Can PET scanning help guide treatment for patients with Hodgkin’s lymphoma?

This study evaluated whether PET scanning after chemotherapy might help predict outcomes and guide treatment for patients with early-stage Hodgkin's lymphoma (HL). This study found that PET scanning can help identify high-risk patients after chemotherapy.

Chemotherapy combined with radiotherapy is the standard of care for patients with HL. This combination is called CMT (combined-modality treatment). CMT is highly effective for 90% of patients.

However, radiotherapy carries a risk of developing secondary cancer later on. PET scanning during treatment may be able to help identify low-risk patients who respond to chemotherapy and do not need radiation. Whether some patients might be able to avoid radiotherapy is unclear.

This study included 1150 patients with HL. Patients were divided into two groups. 575 patients received CMT and 575 patients received chemotherapy only. After 2 cycles of chemotherapy, these patients had PET scans. Only patients with positive scan results (cancer is still present) received radiotherapy. Patients were followed for an average of 45 months.

Overall, 628 patients had negative PET scans after chemotherapy. Of these, 328 received CMT and 300 had chemotherapy only.

Slightly fewer patients who had CMT were still alive 5 years later compared to patients who had chemotherapy only (98.1% vs. 98.4%). However, more patients in the CMT group survived without the cancer worsening compared to the chemotherapy group (93.4% vs. 86.1%). CMT was significantly associated with a 78% lower risk of the cancer worsening.

After PET scanning, 693 patients received radiotherapy. Of these, 353 patients had negative PET scans and 340 patients had positive PET scans. Significantly more patients with negative scans survived without the cancer worsening compared to patients with positive scans (93.2% vs. 88.4%).

This study found that PET scanning after chemotherapy can help identify patients with high-risk HL. The authors suggest that radiotherapy should be given to all patients after chemotherapy to help get rid of any remaining cancer.

This study could not evaluate the long-term effects of radiation treatment because they can occur 20 years after therapy.