Unfortunately, the short answer to this is yes. But fortunately, cancer of the eye, also known as ocular cancers, is rare. The American Cancer Society estimates just under 3500 new cases diagnosed in 2019 across the whole of the United States.
Cancer refers to a condition where abnormal cells grow and multiply in an uncontrolled manner. The proliferation and spread of these cells can damage and destroy healthy cells in the surrounding tissues, interfering with the normal function of vital organ systems in the body. When it comes to the eye, the majority of ocular cancers are considered secondary cancers, which means the malignant cells originated in another part of the body but then spread (or metastasized) to the eye. A primary ocular cancer is one that first began in the eye itself.
The most common primary cancer of the eye is an ocular melanoma. Similar to melanoma of the skin as a result of excessive beach bathing in the California sun, ocular melanomas arise from the melanocyte cells that produce pigment. To make things more complicated, you can also have an amelanotic melanoma, which involves melanocytes that are unable to produce melanin pigment.
Most cases of ocular melanomas occur in an inner part of the eyeball called the uvea. The uvea includes a layer of tissue lining the eyeball known as the choroid; the ciliary body, a structure involved in focusing vision and producing fluid in the eye; and the iris, the visible colored structure at the front of the eye. Out of these three tissues, the most common location for an ocular melanoma is the choroid, with 90% of uveal melanomas originating here. Very rarely, a melanoma can pop up on the conjunctiva, the membrane over the whites of the eyeball.
Small melanomas or those that are far out to the periphery of the retina may often go undetected as they don’t present with pain or any symptoms. In fact, up to 40% of choroidal melanomas are picked up as a coincidental finding on a routine examination – a scary thought considering the metastatic potential of an ocular melanoma via the blood stream, particularly to the liver, means it can be a life-threatening condition. Larger uveal melanomas that induce a retinal detachment, central melanomas affecting the macula and central vision, or iris and conjunctival melanomas that can be observed in the mirror are more likely to be noticed. Symptoms may include:
- A dark freckle on the iris or conjunctiva, especially if you feel this is growing larger
- Distortion of the usual round shape of the pupil associated with a nearby dark spot on the iris
- Floating spots or specks in the vision
- Unexplained flashing lights in the vision, usually in the periphery of your field of view
- Blurry or distorted vision, whether centrally or in your side vision
Those with existing freckles or moles around the eyes are advised to be aware that they herald an increased risk of uveal melanomas.
The treatment of an ocular melanoma depends largely on how big the melanoma is and where it’s located in the eye. Other factors, such as the patient’s general health and the possible side effects of certain treatments may also play a part. Radiation therapy is typically delivered in the form of a little radioactive plaque attached to the eye next to the melanoma; this is the most common method of radiotherapy. In some cases, surgery is the optimal treatment to remove the melanoma. If the cancer is very large or invasive, or in a very complicated location, occasionally the entire removal of the eyeball is recommended in a procedure known as enucleation. Both radiotherapy and surgery have the potential to damage the vision of the effected eye (but it’s probably still better than having melanoma metastases to your liver).
Cancers of the eyelid
Skin cancers of the eyelid can be sneaky little things as they will often start by mimicking a good ol’ garden variety bump in the skin. Though bumps in the eyelid can be due from a number of generally harmless reasons, such as a sty or cyst, be sure to run all unexpected lumps past your eye doctor, especially if it doesn’t resolve within a couple of weeks. Other symptoms of a cancerous lesion of the eyelid include:
- Thickening or swelling of the eyelid
- Ulceration and an open wound, often with crusting
- Chronic infection and inflammation
- Loss or discoloration of eyelashes around a bump
- A growing, spreading bump around the eyelids, whether pigmented or not
Remember that, like the uveal structures of the eyeball, eyelid skin also contains melanocytes and so can be susceptible to malignant melanoma; however, melanomas of the eyelid are rare and comprise less than 1% of eyelid tumors.
The most common cancer of the eyelid is a basal cell carcinoma (BCC), which arises from the basal cell layer of the skin’s epidermis. A BCC typically presents as a slow-growing reddish nodule, usually on the lower eyelid but can appear on the upper lid or on the skin between the corner of the eye and the nose bridge. BCC tumors very rarely metastasize. At the other end of the scale we have squamous cell carcinomas (SCC), which are much less common than BCC but tend to metastasize aggressively, spreading throughout the eye socket, lymph nodes, and other organs in the body. Both BCC and SCC are found at higher rates in older age groups and are typically a result of cumulative UV exposure and damage to the eyelid skin over time. SCC is also associated with cigarette smoking, immunosuppression, and HIV infection.
