Predictive role of positron emission tomography in the outcome of patients with follicular lymphoma.

PURPOSE

The purpose of this study was to evaluate the reliability of positron emission tomography (PET) in patients with follicular lymphoma (FL) after induction treatment.

PATIENTS AND METHODS

In all, 45 previously untreated patients with FL were studied with PET and computed tomography (CT) scans after chemotherapy induction treatment (fludarabine-containing regimens and CHOP [cyclophosphamide/doxorubicin/vincristine/prednisone] chemotherapy). Histopathologic analysis was performed when considered necessary.

RESULTS

After treatment, 4 of 5 patients (80%) who had CT-negative/PET-positive findings experienced relapse/progression, compared with only 1 of 22 patients (4.5%) in the CT-negative/PET-negative subset. Among the 18 patients with CT-positive findings, all 6 patients (100%) who had PET-positive findings experienced relapse or progression, compared with 1 of 12 patients (8.3%) who had PET-negative findings. The 2-year progression-free survival rates were 20% and 90% in the CT-negative/PET-positive and CT-positive/PET-negative subsets, respectively (P = 0.0031). During the follow-up, 2 patients, who presented a PET positivity with a negative CT scan, underwent a lymph node biopsy, which confirmed the presence of FL infiltration.

CONCLUSION

In patients with FL, persisting PET positivity is predictive of early disease progression, because it is still highly likely that patients with PET-negative findings will ultimately progress, but this has not yet been manifested during the period of observation.