Retinoblastoma

Retinoblastoma is a form of cancer that impacts the retina, the light-sensitive tissue located at the back of the eye. This condition is most commonly diagnosed in children. Symptoms of retinoblastoma include eyes that appear to be misaligned (crossed eyes), pain in the eye, vision impairment, and irises differing in color. Treatment strategies usually encompass surgery, chemotherapy, and radiation therapy, with alkylating agents being a common class of drugs used in management.

Causes

• Retinoblastoma develops due to changes in the DNA of retinal cells, disrupting normal cellular functions and leading to unchecked cell growth and tumor formation.

• The key gene involved is the RB1 gene, which acts as a tumor suppressor to control cell growth. Mutations in both copies of this gene can result in the uncontrolled growth of cells, causing retinoblastoma.

• Approximately 60% of these mutations are sporadic, occurring randomly and typically affecting only one eye.

• Around 40% of cases are inherited, with genetic alterations present in all body cells from birth. Inherited forms often affect both eyes and can increase the likelihood of passing the condition to future generations.

• While the precise cause of these genetic changes is not fully understood, the mutation of the RB1 gene is instrumental in developing retinoblastoma.

Symptoms

Retinoblastoma predominantly affects young children and presents with various symptoms. Recognizing these early signs is crucial:

• A white or pale reflection from the pupil, especially noticeable in flash photography, known as leukocoria.

• Misaligned eyes (strabismus).

• Redness and swelling of the eyes.

• Reports of eye pain or discomfort.

• Excess tearing from the eyes.

• Vision issues, including frequent falls or difficulty navigating familiar environments.

Young children may not be able to articulate vision issues, so it is important to consult with a healthcare professional if any changes are observed in a child’s eyes or behavior. Early intervention is key to preventing vision loss and halting cancer progression.

Diagnosis

To diagnose retinoblastoma, a comprehensive process is carried out to confirm the cancer's presence in the eye. This begins with a detailed eye examination by a healthcare professional, often utilizing a special light to detect abnormalities. Young children may require sedation to remain still during the examination. Imaging tests, such as ultrasounds and MRI scans, provide insights into the tumor's size and whether the cancer has extended beyond the eye. Genetic testing is vital in identifying mutations in the RB1 gene, crucial for creating an effective treatment plan and assessing the risk of other potential cancers.

Treatments

The treatment of retinoblastoma is tailored to the tumor's size and location. Typically, chemotherapy is the initial step to shrink the tumor, administered systemically or targeted to the eye. Some cases might require intra-arterial chemotherapy, which delivers medication directly near the eye, or intravitreal chemotherapy, involving direct injections into the eye. For smaller tumors, focal therapies like cryotherapy and laser therapy are employed. If chemotherapy is insufficient, radiation therapy, using plaque radiotherapy or external beam radiation, may be used. In severe cases, surgical removal of the eye (enucleation) might be necessary. The primary aim is to ensure child safety and preserve as much vision as possible.

Medications

Medications are critical in retinoblastoma management:

• Chemotherapy is the standard initial treatment to shrink tumors within the eye and can be delivered via:

• Systemic Chemotherapy: Administered through a vein, reaching the tumor throughout the body.

• Intra-arterial Chemotherapy: Concentrated delivery through an artery leading to the eye.

• Intravitreal Chemotherapy: Direct injection into the eye targeting the tumor.

• The primary goal is to reduce tumor size and preserve eyesight.

• Side effects of chemotherapy can vary; systemic methods may cause nausea or hair loss, while local therapies might result in localized effects, such as swelling around the eye or retina impact.

Prevention

• Retinoblastoma, mainly affecting young children, cannot be completely prevented due to its basis in RB1 gene mutations, which can be inherited or occur spontaneously.

• Retinoblastoma lacks avoidable risk factors seen in some adult cancers. However, genetic counseling can provide insights for families with a history of this condition.

• Genetic testing is advised for those with a family history to assess their risk.

• Early screenings—ideally starting after birth—are vital upon identifying genetic risk for early detection and treatment success.

• Genetic counseling or in vitro fertilization may be considered by those planning a family and concerned about passing on retinoblastoma, aiding informed decisions in healthcare and family planning.