Melanoma
Figure 4: Radioactive Plaque Brachytherapy (Top) Versus Proton Beam Teletherapy (Bottom)
A B
Local Resection Techniques Endoresection
C D
Surgery is performed with a vitrector through a retinotomy or beneath a retinal flap. An air–fluid exchange drains residual subretinal fluid; endolaser photocoagulation is used to destroy any residual intrascleral tumor and to achieve retinopexy. Silicone oil is typically required. Theory suggests that endoresection reduces tumor-related ocular morbidity but adds the risk of vitreoretinal complications (silicone oil removal, secondary rhegmatogenous retinal detachment, intraocular hemorrhage) and tumor dissemination.56
Endoresection comprises the removal of a posteriorly located uveal melanoma through a pars plana vitrectomy, typically after radiation therapy.55
Trans-scleral Tumor Resection
Trans-scleral tumor resection (TSR) can be lamellar or full thickness. The more widely used partial thickness technique involves the preparation of a lamellar scleral flap, ocular decompression by limited pars plana vitrectomy, resection of the tumor together with the deep scleral lamella, suturing of the scleral flap, and intraocular injection of balanced salt solution. Due to initially high tumor regrowth rates, adjunctive radiotherapy has been added before or after TSR.57
A: An intra-operative photograph shows surgical placement of an ophthalmic plaque; B: A graphic demonstration of the relative dose distribution of an I-125 plaque; C: A photograph of a patient receiving proton beam radiation; D: A graphic demonstration of the relative dose distribution of transocular proton beam radiation. Note that the tantalum clips have been surgically placed, now the patient requires head immobilization, and a video camera is used to monitor eye movements.
The Treatment of Choroidal Melanoma Treatment
CM treatment is performed to prevent metastatic disease, to maximize visual acuity, and to preserve the eye. With these goals in mind, there has been an evolution of treatment from primary enucleation and local resection to laser photocoagulation and radiation therapy. At this time, radiation therapy is the most widely accepted alternative to enucleation.49
Enucleation
In most developed countries, enucleation surgery is performed when the CM is considered to be too large for vision-sparing techniques, for extensive extrascleral tumor extension, and for neovascular glaucoma.50 Alternatively, in undeveloped countries eye- and vision-sparing radiation techniques may not be available. The COMS large tumor trial found that 20 Gy (4 Gy per day x five 5 days) did not improve survival after enucleation surgery.51
Hypothesis (that we disseminated metastasis by manipulation during enucleation surgery) was incorrect.52
It is important to note that orbital
tumor recurrence was reported in less than 1 % of cases. If this occurs, it can be treated by local resection of all visible tumor, followed by 50 Gy external beam radiotherapy.53
At The New York Eye Cancer Center, most patients can be fitted with an ocular prosthesis that requires minimal maintenance and has excellent cosmesis.54
Prosthetic ocular motility is typically less than
the natural eye and mucus discharge is common. Patients should be counseled to wear unbreakable polycarbonate glasses to protect the remaining eye.
66
TSR can be considered a relatively high-risk alternative to enucleation of eyes with very large anteriorly placed CM.
Transpupillary Thermotherapy
In the 1950s, Dr Meyer-Schwickerath attempted primary treatment of CM with the xenon-arc laser.61
Since that time others have used argon,
krypton, dye, and, most recently, the infrared spectrum. To date, no laser method has produced acceptable local control, but has added risks including hemorrhage, retinal detachment, edema and traction, scleromalacia with orbital tumor extension, and laser-induced optic neuropathy.
Transpupillary thermotherapy (TTT), as originally described by Oosterhuis and popularized by Shields,62–65
was suggested for the This finding suggests that the Zimmerman
treatment of small tumors, up to 4 mm in height, lying near the optic disk or the fovea (in an effort to spare these structures from damage). With a modified delivery system beam widths between 1 and 3 mm and exposure times of up to one minute are typically generated.66
This
method was reported to offer a local tumor control rate of 76 % (not as successful as radiation therapy).67
control (intraocular and orbital), TTT has largely been abandoned as a primary treatment for CM.68
However, due to failures of local Current patient selection includes very thin
tumors, treatment of circumpapillary tumors that cannot be reached by plaque, and the sandwich technique, where TTT is used in combination with a radiation plaque. At The New York Eye Cancer Center, we use TTT laser for marginal tumor recurrences and in patients who cannot tolerate plaque surgery.
US OPHTHALMIC REVIEW
Primary indications for TSR include large anterior melanomas, where endoresection is not possible, and the ability to tolerate hypotensive anesthesia. Poor local control rates, coupled with a high incidence of post-operative complications (secondary rhegmatogenous retinal detachment, intraocular hemorrhage, ocular hypotony, and phthisis) and concerns about CM dissemination, have limited the widespread use of TSR.58–60
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