Clinical Characteristics and Survival Outcomes of Primary Effusion Lymphoma: A National Cancer Database Study

Introduction: Primary effusion lymphoma (PEL) is a rare HHV8(+) non-Hodgkin lymphoma associated with HIV infection or other causes of immunosuppression. Large-scale studies describing the natural history of this entity are lacking.

Materials and methods: National cancer database (NCDB) was queried for patients diagnosed with PEL between 2004 and 2016. All patients age ≥ 18 years diagnosed with PEL were included. We excluded patients with multiple primary malignancies or lost follow-up. Kaplan-Meier and multivariate cox regression were used in the analyses.

Results: Of the 219 PEL patients included in the analysis, 179 (82%) were males, 161 (74%) Caucasian and 49 (22%) African American. Median age at diagnosis was 60 ± 19 years and median OS (mOS) was 8.5 months. One hundred and fifteen were HIV+, 63 HIV-, 111 received chemotherapy, and 101 did not. Patients who received chemotherapy had better mOS compared to patients who did not receive chemotherapy (13 vs. 3 months, P < .001). This difference was observed in HIV+ patients (22.97 vs. 1.97 months, P = .006), but not in HIV- patients (6.24 vs. 8.20 months, P = .752). On multivariate analysis, chemotherapy treatment was associated with better OS (HR 0.502 95% CI 0.324-0.777; P = .002), whereas HIV status did not affect the OS (HR 0.6 95% CI 0.3-1.4; P = .258).

Conclusion: This largest retrospective analysis on PEL revealed that current chemotherapeutic approach is significantly beneficial for HIV+ patients but not for HIV- patients. The rapid advancement in HIV treatment might be playing a role in survival improvement among HIV+ patients. Novel therapies are needed to improve the survival of patients with PEL, especially in HIV- patients.

Microabstract: PEL is a rare HHV8(+) non-Hodgkin lymphoma. Using national cancer database, we studied clinical characteristics, and outcomes of 219 PEL patients. We found that chemotherapy significantly improved overall survival in HIV+ patients. However, a similar survival improvement was not seen in HIV- patients. Significant improvement in efficacy of antiretroviral therapy is likely contributing to the survival improvement in HIV+ patients.