A 12-Year Study of Slotted Palladium-103 Plaque Radiation Therapy for Choroidal Melanoma: Near, Touching, or Surrounding the Optic Nerve

Abstract

Purpose: To present our 12-year experience with low-energy-photon, slotted eye plaque radiation therapy.

Design: Retrospective interventional case series.

Methods: Setting: The New York Eye Cancer Center.

Study population: Fifty-two consecutive patients with uveal melanomas near, touching, or surrounding the optic disc.

Intervention: Slotted eye plaque radiation therapy.

Main outcome measures: Change in visual acuity, local tumor control, radiation side effects, eye salvage, and systemic metastases.

Results: Tumors were peripapillary within 1.5 mm of the optic disc (n = 8, 15%), juxtapapillary touching ≤180 degrees (n = 23, 44%), or circumpapillary >180 degrees and encircling the disc (n = 21, 41%). Mean follow-up was 47 months (median 34 months, range 6-146 months). Radiation induced a mean 41.2% reduction in tumor thickness. Life table analysis showed that 69% of patients retained their visual acuities ≥ 20/40 and had a vision loss-free survival 84 months after treatment. Also, 90% of patients retained their visual acuity between 20/50 and 20/200 and had a vision loss-free survival 36 months after treatment. Slotted plaque brachytherapy was associated with 4% secondary cataract, 11% neovascular glaucoma, and no dry eye or eyelash loss. Local tumor control (no recurrence) was achieved in 98.1% of patients. Life table analysis showed an overall enucleation-free survival of 93% and metastasis-free survival of 94%.

Conclusions: Slotted plaque radiation therapy provided a normalized plaque-tumor position, such that the entire choroidal melanoma plus a 2- to 3-mm free margin of normal-appearing tissue was included in the targeted zone. At 12 years, slotted plaque radiation therapy resulted in high rates of local tumor control and vision and eye retention.