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What is conjunctival squamous cell carcinoma?
Conjunctival squamous cell carcinoma is the most serious end of a spectrum called ocular surface squamous neoplasia (OSSN) — abnormal growth of the squamous cells covering the conjunctiva, the thin clear membrane over the white of the eye and the inner eyelids, and the adjacent cornea. It usually appears as a fleshy, gelatinous, or whitish growth near the edge of the cornea, often in areas exposed to sunlight, and may cause redness, irritation, or a foreign-body sensation. Risk factors include sun (ultraviolet) exposure, human papillomavirus (HPV) infection, a weakened immune system (including HIV), and the inherited condition xeroderma pigmentosum. Most of these cancers stay on the surface of the eye and grow slowly, so they are highly treatable with excellent results, but if neglected they can invade deeper into the eye or orbit and rarely spread to lymph nodes. Treatment aims to remove or destroy the tumor while preserving the eye and vision. The main approaches are surgical removal with a 'no-touch' technique and freezing of the edges (cryotherapy), and topical chemotherapy or immunotherapy eye drops that treat the whole ocular surface. Radiation — most often plaque brachytherapy, a small radioactive disc placed against the eye — is used for higher-risk, recurrent, or incompletely removed tumors. Outcomes are generally excellent with eye preservation.
The main types
Doctors group conjunctival squamous cell carcinoma by where it starts and how it behaves:
| Type | What it means, simply |
|---|---|
| Ocular surface squamous neoplasia (surface, non-invasive) | Abnormal squamous cells confined to the surface layer of the conjunctiva or cornea; highly curable with surgery and/or topical chemotherapy eye drops. |
| Invasive conjunctival squamous cell carcinoma | The cancer has broken through the surface and invaded deeper tissue; treated with surgery and often radiation, with attention to whether the eye can be preserved. |
| Locally advanced / orbital invasion (uncommon) | Neglected or aggressive tumors that invade the eyeball or eye socket; may require more extensive surgery and radiation, occasionally removal of the eye. |
Staging, in plain terms
Conjunctival squamous cell carcinoma is staged with a dedicated AJCC TNM system that considers the size and extent of the surface tumor (T), whether nearby lymph nodes are involved (N), and whether there is distant spread (M). Most tumors are caught early as small surface lesions with an excellent outlook. The key questions are how deeply the tumor has invaded, whether it can be removed or destroyed while preserving the eye, and whether higher-risk features call for radiation.
| AJCC TNM for conjunctival carcinoma | What it generally means |
|---|---|
| Surface / early (T1–T2) | Tumor limited to the ocular surface. Treated with surgical removal plus cryotherapy and/or topical chemotherapy drops, with excellent cure and eye preservation. |
| Locally invasive (T3) | Tumor invading deeper structures such as the eye or orbit. Treated with surgery and radiation, occasionally requiring removal of the eye if extensive. |
| Regional or distant spread (N+/M+, uncommon) | Spread to lymph nodes (such as in front of the ear) or distant sites. Managed with surgery, radiation, and systemic therapy as appropriate. |
The standard of care
Conjunctival Squamous Cell Carcinoma is almost always treated by a team that may include a surgeon, a medical oncologist, and a radiation oncologist, combining therapies for the best result. The usual building blocks are:
Surgical removal with cryotherapy
A 'no-touch' excision removes the tumor and freezing (cryotherapy) is applied to the edges to destroy residual cells, the traditional cornerstone for localized tumors.
Topical chemotherapy or immunotherapy eye drops
Drops such as mitomycin C, 5-fluorouracil, or interferon treat the entire ocular surface, useful as primary treatment or after surgery to reduce recurrence.
Radiation (plaque brachytherapy or external beam)
A small radioactive plaque placed against the eye, or external-beam radiation, treats higher-risk, recurrent, or incompletely removed tumors while preserving the eye.
Sun protection and risk-factor management
Ultraviolet protection and attention to HPV and immune status (including HIV) lower the risk of recurrence and new tumors; regular eye exams catch problems early.
How radiation treatment works
Radiation damages the DNA inside cancer cells so they can no longer divide and survive, while healthy cells repair themselves more effectively. In conjunctival squamous cell carcinoma, the most common form of radiation is plaque brachytherapy: a small disc holding a radioactive source is temporarily placed directly against the surface of the eye over the tumor bed, delivering a high, concentrated dose to the thin layer where the cancer lives while sparing the lens, retina, and optic nerve deeper inside. This is used for higher-risk, recurrent, or incompletely removed tumors and helps preserve the eye and vision. External-beam radiation may be used for more extensive disease. Radiation is given over a short period and, once the temporary plaque is removed, leaves no radioactivity in your body, so you remain safe to be around family and children. The overall goal is to control the cancer while keeping the eye.
The main ways radiation is delivered for conjunctival squamous cell carcinoma:
Surgery
A no-touch excision removes the visible tumor with a margin, combined with cryotherapy to the wound edges; reconstruction of the ocular surface may be needed for larger tumors.
Plaque brachytherapy
A small disc holding a radioactive source is temporarily stitched to the eye over the tumor bed, delivering a concentrated dose to the surface while sparing deeper eye structures.
Topical (eye-drop) therapy
Chemotherapy or immunotherapy drops bathe the whole ocular surface, treating diffuse or hard-to-reach disease without cutting, often over several weeks.
Latest studies shaping care
Care keeps improving — often toward getting the same excellent results with less burden on patients. A few developments:
Topical chemotherapy as effective primary treatment: Studies show that topical agents such as 5-fluorouracil, mitomycin C, and interferon can clear ocular surface squamous neoplasia with high success rates, either as primary treatment or to reduce recurrence after surgery.[1]
Ocular surface squamous neoplasia treatment reviews (2018–2024)
Plaque brachytherapy for high-risk and recurrent tumors: Ocular oncology series support plaque brachytherapy for invasive, recurrent, or incompletely excised conjunctival squamous cell carcinoma, achieving high local control with eye preservation.[2]
Conjunctival carcinoma brachytherapy series (2017–2024)
HPV, ultraviolet light, and immune status as risk factors: Research links conjunctival squamous cell carcinoma to ultraviolet exposure, HPV infection, and immunosuppression (including HIV), informing prevention and the more aggressive behavior seen in immunocompromised patients.[3]
OSSN epidemiology and HPV studies (2016–2023)
Common questions
Will I lose my eye? Almost always no. Most conjunctival squamous cell carcinomas are caught as surface tumors and are cured while fully preserving the eye and vision, using surgery, eye drops, and — when needed — plaque radiation. Removing the eye is reserved for rare, neglected, or deeply invasive tumors.
Can it be treated with eye drops instead of surgery? Often, yes. Topical chemotherapy or immunotherapy drops can treat the entire ocular surface and are used either as the primary treatment or after surgery to lower the chance of recurrence. Your ophthalmic oncologist will recommend surgery, drops, radiation, or a combination based on your tumor.
Why did I get this, and can I prevent another? Sun (ultraviolet) exposure, HPV infection, and a weakened immune system raise the risk. Protecting your eyes from the sun with sunglasses and a hat, and addressing immune-related conditions, lowers the chance of recurrence and new tumors. Regular eye exams help catch any new lesion early.
References
Numbered sources for the studies cited above. Links open the primary publication on PubMed or the publisher’s site.
- Ocular surface squamous neoplasia treatment reviews (2018–2024) (no indexed identifier — see your care team) ↩
- Conjunctival carcinoma brachytherapy series (2017–2024) (no indexed identifier — see your care team) ↩
- OSSN epidemiology and HPV studies (2016–2023) (no indexed identifier — see your care team) ↩