Intra-arterial chemotherapy delivers most precise treatment for retinoblastoma

J. William Harbour, M.D.
Ophthalmology

Before the early 2000s, systemic chemotherapy was the best medical treatment available for retinoblastoma – a rare childhood cancer that develops in the retina in the eye.

While systemic chemotherapy, where cancer drugs are infused into the body through the veins, can be an effective treatment for retinoblastoma, sending such strong medications through a young child’s body can harm healthy cells and cause side effects such as weight loss, anemia, and increased risk of infection. And if the tumor doesn’t respond to systemic chemotherapy or the cancer recurs, the child’s eye might have to be removed to keep the cancer from spreading.

Today, UT Southwestern offers intra-arterial chemotherapy (IAC), a much more precise method of delivering a higher concentration of chemotherapy drugs directly to a retinoblastoma tumor through the artery that goes directly into the eye. Developed in Japan and further optimized in the U.S., IAC can eliminate cancer cells with significantly fewer side effects – and it increases the chances of saving a patient’s eye.

Retinoblastomas are classified into five groups, Groups A-E. Group A are the smallest tumors that are contained to the retina, and Group E are the largest tumors that represent a very high risk of losing the eye. In Group A-D retinoblastomas, IAC is over 90% successful in saving the eye, compared with 40%-50% success using systemic chemotherapy. And in Group E, IAC can save 30%-40% of patients’ eyes, when before the rate was next to zero.

As a center of excellence in ocular oncology, UT Southwestern is one of few ocular oncology centers in the U.S. with the expertise and advanced equipment to provide IAC. Partnering with Children’s Health, our joint retinoblastoma program includes an array of specialists that patients will have access to all under one roof:

• Ocular oncologists
• Pediatric oncologists
• Pediatric endovascular neurosurgeons
• Pediatric ophthalmologists
• Anesthesiologists
• Genetic counselors

With a cancer as rare as retinoblastoma ­– just 200-300 children are diagnosed with it in the U.S. each year – the first step toward successful treatment is to get an accurate diagnosis, and that often starts with an unexpected image in a baby’s photograph.

Diagnosing retinoblastoma

Retinoblastoma can develop before birth, and the average age of diagnosis is younger than 2 years old. Approximately 40% of cases are a hereditary form of the disease that can be passed on in the family.

If we know a family has a history of retinoblastoma, we screen the baby at 4 weeks old. However, because the disease is so rare, it is not practical to screen every newborn.

In most cases, families realize something is wrong after seeing a white pupil reflex of their baby. When the smartphone or camera flash goes off, a healthy eye may appear red in the photo because the light bounces off the blood vessels in the baby’s retina. But when a baby has retinoblastoma, the retina is replaced by a white tumor that causes the pupil reflex to appear white – a condition called leukocoria.

Having a lazy eye (strabismus) can be another symptom of retinoblastoma. Because the tumor interferes with vision, the eye may drift toward the nose or ear if the eye is not seeing and the brain is ignoring it. While parents are sometimes told that a lazy eye can be normal, it should be always be checked by a pediatric ophthalmologist. Even if a tumor is not to blame, there may be another important cause of strabismus that needs to be addressed.

If retinoblastoma is suspected by a pediatrician, the child may be sent to a pediatric ophthalmologist or directly to an ocular oncologist. To diagnose retinoblastoma, an ocular oncologist will need to perform an examination under anesthesia, which may include imaging studies such as fundus photography and ultrasonography. The eyes and brain also need to be evaluated with MRI. Blood testing may be indicated to look for a mutation in the retinoblastoma (RB1) gene.

More than 95% of cases in the U.S. are diagnosed before the cancer spreads beyond the eye, and in many of these cases, the child may be a candidate for IAC.

I am an ocular oncologist who has provided state-of-the-art care for children with retinoblastoma for more than 25 years. I have extensive experience with IAC and have shared this expertise with doctors from around the world. All the experts on our IAC team have specialized training in navigating the small, delicate tissues of very young children. Our medical center is equipped with specialized pediatric equipment to provide our youngest patients with safe, effective treatment.

How intra-arterial chemotherapy is performed

The baby is placed under general anesthesia and will be asleep during the procedure. A highly trained pediatric endovascular neurosurgeon will make a small incision in the skin to access either the femoral artery in the baby’s leg or the brachial artery in the upper arm. They will insert a tiny, flexible tube called a catheter into the artery.

Under advanced fluoroscopic imaging, the neurosurgeon will guide the catheter through the baby’s blood vessels to reach the ophthalmic artery, which feeds the retina of the affected eye.

‘As a center of excellence in ocular oncology, UT Southwestern is one of few centers in the U.S. with the expertise and advanced equipment to provide IAC. Partnering with Children’s Health, our joint retinoblastoma program includes an array of specialists that patients will have access to all under one roof.’J. William Harbour, M.D.

Then, chemotherapy is gently delivered directly into the eye and the tumor, so a higher dose of chemotherapy can be given than with systemic chemotherapy with much lower risk of negative side effects. This allows us to save the eyes of more children with locally advanced retinoblastoma.

After the procedure, the catheter is removed and the incision is closed. The baby is awakened from anesthesia and rests in the recovery room. Most patients can go home the day of the procedure.

Approximately 3-4 weeks later, another examination under anesthesia is performed to monitor tumor response and to perform localized therapies such as laser and intraocular chemotherapy injections as needed to supplement the IAC. Blood will be taken to check the baby’s blood cell counts to determine whether they are ready to undergo another IAC if needed. Using our advanced treatment protocol, most patients will need no more than three IAC treatments.

The child is examined frequently until the tumor is under good control, then the time between examinations can begin to be spread out. If the child has a hereditary form of retinoblastoma, arrangements are made for the family to see a genetic counselor to discuss the baby’s risk of other conditions or whether other family members should be screened.

Cutting-edge research, clinical care for eye cancer

J. William Harbour, M.D., Chair of UT Southwestern’s Department of Ophthalmology, is an ocular oncologist, with expertise in treating eye tumors such as uveal melanoma, retinoblastoma, and lymphoma. He has pioneered new surgical methods in fine needle biopsy, laser treatment, and brachytherapy of ocular tumors.

Refining IAC through research

Our ocular oncology team is continually evaluating new and more advanced methods for treating retinoblastoma. I have developed a modified approach to IAC that reduces the total number of treatment sessions required in most children. In August 2022, my collaborators and I published research in the journal Science Advances in which we identified a protein, estrogen-related receptor gamma (ESRRG), that becomes more active in retinoblastoma. In the future, using medicines that inhibit ESRRG may enable us to save even more eyes with fewer side effects.

Though no cancer treatment is perfect, mastering IAC has brought us one step closer to saving eyes and lives of children with retinoblastoma. As research advances, we are committed to delivering new and leading-edge therapies to our patients.

To request an evaluation by Dr. Harbour and the ocular oncology service at UT Southwestern and Children’s Health, call 214-456-7947.