Given the confined space of the bony orbit, any neoplasm, of the orbit can present with a varying mixture of similar, signs and symptoms of globe displacement, eyelid, swelling, blepharoptosis, limitation in eye movement,, conjunctival chemosis, hyperemia, elevated intraocular, pressure, chorioretinal folds, and optic nerve compression, as well as other cranial neuropathies.1 Malignant, tumors grow rapidly, with symptoms developing over, months to weeks. Due to the rapid growth and tendency, to involve sensory nerves, pain is a more common (but, not necessary) feature of a malignant orbital tumor.2 On, imaging, malignant lesions tend to be infiltrative, not, respecting the natural boundaries of anatomic compartments, and causing bone erosion and destruction rather, than remodeling. These general rules have exceptions., Not all lesions can be classified into benign or malignant, based on clinical presentation and imaging findings;, therefore, most will require tissue biopsy.3 Treatment, is multidisciplinary, with oncology, radiation oncology,, and other specialties as needed. Staging orbital tumors, with the most recent AJCC TNM classification ensures, improved multidisciplinary communication and patient, care.4 The topics of orbital tumor classification and differential, diagnosis are covered elsewhere in this book (see, Chapters 42 and 43). In the current chapter, we focus, on the diagnosis and specific management of common, malignant orbital neoplasms.
Chapter Keyword: radiation
Finger’s Methods for Ophthalmic Plaque Surgery
Plaque surgical techniques are rarely described in the literature. 1-6 When available, they are typically found in the methods sections of papers describing a new radiation source or plaque position verification technique.3,7-14 This understates their importance in that our surgical methods affect the incidence of secondary radiation complications, local control, and thus metastasis.1,15-17 Plaque modality, construction, and medical physics calculations are critical foundational elements of treatment success.4,18-20 Significant research indicates that failure of local control is associated with a 6.3x hazard for metastatic disease.15,21 My techniques have been refined over the last 35 years, leading to a current local control rate greater than 99% as measured by doctor-reported outcomes.22,23 Herein, I offer my thoughts, methods, and experience with surgical ophthalmic plaque radiation therapy. The lack of consensus guidance is related to the complexity of plaque therapy. For example, there exist a variety of radiation plaque modalities: palladium-103 (103Pd), iodine-125 (125I), ruthenium-106 (106Ru), strontium-90 (90Sr), and most recently yttrium-90 (90Y).24-28 In addition, ophthalmic plaques come in different shapes and sizes.18,20 Although the American Brachytherapy Society (ABS) together with the American Association of Physicists in Medicine (AAPM) have published guidelines for ophthalmic plaque brachytherapy for choroidal melanoma and RB, there exist nuances that were beyond the scope of that multicenter, international effort.18,29 Intraocular tumors also occur at different intraocular locations.30 Clearly, epicorneal plaque positioning differs from that on the posterior pole, particularly due to optic nerve sheath obstruction.6,17,31,32 However, there are commonalities and differences that need be described to improve ophthalmic plaque surgery.
A Review of Ophthalmic Plaque Brachytherapy Consensus Guidelines
Brachytherapy involves the application of a radioactive, source inside or close to a tumor or benign growth.1 During, application, this radiation is delivered continuously, but over a fixed amount of time. Therefore, in radiation, oncology there exist short-term (temporary) implants, and long-term (even permanent) implants. Temporary, brachytherapy implants can be either low-dose rate, (LDR) or high-dose rate (HDR), requiring days or minutes, of application respectively. In radiation oncology,, brachytherapy is used because it is conformal, allowing, irradiation of targeted tissue volume with limited radiation, to nearby healthy tissues.1-3, As early as 1911, Dr. Albert Terson used radium to prevent, pterygium recurrence.4 Since that time, a number of, beta and gamma applicators have been important tools, for delivering radiation within the eye and orbit.2,3 Given, the small size of the eye and proximity of visually significant, structures, precise calculation of the radiation, dose to these vital structures is essential.5,6 However,, there exists scant clinical research comparing the efficacy, of various methods and brachytherapy types. The, closest research includes a 2012 American Association, of Physicists in Medicine (AAPM) comparison of, iodine-125 (125I) versus palladium-103 (103Pd) sources, used in eye plaques which included a review of ophthalmic, brachytherapy.7 Then, in 2014 the American, Brachytherapy Society (ABS) OOTF together with the, AAPM published a 47-person consensus, multicenter,, international OOTF guideline for plaque brachytherapy, of choroidal melanoma and RB.8 We suggest that all, eye cancer specialists obtain these open-access publications, and integrate their recommendations into clinical, practice. Lessons learned from these 2 publications are, presented in this chapter.
