The Prognostic Value of PET/CT Following Induction Therapy in Follicular Lymphoma

A new retrospective study demonstrates the prognostic value of PET-CT scans for patients with follicular lymphoma.

Dr. Judith Trotman, reporting at the American Society of Clinical Oncology annual meeting, said that positron emission tomography–computed tomography performed at the end of induction therapy is strongly predictive of both progression-free and overall survival.

Her team analyzed data on 246 PET-CT scans performed following chemoimmunotherapy in three clinical trials. What they found was that patients with 18-fluorodeoxyglucose (FDG) uptake of 4 or greater on the 5-point Deauville scale for postinduction response assessment, had a four times higher risk for disease progression, compared with patients who became PET negative after induction.

At 4.5 years of follow-up, median progression-free survival (PFS) was 16.9 months for patients with a PET uptake of 4 or greater on the scale, versus 74 months for PET-negative patients.

Overall survival at 4.5 years for patients with a higher uptake of FDG PET was 87 percent, compared with 97 percent for patients who were PET negative after induction.

The study results also showed that conventional CT assessment provides only limited additional value, and that "PET-CT applying the 5-point scale should be the new gold standard for therapeutic response assessment in this lymphoma."

Added Dr. Trotman, "We argue that for the patients who remain PET positive, follicular lymphoma is no longer an indolent histology."

Source: ASCO