The impact of radiation therapy in patients with diffuse large B-cell lymphoma with positive post-chemotherapy FDG-PET or gallium-67 scans.
BACKGROUND
2-[fluorine-18]fluoro-2-deoxy-D-glucose-positron emission tomography (PET) and gallium-67 citrate (gallium) response after chemotherapy are powerful prognostic factors in diffuse large B-cell lymphoma (DLBCL). However, clinical outcomes when consolidation radiation therapy (RT) is administered are less defined.


METHODS
We reviewed 99 patients diagnosed with DLBCL from 1996 to 2007 at Duke University who had a post-chemotherapy response assessment with either PET or gallium and who subsequently received consolidation RT. Clinical outcomes were estimated using the Kaplan-Meier method and compared using the log-rank test.


RESULTS
Median follow-up was 4.4 years. Stage distribution was I-II in 70% and III-IV in 30%. Chemotherapy was R-CHOP or CHOP in 88%. Median RT dose was 30 Gy. Post-chemotherapy PET (n = 79) or gallium (n = 20) was positive in 21 of 99 patients and negative in 78 of 99 patients. Five-year in-field control was 95% with a negative PET/gallium scan versus 71% with a positive scan (P < 0.01). Five-year event-free survival (EFS; 83% versus 65%, P = 0.04) and overall survival (89% versus 73%, P = 0.04) were also significantly better when the post-chemotherapy PET/gallium was negative.


CONCLUSIONS
A positive PET/gallium scan after chemotherapy is associated with an increased risk of local failure and death. Consolidation RT, however, still results in long-term EFS in 65% of patients.
Dorth
J A
JA
Department of Radiation Oncology, Division of Medical Oncology, Duke University Medical Center, Durham, USA.
Chino
J P
JP
Prosnitz
L R
LR
Diehl
L F
LF
Beaven
A W
AW
Coleman
R E
RE
Kelsey
C R
CR
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D005710:Gallium Radioisotopes; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography
D000970:Antineoplastic Agents; D005710:Gallium Radioisotopes; D019788:Fluorodeoxyglucose F18