Single gene mutations and prognosis in limited-stage follicular lymphoma treated with radiation therapy.

Radiotherapy is routinely used for management of limited-stage follicular lymphoma (FL), yet half of patients ultimately relapse. We hypothesized that the presence of specific gene mutations may predict outcomes. We performed targeted sequencing of a 69-gene panel in 117 limited-stage FL patients treated with radiotherapy and identified recurrently mutated genes. CREBBP was most frequently mutated, and mutated CREBBP was associated with inferior progression-free survival, though not after false discovery rate adjustment. This association failed to validate in an independent cohort. We conclude that recurrent gene mutations do not predict outcomes in this setting. Alternative biomarkers may offer better prognostic insight.

Validation of the RHL30 digital gene expression assay as a prognostic biomarker for relapsed Hodgkin lymphoma.

Despite continuing improvements in the management of classical Hodgkin lymphoma (cHL), relapse remains associated with a risk of lymphoma-related mortality. The biological composition of relapse tumour biopsies shows interpatient variability, which can be leveraged to design prognostic biomarkers. Here, we validated the RHL30 assay, a previously reported gene expression model in an independent cohort of 41 patients with relapsed cHL. Patients classified as high-risk by the RHL30 assay had inferior failure-free survival (FFS) after autologous stem cell transplantation (2-year FFS 41% vs. 92%, P = 0·035). The RHL30 model is a robust biomarker that risk-stratifies patients considered for autologous stem cell transplantation.

Identification of genetic subtypes in follicular lymphoma.

Follicular lymphoma (FL) exhibits considerable variability in biological features and clinical trajectories across patients. To dissect the diversity of FL, we utilized a Bernoulli mixture model to identify genetic subtypes in 713 pre-treatment tumor tissue samples. Our analysis revealed the existence of five subtypes with unique genetic profiles that correlated with clinicopathological characteristics. The clusters were enriched in specific mutations as follows: CS (CREBBP and STAT6), TT (TNFAIP3 and TP53), GM (GNA13 and MEF2B), Q (quiescent, for low mutation burden), and AR (mutations of mTOR pathway-related genes). The subtype Q was enriched for patients with stage I disease and associated with a lower proliferative history than the other subtypes. The AR subtype was unique in its enrichment for IgM-expressing FL cases and was associated with advanced-stage and more than 4 nodal sites. The existence of subtypes was validated in an independent cohort of 418 samples from the GALLIUM trial. Notably, patients assigned to the TT subtype consistently experienced inferior progression-free survival when treated with immunochemotherapy. Our findings offer insight into core pathways distinctly linked with each FL cluster and are expected to be informative in the era of targeted therapies.

Outcomes of stage I/II follicular lymphoma in the PET era: an international study from the Australian Lymphoma Alliance.

Management practices in early-stage (I/II) follicular lymphoma (FL) are variable and include radiation (RT), systemic therapy, or combined modality therapy (CMT). There is a paucity of data regarding maintenance rituximab in this cohort. We conducted an international retrospective study of patients with newly diagnosed early-stage FL staged with positron emission tomography (PET)-computed tomography and bone marrow biopsy. Three hundred sixty-five patients (stage I, n = 221), median age 63 years, treated from 2005-2017 were included, with a median follow-up of 45 months. Management included watchful waiting (WW; n = 85) and active treatment (n = 280). The latter consisted of RT alone (n = 171) or systemic therapy (immunochemotherapy [n = 63] or CMT [n = 46]). Forty-nine systemically treated patients received maintenance rituximab; 72.7% of stage I patients received RT alone, compared to 42.6% with stage II (P < .001). Active therapies yielded comparable overall response rates (P = .87). RT alone and systemic therapy without maintenance rituximab yielded similar progression-free survival (PFS) (hazard ratio [HR], 1.32; 95% confidence interval [CI], 0.77-2.34; P = .96). Maintenance rituximab improved PFS (HR, 0.24; 95% CI, 0.095-0.64; P = .017). The incidence of transformation was lower with systemic therapy compared to RT or WW (HR, 0.20; 95% CI, 0.070-0.61; P = .034). Overall survival was similar among all practices, including WW (P = .40). In the largest comparative assessment of management practices in the modern era, variable practices each resulted in similar excellent outcomes. Randomized studies are required to determine the optimal treatment in early-stage FL.