Management of Radiation Retinopathy
Radiation therapy for uveal melanoma offers high, local control rates. Radiation therapy has been proven, noninferior to enucleation for the prevention of metastatic, melanoma by the medium-sized melanoma trial, of COMS.1 In 2014, the consensus guidelines produced, by the AJCC-OOTF for the American Brachytherapy, Society (ABS) and American Association of Physicists, in Medicine (AAPM) showed that only a few tumors are, considered untreatable by ophthalmic brachytherapy, plaques.2 This shift to eye-conserving radiation therapy, is supported by patients who prefer to keep vision and, their eye., Recent research has focused on vision preservation., Although radiation-related cataracts are common, surgical, vision rehabilitation by lens replacement is both safe, and effective. In contrast, the macular retina and optic, disc are irreplaceable, leaving retinopathy and optic neuropathy, as the most common, irreversible, sight-limiting, side effects of irradiation. Depending on the dose, dose, rate, and thus treatment modality, up to 50% of patients, with posterior uveal melanoma are at risk.3 In the past,, prior to undergoing radiation therapy, patients with posterior, and select large choroidal melanomas were told to, expect severe radiation-related vision loss.4, However, since 2006, Dr. Finger found that anti-VEGF, therapy slowed or stabilized radiation maculopathy and, optic neuropathy.5-8 This discovery ushered in a new era, where treatment not only provides local cancer control, but also makes long-term vision preservation an attainable, goal.
Treatment of Choroidal Melanoma
Uveal melanoma (UM) management is based on tumor, characteristics, prognostic factors, local availability of, treatment modalities, and patient preference.1 A detailed, discussion between the physician and the patient helps, navigate the complex shared decision-making process, (see Chapter 7). Herein, we discuss UM treatment, options (Mind map 28-1).
Metastatic Cancer to the Eye, Lids, and Orbit
Though innumerable scientific articles start with “the most common intraocular malignancy is choroidal melanoma,” choroidal metastases are much more common.1 Uveal metastases are seen histologically at postmortem in up to 12.6% of patients dying from metastatic cancer.2 However, clinically observable metastatic disease has been noted in only 2%–7% of patients with dissem-inated disease.3-5 Similarly, orbital metastases have been found in up to 5% of patients with systemic malignancy.6,7 This disparity is likely due to the patients being asymptomatic, having little time to live, or a combination of both.5,8 Further, systemic treatment may render the ocular metastasis occult, leaving the patient and oncologist unaware of its existence. , However, the life expectancy for patients with metastatic disease from cancers that commonly spread to the eye has improved over time, particularly in the case of breast cancer.9,10 This longevity has resulted in increased numbers of patients needing ocular treatment to prevent vision loss and ensure their quality of life.11,12 Further, ocular metastases may be the first presentation of systemic disease. One study found that uveal metastases from lung carcinoma (47%), pancreatic cancer (37%), and lung carcinoid (33%) often preceded the systemic diagnosis; by contrast, 94% of patients with breast metastases had a history of the disease.13 Other studies have reported similar results.9,14,15 Similarly, 15% of patients with orbital metastases do not have a cancer diagnosis at presentation.7 Some ocular metastases may, albeit rarely, occur after a tumor has been in remission for years (reported up to 43 years later), which may be a diagnostic shock.16-18 The ocular presentation of metastatic disease is also changing. For instance, because the eye is a relatively immunologically privileged site, vitreous metastases of cutaneous melanoma (Fig. 35-1) are increasingly common in patients on checkpoint inhibitors and who are otherwise in remission.19,20 Prior to this therapy, vitreous involvement was seen only in 18% of eye, lid, or orbital cutaneous melanoma metastases.21 , Further, there has been an evolution of local therapies. The goal of local treatment is to retain vision. Thus, observation for response to systemic therapy may work but risks vision loss in cases where the reattachment of the macula is delayed. Treatments to decrease exudative retinal detachments include laser (e.g., PDT), intravitreal anti-VEGF injections, and steroid implants.22 Larger tumors may be treated with EBRT and smaller extramacular tumors with plaque brachytherapy. However, both forms of radiation carry dose-dependent risks of long-term side effects in longer-lived patients.23 Finger has used anti-VEGF drugs as a bridge therapy to more definitive EBRT irradiation.