By Lorraine L. Janeczko
NEW YORK (Reuters Health) - 8/2/2019
How well orbital lymphoma (OL) patients do depends mainly on which of four subtypes they have, a new case series suggests.
Most OLs are of B-cell origin, and extranodal marginal zone B-cell lymphoma (EMZL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and mantle cell lymphoma (MCL) are the most frequent subtypes, researchers note in the American Journal of Ophthalmology, online November 9.
"The histological subtype was found to be the main predictor for outcome, with EMZL and FL patients having a markedly better prognosis than DLBCL and MCL," Dr. Steffen Heegaard of the University of Copenhagen and her colleagues report.
The team reviewed a series of cases to categorize the clinical features of subtype-specific OL in patients treated at seven eye cancer centers on several continents over 37 years.
The researchers reviewed the records of 797 patients with a histologically verified orbital lymphoma for data on survival, disease-specific survival, and progression-free survival. The median patient age was 64 and half were male.
Almost all the lymphomas (98%) were of B-cell origin. EMZL was the most frequent subtype (57%), followed by DLBCL at 15%, FL at 11% and MCL at 8%.
Localized Ann Arbor stage IE EMZL and FL were often treated with external beam radiation therapy, while DLBCL, MCL and disseminated EMZL and FL were mainly treated with chemotherapy.
EMZL and FL patients had much better 10-year disease-specific survivals (92% and 71%, respectively) than DLBCL and MCL patients (41% and 32%).
The new results are important, three experts who were not involved in the study told Reuters Health by email.
"The study further supports EMZL as the most frequent subtype of lymphoma involving the orbit and that, if the tumor is isolated to the orbit, it can be successfully treated with orbital irradiation and have an excellent prognosis," said Dr. Louise A. Mawn, a professor ophthalmology and neurological surgery at Vanderbilt University Medical Center in Nashville, Tennessee.
"The findings do not surprise me," she said. "The American Academy of Ophthalmology literature review published in January 2018 (cited by this current publication) also found that the majority of lymphomas involving the orbit were EMZLs and that they were successfully treated with orbital irradiation."
Dr. Mawn added that the study's "large volume of patients provides credible evidence of the efficacy of orbital irradiation for localized orbital involvement in a hematologic malignancy."
Dr. Anthony B. Daniels, an assistant professor of ophthalmology and visual sciences, cancer biology, and radiation oncology at Vanderbilt University Medical Center in Nashville, Tennessee, echoed Dr. Mawn's take on the findings.
"While not surprising, these results validate the approach of radiation monotherapy for localized, more-indolent orbital lymphomas such as extranodal marginal zone B-cell lymphoma and follicular lymphoma," Dr. Daniels said.
"The multi-institutional and international aspects of the study suggest that treatment choices at large referral centers around the world could potentially be guided by these study results, regardless of geographic setting," he added.
Dr. Krishna A. Rao, an associate professor in the department of internal medicine at the Southern Illinois University School of Medicine in Springfield, explained, "The orbit is a rare site of recurrence; thus, we have limited knowledge of the tumor's natural history, demographics, and subtypes. Confirming these facts in a multicenter international study... helps lay the foundation for understanding this entity."
In the future, he said, "studies may be initiated on specific subtypes of this entity in a prospective fashion to impact therapy, particularly for more aggressive variants." Dr. Heegaard was unable to respond by press time.
SOURCE: https://bit.ly/2Ag6xzN Am J Ophthalmol 2018.