Retinoblastoma, A Success Story In The Fight Against Cancer

Retinoblastoma is a cancer of the eye. The cancer starts in the retina — the light sensing part of the eyeball on the inside of your eye.

Image Source: ​Retinoblastoma Labeled Diagram

Retinoblastoma is usually a cancer of young children, but in rare cases even adults can suffer from this cancer. It is the most common eye cancer of childhood. Incidence may vary from 1/18,000 births in developed nations to 1/12,000 births in developing nations.
It can be heritable as well as non-heritable. The non-heritable type is the most common type accounting to about 90-93% of all retinoblastomas.

What makes treatment of Retinoblastoma so successful than other cancers?
Reasons for high success rate are many

1. Genetic basis of the tumour being identified
2. Early diagnosis of the tumour
3. Multiple treatment options
4. Cutting edge basic and clinical research

Genetic basis

At the beginning of the 20th century the survival rate of children with Retinoblastoma was less than 17%. After modest success for many decades the discovery of the Rb1 gene mutation (1986) was game changing.More than 70 years ago, it was recognized that retinoblastoma sometimes has a genetic basis and that the pattern (when genetic) is classic Mendelian autosomal dominant. It was not until Alfred Knudson proposed his two-hit hypothesis and the subsequent molecular confirmation of his calculation that it was recognized that this autosomal-dominant pattern is caused by the loss of a normally occurring gene that is now referred to as the RB1. Although it was originally thought to be of importance only in retinal cancers, it is now recognized that loss of the normal RB1 gene is an important step in cancer development in most adult non ocular cancers.

Early Diagnosis
Early detection of Retinoblastoma is the key.

Leukocoria– which translates to white pupil- in other words whitish appearance from the centre of the eye is the most important sign of Retinoblastoma, which brings it to the attention of the parents to seek help.

Image Source: ​Medscape: Medscape Access

There are other signs too but Leucocoria  is the most common sign. This early sign and hence early diagnosis is also responsible for high cure rates seen in Retinoblastoma.

Treatment options
The biggest advantage in the treatment of Retinoblastoma is that it is responsive to mutiple options of treatment unlike other tumours.
The characteristics of the tumour is

1. Extremely chemosensitive and hence it has high response to chemotherapy
2. Radiosensitive, so Radiotherapy is an option even when the tumour has spread outside the eyeball.
3. It is amenable various local therapy like Laser therapy, thermal therapy, cryotherapy and plaque brachytherapy. This is possible because we can visualize the tumour using an ophthalmoscope.
4. When only one eye is involved, Surgery – Enucleation can sometimes give permanent cure from the cancer.

Pioneering research
As it stands today, in the best centers in the world for Retinoblastoma care, the success rates are staggering-

1. 95% Life salvage
2. 90% Eye salvage
3. 85% Vision salvage

This is staggering because just 50 years ago, the rates of survival in children with retinoblastoma was less than 30% even in the best centers.

Today Retinoblastoma is treated using a team based approach. The team consists of an Ocular Oncologist, Pediatric Oncologist, Radiation Oncologist, Pathologist, Interventional radiologist and an Ocularist. This approach has resulted in fantastic success in care for children with Retinoblastoma.

February 15th was International Childhood cancer day. The motto for Retinoblastoma Awareness is:

“Fight the white”

I’ve written about Retinoblastoma talking more about Dr. Zimmerman family story and my personal experience in my blog post- Hope and Heartbreak: The two sides of Retinoblastoma

The above article is based on an answer I wrote on Quora

Why is Retinoblastoma so treatable and has such a high survival rate when compared to various other cancers? Are there any specific reasons for the same?

If you have any questions I would be happy to answer in the comments section.

I do not have any financial interests to declare regarding the above article and it is intended to educate the general public including medical professionals about eye conditions.

References:

1. David H. Abramson. Retinoblastoma in the 20th Century: Past Success and Future Challenges The Weisenfeld Lecture. Investigative Ophthalmology & Visual Science August 2005, Vol.46, 2684-2691. doi:10.1167/iovs.04-1462
2. Collins MZ. Retinoblastoma: The Zimmerman Family Story. JAMA Ophthalmol. 2014;132(5):519-520. doi:10.1001/jamaophthalmol.2014.467.
3. Xu K, Rosenwaks Z, Beaverson K, Cholst I, Veeck L, Abramson DH. Preimplantation genetic diagnosis for retinoblastoma: the first reported liveborn. Am J Ophthalmol. 2004;137(1):18-23.
4. Abramson DH, Shields CL, Munier FL, Chantada GL. Treatment of Retinoblastoma in 2015: Agreement and Disagreement. JAMA Ophthalmol. Published online September 17, 2015. doi:10.1001/jamaophthalmol. 2015.3108.
5. Retinoblastoma: Recent Update and Management Frontiers.
6. Manjandavida, Fairooz P. MD; Honavar, Santosh G. MD; Shields, Carol L. MD; Shields, Jerry A. MD [Editorial] Asia-Pacific Journal of Ophthalmology. 2(6):351-353, November/December 2013.
7. Alex Melamud, Rakhee Palekar, Arun Singh, Cleveland Clinic Foundation, Cleveland, Ohio Am Fam Physician. 2006 Mar 15;73(6): 1039-1044.