plaque radiotherapy for uveal melanoma

Strategies to Minimize Radiation Maculopathy

Yonah ZiembaSKMC, MS3

Radiotherapy for Uveal Melanoma:

OutlineI. Patient presentation

II. 3 Treatment Options: Plaque vs Proton Beam vs

Enucleation

III. 3 Clinical Questions, 3 Major Studies

IV. Back to the Patient

• US incidence 1,500 cases/year.• White >> Black, Men > Women • Melanoma is the most common primary

intraocular malignancy in adults, at 75%.• #2 = Retinoblastoma. Only 13%.

Epidemiology

Patient Presentation

• JK is a 51y/o gentleman presenting w 3 mo of intermittent photopsia in the left eye.

• Exposure to arc welding.• Choroidal lesion measuring 10 x 8 mm in

left eye noted on Fundus exam.• Visual acuity was 20/20.

Fundus Exam

Fluorescein Angiography Ultrasound

• Work-up: fundus exam, ultrasound and fluorescein angiography.

• Measurements: diameter by fundus exam, thickness by ultrasound

• Biopsy: not done until after radiation for risk of seeding.

Diagnosis

3 Treatment Options• Enucleation

Last resort

• Proton BeamUseful when > 5 mm thickness

• Plaque Brachytherapy Useful when < 5 mm

thickness

• prior to 1970

• refractory cases

Enucleation

Enucleation and Prosthesis

Proton Beam

Plaque

Plaque

• Most common form of treatment• Good for thin tumors, not thick tumors

Plaque

• Commonly Iodine-125 T1/2: 59.4 d

Av Energy: 35.5 keV

• Not possible over optic nerve due to anatomy

3 Clinical Questions

I. Is radiation effective?

II. Does radiation cause vision loss?

III. Can prophylaxis prevent vision loss?

• Question: Is Radiotherapy as effective as enucleation?

• Design: Randomized multi-center clinical trial of iodine 125 brachytherapy vs enucleation.

• Conclusion: No difference in survival betweenI-125 brachytherapy vs enucleation.

• Impact: Brachytherapy usually first line treatment.

JAMA Ophthalmology, Dec 2006

JAMA Ophthalmology, Sept 2000

J of Ophthalmology Vol 121, Jan 2014

Back to our patient…• JK’s melanoma was treated with iodine-125

plaque. 7185 cGy to the apex and 17,023 cGy to the base of the tumor.

• 3355 cGy was delivered to the fovea and4235 cGy to the optic disc.

• To minimize maculopathy, JK received anti-angiogenic treatment.

• Bevacizumab injections• Photocoagulation (laser)

• Lesion reduced to a 3 mm scar

Before After

2 Year Follow Up

• Patient retained perfect 20/20 vision!• Attributed to the anti-angiogenic treatment. • Case was published as a success story

in Retina Today.

Retina Today, March 2013

ConclusionsI. Wills Eye protocol for work-up of non-metastatic

melanoma differs from other tumors: - No biopsy, CT or MRI- Diagnosis via fundus exam- Thickness measured by ultrasound

II. Isodose patterns of Plaque vs Proton: - Plaque ➞ Steep gradient ➞ Thin tumors- Proton Beam ➞ Wide plateau ➞ Thick tumors.

III. Radiotherapy cures ocular tumors, yet causes maculopathy

IV. Bevacizumab expected minimize maculopathy- Too early for long term studies

Thank you!