Sometimes a clinical examination is enough to differentiate a BCC from an SCC, though a tumor biopsy is usually recommended to confirm the diagnosis and also help determine the extent of the carcinoma growth. Surgical excision is typically the recommended treatment for both SCC and BCC though depending on the individual case, other options are available, such as cryotherapy, radiotherapy, or topical chemotherapy. If surgical excision has been performed, most patients will need reconstructive surgery afterward to restore the appearance and function of the eyelids.
Though a bit of a mouthful to say, retinoblastoma deserves a mention as it is the most common ocular cancer in children. Every year in the US, about 250 to 350 children are diagnosed with retinoblastoma.
A mutation in a gene known as RB1 in either one or both eyes leads to uncontrolled growth of the developmental retinoblast cells of the eye. The usual plan is for these retinoblasts to mature into retinal cells but as we know, things don’t always go to plan. The uninhibited proliferation of retinoblast cells forms a cancerous tumor, which can destroy healthy eye tissue as it grows, damaging vision along the way. If not caught and treated in time, retinoblastomas can metastasize not only to the surrounding structures of the eye but also to the brain, lymph nodes, and other organs such as the liver and bone marrow.
The most common sign of retinoblastoma in children is what’s called leukocoria, or a white pupil. Usually reflexes from the pupil are red or pink; a white glint in the eye is often first picked up by a parent, easily noticed in pictures after flash photography or when looking at the child at a certain angle. Another sign is a lazy eye, meaning the eye movements do not coordinate properly when looking in a particular direction. Though lazy eye is often considered a condition in itself and may be due to a number of factors other than eye cancer, on occasion it can be the result of a retinoblastoma in the misdirected eye. Any indication of a lazy eye or a white reflex to the pupil should be investigated immediately by an eye doctor.
90% of children with retinoblastoma are treated successfully but the prognosis deteriorates significantly if the tumor spreads outside the eye.
How You Can Reduce Your Risk
Not all risk factors for ocular cancers are avoidable. Certain characteristics cannot be changed, such as:
- Ethnicity – Caucasians and fair-skinned races are at a generally higher risk of compared to African Americans, Asians, or Latinos. The exception is with retinoblastomas, which doesn’t discriminate against race.
- Age – as with most diseases, the risk of eye cancer increases with increasing age. If you find a way to reverse aging be sure not to keep that information to yourself.
- Gender – melanomas, BCC and SCC are typically found more commonly in males than females. Retinoblastomas tend to occur equally between boys and girls.
- Genetics – a family member with eye cancer doesn’t guarantee an eye cancer diagnosis for the rest of the family but can present a risk factor to be aware of. Children born to parents with a history of retinoblastoma are encouraged to be screened from a very young age.
UV exposure is considered to be the greatest risk factor for BCC and SCC of the eyelids; luckily, this is one risk factor that can be controlled. Shading the eyes from the sun with a hat and sunglasses is a good way to reduce damage to the skin from ultraviolet radiation. Also, being diligent with regular checks with your eye doctor, even if you think everything is dandy, will help to catch any suspicious lesions early and may just give you the best chance of saving an eye.
Key statistics for eye cancer. https://www.cancer.org/cancer/eye-cancer/about/key-statistics.html
Choroidal melanoma. https://eyecancer.com/eye-cancer/conditions/choroidal-tumors/choroidal-melanoma/
What is ocular melanoma? https://www.aao.org/eye-health/diseases/what-is-ocular-melanoma
Choroidal melanoma – Latin America. https://www.aao.org/topic-detail/choroidal-melanoma–latin-america
Risk factors for eye cancer. https://www.cancer.org/cancer/eye-cancer/causes-risks-prevention/risk-factors.html
Malignant melanoma of the eyelid. https://eyecancer.com/eye-cancer/conditions/eyelid-tumors/malignant-melanoma-eyelid/
Squamous carcinoma of the eyelid. https://eyewiki.aao.org/Squamous_Carcinoma_of_the_Eyelid
Basal cell carcinoma (eyelid cancer). https://eyecancer.com/eye-cancer/conditions/eyelid-tumors/basal-cell-carcinoma-eyelid-cancer/
The difference between basal cell carcinoma and squamous cell carcinoma. https://www.sensushealthcare.com/blog/difference-basal-cell-squamous-cell-skin-cancers/
Eyelid cancer guide. https://www.cancer.net/cancer-types/eyelid-cancer/overview
About retinoblastoma. https://www.cancer.org/cancer/retinoblastoma/about.html
Basal-cell carcinoma incidence and associated risk factors in US women and men. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3775544/
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