Choroidal melanoma

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Classification according to ICD-10
C69 Malignant neoplasm of the eye and the appendages
C69.3 Choroid
ICD-10 online (WHO version 2019)
Choroidal melanoma on magnetic resonance imaging ( T1 with contrast agent )

The choroidal melanoma (also: malignant uveal melanoma ) is the most common malignant primary tumor of the eye . In Europe, the incidence rate is 1 in 100,000 per year. The uveal melanoma develops directly in the choroid ( choroid ) of the eye of degenerated melanocytes . For this reason, most choroidal melanomas are darkly pigmented. The risk of the disease increases with age and reaches a maximum between the ages of 60 and 70. About half of all patients develop metastases , which usually first manifest in the liver and often lead to death within a few months. In contrast to the malignant melanoma of the skin (cutaneous melanoma), the metastasis of the choroidal melanoma is initially exclusively hematogenous (via the bloodstream), because the choroid has no lymphatic vessels . This anatomical peculiarity inside the eye ensures that tumor cells of the choroidal melanoma can initially grow unaffected by the immune system ( immune privilege ). In contrast to cutaneous melanoma, UV radiation should not be the primary cause of the tumor in the choroidal melanoma . The glass body in the eye should in fact absorb most of the incident UV radiation.

state of research

The investigation of tumors removed from the eye has shown that the metastatic disease is closely associated with a genetic abnormality in the tumor, namely the loss of a chromosome 3 (monosomy 3). While tumors with two intact chromosomes 3 only very rarely cause recognizable metastases, most patients with monosomy 3 develop metastases in the primary tumor. Such a close relationship between genetic abnormalities and clinical behavior has not otherwise been found in any solid tumor, which clearly distinguishes this tumor disease from cutaneous melanoma. This monosomy 3 typing or a characterization of the gene expression profile (DecisionX test) should be carried out after the detection of this tumor in order to classify the malignancy. Despite intensive efforts, even modern therapies such as kinase inhibitors or checkpoint blockade antibodies have so far not shown any significant improvement in the survival rate in choroidal melanoma patients. The classic clinical risk factors for the formation of metastases include the size and location of the choroidal melanoma in the eye. The involvement of the choroidal melanoma in the ciliary body is rated as a bad sign.

Symptoms and ailments

If the tumor is at the point of sharpest vision or if the tumor has caused retinal detachment, there will be significant changes in the visual performance of the affected eye. Choroidal melanomas are often discovered by chance during routine ophthalmological examinations. Characteristics of the tumor, such as melanin pigmentation, position in the eye and growth tendencies of the tumor suggest a choroidal melanoma, which is clearly differentiated from the nevus (birthmark) of the choroid.

Investigation methods

  • Echography : ultrasound examination to determine the position and extent of the tumor
  • Fluorescence - angiography : photographic representation of the blood vessels in the eye with the help of fluorescent dyes

Treatment methods

A combination of the listed treatment methods is often used.

radiotherapy

a) Brachytherapy (therapy with radiation carriers)
With this form of radiation therapy, small metal shells (applicators ) are sewn onto the outer layer of the eye (dermis = sclera ). The tumor is located inside the eye exactly at the treated area. The sewn applicator contains radioactive material inside . The duration of the irradiation (1–14 days) is calculated based on the tumor size.
The following isotopes are mainly used:
Ruthenium -106 ( beta radiation ) for tumors up to 7 mm in height
Iodine -125 ( gamma radiation ) for larger tumors
Palladium -103 (gamma radiation)
b) Teletherapy ( proton radiation therapy )
The irradiation of the tumor with accelerated protons , in a cyclotron - particle are generated, is suitable for tumors with up to 15 mm diameter.
The precise alignment of the eye or the diseased tissue with the particle beam is crucial for successful treatment and preservation of the optic nerve. For this purpose, special devices are used in the corresponding irradiation devices that allow either the eye or the surrounding anatomy to be oriented to the beam. Metallic markers are also commonly used for this. When attached to the eyeball, they can provide information about the orientation of the eye to the treatment beam in fluoroscopic images.

Radiosurgery

Choroidal melanoma patients treated with radiosurgery usually go through a standardized outpatient procedure. Immediately after the retrobulbar anesthesia , a contrast medium MRI ( magnetic resonance tomography ) and a planning-relevant CT ( computed tomography ) are performed. On the basis of this image data, the target volume of the tumor is determined and the favorable radiation directions and the dose are calculated. Publications usually report a median dose of 20 Gy (18 to 22 Gy), depending on the location and size of the tumor. Radiosurgical treatment takes place on an outpatient basis and without restraint of the patient in a single session.

Analyzes show that robot-controlled radiosurgery (e.g. with the Cyberknife ) can be an effective eye-preserving option even for medium to large choroidal melanomas. The local tumor control and toxicity are comparable to more lengthy radiotherapy techniques.

Laser therapy
Strong heating of small tumors by laser beam
Cryotherapy
Extreme cooling of small tumors to −78 ° C using a cold stick
Surgical removal of the tumor
Enucleation
Removal of the eye
vaccination
Antigen-specific stimulation of the immune system against one's own tumor cells after removal of the tumor (phase III study at 8 German eye clinics)

literature

Web links

Individual evidence

  1. ↑ Andrea Schmidt-Pokrzywniak, Karl-Heinz Jöckel , Norbert Bornfeld, Andreas Stang: Case-control study on uveal melanoma (RIFA): rational and design. In: BMC Ophthalmology. 4, 2004, 11, ISSN  1471-2415 , doi: 10.1186 / 1471-2415-4-11 , PMID 15318944 .
  2. ↑ Holger Voigt: Malignant melanoma. Springer-Verlag, 2013, ISBN 978-3-642-70460-4 , p. 56 ( limited preview in the Google book search).
  3. ↑ Choroidal Melanoma - Medical Information. In: radioonkologie.uniklinikum-leipzig.de. April 15, 2015, accessed October 9, 2017 .
  4. ↑ Boris Peter Selby, Georgios Sakas, Stefan Walter, Wolf-Dieter Groch, Uwe Stilla : Pose estimation of eyes for particle beam treatment of tumors. In: Alexander Horsch, Thomas M. Deserno, Heinz Handels, Hans-Peter Meinzer (eds.): Image processing for medicine 2007. Algorithms - Systems - Applications. Proceedings of the workshop from 25. – 27. March 2007 in Munich. Springer, Berlin a. a. 2007, ISBN 978-3-540-71090-5 , pp. 368-374, doi : 10.1007 / 978-3-540-71091-2_74 .