Conjunctival squamous cell carcinoma (CSCC) is a malignant growth that develops on the conjunctiva. This clear, thin membrane covers the white part of the eye, known as the sclera, and lines the inner surface of the eyelids. While a form of cancer, CSCC typically exhibits a slow growth pattern, allowing for timely identification.
Causes and Risk Factors
Exposure to ultraviolet (UV) radiation from sunlight is a primary cause of conjunctival squamous cell carcinoma. Prolonged exposure to UV-B rays can damage DNA in conjunctival cells, leading to uncontrolled growth. Individuals living closer to the equator or those with outdoor occupations often face higher cumulative UV exposure, increasing susceptibility.
Infection with certain types of human papillomavirus (HPV) is another factor in some CSCC cases. High-risk HPV types, such as 16 and 18, have been detected in conjunctival tumor samples, suggesting a link to cellular changes that form these growths.
Conditions that weaken the immune system also increase the risk of CSCC. Immunosuppression, such as from HIV/AIDS or medications after an organ transplant, reduces the body’s ability to fight abnormal cell proliferation. This diminished immune surveillance allows potentially cancerous cells to grow unchecked.
Other risk factors include advanced age, with higher incidence in older populations, and male gender, which shows slightly higher prevalence. Smoking is also a contributing factor.
Symptoms and Diagnosis
Conjunctival squamous cell carcinoma often presents as a visible growth on the white part of the eye, usually near the limbus, the border between the cornea and sclera. This growth can appear pinkish, white, or yellowish, sometimes with a gelatinous or fleshy texture, and may have fine blood vessels on its surface. Patients might also notice persistent localized redness that does not resolve with typical eye drops.
A common complaint is a persistent feeling of having a foreign body or something irritating in the eye, along with general discomfort. If the growth extends onto the cornea, it can cause blurred vision or changes in the eye’s surface. These symptoms prompt a visit to an ophthalmologist for a thorough examination.
The diagnostic process begins with a comprehensive visual examination by an ophthalmologist using a slit lamp. This specialized microscope allows for a magnified view of the eye’s surface, enabling the doctor to assess the size, shape, and characteristics of any suspicious lesions. The definitive diagnosis of CSCC requires a biopsy.
During a biopsy, a small tissue sample is removed from the suspicious growth and sent to a pathology laboratory for microscopic examination. Pathologists analyze the cells to confirm squamous cell carcinoma and determine its characteristics. Impression cytology, a less invasive technique, can also be used; it involves gently pressing a special filter paper onto the lesion to collect surface cells for analysis, providing a preliminary indication of the growth’s nature.
Treatment Modalities
Surgical excision is the primary treatment for conjunctival squamous cell carcinoma. The goal is to completely remove the tumor while preserving healthy tissue. Surgeons carefully cut out the visible lesion along with a small margin of surrounding healthy conjunctiva to ensure no cancerous cells remain.
Following surgical removal, adjunctive therapies are often used to reduce recurrence. Cryotherapy, which involves freezing tissue, is applied to the edges of the surgical site. This technique helps destroy any microscopic cancer cells left behind after excision, minimizing the risk of local recurrence.
Topical chemotherapy eye drops are another common adjunctive treatment. Medications such as Mitomycin C, 5-fluorouracil (5-FU), or Interferon alfa-2b are applied directly to the eye, typically for several weeks or months after surgery. These drops work by inhibiting the growth of remaining cancerous cells or stimulating the immune system to target them. The specific choice of medication and duration of treatment depend on the tumor’s characteristics and the individual patient’s needs.
For more advanced cases or tumors difficult to remove surgically, plaque radiation therapy may be considered. This involves placing a small, radioactive disc directly onto the eye near the tumor for a specific period. The radiation emitted from the plaque targets and destroys cancerous cells while minimizing damage to surrounding healthy ocular structures.
Prognosis and Recurrence
The long-term outlook for individuals diagnosed with conjunctival squamous cell carcinoma is favorable, especially when identified and treated early. The localized nature of most CSCCs contributes to a high success rate with appropriate therapeutic interventions. The primary concern after initial treatment is the potential for local recurrence, meaning the tumor reappears in or near the original site.
Regular follow-up appointments with an ophthalmologist are important for all patients. These appointments involve detailed examinations of the eye’s surface using a slit lamp to monitor for any signs of new growths or changes. The frequency of these check-ups may decrease over time but often continues for several years to ensure long-term surveillance.
Adopting preventative measures after treatment is important for reducing future risk. Consistently wearing sunglasses that block 99-100% of both UVA and UVB radiation can significantly limit ocular exposure to harmful ultraviolet rays. This measure directly addresses a primary risk factor, contributing to the prevention of new or recurrent lesions on the conjunctiva.