Experience in the treatment of primary malignant tumors (retinoblastoma and osteosarcoma): analysis of the clinical case

Background. Retinoblastoma is a malignant intraocular tumor developing from the retinal neuroectoderm and diagnosed primarily in young children. This type of cancer is associated with a high risk of multiple primary tumors emerging after treatment completion. Multiple primary tumors are two or more independent tumors developing in one patient. Treatment of this disease is challenging.Objective – to evaluate the impact of risk factors on the efficacy of therapy for multiple primary tumors and to analyze treatment outcomes.Materials and methods. A 2-year-old boy was diagnosed with bilateral retinoblastoma (OD – stage T3bN0M0 and OS – stage T3cN0M0). He received special treatment from September 2005 to November 2006. In 2012, the patient underwent cataract surgery: the lens was removed, then an intraocular lens was installed, and laser dissection of the posterior capsule of the lens was performed. Six years later, in August 2018, the patient was diagnosed with osteosarcoma. The boy received combination organ-sparing therapy according to the EURAMOS-1 treatment protocol for osteosarcoma. During therapy, he developed a secondary tumor, namely osteoblastic osteosarcoma. Both the boy and his father were found to have a mutation in the RB1 gene.Results. Currently, patient’s condition is satisfactory; he has no complains. The boy is in remission for 2 years.Conclusion. The development of secondary tumors depends on the genetic factors, type of treatment for primary tumor, and environmental factors. Therefore, it is extremely important to assess risk factors for multiple primary tumors at the moment of primary retinoblastoma detection. The results of such assessment will help to choose an optimal treatment strategy.