Every year, eye cancer occurs in 1.89 male and 1.81 female Singaporeans per million people. While eye cancer might seem uncommon compared to other types of cancer, it is still a condition that you need to be aware about. Lack of knowledge about less common types of cancer, like eye cancer, can hinder us from getting the treatment we need when we don’t respond quickly enough at an early stage. What is eye cancer, how do we recognise it, and how can we treat it? This article will discuss all these and more.
What is Eye Cancer?
Eye cancer is a term that is used to refer to any cancer that begins in the eye. There are three major areas in the eye: the eyeball (globe), the tissues surrounding the eyeball (orbit) and the adnexal structures around the eye like eyelashes and tear glands.
Eye cancer can affect any of those areas and is classified differently based on which area it affects. Cancers that affect the area inside the eyeball are known as primary intraocular cancers and cancers that began in other parts of the body and spread to the eye are known as secondary intraocular cancers. Breast and lung cancer are the most common types of cancer that can spread to the eyes. They often spread to the uvea which is the middle layer of the eye that contains the iris.
Types of Eye Cancer
Here are some of the major types of eye cancer:
Retinoblastoma is the most common type of eye cancer in Singapore, accounting for 53.6% of all eye cancer cases between 1968 and 1995. It begins in the retina, which is the layer of nerve cells lining the back of the eye. The nerve cells in the retina change and multiply and eventually form a tumour inside the eye. The cancer can spread to other parts of the body like the brain and the spine.
Retinoblastoma is common among children, who may develop it because of some genes inherited from their parents. Children with retinoblastoma linked to genetic causes tend to get the cancer at a young age in both eyes.
2. Intraocular melanoma
Intraocular melanoma is the most common type of eye cancer among adults. Intraocular melanoma affects the uveal tract, which is the middle layer of tissue in the eye between the inner layer containing the retina and the outer layer containing the choroid. This type of eye cancer commonly affects people aged 60 and above. Studies have shown that smoking can increase the risk of intraocular melanoma. Family members of people with intraocular melanoma are not usually screened for this type of eye cancer as this condition is not considered to be hereditary. As this type of cancer is rarely painful and does not present many obvious symptoms, it can be hard to detect.
Lymphoma is most commonly seen as a type of blood cancer, but it can also affect the eyes. Known as primary intraocular lymphoma, it can develop in the retina and also affect the optic nerve at the back of the eye. Most people with primary intraocular lymphoma develop it in both eyes. People with autoimmune disorders like rheumatoid arthritis are at risk of developing this type of eye cancer. Being on medication to prevent the body’s rejection of transplanted organs can also be a risk factor.
4. Squamous cell carcinoma
Squamous cell carcinoma is a type of cancer that primarily affects the skin but can also affect the eyes. Squamous cell carcinoma of the eyes involves a painless growth that gradually spreads over the eyes. Exposure to UV sun radiation is a major risk factor for this type of eye cancer, as well as conditions like the human immunodeficiency virus (HIV) that involve weakened immune systems. Most of those who are affected are women and middle-aged people.
Eye Cancer Symptoms
Here are some common symptoms of different types of eye cancer:
- A bright circular patch in the middle of the iris in one or both eyes. This is a recognisable sign of retinoblastoma.
- A dark patch extending from the middle of the pupil (circular black spot in the middle of your eye) to the edge of your iris (coloured portion of your eye that contains the pupil). This can be a sign of intraocular melanoma.
- Constant feeling of irritation in the eyes
- Floaters (a collection of small dots) or flashes in your vision
- Loss of vision in one or both eyes
- Sensitivity to light
Stages of Eye Cancer
Like other types of cancer, eye cancers go through stages of increasing severity. These stages help doctors to identify which stage the disease is at so that they can use the most effective treatment for it.
The TNM staging system is generally used for most types of eye cancer. T stands for tumour, used to describe the size and location of any tumours in the eye. N stands for nodes and is used to check whether the cancer has spread to the lymph nodes. M stands for metastasis, which refers to whether the cancer has spread to other parts of the body. Different tumour stages are used to measure tumours for melanoma of the iris and melanoma of the choroid.
Other types of eye-related cancers like retinoblastoma and squamous cell carcinoma use different forms of the TNM system with different criteria for each stage. Staging can be very complicated and difficult to understand, so you should check with your doctor if you are unclear about what stage your cancer is at.
