Effects on Periocular Tissues after Proton Beam Radiation Therapy for Intraocular Tumors

BACKGROUND: To present our experience on orbital and periorbital tissue changes after proton beam radiation therapy (PBRT) in patients with intraocular tumors, apart from treatment outcomes and disease control. METHODS: Medical records of 6 patients with intraocular tumors who had been treated with PBRT and referred to oculoplasty clinics of two medical centers (Seoul National University Hospital and Seoul Metropolitan Government-Seoul National University Boramae Medical Center) from October 2007 to September 2014 were retrospectively reviewed. The types of adverse effects associated with PBRT, their management, and progression were analyzed. In anophthalmic patients who eventually underwent enucleation after PBRT due to disease progression, orbital volume (OV) was assessed from magnetic resonance (MR) images using the Pinnacle3 program. RESULTS: Among the six patients with PBRT history, three had uveal melanoma, and three children had retinoblastoma. Two eyes were treated with PBRT only, while the other four eyes ultimately underwent enucleation. Two eyes with PBRT only suffered from radiation dermatitis and intractable epiphora due to canaliculitis or punctal obstruction. All four anophthalmic patients showed severe enophthalmic features with periorbital hollowness. OV analysis showed that the difference between both orbits was less than 0.1 cm before enucleation, but increased to more than 2 cm3 after enucleation. CONCLUSION: PBRT for intraocular tumors can induce various orbital and periorbital tissue changes. More specifically, when enucleation is performed after PBRT due to disease progression, significant enophthalmos and OV decrease can develop and can cause poor facial cosmesis as treatment sequelae.

Curent advances and stretegies for reducing the side effects of radiation therapies used for various types of cancers.

Cancer originates from the abnormal expression or activation of positive regulators and functional suppression of negative regulators. The World Health Organization (WHO) estimates that 84 million people will die of cancer between 2005 and 2015 without intervention. Research suggests that one-third of cancer deaths can be avoided through prevention. Major cancer treatment modalities are surgery, radiation therapy and chemotherapy. Radiation therapy is an important cancer treatment method and is used for approximately 50% of all cancer patients with varying success. Therapy uses high-energy waves or particles to destroy cancer cells. It can be used basically for three main reasons: to achieve high radiation dose into tumors; minimizing dose into surrounding normal tissues; to avoid complications as far as possible. The recent advances in this treatment method have led to the improvement in cancer death statistics. It can also be combined with surgery or chemotherapy for better results. This review covers general applications, various side effects/agents and factors affecting to get rid of these effects and strategies to improve radiation therapy.