The Essential Eye Cancer Podcast
Many kinds of radiation have been used to treat choroidal melanoma. However, they can be divided into two main categories, implanted radiation plaques and externally administered radiation beams. While the most common radiation plaques include: ruthenium-106, iodine-125 and palladium-103, external beam is dominated by proton therapy. The literature suggests that both plaques and proton beam can be used to destroy intraocular tumors. However, they are very different in their radiation dose distribution within the eye and orbit. These differences result in a different pattern, incidence and distribution of radiation side-effects. This episode examines how each form of radiation is applied, the ability of each form of radiation to compensate for eye movements as well as what results the patient and doctor should expect over time. This podcast episode presents Dr. Finger’s decades of experience with ophthalmic radiation therapy, his knowledge gained working with the American Academy of Physicists in Medicine and as Chair of the 2014 AJCC-OOTF Ophthalmic Plaque Radiation Therapy Guideline Initiative for the American Brachytherapy Society.
There exist many different types of orbital cancers. Typically diagnosed by biopsy, few can be completely removed. In these cases, radiation therapy offers a method to treat residual and even clinically undetectable microscopic left over tumor cells. Most of these orbital cancers can be safely cured with relatively low dose radiation that is easily tolerated by the eye. In those cases, the tumor is cured and the eye continues to function. These patient need to be monitored with periodic eye examinations for late occurring radiation complications (eg. cataract, retinopathy, optic neuropathy). However, there also exists orbital cancers that cannot be controlled with low dose irradiation. Many of those cancers will treated by removal of entire orbit (including the eye). This results in no possibility of vision and a poor cosmetic result. When high dose irradiation is needed to spare the eye, vision and improve cosmesis, Dr. Finger utilizes a specialized technique called “Brachytherapy Boost.” This involves temporary surgical placement of radiation sources into part of the orbit to increase treatment of the tumor bed. Then an overlay of external radiation treats the entire orbit. These two types of radiation overlap in the implanted radiation zone, effectively increasing the dose where is it is needed while decreasing irradiation to the normal parts of the eye. Finger’s brachytherapy boost technique has allowed Dr. Finger to improve cosmesis, spare vision and preserve eyes for patients with radiation resistant orbital tumors. This podcast discusses Dr. Finger’s experience with Brachytherapy Boost for tumor control in patients.
The American Joint Committee on Cancer along with the International Union for Cancer Care have long supported the use of a standard language to define patients with cancer. The 7th and 8th editions of the AJCC-UICC staging systems have now been adopted and function to improve eye cancer research and clinical care. The major ophthalmic journals now require its use for research publications as to allow them to be compared and or combined in multivariate analysis. The largest ophthalmic societies now expect both tumor and patient staging in presentation. Clearly, the use of AJCC-UICC tumor staging has brought ophthalmic oncology into the mainstream of world-wide cancer care.
There exists a multitude of radiation modalities used to treat ocular, orbital, and adnexal tumors. Each type of radiation machine or method has a characteristic pattern of dose distribution within the eye and orbit. The specific pattern and amount of radiation dose delivered to the eye and orbit can be used to predict radiation-related side-effects. Therefore, some methods are better than others. This podcast provides an overview of radiation sources and explains their differences from an ophthalmic perspective.
Orbital radiation therapy has long provided eye and vision sparing treatments for patients with benign and malignant tumors. These include tumors that originate in the orbit and those that extend from the central nervous system, skin, sinuses, and conjunctiva. Each tumor is characterized by an inherent radiation sensitivity. Each orbital location will require a customized approach. However, there exists a multitude of radiation modalities for each purpose. Careful source selection based on creating a conformal treatment zone with relative sparing of normal ocular structures will provide each patient with an optimal chance for globe salvage, vision retention, and local tumor control.
Lasers have long been used to treat eye diseases. Though largely unsuccessful as primary treatment for intraocular cancers, laser continues to play an important role in ophthalmic oncology care. This podcast presents the history of ophthalmic laser treatment as well as a disease by disease analysis of its efficacy. Herein, is described its use to successfully treat subretinal neovascularization, exudative retinal detachment, retinoblastoma, and retinal capillary hemangioma. Clearly, laser therapy continues to play a role in ophthalmic oncology care.
In 2014, the first multicenter, international consensus guidelines for ophthalmic plaque radiation therapy was "open access" published in the journal "Brachytherapy." Dr. Finger was selected to Chair the Ophthalmic Oncology Task Force which he assembled to discuss, survey, and create these guidelines. In total, this committee included 47 eye cancer specialists from 10 countries. In this Podcast, Dr. Finger summarizes their most important findings.
Oculodermal melanocytosis or the Nevus of Ota means that there are increased numbers of cells called melanocytes in the eyelid skin, sclera and uveal vascular layer of the eye. Typically presenting at birth, it can increase during puberty and pregnancy. The pigmentation can follow the distribution of the trigeminal nerve and can therefore extend to the palate. The pigmentation and be complete or partial. When the eye is affected alone, it is called ocular melanosis. The increased numbers of melanocytes cause thickening of affected tissues and increase the patients risk for choroidal melanoma. Though there is no treatment for the pigmentation, close serial surveillance for malignant transformation and secondary glaucoma is warranted.
Tumors and cancers commonly occur on the eyelids. Most have been associated with sun (ultraviolet UV-ray) exposure. The most common eyelid cancer is basal cell carcinoma, but squamous carcinoma, sebaceous carcinoma, and melanoma can occur. If the tumor doesn't have a classic, diagnostic appearance, a small biopsy for pathology evaluation may be needed. This podcast describes the clinical characteristics of these tumors, how they grow, and even spread to other parts of the body.
Tumors and cancers commonly occur on the eyelids. Once the clinical or pathologic diagnosis is established it is time to consider treatment. Eye cancer specialists will recommend either removal or destruction of the eyelid cancer. Depending on the type, size, and location of the tumor, different surgical or treatment strategies will be used. These treatments can range from simple surgical excision of the tumor and margins or Moh's microsurgical resection, typically followed by oculoplastic surgical repair. When tumors invade around the eye, into the orbit, brain, or sinuses, treatment becomes more complex. In these cases, orbitotomy, exenteration, radiation, and even chemotherapy may be needed.