Many patients with DLBCL may not need radiation after clear PET scan
ORLANDO — Nearly 90% of patients with limited-stage diffuse large B-cell lymphoma maintained excellent outcomes after four cycles of R-CHOP with PET-directed therapy, according to study findings presented at ASH Annual Meeting and Exposition.
Patients with non-bulky stage I/II untreated DLBCL received standard R-CHOP therapy and an interim PET scan on day 15-18 of cycle 3, according to the abstract.
“It was important to conduct the study to fine tune the treatment of patients with limited stage DLBCL,” Daniel O. Persky, MD, from the University of Arizona Cancer Center, told HemOnc Today. “The study used PET scan after three cycles of R-CHOP to give more treatment to patients with positive scan, and less treatment to patients with negative PET scan.”
In the study, known as S1001, patients with negative PET scan continued with one additional cycle of R-CHOP, while those with positive PET scan underwent involved field radiation therapy (IFRT) plus additional boost to areas where the scans showed fast-growing cancer cells within 5 weeks of the third cycle of R-CHOP. After this, patients received ibritumomab tiuxetan 3 to 6 weeks after completing IFRT and had a final PET scan 12 weeks after treatment completion.
Only 5 relapses occurred in 132 eligible patients and four patients with “double hit” lymphomas remained in remission, according to Persky.
The researchers reported that five patients progressed and two died of lymphoma during the follow-up period (median = 4.5 years).
Eighty-nine percent of patients maintained excellent outcomes after four cycles of R-CHOP with PET-directed therapy and 11% of patients were interim-PET-positive and required radiation – although they also had excellent outcomes. Overall, 128 patients had an interim PET scan centrally reviewed; of these, 110 were interim PET-negative and 18 were interim-PET-positive.
Persky and colleagues reported that the 5-year, progression-free survival estimate was 87% and the overall survival estimate was 90%, with similar outcomes observed for interim-PET-positive and -negative patients having similar outcomes (PFS: 86% vs. 88%; OS: 93% vs. 91%).
This study also confirmed the distinct biology of limited stage DLBCL, with predominance of GCB origin (68%) and the head and neck location (66%), according to the abstract.
“Together with FLYER trial for younger favorable risk patients, S1001 establishes that four cycles of R-CHOP without radiation are sufficient for the majority of patients with limited stage DLBCL,” Persky told HemOnc Today. – by Savannah Demko
Persky DO, et al. Abstract 349. Presented at: ASH Annual Meeting and Exposition; December 7-10, 2019; Orlando, Florida.
Disclosures: Persky reports consulting for Bayer and Sandoz as well as being a member of the Independent Data Monitoring Committee for Debiopharm and Morphosys.