Session: 623. Mantle Cell, Follicular, and Other Indolent B Cell Lymphomas: Clinical and Epidemiological: Poster III
Hematology Disease Topics & Pathways:
Research, adult, epidemiology, Clinical Practice (Health Services and Quality), Lymphomas, elderly, Clinical Research, Diseases, indolent lymphoma, clinical procedures, Lymphoid Malignancies, young adult , Technology and Procedures, Study Population, Human, imaging
Methods: The LEO cohort is a prospective cohort from 8 academic cancer centers in which patients are enrolled within 6 months of lymphoma diagnosis and followed. We extracted baseline data of MZL patients enrolled in the LEO cohort between 5/2015 and 2/2020. BM biopsy was used as a gold standard for BM involvement. In addition, radiology reports were reviewed for PET/CT-suggested BM involvement. Event-free survival (EFS) defined as time from diagnosis to relapse/progression, retreatment, or death due to any cause and overall survival (OS) defined as time from diagnosis to death due to any cause were estimated by Kaplan-Meier.
Results: Of 706 MZL patients enrolled in LEO, 311 (44%) with data on BM status by both biopsy and PET/CT were included in the analysis. Patients’ characteristics were median age 64 (range 24-89) years with most <70 years (n=217, 69.8%), non-Hispanic (n=264, 84.9%) white (n=276, 88.7%), without B symptoms (n=246, 79.1%), and normal LDH (n=185, 59.5%). The most common MZL subtype was extranodal (EMZL, n=208, 66.9%) followed by nodal (NMZL, n=61, 19.6%) and splenic (SMZL, n=42, 13.5%). Stage distribution was as follows: early-stage (I-II; n=134, 43.1%), advanced-stage (III-IV; n=159, 51.1%), and unknown (n=18, 5.8%). BM biopsy was positive in 99 (31.8%) and negative in 212 (68.2%) patients.
Across all MZL subtypes, biopsy-proven and PET/CT-suggested BM involvement was present in 11.6% (n=36/311), and positive BM biopsy with negative PET/CT was observed in 20.3% (n=63/311) (EMZL=9.6%, n=20/208; NMZL=31.1%, n=19/61; and SMZL=57.1%, n=24/42). For EMZL, 15.9% (n=33) demonstrated pathologically confirmed BM involvement, and among those patients PET/CT was positive in 39.4% (n=13) and negative in 60.6% (n=20). For NMZL, 50.8% (n=31) demonstrated pathologically confirmed BM involvement, and among those patients PET/CT was positive in 38.7% (n=12) and negative in 61.3% (n=19). Most patients (83.3%, n=35) with SMZL demonstrated pathologically confirmed BM involvement, with positive PET/CT in 31.4% (n=11) and negative in 68.6% (n=24). Considering BM result from biopsy as the standard, PET/CT-based sensitivity and specificity in EMZL, NMZL, and SMZL were 39.4% & 98.9%, 38.7% & 100%, and 31.4% & 100%, respectively. PET/CT-based positive and negative predictive values in EMZL, NMZL, and SMZL were 86.7% & 89.6%; 100% & 61.2%; and 100% & 22.6%, respectively.
With a median follow up of 35.4 months there were 70 EFS events and 18 OS events across all MZL subtypes. The 2-year EFS and OS were 81.7% (95%CI 76.8-85.7%) and 96.8% (95%CI 93.9-98.3%), respectively. The 2-year EFS and OS by histology were EMZL= 84.7% (95%CI 78.7-89.1%) & 97.2% (95%CI 93.5-98.8%); NMZL= 69.6% (95%CI 56.1-79.6%) & 96.5% (95%CI 86.9-99.1%); and SMZL= 85.6% (95%CI 70.7-93.3%) & 95.2% (95%CI 82.3-98.8%), respectively. Acknowledging the low number of events and unspecific criteria for treatment selection, those patients exhibiting pathological BM involvement (n= 99) did not show significantly different EFS (p=0.097) (EMZL p=0.48; NMZL p=0.68; and SMZL p=0.75, respectively) or OS (p=0.978) (EMZL p=0.46; NMZL=0.53; and SMZL=0.21, respectively) compared to those without BM disease.
