Surgeons devise new protocol to classify stages of retinoblastoma

NEW YORK — A simpler classification system is warranted to assess, treat and predict the prognosis for retinoblastoma, Carol L. Shields, MD, told attendees here during the annual meeting of the American Society of Retina Specialists.

Current classification systems are hard to remember, too complex or obsolete, Dr. Shields said. To demonstrate this point, Dr. Shields and colleagues at Wills Eye Hospital classified 158 eyes with retinoblastoma according to both the current Reese-Ellsworth classification system and the Philadelphia classification system, which they developed.

When eyes were classified according to Reese-Ellsworth, Dr. Shields said she noted an “erratic correlation” between the stage of the disease and the success of the treatment. The Philadelphia system, in contrast, allowed researchers to accurately predict patient prognosis, she noted.

“It’s a nice smooth correlation with advancing degrees,” Dr. Shields said.

The Philadelphia system is based on five levels of clinical findings: tumor alone (group 1), tumor with subretinal fluid (group 2), tumor with focal seeds (subretinal seeds, group 3a; vitreous seeds, group 3b), tumor with diffuse seeds (subretinal seeds, 4a; vitreous seeds, 4b) and tumor with neovascular glaucoma or invasion into adjacent tissue (group 5).

All of the patients in group 1, 91% in group 2, 68% in group 3a, 54% in group 3b, 17% in group 4a and 11% in group 4b responded successfully to chemotherapy. Patients classified in group 5 were always managed by enucleation, according to Dr. Shields.

The Philadelphia classification is also easier to remember and less subjective than the Reese-Ellsworth classification, she said.