prevent tumor-related deaths for many patients. The use of preoperative external radiation as an adjunct to enucleation for large choroidal melanomas is unsupported by data from the COMS trial. The use of radiation with either brachytherapy or charged particles for the management of medium-size choroidal melanomas is well supported on the basis of long-term follow-up studies. There is a trend toward treatment of smaller choroidal melanomas. Treatment of melanomas should be directed toward minimizing the potential for recurrences as recurrent melanomas are associated with an increased rate of metastatic disease. Gains in our ability to manage choroidal melanoma will likely be modest at best until effective systemic therapies can be identified.

Late orbital recurrence of a choroidal melanoma following internal resection: report of a case and review of the literature

The management of uveal melanomas always has been a challenge to the clinicians and has evolved from the era of eye-removing surgeries to elimination of the tumor by the body's own immune system through vaccines. Evaluating the outcome of each strategy improves our understanding of the disease process and helps us to improvise on the existing modalities of treatment. Internal resection of choroidal melanomas has been described as one of the treatment modalities for this malignant tumor. Tumor recurrences reported following this surgical procedure have been uncommon. We report a rare case of a 61-year-old Caucasian woman who presented with a 2-month history of progressive, painful proptosis in her right eye. Thirteen years ago she underwent internal resection of an intraocular choroidal melanoma in the same eye and had no evidence of metastatic disease. Magnetic resonance imaging demonstrated a mass occupying the superotemporal portion of the right orbit adjacent to the globe and behind the area of prior internal resection. Biopsy of the lesion and the subsequent A right orbital exenteration confirmed the diagnosis of recurrent malignant melanoma. Twenty-four months following exenteration the patient continues to be free of metastatic disease. Since internal surgical resection was described in 1984, this is the latest known recurrence of a posterior choroidal melanoma. In this review, we highlight the clinical features of this rare case and discuss in brief the rationale of various treatment modalities for choroidal melanoma.

Thermotherapy in the management of choroidal melanoma

During the past 20 years of enucleation, which was the standard treatment for choroidal melanoma over more than a century, has largely been replaced by eye salvaging therapies such as radiotherapy or local resection. In 1995 transpupillary thermotherapy (TTT) using an infrared diode laser was introduced as a new conservative therapy for patients with choroidal melanoma. TTT can be defined as a heat treatment modality, which is delivered through a dilated pupil to the tumour surface. The technique uses a wide diode laser beam diameter with a low irradiance and a long exposure time. TTT induces tumour necrosis at sub-photocoagulation levels by a direct cell destructive effect with only a few ocular complications. TTT can be performed as sole therapy or combined with plaque radiotherapy, thus permitting a lower radiation dose. For amelanotic tumours dye-enhanced TTT with indocyanine green can be used. In this paper we review the role of sole or combined TTT, related to the current other treatment modalities for choroidal melanoma.