Ongoing Trial: The GABLE research study is comparing several different imaging methods to guide treatment for people with brain cancer

The most common type of brain tumor in adults is known as glioblastoma (GLEE-oh-blas-TOH-muh). It makes up about half of all brain cancer diagnoses. Unfortunately, because it is aggressive and fast-growing, it is difficult to treat, and survival rates are low. The standard first treatment is surgery to remove as much of the tumor as possible. Then, patients have radiation therapy and chemotherapy with a drug called temozolomide (teh-moh-ZOH-loh-mide). While this approach can help patients live longer, it is not a cure.

Currently, doctors use magnetic resonance imaging (MRI) to measure whether the treatment is working. However, sometimes MRI scans can give confusing results, and a brain tumor can look like it is still growing (progressing) when it is not. As a result, oncologists hesitate to give patients more treatment for progression until they can confirm tumor growth through more imaging. As with any cancer, waiting too long can make further treatment less effective, but treatment that is too early or too much can also carry risks and side effects.

The GABLE study, also known as EAF223, is comparing several different imaging methods to see which, if any, is better than MRI. The trial will also look at how accurate each imaging technique is at predicting treatment and survival outcomes. Researchers hope that this information will help doctors improve treatment plans for patients with glioblastoma.

To be eligible, patients must be newly diagnosed with glioblastoma and planning to receive the usual treatment of radiation therapy and chemotherapy. They must have already had surgery for this cancer within 7 weeks of starting the study (and no further surgeries planned or needed). They must have had two MRIs, one before surgery and one after.

All study patients will receive the usual treatment of radiation therapy and chemotherapy (temozolomide) at the same time. Then, they will have a standard MRI scan as part of the routine imaging they would normally receive. If doctors notice certain changes on the MRI, they will perform a different type of imaging using positron emission tomography (PET). This special imaging method (called 18F-fluciclovine PET) is already approved by the US Food and Drug Administration for patients with prostate cancer.

The first 60 patients in GABLE will have PET scans. Then, the study will briefly pause so researchers can review the results. If the PET scan appears to be helpful, the study will continue as planned. If the PET scan does not appear to be helpful, the rest of the patients who join the trial will instead have a different kind of imaging called magnetic resonance spectroscopy (spek-TROS-kuh-pee). All patients in the study will be followed by their doctor for up to 6 years.

Learn more about GABLE (EAF223) at ecog-acrin.org.