Positive Pre-Allogeneic Hematopoietic Cell Transplantation (alloHCT) PET Scan in Patients with Non-Hodgkin Lymphoma (NHL) Predicts Higher Risk of Relapse but Has No Impact on Survival

 

Introduction: A negative PET scan predicts improved outcomes of autologous HCT in lymphoid malignancies. However, the prognostic utility of pre-transplant PET scan status in predicting outcomes of alloHCT in NHL is unclear. We examined the impact of pre alloHCT PET scan status on the outcomes of NHL patients reported to the CIBMTR.

 

Methods: Adult patients with follicular lymphoma, diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL) and T- or NK-cell NHL undergoing alloHCT between 2007-12 were eligible. Chemorefractory pts (by CT criteria), and cases where interval between PET scan and alloHCT was >3 months were excluded.

Results: Three hundred and thirty six patients eligible for this analysis were divided into PET+ve and PET-ve groups, based on pre alloHCT PET status, as determined by individual transplant centers. Baseline patients characteristics shown in Table. Patients in the PET+ve cohort were more heavily pretreated, and more frequently had extranodal disease, marrow involvement and bulky disease. The non-relapse mortality (NRM), relapse/progression, progression free survival (PFS) and overall survival (OS) of PET-ve vs. PET+ve groups at 3years were 27% vs.18% (p=0.05), 27% vs. 38% (p=0.02), 47% vs. 44% (p=0.66) and 59% vs. 58% (p=0.81), respectively. On multivariate analysis, PET+ve status was associated with a higher risk of relapse/progression (RR 1.76; 95%CI 1.19-2.6; p=0.004), but was not predictive of inferior OS (RR 1.29; 95%CI 0.92-1.8; p=0.13), PFS (RR 1.28; 95% CI 0.95-1.72; p=0.09) or NRM (RR 0.79 95%CI 0.50-1.24; p=0.31). PET status had no impact on incidence of grade II-IV acute GVHD and chronic GVHD.

Conclusions: A positive pre-alloHCT PET scan in otherwise chemosensitive NHL patients is associated with a modestly increased risk of relapse/progression, but is not predictive of inferior OS and PFS. The results of PET imaging may direct the early post-transplant interventions to prevent relapse, however positive PET should not preclude alloHCT.

 

	Negative PET N=171	Positive PET N=165
Median Age, range	54 (19-71)	55 (18-70)
KPS ≥90%	123 (72)	105 (64)
Diagnosis Follicular NHL DLBCL MCL T/NK-cell NHL	41 (24) 40 (23) 41 (24) 49 (29)	63 (38) 45 (27) 28 (17) 29 (18)
Response with CT @HCT    CR    PR	141 (82) 30 (18)	13 (8) 152 (92)
≥ 3 chemotherapy lines preHCT	88 (57)	106 (70)
Extranodal disease at HCT	20 (12)	58 (35)
Bone Marrow involved at HCT	8 ( 5)	22 (13)
Interval from diagnosis to HCT, months	27 (3-208)	27 (4-352)
Bulky Disease	1 ( 1)	16 (10)
Interval between PET & HCT, months	1 (0.2-2.8)	1 (0.07-2.8)
Prior autoHCT	40 (23)	29 (18)
Donor type   Sibling   Adult unrelated donor    Umbilical cord blood	62 (36) 83 (49) 26 (15)	60 (36) 78 (48) 27 (16)
Conditioning Myeloablative RIC             NMA	47 (27) 69 (40) 55 (32)	43 (26) 67 (41) 55 (33)
Median FU, months	49	48

 

---