MIAMI BEACH – Patients with Hodgkin’s lymphoma may be spared additional radiotherapy following chemotherapy if they have a negative positron-emission tomography result, investigators from the German Hodgkin Study Group reported.
The negative predictive value for FDG (18fluorodeoxyglucose)–PET at 1 year was 94%, said Dr. Rolf P. Mueller of the University of Cologne (Germany). Among patients who had residual tumors measuring 2.5 cm or greater in diameter following chemotherapy, only 4% of those who were negative for residual disease on FDG-PET scans relapsed or required additional radiotherapy, compared with 11% of FDG-PET–positive patients.
Dr. Rolf P. Mueller
"Thus, only those advanced-stage Hodgkin lymphoma patients with residual disease who are PET-positive patients might need additional radiotherapy," Dr. Mueller said at the annual meeting of the American Society of Radiation Oncology (ASTRO).
The investigators also found a significant difference in time-to-progression favoring PET-negative patients (P =.008) with Hodgkin’s lymphoma, also known as Hodgkin’s disease.
The percentage of patients who received radiation in this clinical trial, designated GHSG (German Hodgkin Study Group) HD-15, was 11%, compared with 70% of patients in the group’s GHSG-9 trial, Mueller noted. GHSG-15 studied the role of FDG-PET for evaluating residual disease and relapse risk among patients with advanced-stage Hodgkin’s lymphoma who had undergone six to eight cycles of chemotherapy with the BEACOPP regimen (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone) (J. Clin. Oncol. 2003;21:1734-9).
Early results were published in 2008 (Blood 2008;112: 3989-94). In the current report, Mueller presented data on a larger cohort.
All patients with a partial response or better and a residual mass measuring 2.5 cm or greater received FDG-PET scans. Of the 728 patients with residual disease following BEACOPP, 540 (74.2%) were PET negative, and 188 were PET positive. Mueller presented data on 701 patients who had at least 1 year of follow-up.
At 1 year, 96% (522) of PET-negative patients had neither progression nor relapse, compared with 11% of those who were PET positive. Of the PET-negative patients, 23 experienced disease progression (eight in the residual mass, six with new disease outside of the mass, and nine with progression/relapse in both areas). An additional eight PET-negative patients required additional radiotherapy.
The study was funded by the member centers of the GSHG. Dr. Mueller had no conflict of interest disclosures.