Although surgery is still the gold standard for ocular surface tumors, consider the pros and cons of topical chemotherapy as appropriate.
Reviewed by Kathryn A. Colby, MD, PhD
Determining the best treatment for ocular surface tumors is not always easy, said Kathryn A. Colby, MD, PhD.
As an example, Dr. Colby shared a challenging case of a healthy Caucasian woman in her early 50s who had an amelanotic conjunctival and corneal lesion for the past 7 years. The lesion had some recent growth. The patient had no personal or family history of malignancy.
“We discussed at length the options, including what I consider the gold standard--surgical excision with cryotherapy and ocular surface reconstruction--versus preoperative chemotherapy to reduce the size of the tumor, especially with the large corneal component,” said Dr. Colby, the Louis Block Professor of Ophthalmology and Visual Science, and Chair, Department of Ophthalmology and Visual Science, The University of Chicago Medicine and Biological Sciences, Chicago.
The patient opted to try topical chemotherapy with interferon alpha-IIb (1 million units four times a day).
Per Dr. Colby’s usual protocol with topical interferon, she had the patient return at 4 to 6 weeks to see if the lesion had some response.
“There was no issue with tolerability, but the lesion was larger, and there was now pigment on the surface,” Dr. Colby said.
After surgery the following day, pathology examination revealed that it was a malignant amelanotic melanoma. Since surgery, the patient has done well.
However, Dr. Colby believes the challenge with this case raises questions about the best management of ocular surface tumors. Some pearls include the following:
1. Consider surgery first
This is what Dr. Colby still considers the gold standard. It also enables the surgeon to provide a definitive diagnosis. This can be useful for tumors of different types that can have a similar appearance.
2. Weigh the pros and cons of chemotherapy
Topical chemotherapy, which is not approved by the FDA, treats the entire ocular surface.
“We know ocular surface squamous neoplasia [OSSN] results from sun exposure,” she said. “It makes sense that the whole surface of the exposed conjunctiva is at risk.”
Another advantage is it avoids the risk of scarring and infection that can occur with surgery. Topical chemotherapy works well in some patients, and overall, it is less expensive for the health-care system.
However, she adds that response to topical chemotherapy can be slow (taking months for lesion resolution) and does not provide a tissue-based diagnosis.
Many times, insurers--who tend to balk because it is not FDA approved-do not approve it.
“I have very poor luck in getting topical chemotherapy approved despite my pleading with them,” Dr. Colby said.
Literature reports show that interferon can be used topically or subconjunctivally with success for OSSN at 1 million units per cc. It also can reduce recurrence in the setting of topical margins, Dr. Colby said.
For now, there are no prospective, randomized trials to determine definitively if surgery or topical interferon treatment is better for OSSN, she added.
3. Do not violate Bowman's membrane
If opting for surgery, be careful not to violate Bowman’s membrane, which is a natural barrier against the tumor spreading in the cornea.
4. Use cryotherapy as an adjuvant
It is clear from the literature that not applying cryotherapy at the time of the initial surgery increases the risk of tumor recurrence.
For conjunctival melanoma, lack of cryotherapy also increases the risks of metastasis and death.
5. Reconstruct the ocular surface with amniotic membrane
“I’m a big fan of amniotic membrane,” Dr. Colby said. “You can take more uninvolved tissue around the tumor and still have a wonderful outcome.”
6. Treat the entire patient
“I’ve treated many skin cancers just by looking at the patient before I sit down and turn the lights out,” she said. Encourage patients with ocular surface tumors to see a dermatologist for a skin evaluation
7. Consider new technology to help with diagnoses
Dr. Colby cited the work of Carol Karp, MD, of Miami, which has shown that high-resolution anterior segment OCT can help distinguish squamous lesions from amelanotic melanoma. She also praised Dr. Karp’s published reports in the area of ocular surface tumors and interferon.
Kathryn A. Colby, MD, PhD
This article was adapted from Dr. Colby’s presentation during Cornea Subspecialty Day at the 2016 meeting of the American Academy of Ophthalmology. She has no related disclosures.