Most people diagnosed with early-stage, or limited, diffuse large B-cell lymphoma (DLBCL) may be able to safely skip radiation treatment after a clear positron-emission tomography (PET) scan, according to new clinical trial results from SWOG presented by Persky et al at the 2019 American Society of Hematology (ASH) Annual Meeting & Exposition (Abstract 349).
Daniel Persky, MD
Daniel Persky, MD, Associate Professor at the University of Arizona Cancer Center and lead investigator of the SWOG study, said the research results are good news for patients. “Radiation treatment, like all cancer treatments, has side effects,” he said. “It can be painful and cause rashes or burns, as well as fatigue. It can also increase patients' risk of developing other cancers. If we can spare people the pain, time, and cost of radiation and give a simpler course of treatment, it's a win.”
Methods
Dr. Persky and his team enrolled 132 eligible patients with stage I and II DLBCL for the trial. There was no age limit for enrollment, so patients skewed older, with a median age of 62 years. All patients received standard rituximab/cyclophosphamide/doxorubicin/vincristine/prednisone (R-CHOP) therapy, and then underwent a PET scan after their third cycle of treatment. Scans were reviewed by the same group of radiologists in real time.
Patients with a negative PET scan received one additional cycle of R-CHOP to complete their treatment, for a total of four rounds of chemotherapy. Patients with a positive scan underwent involved-field radiation therapy (IFRT) to their affected lymph nodes and a booster treatment in areas where the scans showed fast-growing cancer cells. Three to 6 weeks later, these patients received treatment with ibritumomab tiuxetan, a radioimmunotherapy treatment that couples a rituximab-like monoclonal antibody to a radioactive particle. Twelve weeks after treatment completion, every patient had a final PET scan. Patients were then followed for an average of about 5 years after treatment.
Results
During this follow-up period, 11 patients died, but only 2 died from lymphoma. Five patients had relapsed disease; of those five, three had received the experimental treatment of only four rounds of R-CHOP. One patient had a positive PET scan, but declined radiation. The other went off treatment altogether after one round of chemotherapy.
"If we can spare people the pain, time, and cost of radiation and give a simpler course of treatment, it's a win.”— Daniel Persky, MD
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For survivors of both treatment groups, outcomes were excellent. Results showed that 91% of people who received no radiation were alive 5 years after treatment, and 89% were cancer-free. For patients who did receive radiation, 93% were alive 5 years after treatment, and 86% were cancer-free.
With 89% of patients in remission after just four rounds of chemotherapy, Dr. Persky believes PET-directed therapy will be the new standard of care for limited DLBCL, particularly when coupled with results presented by Poeschel et al at the 2018 ASH Annual Meeting. Those earlier findings showed that a subgroup of younger patients respond well to four—rather than six—cycles of R-CHOP, along with two cycles of rituximab monotherapy.
“In both studies, we find that many patients can forgo radiation and get less chemo[therapy], and still get excellent results,” said Dr. Persky. “This means people can heal from treatment sooner and that care costs can go down. I think doctors and patients can agree: The less cancer treatment, the better.”
Disclosure: Funding for the trial was provided by the National Institutes of Health/National Cancer Institute and Spectrum Pharmaceuticals. For full disclosures of the study authors, visit ash.confex.com.
