31 Uveal Melanoma

Uveal Melanoma

6

THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 15/04/2020

optic nerve sheath, thus expanding its total width to a 5- to 6-mm optic nerve sheath diameter. This difference creates an offset to proper plaque placement. Slotted plaques were devised with 8-mm openings. A slot allows the optic nerve sheath to enter the plaque carrier, thus more posteriorly locate the Iodine-125 seed sources and move the target volume into a normalized position surrounding the choroidal melanoma. It is important to note that plaque slots make dosimetry more complex. In these particular cases using Iodine-125 treatment, medical physicists must locate seed sources to both ‘‘fill-in’’ the gap created by the slot and cover the target volume. Ruthenium applicators with an opening for the optic nerve (COB) are also available. For large, completely encircling juxtapapillary melanomas proton beam radiotherapy is an alternative treatment. In addition, patients unsuitable for

brachytherapy or resection can be treated with proton beam radiotherapy or stereotactic radiosurgery. The ABS-OOTF recommends that plaque procedures should be performed in specialized medical centres with expertise in ophthalmic brachytherapy. Such centers should include a team composed of at least a subspecialty-trained plaque surgeon, a radiation oncologist and a medical physicist experienced in plaque brachytherapy. Communication between them is critical for any successful brachytherapy program.The ocular oncologist provides data related to tumour localization (choroid, ciliary body, iris) and basal diameters, thickness, distance from the sensitive areas of the fovea and optic disc. The plaque choice is made to encompass the tumour with margin on all sides; plaque apertures should exceed

TABLE 1 AJCC CLASSIFICATION OF POSTERIOR UVEAL MELANOMA (CHOROIDAL AND CILIARY BODY), T CATEGORY Thickness (mm) >15.0 4 4 4 4 4

4 4 3 3 3 2

4 4 4 4 4 4

12.1 to 15.0 9.1 to 12.0

3 3 2 1 1

3 3 2 1 1

3 3 2 1 1

3 3 2 2 1

3 3 3 2 2

6.1 to 9.0 3.1 to 6.0

≤ 3.0

≤ 3.0

3.1-6.0

6.1-9.0

9.1-12.0

12.1-15.0

15.1-18.0

>18.0

Largest basal diameter (mm)

TABLE 2 AJCC CLASSIFICATION OF POSTERIOR UVEAL MELANOMA (CHOROIDAL AND CILIARY BODY), T CATEGORY SUBCLASSIFICATION T Category T Criteria TX Primary tumor cannot be assessed T0 No evidence of primary tumor

TABLE 3 AJCC CLASSIFICATION OF POSTERIOR UVEAL MELANOMA (CHOROIDAL AND CILIARY BODY), REGIONAL LYMPH NODES AND DISTANT METASTASIS N Category N Criteria NX Regional lymph nodes cannot be assessed N0 No regional lymph nodes involvement N1 Regional lymph nodes metastasis or discrete tumor deposits in the orbit N1a Metastasis in one or more regional lymph node(s) N1b No regional lymph nodes are positive, but there are discrete tumor deposits in the orbit that are no contigious to the eye M Category M Criteria M0 No distant metastasis by clinical classification M1 Distant metastasis M1a Largest diameter of the largest metastasis ≤3,0cm M1b Largest diameter of the largest metastasis 3,1-8.0cm M1c Largest diameter of the largest metastasis ≥8,1cm

Tumor base ≤9mm with thickness ≤6mm Tumor base 9.1-12mm with thickness ≤3mm

T1

T1a

Tumor size category 1 without ciliary body involvement and extraocular extension

T1b

Tumor size category 1 with ciliary body involvement

T1c

Tumor size category 1 without ciliary body involvement but with extraocular extension ≤5mm in largest diameter

T1d

Tumor size category 1 with ciliary body involvement and extraocular extension ≤5mm in largest diameter

Tumor base ≤9mm with thickness 6.1-9mm Tumor base 9.1-12mm with thickness 3.1-9mm Tumor base 12.1-15mm with thickness ≤6mm Tumor base 15.1-18mm with thickness ≤3mm

T2

T2a

Tumor size category 2 without ciliary body involvement and extraocular extension

T2b

Tumor size category 2 with ciliary body involvement

T2c

Tumor size category 2 without ciliary body involvement but with extraocular extension ≤5mm in largest diameter

T2d

Tumor size category 2 with ciliary body involvement and extraocular extension ≤5mm in largest diameter

Tumor base 3.1-9mm with thickness 9.1-12mm Tumor base 9.1-12mm with thickness 9.1-15mm Tumor base 12.1-15mm with thickness 6.1-15mm Tumor base 15.1-18mm with thickness 3.1-12mm

T3

T3a

Tumor size category 3 without ciliary body involvement and extraocular extension

T3b

Tumor size category 3 with ciliary body involvement

T3c

Tumor size category 3 without ciliary body involvement but with extraocular extension ≤5mm in largest diameter

T3d

Tumor size category 3 with ciliary body involvement and extraocular extension ≤5mm in largest diameter

Tumor base 12.1-15mm with thickness >15mm Tumor base 15.1-18mm with thickness >12mm Tumor base >18mm with any thickness

T4

T4a

Tumor size category 4 without ciliary body involvement and extraocular extension

T4b

Tumor size category 4 with ciliary body involvement

T4c

Tumor size category 4 without ciliary body involvement but with extraocular extension ≤5mm in largest diameter

T4d

Tumor size category 4 with ciliary body involvement and extraocular extension ≤5mm in largest diameter

T4e

Any tumor size category with extraocular extension >5mm in largest diameter