Добавил:
kiopkiopkiop18@yandex.ru t.me/Prokururor I Вовсе не секретарь, но почту проверяю Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Скачиваний:
0
Добавлен:
28.03.2026
Размер:
11.93 Mб
Скачать

218

G.D. Camoriano and D.S. Gombos

choroidal lesions. A-scan ultrasonography often shows moderateto high-amplitude internal reflectivity. The thickness and largest basal diameter of metastatic foci can be determined by B-scan ultrasonography, which usually shows moderate-to-high acoustic solidity. Ultrasonography may be particularly helpful when a view of the fundus is compromised by a dense cataract or other optical media opacity, such as vitreous hemorrhage.

Other imaging modalities that may help establish the diagnosis of uveal metastasis include fluorescein angiography and ocular coherence tomography. Fluorescein angiography of choroidal lesions may reveal early blockage of the choroidal circulation, which is associated with hypofluorescence in the arterial and early venous phases and leakage in the later phases. In contrast to the double circulation pattern sometimes seen with primary uveal melanoma, no large intralesional blood vessels are normally seen in choroidal metastases. Ocular coherence tomography provides a cross-sectional image of the retina, retinal pigment epithelium, and choriocapillaris, which may further aid in mapping these lesions and demonstrating subretinal fluid.

Magnetic resonance imaging should be considered, especially when central nervous system (CNS) involvement is suspected [9]. Magnetic resonance imaging may also help differentiate metastatic lesions from primary choroidal melanoma, as the latter often exhibits high signal intensity on T1-weighted images. Computed tomography or magnetic resonance imaging of the CNS is indicated in all patients with newly diagnosed metastases and should be part of any staging workup to rule out CNS metastasis.

The differential diagnosis of uveal metastasis includes amelanotic nevus, amelanotic melanoma, granulomatous iritis, lymphoma, leukemia, leiomyoma, choroidal osteoma, choroidal hemangioma, and eccentric disciform degeneration. If, after a complete workup, the diagnosis of uveal metastasis remains elusive because of an atypical presentation or failure to identify the primary tumor, a biopsy may be considered. However, the benefits of pathologic verification of the lesion and prediction of the primary tumor site must be carefully weighed against the risk of complications related to the procedure itself or the possibility of tumor spread by seeding. Biopsy techniques include ab externo and ab interno approaches, including pars plana fine-needle aspiration biopsy. Of these techniques, fine-needle aspiration biopsy is the least invasive and has a reported sensitivity of up to 84% after cytological analysis. The main risks associated with this procedure are dissemination of tumor cells along the needle tract or into the bloodstream and ocular complications leading to visual loss and blindness (endophthalmitis, vitreous hemorrhage, rhegmatogenous retinal detachment, or suprachoroidal hemorrhage).

16.6 Treatment

Once the diagnosis of uveal metastasis is made, close collaboration with an oncologist is essential to provide the best care for the patient. This is particularly important in cases in which the ophthalmologist initially makes the diagnosis in a patient with

16 Uveal Metastases from Solid Tumors

219

no history of cancer. In this setting, an oncology consultation should take place promptly to determine the location of the primary tumor and to dictate systemic treatment. Several treatment modalities have been investigated and are presented in the following sections. These therapies aim at selectively targeting the metastatic foci while minimizing collateral damage and optimizing visual outcomes.

16.6.1 Observation

Not all uveal metastases are considered sight threatening or require specific ocular therapy. Ophthalmologists may choose to follow lesions that remain stable in size, are asymptomatic, or are not threatening the macula or the optic nerve. Often these lesions are diagnosed in patients who have undergone prior systemic treatment, such as chemotherapy, and are detected on routine ophthalmic examination. In such cases, local treatment is not likely to result in any appreciable benefit.

16.6.2 External-Beam Radiation Therapy

External-beam radiation therapy is an excellent treatment modality for most uveal metastatic lesions. It is well suited for the patient with bilateral multifocal disease and should be considered when the macula is threatened or involved in one or both eyes. Treatment is usually tailored, in part, to the type of primary lesion and its relative radiosensitivity. When CNS lesions are identified at the same time as uveal metastasis, whole brain radiation therapy inclusive of both globes may be indicated. Close coordination with the treating radiotherapist is essential to review the size and ocular location of the tumor foci. In select cases (with posterior tumors), a lenssparing approach can be used, decreasing ocular side effects such as dry eye and cataract formation. In most cases, radiation therapy is well tolerated and has minimal side effects, such as lash loss and dry eye, which can be addressed with the use of supplemental artificial tears. Cataracts, if clinically significant, can be removed in the usual fashion; however, given that most patients with uveal metastasis have a short life expectancy (see Section 16.7), cataracts often do not become a clinically significant complication [4, 10].

16.6.3 Chemotherapy

In some cases, systemic chemotherapy can be used to treat ocular metastatic lesions. Generally, newly diagnosed patients with systemic disease that includes ocular involvement are candidates for systemic chemotherapy. If systemic chemotherapy is considered, the oncologist and ophthalmologist should review the relative ocular and CNS penetration of the chemotherapeutic regimen selected. Patients should be monitored closely with each cycle of treatment since initial regression may be

220

G.D. Camoriano and D.S. Gombos

followed by late recurrence. Adjuvant radiation therapy or laser hyperthermia therapy may be necessary. In many cases, there is good correlation between ocular and systemic response. We have observed that uveal metastases from newly diagnosed breast cancers are most responsive to systemic chemotherapy.

16.6.4 Plaque Brachytherapy

Brachytherapy is an excellent modality for select patients with choroidal metastasis. Patients with a single isolated tumor focus and no CNS disease are good candidates for this approach. Iodine 125 and ruthenium plaques are the most common sources used. Charged-particle radiation therapy has also been described. Careful presurgical measurements are critical to ensure that the basal and apical dimensions of the metastatic tumor are considered in radiation and dosimetric planning. Treatment dose is dependent on the relative radiosensitivity of the primary lesion [1012].

16.6.5 Transpupillary Thermotherapy

For most patients, transpupillary thermotherapy (laser hyperthermia) is not a firstline modality in the treatment of uveal metastases. However, in treating recurrent disease, transpupillary thermotherapy can be a helpful adjunct in the management of select lesions. Smaller pigmented tumors tend to respond best to this type of therapy. The treatment is administered in an outpatient setting and requires local retrobulbar anesthesia. Before treatment is begun, a review of the patient’s blood counts should be performed to ensure that retrobulbar injection can be performed safely with minimal risk of orbital hemorrhage. Most centers administer multiple treatment cycles at intervals over a 1–3 month period. We have found transpupillary thermotherapy to be helpful in cases in which there was a relative contraindication to ocular radiation therapy in the form of either prior radiation therapy or concurrent chemotherapy; however, transpupillary thermotherapy is associated with a higher risk of scotoma than other modalities.

16.6.6 Enucleation

In severe and advanced cases of uveal metastases that involve poor visual prognosis and ocular pain, enucleation may be considered. In such cases, the surgeon should carefully assess the patient’s systemic disease and life expectancy as well as whether the patient’s pain or glaucoma can be controlled using alternative methods. Enucleation can provide local tumor control in patients with otherwise nonresponsive lesions.