Evaluating the use of PET scanning after first-line treatment for follicular lymphoma

This study evaluated the value of PET (positron emission tomography) scanning after first-line (primary) chemoimmunotherapy in patients with previously untreated follicular lymphoma (FL). This study concluded that PET scanning is a better imaging technique than CT (computed tomography) for assessing treatment response in these patients.

Chemoimmunotherapy regimens involving rituximab (Rituxan) remain the standard of care for patients with FL. However, many patients eventually experience relapse (cancer recurrence). Approximately 20% of patients have a poor prognosis that does is not determined during CT scan diagnosis.

PET scanning after initial treatment can be used to evaluate how well a patient responds to treatment. This scan can help determine treatment outcomes for patients with FL. The results of the scan can then guide further treatment. The value of after-treatment PET scanning for patients with FL remains under investigation.

This study involved 1202 patients with previously untreated FL. Patients received first-line chemotherapy with either rituximab or obinutuzumab (Gazyva). Then, 595 (49.5%) patients underwent PET scanning before and after treatment. Only these patients were included in the current analysis. Patients were followed-up for an average of 43.3 months.

Overall, 81.7-86.9% of patients in the PET group responded to treatment. 65.5-75.6% of patients achieved a complete response (disappearance of all signs of cancer) determined by PET scanning. According to a CT scan, the complete response was achieved by 29.9% of patients.

At follow-up, the 2.5-year progression-free survival (patients still alive 2.5 years later without tumor growth or spread) was significantly higher in patients who achieved a complete response on PET scan than those who did not (87.4-87.8% vs. 54.9-72%). A complete response on PET scanning after first-line treatment was associated with a 60-80% lower risk of disease progression.

This study concluded that PET scanning is a better imaging technique than CT for assessing response to first-line chemoimmunotherapy in patients with FL.

This study was retrospective, meaning it looked back in time to analyze data. This study received funding support from Hoffman-La Roche, the manufacturer of obinutuzumab.