Fewer than 8% of cases of nodular lymphocyte–predominant Hodgkin lymphoma (NLPHL) transformed to diffuse large B-cell lymphoma (DLBCL), based on a large prospective single-center study with long-term follow-up.
This rate was lower than the risk of transformation reported for transformed follicular lymphoma or chronic lymphocytic leukemia, according to Dr. Saad Kenderian and his associates at the Mayo Clinic, Rochester, Minn. Transformation was significantly associated with splenic involvement at presentation and with prior chemotherapy exposure, but did not worsen overall survival, they added.
“To our knowledge, this cohort represents the largest analysis to date of consecutive patients with NLPHL,” they said.
The study comprised 222 patients with newly diagnosed NLPHL who were treated at Mayo Clinic between 1970 and 2011. Median age at diagnosis was 40 years, and two-thirds of patients were men. The median follow-up period was 16 years (Blood 2016;12:1960-6. doi: 10.1182/blood-2015-08-665505).
During follow up, 17 cases (7.6%) transformed to DLBCL, for a transformation rate of 0.74 cases for every 100 patient-years, the investigators said. Median time to transformation was 35 months (range, 6-268 months). Predictors of transformation included any prior chemotherapy exposure (P = .04) and splenic involvement (P = .03). The rates of 40-year freedom from transformation were 87% when there was no splenic involvement and 21% when the spleen was involved, and were 87% if radiation therapy was used as a single modality compared with 77% in patients treated with prior chemotherapy or chemoradiation.
Five-year overall survival was 76% in patients with transformed disease, which was similar to overall survival among patients whose disease did not transform to DLBCL, the researchers noted.
Other studies of NLPHL have reported anywhere from a 2% to a 17% transformation rate, but those studies had smaller sample sizes, shorter follow-up periods, and less rigorous enrollment criteria and methods to confirm transformation, the investigators noted. “The finding of splenic involvement as a risk factor for transformation was reported by previous investigators. Interestingly, the association between exposure to prior chemotherapy and reduced freedom from transformation has not been reported in the past, but it has been observed in other low-grade lymphoma studies,” they added. “In contrast to follicular lymphoma, transformed NLPHL is not associated with an adverse impact on OS, suggesting a possibly different biology of transformation.”
The research was partially supported by Lymphoma SPORE and the Predolin Foundation. The investigators had no disclosures.