Monday, September 15, 2014
Retinoblastoma expert David Abramson discusses how treatments and survival rates have greatly improved for this rare pediatric eye cancer.
Adding to another banner year for the precedent-setting programs at Memorial Sloan Kettering, 2014 marks the 100th anniversary of the establishment of its retinoblastoma program, the oldest such program anywhere for the treatment of this rare pediatric eye cancer.
Later this week, MSK will host a two-day meeting during which retinoblastoma experts from around the world will present case studies and discuss the latest treatments for the disease.
We spoke with David Abramson, Chief of the Ophthalmic Oncology Service in the Department of Surgery, about the causes of retinoblastoma and how treatment has changed.
How does retinoblastoma originate and what are its causes?
Retinoblastoma is caused by mutations in a gene called RB1. When the protein encoded by RB1 works normally, it prevents cells from becoming cancerous. But when it’s mutated, cells are allowed to multiply and grow out of control, leading to cancer.
All cases of retinoblastoma have a genetic component, but there are two different types. About 50 to 60 percent of cases are caused by mutations that originate in a single cell in the eye and grow and spread from there. The other 40 to 50 percent are germline mutations, which means they occur in the DNA of every cell in the body.
In some cases, germline mutations are inherited from parent to child, but more commonly these mutations occur randomly early in development.
Another thing that’s important to note is that mutations in RB1 are linked to other types of cancer as well as retinoblastoma. We test all of our retinoblastoma patients for germline RB1 mutations, and those patients need to be closely followed for the rest of their lives to watch for the development of other cancers. There is also a 50 percent chance that patients with germline mutations can pass them on to their children.Back to top
How is retinoblastoma diagnosed?
Retinoblastoma is the only childhood cancer that pediatricians regularly screen for, and they are required to do it at every well-baby visit for the first two years. But in fact, almost all cases are first picked up by a family member.
Unlike most other cancers, where you have to do a blood test or a CT or an MRI to find it, this is a cancer that you can visibly see. What parents usually notice is a glint or a glare or some other whiteness within the pupil.
About three-quarters of retinoblastoma patients have cancer in one eye, while the rest develop it independently in both eyes.Back to top
Could you explain how treatment has evolved?
One of the most remarkable things about retinoblastoma is that in 100 years, we’ve gone from a disease that was near-uniformly fatal to one where — at least at MSK — more than 99 percent of children survive. That’s pretty impressive for a childhood cancer.
The original treatment for retinoblastoma was removal of the affected eye or eyes, and until very recently, that was still the most common treatment worldwide. But obviously it’s not ideal. You can cure the patient, but you are sacrificing one or both eyes, and have all the consequences that go with that.
In the early 1900s, doctors learned that they could save the eye and cure the cancer using radiation therapy, first with external beam and later with small radioactive disks inserted near the tumors. But although patients were able to keep their eyes, in most cases they still had no vision.
In 1959 laser treatment was developed, and in 1969 cryotreatment, or freezing the tumors, began. In the 1990s patients were given systemic chemotherapy first, to shrink the tumor enough that it could be treated successfully by lasers, freezing, or radiation. And these treatments often allowed patients to keep their eyes and their vision.
But especially for patients who had the RB1 germline mutation, the likelihood of developing second cancers was greatly increased due to exposure to the radiation and chemotherapy, so it still wasn’t ideal.Back to top
What about treatment today?
The turning point was May 2006, when my colleagues and I — including Pierre Gobin from NewYork-Presbyterian — introduced a retinoblastoma treatment that changed everything. We called it ophthalmic artery chemosurgery. This procedure involves threading a thin catheter from an artery in the groin all the way up to the eye and using it to insert just a few drops of a very powerful chemotherapy drug directly into the one blood vessel — the ophthalmic artery — that supplies the eye.
This is a very safe, effective outpatient procedure that cures the cancer while saving the eye or eyes, and often the vision, and it has completely transformed the landscape of treatment. It does not increase the risk of later cancers, and most patients have no side effects.
But although we now have a 99 percent cure rate in patients whose disease is caught before it spreads, I am always looking forward. My team and I are working on some new things that may be just as exciting, but are even simpler and safer. We also have some clinical trials for metastatic disease, which is not very common in the United States anymore, but for those who do have it, these new treatments are important.Back to top
What makes MSK special?
We have the most extensive long-term data on the largest number of retinoblastoma patients in the world. For 30 years, we’ve collaborated with the National Institutes of Health to continue following these patients — and in many cases, their children and even grandchildren.
Because of the nature of treatment for retinoblastoma today, it can’t be done by one physician. It requires specialized nurses, anesthesiologists, pathologists, radiologists, radiation oncologists, pharmacists, genetic counselors, and technicians. And Memorial Sloan Kettering has all of those pieces in place, as well as a dedicated space for treating these patients.
Thanks to the Internet, we have patients from all over the country and around the world who know that we have these resources, and they come to MSK. We also have families that we have been treating for three generations, a testament in part to the increasing survival rates that we’ve seen.Back to top