Hodgkin Lymphoma: the Changing Role of Radiation Therapy in Early-Stage Disease—the Role of Functional Imaging

Patterns of Failure and Survival Outcomes after Total Lymphoid Irradiation and High-Dose Chemotherapy with Autologous Stem Cell Transplantation for Relapsed or Refractory Classical Hodgkin Lymphoma

PURPOSE

The patterns of failure and long-term outcomes of patients with relapsed or refractory classical Hodgkin lymphoma treated with total lymphoid irradiation (TLI) and high-dose chemotherapy followed by autologous stem cell transplantation (aSCT) are reported.

METHODS AND MATERIALS

Patients with biopsy-proven primary refractory or relapsed classical Hodgkin lymphoma who received salvage chemotherapy and accelerated hyperfractionated TLI before high-dose chemotherapy and aSCT were included. Patterns of failure were delineated after fusing pretransplant planning computed tomography to the scan reporting the first failure. Survival rates were computed using the Kaplan-Meier method. Multivariate analysis using proportional hazards regression was done to determine prognostic factors for overall survival (OS) and progression-free survival (PFS).

RESULTS

Between 1993 and 2016, 89 patients underwent salvage treatments. Twenty patients failed at a median of 6.1 months after aSCT. Posttreatment scans were available for 16 patients who failed in a combined 43 different sites, 11 of which were extranodal. Patients failed at multiple sites, mostly within radiation fields. The 5-, 10-, and 15-year OS rates were 72.8%, 68.0%, and 58.3%; PFS rates were 73.3%, 68.5%, and 58.7%; event-free survival rates were 72.3%, 67.5%, and 57.8% respectively. The 5- and 10- year actuarial local control rates were both 77.6%. Complete response (CR) to salvage chemotherapy was associated with statistically significant improvements in OS and PFS. Eight patients developed secondary malignancies; 5 were hematologic and 3 were solid tumors.

CONCLUSIONS

Most failures were within the irradiated volume, which reflects the treatment-resistant disease biology. As part of a conditioning regimen, TLI yields good survival outcomes, particularly in patients achieving CR before transplant. However, need for RT in this setting should be assessed and new strategies should be developed to combat the treatment-resistant biology, especially in patients with less than CR after salvage chemotherapy.

Role of FDG PET-CT in the treatment management of Hodgkin lymphoma

Fluorodeoxyglucose (FDG) positons emission tomography (PET)-computed tomography (CT) is used in many ways at baseline and during the treatment of patients with Hodgkin lymphoma. Many properties of the technique are used in the different steps of patient's management. Initial staging with PET-CT is more accurate than conventional imaging and PET-CT also became the gold standard imaging at the end of treatment with a negative PET-CT mandatory for reaching a complete remission. Early assessment of response by PET-CT is one of the most powerful prognostic factors for progression-free survival of patients with localized and advanced stages and allows guiding treatment. Conversely, previous studies showed that there is no role of FDG PET-CT for the patient's follow-up.

Racial and Ethnic Disparities in the Pediatric Hodgkin Lymphoma Population

BACKGROUND

Little is known about the association between race/ethnicity and survival in pediatric Hodgkin lymphoma (HL) patients. In a state-wide pediatric cohort diagnosed with HL, we assessed demographic, disease, and treatment characteristics associated with overall survival (OS). We then attempted to validate these findings and assess disease-specific survival (DSS) in a national Surveillance, Epidemiology, and End Results (SEER) cohort.

PROCEDURE

HL patients of 0.1-21 years diagnosed from 1981 to 2010 were evaluated using the Florida Cancer Data System (FCDS). Kaplan-Meier curves estimated OS from 5 to 25 years based on race/ethnicity, treatment, decade of diagnosis, and sex. Multivariate Cox proportional hazard regressions tested independent factors associated with differences in OS. These methods were replicated in the SEER with additional assessment of DSS.

RESULTS

A total of 1,778 patients were identified in the FCDS and 6,027 in the SEER. Median diagnosis age was 17 years in both cohorts. In the FCDS, Blacks had worse OS than Whites and Hispanics at 25 years (33% vs. 49.2% vs. 44.7%, respectively; P = 0.0005), and Black race was associated with inferior OS on multivariate regression (hazard ratio [HR]: 1.81, P = 0.0003). In the SEER, Blacks had inferior OS (Blacks 74.2% vs. Whites 82% vs. Hispanics 82%; P = 0.0005) and DSS (85.7% vs. 90.8% vs. 88.1%, respectively; P = 0.0002) at 25 years. Hispanic males had inferior DSS compared to White males (84.8% vs. 90.6%; P = 0.0478), and Hispanic race was a predictor for inferior DSS on multivariate analysis (HR: 1.238; P < 0.0001).

CONCLUSIONS

Racial/ethnic disparities persist in the pediatric HL population despite modern treatment; underlying causes of these disparities are complex and need further examination.