Primary transpupillary thermotherapy for small choroidal melanoma in 256 consecutive cases: outcomes and limitations

The objective of this report was to evaluate ocular and systemic outcomes after primary transpupillary thermotherapy for choroidal melanoma and to identify the limitations of this treatment method.

Noncomparative interventional case series.

The participants included 256 patients with newly diagnosed choroidal melanoma.

The outcome measures included local tumor recurrence and visual acuity.

Before treatment, the mean tumor base was 7.1 mm, and mean tumor thickness was 2.7 mm. Overlying subretinal fluid was present in 215 cases (84%) and orange pigment on the tumor surface in 200 cases (78%). All tumors showed either photographic documentation of growth (114 cases; 45%) or substantial risk factors for growth (142 cases; 55%). After a mean of three treatment sessions, complete tumor control without recurrence was found in 232 cases (91%) and recurrence in 24 cases (9%). The mean time to recurrence was 22 months, and the mean recurrent tumor size was 3.8 mm base and 2.4 mm thick. Of the recurrent tumors, additional thermotherapy was successful in controlling 13 (5%), plaque radiotherapy in 8 (3%), and enucleation in 3 (1%). Using multivariable analysis, the risk factors for tumor recurrence included increasing number of thermotherapy sessions (reflecting less responsive tumor) (P = 0.0001) and optic disc overhung by tumor (P = 0.03). Kaplan Meier estimates revealed that 4% showed recurrence at 1 year, 12% at 2 years, and 22% at 3 years follow-up. When analyzing those 214 patients without multivariable risk factors for recurrence, Kaplan Meier estimates for recurrence were 2% at 1 year, 8% at 2 years, and 10% at 3 years. The visual acuity after treatment was 20/20 to 20/40 in 128 cases (50%), 20/50 to 20/100 in 47 (18%), and 20/200 or worse in 81 (32%). Using multivariable analysis, the most statistically significant factors at initial visit that were predictive of poor visual acuity (20/200 or worse) after treatment included documented tumor growth before treatment (P = 0.0001), mushroom tumor configuration (P = 0.002), initial symptom of blurred vision (P = 0.008), poor initial visual acuity (P = 0.005), superior quadrant tumor location (P = 0.03), underlying diabetes mellitus (P = 0.04), and optic disc overhung by tumor (P = 0.04). Tumor-related mortality occurred in two patients (1%), one of whom showed complete tumor regression to thermotherapy and the other with diffuse choroidal melanoma and local tumor margin recurrence.

Transpupillary thermotherapy is an effective treatment for certain small choroidal melanomas. Appropriate tumor selection is critical to successful treatment. Patients with tumors abutting or overhanging the optic disc or those requiring more than three sessions for tumor control are more likely to develop ultimate tumor recurrence. Transpupillary thermotherapy can cause damaging effects to the retina, leading to visual loss shortly after treatment.