Disease Description (Causes and Symptoms)
- Definition: Retinoblastoma is a childhood malignant tumor that arises in the retina (the light-sensing tissue at the back of the eye). It is mainly diagnosed during infancy and early childhood (mostly before age 5).
- Causes/Pathophysiology: Loss or mutation of the RB1 tumor suppressor gene (at the 13q14 region of chromosome 13) prevents retinal precursor cells from differentiating normally, causing them to proliferate and form a tumor. In the heritable form (a germline mutation present from the embryonic stage), there is a tendency toward bilateral disease (or a family history), while the nonheritable form generally occurs in only one eye. Loss of both homologous genes (the “two-hit” mechanism) is common.
- Epidemiology: Occurs in approximately 1 in every 15,000–20,000 births. Most cases occur before age 5. The heritable form is associated with bilateral disease or a family history.
- Main symptoms: The pupil appears to shine white (leukocoria), strabismus, decreased vision, pupil dilation/abnormal light response, increased eye size (especially when glaucoma develops), and, in cases of proptosis or invasion of tissues around the eye, pain and swelling. Rarely, it may metastasize to the brain, bone marrow, or other sites, and patients with the hereditary form have an increased risk of tumors in the brain (so-called “trilateral retinoblastoma”—the cerebellum/pineal gland).
Treatment Methods (Standard Treatment · Precautions · Self-Management)
- Treatment principles: Treatment is tailored according to the extent of the tumor (whether it is confined within the eye and its stage), the patient’s hereditary status, and the possibility of preserving vision. The priority is saving the patient’s life, followed by preserving the eye and vision.
- Local treatment (for early-stage, small lesions)
- Laser photocoagulation
- Cryotherapy
- Local thermotherapy for small tumors
- Plaque (sutured) radiation, when available
- Systemic/Local Chemotherapy
- Systemic chemotherapy (chemoreduction): Standard drugs such as vincristine, carboplatin, and etoposide are used, followed by local treatment after reducing the tumor size.
- Direct ophthalmic artery infusion (intra-arterial chemotherapy / ophthalmic artery chemosurgery): Improves eye-preservation rates by delivering a high concentration of medication locally.
- Intravitreal chemotherapy: Used in cases with vitreous involvement (e.g., non-particulate tumor cells), with drugs such as melphalan.
- Radiation therapy
- External-beam radiation (external radiation) was widely used in the past, but is now used only selectively because of the increased risk of secondary tumors (such as osteosarcoma) later in patients with the hereditary form.
- Local radiation, such as plaque therapy, may be possible.
- Enucleation
- Performed when the tumor is extensive and eye preservation is impossible, when there is a risk to life, or when visual recovery is unlikely even after treatment.
- Adjunctive treatment and follow-up
- If metastasis is suspected: bone marrow examination, cerebrospinal fluid examination (lumbar puncture), systemic CT/MRI, etc.
- RB1 genetic testing and family testing, and genetic counseling.
- Precautions/Complication management · Self-management
- Monitor acute side effects related to chemotherapy (vomiting, bone marrow suppression, risk of infection) and chronic side effects (such as hearing loss).
- After enucleation, an ocular prosthesis and psychosocial support are needed.
- In hereditary cases, the long-term risk of secondary cancers (osteosarcoma, skin cancer, etc.) is increased—regular follow-up is necessary.
- Minimize radiation therapy as much as possible (especially in patients with the hereditary form).
- Prognosis summary: With early diagnosis and treatment, survival rates are very high (overall survival > 95% in high-income regions). However, the rates of eye and vision preservation vary depending on the stage and treatment method.
Checklist Before an Outpatient Visit (What to Bring · Example Questions)
- Recommended items to bring
- The child’s medical history, birth records, and family medicine records (if possible)
- Family history information (eye cancer, childhood cancer, osteosarcoma, etc.)
- A list of current medications and allergy information
- Files or CDs of previous ophthalmologic examination results (fundus photographs, ultrasound, MRI/CT, etc.)
- The time symptoms began and photographs showing changes (especially photographs showing leukocoria)—helpful for diagnosis
- Physical structure (photographs of the eye) or a referral document (medical opinion letter)
- Example questions to prepare before the outpatient visit (information to bring for the doctor and medical team)
- “Have you recently observed leukocoria or strabismus (including in photographs)?”
- “Has anyone in the family had childhood cancer or a history of retinoblastoma?”
- “Have there been any changes in the child’s development (including estimated vision)?”
- Symptoms to observe and record during the outpatient visit
- Leukocoria (photographs/parental report), strabismus or decreased vision, changes in eye size, pain or increased tearing, and systemic symptoms (fever, loss of appetite, weight loss, etc.)
Examples of General Questions to Ask the Doctor
- Regarding treatment
- “What stage (e.g., ICRB A–E) is our child’s lesion? How likely is vision preservation?”
- “What is the recommended first-line treatment, and why?”
- “What are the main side effects and complications of treatment, and how are they managed?”
- Regarding diagnosis and testing
- “Is genetic (RB1) testing necessary? How long will it take to receive the results?”
- “Which test is needed, MRI or CT? Is there any concern about radiation exposure?”
- Regarding follow-up and prognosis
- “What will the follow-up examination schedule be after treatment? Is lifelong follow-up necessary?”
- “What are the recommendations for testing siblings?”
Examples of Disease-Specific Questions
- Regarding hereditary status/family testing
- “In our child’s case, is it the hereditary form (RB1 germline mutation)? When and how should genetic testing be conducted for siblings and parents?”
- Regarding eye preservation and treatment options
- “Can intra-arterial chemotherapy or intravitreal chemotherapy be attempted? What are the success rates and risks of each?”