Diffuse Large B Cell Lymphoma

Positron Emission Tomography–Directed Therapy for Patients With Limited-Stage Diffuse Large B-Cell Lymphoma: Results of Intergroup National Clinical Trials Network Study S1001

In the September 24, 2020 edition of Journal of Clinical Oncology, Daniel Persky and colleagues report on the results of PET directed therapy in limited stage DLBCL.

PURPOSE

Approximately 1/4-1/3 of diffuse large B-cell lymphoma patients present with limited stage disease.  They tend to have improved overall survival compared to advanced-stage disease patients but with continuous relapse risk regardless of primary treatment approach. The recommended treatment is an abbreviated course ( 4 cycles ) or R-CHOP and radiation therapy.  A PET directed clinical trial was structured to assess the efficacy of radiotherapy postchemotherapy.

METHODS

Patients with non-bulky (< 10 cm) stage I/II newly diagnosed, untreated DLBCL received 3 cycles of R-CHOP and underwent an interim PET/CT. Patients with a negative iPET proceeded with 1 additional cycle of R-CHOP, while those with a positive iPET received involved field radiation therapy followed by ibritumomab tiuxetan radioimmunotherapy.

Of the 158 patients enrolled, 132 were eligible and 128 underwent iPET, which was positive in 14 (11%) of the patients. With a median follow-up of 4.92 years (range, 1.1-7.7 years), only 6 patients progressed and 3 died as a result of their disease. 11 patients died from non-lymphoma causes at a median age of 80 years. The 5-year PFS estimate was 87% (95% CI, 79% to 92%) and the OS estimate was 89% (95% CI, 82% to 94%), with iPET-positive and iPET-negative patients having similar outcomes.

The authors concluded “to our knowledge, S1001 is the largest prospective study in the United States of limited-stage DLBCL in the rituximab era, with the best NCTN results in this disease subset. With PET-directed therapy, 89% of the patients with a negative iPET received R-CHOP × 4, and only 11% had a positive iPET and required radiation, with both groups having excellent outcomes. The trial establishes R-CHOP × 4 alone as the new standard approach to limited-stage disease for the absolute majority of patients.

Reference:

Positron Emission Tomography–Directed Therapy for Patients With Limited-Stage Diffuse Large B-Cell Lymphoma: Results of Intergroup National Clinical Trials Network Study S1001

https://ascopubs.org/doi/abs/10.1200/JCO.20.00999

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