Ocular surface squamous neoplasia (OSSN) is a benign or malignant tumor of the ocular epithelium. Cancer can affect the conjunctiva and the cornea’s surface and sometimes penetrate the eyeball, orbit, and nasolacrimal system.

Risk factors for OSSN include exposure to solar UV-B radiation, cigarette smoke, human papillomavirus, human immunodeficiency virus, petroleum products, immunosuppressant medication after organ transplantation, and corneal transplantation.

OSSN is treated with topical agents such as mitomycin C, fluorouracil, and interferon-alpha-2b. The advantage of these drugs over the surgical treatment of OSSN is that they cover the entire surface of the eye, so they act not only on the affected area but also on distant parts of the eye, in which OSSN may develop asymptomatically.

Interferon-Alpha-2b is Safe to Treat OSSN

Interferon (IFN) is a signaling molecule that triggers an immune response against viruses and tumors. Interferon-alpha-2b is approved by the US Food and Drug Administration for treating chronic hepatitis B and C, human papillomavirus, AIDS-related Kaposi’s sarcoma, and certain cancers.

Compared to mitomycin C and fluorouracil, IFN-alpha-2b is more expensive, but interferon is the safest drug for treating OSSN:

Treating Efficiency

American scientists investigated the efficacy and safety of interferon-alpha-2b for treating patients with OSSN. The study involved 20 people. Patients received only topical interferon without subconjunctival injections. IFN-alpha-2b eye drops at a dosage of 1 million IU/ml were administered 4 times a day for at least 1 month after complete clinical resolution of the tumor. Treatment response was monitored at follow-up visits every 3–6 months. The duration of treatment varies depending on the cancer reaction.

Before treatment, patients received various OSSN therapies: surgical treatment, cryotherapy, local application of mitomycin C, and topical application of interferon-alpha-2b. The main reason for using local interferon-alpha-2b was the impossibility of surgical removal of the tumor and the poor visual acuity of the healthy eye.

Despite prior treatment, 23 different tumors were identified in 21 eyes in 20 patients at baseline. In none of the patients, cancer has spread to the lymph nodes or metastasized. The stages of the tumors included:

  • Tis – early cancer that has not spread to adjacent tissues – 13% of patients.
  • T3 – the tumor has grown into the ciliary body and/or choroid and spread to the eye’s sclera – 87% of patients.

Treatment Results

After topical treatment with interferon-alpha-2b, the tumor resolved entirely in 83% of cases, on average, within 6 months.

The surface area of ​​the tumor was reduced by:

  • 58% – up to 3 months;
  • 79% – from 3 to 6 months;
  • 98% – from 6 to 12 months;
  • 100% – from 12 to 24 months.

Tumors affecting the cornea were significantly reduced over an average of 6 months. Furthermore, tumors that do not affect the cornea – in 12 months.

In 17% of cases, the tumor resolved partially. During 4 months of treatment, the surface area of ​​the tumor decreased by an average of 44%. Subsequently, these patients underwent surgical or photodynamic therapy combined with a single subconjunctival injection of IFN-alpha-2b at a dosage of 5 million IU/ml.

One patient had multiple pre-existing ocular surface neoplasias and xeroderma pigmentosum, a disease that increases sensitivity to UV radiation. As a result of 4 months of treatment with interferon, the tumor in this patient decreased by 51%, after which the tumor area did not change for 8 months. This patient was recommended long-term local therapy with interferon-alpha-2b.

One patient with Tis stage OSSN had tumor recurrence after 3 months. Two patients with stage T3 OSSN developed a new tumor elsewhere within 8 months. Recurrent and new tumors were treated with cryotherapy, topical application of IFN-alpha-2b and/or surgical excision.

Visual acuity after treatment with interferon-alpha-2b:

  • improved by 3 or more lines – in 14% of cases;
  • remained stable with a difference of fewer than 3 lines – in 81% of cases;
  • deteriorated by 3 or more lines – in 5% of cases.

Decreased visual acuity was associated with cataract progression. There were no systemic metastases or deaths.

Side effects of topical interferon-alpha-2b for the treatment of OSSN

  • Conjunctival hyperemia – 10%.
  • Follicular hypertrophy – 10%.
  • Giant papillary conjunctivitis – 5%.
  • Irritation – 5%.
  • Damage to the corneal epithelium – 5%.
  • Flu-like symptoms – 5%.

All side effects disappeared within 1 month after topical therapy was discontinued.

Conclusion

Of the 23 ocular tumors, 83% resolved thoroughly after treatment with interferon-alpha-2b. The remaining 17% was resolved partially.

Cancer penetrated the lymph nodes and formed metastases in none of the cases. Entirely resolved in 6 months:

  • 67% of Tis tumors that have not spread to adjacent tissues;
  • 85% of stage T3 tumors have grown into the ciliary body and/or choroid and applied to the eye’s sclera.

Treatment with interferon-alpha-2b at a dosage of 1 million IU/ml rarely caused side effects. All side effects resolved spontaneously within 1 month after cessation of therapy.

Topical interferon-alpha-2b is effective and safe for treating squamous cell neoplasia of the ocular surface, not only a precancerous Tis condition but also stage T3, a more profoundly penetrating malignancy. Interferon treatment should only be initiated after histopathological confirmation of OSSN.

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Topical Interferon Alfa-2b for Management of Ocular Surface Squamous Neoplasia in 23 Cases

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