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OCULAR PATHOLOGY : FROM IMMEDIATE ASSESSMENT FOR EYE TUMORS TO BETTER HEADGEAR FOR ASTRONAUTS A check of the biopsy tissue for adequacy of tumor sampling assures that tumoral tissue has been obtained and that enough material is available for diagnosis and molecular prognostic profile. This aids the surgeon in diagnosis and determines the course of treatment and follow-up for the patient.
Dr. Patricia Chévez-Barrios is the director of the Ocular Pathology Research Laboratory at Houston Methodist Hospital. She is one of three pathologists worldwide participating in the first prospective, multicenter, multinational trial of retinoblastoma, the most common ocular malignancy in children. This trial established treatment criteria and protocols for retinoblastoma after eye removal. “If the tumor is inside of the eye, then it’s curable about 96 percent of the time. But if the tumor is outside of the eye, especially when it is spreading to the brain, the mortality rate is very high, and the cure rate drops to 20 percent or lower,” says Dr. Chévez-Barrios.
Most recently, the Houston Methodist Department of Pathology and Genomic Medicine teamed with NASA to study the impact of space travel on vision. By examining the eyes of mice sent to the International Space Station for 13 days, the ocular pathologist is able to observe certain oxidative and mechanical changes. Early cataract formation, macular degeneration and possible mechanical changes in the back of the eye and optic nerve have been observed in astronauts. Work in this area may lead to better understanding the role of insulation in exposure to radiation (the cause of oxidative damage) and against potential trauma caused by forceful acceleration at takeoff and reentry as well as the mechanical stresses caused by different fields of gravity.
A more surprising ocular malignancy is melanoma. Research in the past decade has shown that certain types of molecular changes act as a signal to identify patients who may develop metastatic disease. A tissue sample from the intraocular tumor is required for molecular testing which, historically, has not been part of the diagnosis and treatment of these patients. Pathologists at Houston Methodist employ a method for testing the adequacy of tumor sampling during the surgical procedure. “We have a mobile microscope and stains. We go to the OR with our microscope and are there with the surgeon who is doing the intraocular biopsy. The surgeon aspirates a small amount of tissue and we can do an ‘adequacy check’ right there,” says Dr. Chévez-Barrios.
“If the tumor is inside of the eye, then it’s curable about 96 percent of the time. But if the tumor is outside the eye, especially in the brain, the mortality rate is very high, and the cure rate drops to 20 percent.” Patricia Chévez-Barrios, MD
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Houston Methodist Department of Ophthalmology