Can FDG-PET/CT help predict T-cell therapy outcomes for patients with B-cell NHL?

This study investigated the role of PET/CT scanning in the treatment of patients with recurrent or hard-to-treat B-cell non-Hodgkin’s lymphoma (NHL) after T-cell therapy. This study found that PET/CT scanning helped predict the effectiveness and side effects of treatment for these patients.

Chemoimmunotherapy remains the standard first-line treatment for patients with B-cell NHL. While most patients respond to treatment, relapse (cancer recurrence) is common. Many patients also develop tumors that no longer respond to treatment (refractory). FDG-PET/CT scanning is used to evaluate how well patients respond to treatment. This scanning is used to visualize the cancer cells and help guide the course of treatment.

CAR T-cell therapy helps the immune system fight cancer cells. This treatment is usually given after chemotherapy. First, T-cells (immune cells) are removed from the blood and genetically modified to make a special protein called CAR. This protein helps the T-cells attack cancer cells. Then, these CAR T-cells are reintroduced into the patient to attack the cancer cells. It is unclear whether FDG-PET/CT scanning can help predict T-cell therapy outcomes for patients with B-cell NHL.

This study looked at the results of a study that included 41 patients with relapsed or refractory B-cell NHL. FDG-PET/CT scanning was used before and after treatment to evaluate how well these patients responded to CAR T-cell therapy. Patients were followed up for an average of 7 months.

At follow-up, 92.7% of all patients responded to treatment. 58.5% achieved a complete response (no signs of cancer after treatment; CR). 34.1% achieved a partial response (tumor shrinkage). On average, patients were still alive for an average of 209 days, with an average of 132 days of no tumor growth or spread.

FDG is a radioactive form of glucose (sugar) that can be detected on a scan. Cancer cells absorb more FDG than healthy ones, so a high FDG uptake means that there are more cancer cells present. Significantly more patients with lower FDG uptake were still alive 1 year later than patients with higher uptake (100% vs. 44.9%). Also, significantly more patients with lower uptake were still alive without tumor growth or spread (59.6% vs. 0.0%).

Cytokine release syndrome (CRS) is a side effect of T-cell therapy. The treatment triggers the massive release of molecules called cytokines, which leads to various symptoms such as fever, tiredness, joint and muscle pain, or digestive problems. 82.9% of all patients developed CRS. 14.6% of cases were moderate. A high FDG uptake was significantly associated with 48.1% higher odds of developing CRS.

Coagulation disorders (blood unable to form clots) are another side effect of CAR T-cell therapy. 85.4% of patients had this side effect. Significantly more patients who had a high FDG uptake had this side effect than patients who had a lower uptake (25 patients, 96.2% vs. 6 patients, 54.5%).

This study found that PET/CT scanning helped predict the effectiveness and side effects of treatment for these patients. The authors suggest that this scanning may help guide chemotherapy treatment given before T-cell therapy.

This study looked back in time to analyze medical records data. This study also had a small number of patients. Larger studies are needed to confirm these results.