Conclusions: While PET/CT may be positive in nodal and some extranodal locations, assessment of BM involvement by PET/CT is characterized by a low sensitivity across all MZL subtypes and low negative predictive value in SMZL, underscoring the limitations of current Lugano criteria in staging MZL. With currently relatively limited follow-up, we did not observe significantly different survival based on BM status.
Disclosures: Alderuccio: ADC Therapeutics: Consultancy, Research Funding; Pyramid: Consultancy; Agios: Consultancy. Koff: Atara BioTherapeutics: Research Funding; Gamida Cell: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees; Oncternal Therapeutics: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Viracta Therapeutics: Research Funding. Chihara: Eisai: Honoraria; AstraZeneca: Honoraria. Martin: ADCT: Consultancy; AstraZeneca: Consultancy; Beigene: Consultancy; BMS: Consultancy; Daiichi Sankyo: Consultancy; Epizyme: Consultancy; Genentech: Consultancy; Janssen: Consultancy; Regeneron: Consultancy; Takeda: Consultancy. Kahl: AstraZeneca: Consultancy, Research Funding; ADT Therapeutics: Consultancy; Roche: Consultancy; Genentech: Consultancy, Research Funding; Abbvie: Consultancy, Research Funding; MEI: Consultancy; AcertaPharma: Consultancy; Pharmacyclics: Consultancy; Celgene/BMS: Consultancy, Research Funding; Beigene: Consultancy, Research Funding; Kite: Consultancy; Janssen: Consultancy; Incyte: Consultancy; Hutchmed: Consultancy, Research Funding; Seattle Genetics: Consultancy; TG Therapeutics: Consultancy; Genmab: Consultancy; Research To Practice: Speakers Bureau. Cohen: Aptitude Health: Consultancy; Kite Pharma/Gilead: Consultancy; BMS/Celgene: Research Funding; Lilly Oncology/Eli Lilly: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Janssen: Consultancy; Takeda: Research Funding; Genentech: Research Funding; HutchMed: Consultancy, Research Funding; Astrazeneca: Consultancy, Research Funding; Novartis: Research Funding. Cerhan: NanoString: Research Funding; GenMab: Research Funding; Genentech: Research Funding; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Protagonist: Membership on an entity's Board of Directors or advisory committees. Flowers: Iovance: Research Funding; Cellectis: Research Funding; EMD: Research Funding; Guardant: Research Funding; Eastern Cooperative Oncology Group: Research Funding; Burroughs Wellcome Fund: Research Funding; Ziopharm: Research Funding; Denovo Biopharma: Consultancy; Genmab: Consultancy; V Foundation, Cancer Prevention and Research Institute of Texas: CPRIT Scholar in Cancer Research: Research Funding; National Cancer Institute: Research Funding; Spectrum: Consultancy; Janssen Pharmaceutical: Research Funding; Amgen: Research Funding; Allogene: Research Funding; Adaptimmune: Research Funding; Kite: Research Funding; Morphosys: Research Funding; Acerta: Research Funding; NPower: Current holder of stock options in a privately-held company; Takeda: Research Funding; Sanofi: Research Funding; Foresight Diagnostics: Consultancy, Current holder of stock options in a privately-held company; BeiGene: Consultancy; Genentech/Roche: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; SeaGen: Consultancy; Celgene: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics/Janssen: Consultancy; Abbvie: Consultancy, Research Funding; Karyopharm: Consultancy; 4D: Research Funding; Xencor: Research Funding; Pharmacyclics: Research Funding; Pfizer: Research Funding. Lossos: NCI: Research Funding; Adaptive: Honoraria; LRF: Membership on an entity's Board of Directors or advisory committees.