Eye Cancer Diagnosis
To see if you might have eye cancer you should visit an ophthalmologist, a specialist in eye diseases. You can get a referral to an ophthalmologist in a hospital to go through tests for eye cancer. Your ophthalmologist will check your vision and eye movement, as well as ask you about any symptoms you might have. Your ophthalmologist may then conduct a biopsy by inserting instruments into the inner fluid of the eye to detect any abnormalities inside.
If you are found to have a tumour in your eye, your doctor may also carry out a targeted tumour examination which involves taking a tissue sample from the tumour. A sentinel lymph biopsy may also be done to check if the cancer has spread to the lymph nodes which are located near the eyes.
Ultrasound is also a common method used to check for eye melanomas as the ultrasound waves will bounce off growths in the eye, allowing them to be detected in diagnostic tests. The echoes are converted into images on a computer screen. A chest X-ray might also be conducted to check if the cancer has spread into the lungs. An ultrasound may also be done of the liver, another organ which eye cancer commonly spreads to.
Eye Cancer Treatment
Eye cancers can be treated with both chemotherapy and radiation therapy. Chemotherapy is generally only used when the cancer has become widespread. The drugs used in chemotherapy could be injected into an eye, taken orally as pills, or injected into a vein using an IV. Chemotherapy targets cells which multiply quickly. This makes it effective against cancer cells, but it is also likely to target cells in other parts of the body like the hair follicle and bone marrow cells. Side effects include hair loss, tiredness, nausea and vomiting, diarrhea and constipation. Chemotherapy may also cause blood cell count to decrease, leading to bruising and fatigue from a lack of red blood cells. Let your doctor know about your side effects so that they can prescribe medicine to manage them.
Radiation therapy involves using high levels of radiation to kill cancer and tumour cells in your body. External radiation therapy will aim radiation from a machine at the site of your cancer and is used to treat cancer that is concentrated in a certain body part. Internal radiation therapy involves putting a source of radiation into your body, which can be solid or liquid. The material will travel through your bloodstream and destroy cancer cells that it encounters. Radiation therapy will vary based on pre-existing factors like your age and other medical conditions which you will need to declare to a doctor before beginning treatment. This treatment method may also damage healthy cells near the cancer site. Speak to your doctor to learn more about potential side effects and how to work to avoid them.
Surgery under a microscope might be used to remove tumours, as well as other abnormalities like growths inside the eye from squamous cell carcinoma. Cryotherapy, a treatment method where the growths are repeatedly frozen in cycles, might also be used to remove growths inside the eye.
Managing cancer treatment can be a long and painful process. Homage is here to ensure that you go on the path to recovery with the support you require. Our trained Care Pros can provide you with specialised cancer care to aid you in several aspects of your daily life at all stages of cancer. We can provide medical escorts, rehabilitation therapy, medication reminders, palliative care and night care to help you meet your needs. With us, you can set out on your path to recovery without fear.
- Boyd, K. (2021, May 5). What Is Eye Lymphoma? American Academy of Ophthalmology. https://www.aao.org/eye-health/diseases/eye-lymphoma
- Chemotherapy for Eye Cancer. (n.d.). American Cancer Society. Retrieved July 18, 2021, from https://www.cancer.org/cancer/eye-cancer/treating/chemotherapy.html
- Egan KM, Gragoudas ES, Seddon JM, Walsh SM. Smoking and the risk of early metastases from uveal melanoma. Ophthalmology. 1992 Apr;99(4):537-41. doi: 10.1016/s0161-6420(92)31936-0. PMID: 1584571.
- Gichuhi, S., & Sagoo, M. S. (2016). Squamous cell carcinoma of the conjunctiva. Community eye health, 29(95), 52–53.
- Lee SB, Au Eong KG, Saw SM, Chan TK, Lee HP. Eye cancer incidence in Singapore. Br J Ophthalmol. 2000 Jul;84(7):767-70. doi: 10.1136/bjo.84.7.767. PMID: 10873991; PMCID: PMC1723550.
- Radiation Therapy for Cancer. (2019, January 8). National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/radiation-therapy
- The American Society of Retina Specialists. (n.d.). Intraocular Melanoma – The American Society of Retina Specialists. ASRS. Retrieved July 16, 2021, from https://www.asrs.org/patients/retinal-diseases/40/intraocular-melanoma
- What Is Eye Cancer? (n.d.). American Cancer Society. Retrieved July 14, 2021, from https://www.cancer.org/cancer/eye-cancer/about/what-is-eye-cancer.html
- What Is Retinoblastoma? (2020, October 30). American Academy of Ophthalmology. https://www.aao.org/eye-health/diseases/what-is-retinoblastoma