Background/aim To evaluate the safety and efficacy of ruthenium-106 (Ru-106) plaque brachytherapy in managing invasive ocular surface squamous neoplasia (OSSN).

Methods This is a retrospective, non-comparative, interventional case series of 42 eyes with OSSN with histopathologically-proven corneal stromal and/or scleral invasion that underwent Ru-106 plaque brachytherapy. Main outcome measures were tumour regression, eye salvage, final visual acuity, treatment complications and metastasis.

Results At presentation, the mean tumour basal diameter was 9.3 mm (range 5–26 mm) and thickness 3.1 mm (range 1.5–11 mm). Prior treatment included excision biopsy in two patients (5%), incision biopsy and topical interferon in one each (2%). Following excision with 4 mm clinically clear margins, corneal stromal and/or scleral invasion of OSSN was confirmed in all 42 cases, with the excised base showing invasive squamous cell carcinoma. A total dose of 5000 cGy over a mean duration of 19.7 hours (range 7–41 hours) was provided to an axial depth of 2 mm using Ru-106 surface plaque. Over a mean follow-up of 36.9 months (range 22.3–72 months), complete tumour regression was achieved in all eyes (100%). Two eyes (5%) showed conjunctival tumour growth remote from the site of prior treatment. Visual acuity was maintained at ≥20/200 in 35 eyes (83%), with a loss of >2 Snellen lines in 1 eye (2%). There was no evidence of regional lymph node or systemic metastasis.

Conclusion Histopathology-guided use of Ru-106 surface plaque brachytherapy is a safe and an effective adjuvant therapy in the management of corneal stromal and/or scleral invasion of OSSN.