Study: PET-CT scan better than CT scan in predicting relapse of follicular lymphoma

The Discover IQ PET-CT scanner.--Courtesy of GE

Positron emission tomography/computed tomography (PET-CT) rather than conventional CT scanning should be used to image and assess follicular lymphoma, concludes a study in The Lancet Haematology.

"Our findings have important implications for patients with follicular lymphoma, a common and usually slow-growing lymphoma. Compared to conventional CT scanning, PET-CT is more accurate in mapping out the lymphoma and better identifies the majority of patients who have a prolonged remission after treatment," said study co-author Dr. Judith Trotman of the University of Sydney, Australia, in a statement.

PET-CT scanning is better at distinguishing between patients who are in prolonged remission and those likely to relapse following chemotherapy, as it employs the tracer molecule 8F-fluorodeoxyglucose to detect lymphoma cells, the authors say in the release.

The study analyzed data from 246 patients who were given both types of imaging within three months of their last dose of chemotherapy. Of patients receiving positive PET-CT scan, 23.2% were progression-free at four years, compared to 63.4% of patients with a negative PET-CT scan. The groups' four-year survival rate was 87.2% and 97.1% respectively. Those with positive PET-CT scan were 3.9 times more likely to experience progression-free survival based on a median follow-up of 54.8 months, while those with a positive CT scan were only 1.7 times more likely.

"Our study shows that PET-CT is much better in evaluating treatment response and is an early predictor of survival. This greater accuracy will assist physicians to more effectively monitor their patients. We expect this research will result in PET-CT imaging replacing CT, becoming the new gold standard to evaluate patients with follicular lymphoma after treatment. Importantly, it will be a platform for future studies of response-adapted therapies aimed to improve the poor outcomes for those patients who remain PET positive," Trotman said in a statement.

Follicular lymphoma is the most common type of non-Hodgkin lymphoma, according to the Lymphoma Research Foundation. Non-Hodgkin lymphoma is a type of cancer that that starts in the body's immune system cells known as lymphocytes.

GE Healthcare ($GE), Siemens and Philips Healthcare ($PHG) make both types of imaging devices.

- read the release
- here's the study abstract