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Abstract: EP1264

Type: E-Poster Presentation

Session title: Stem cell transplantation - Clinical

Background

Approximately 30% of patients(pts) with high-intermediate/high IPI risk groups (IPI ≥2) diffuse large B-cell lymphoma (DLBCL) have relapsed after the frontline regimens. High-dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation (auto-HSCT) in the first remission can be an effective option to decrease the relapse rate in these patients.

Aims

Preliminary evaluation of the efficacy of the HDCT with auto-HSCT in the first remission for stage IV DLBCL patients with IPI ≥2.

Methods
108 pts, which fit the following criteria: DLBCL NOS, age 18-65, stage IV, IPI ≥2, treated by x6 CHOP/EPOCH/H-CVAD + R in frontline from 01.01.2010 to 31.12.2019 at NMRC of Oncology named after N.N.Petrov of MoH of Russia were retrospectively analyzed.

If patients achieved complete response (CR) or partial response (PR) after frontline, they enrolled into upfront HDCT with auto-HSCT group (Group 1, n=38) or follow-up group (Group 2, n=70) based on multidisciplinary team (MDT) decision.

High LDH had 84% (32/38) pts in Group 1 and 81,4% (57/70) pts in Group 2; more than one extranodal involvement had 78,9% (30/38) pts in Group 1 and 75,7% (53/70) pts in Group 2. MYC and BCL-2 coexpression were analyzed in 84% (32/38) pts samples in Group 1 and 65,7% (46/70) in Group 2 and were present in 46,8% (15/32) pts samples in Group 1 and 28,2% (13/46) in Group 2.

An independent two-sample T-test and one-tailed p-value were used to determine the difference in relapse rate between Group 1 and Group 2.

Results

CR after induction was achieved in 61% (23/38) pts in Group 1. After HDCT with auto-HSCT, the CR rate increased to 97% (37/38) and continues for a median of 30 (7-56) months in 87% (33/38) pts. It demonstrates the statistically significant difference - tα = 4,42 (p ≤ 0,00001). Early relapses were diagnosed in 6% (2/38) pts, late relapses in 6% (2/38) pts. HDCT associated mortality (infection) has occurred in 3% (1/38) pts.

Group 2 patients achieved CR in 81% (57/70) cases. CR continues for median 38 (8-73) months in 67% (47/70) pts. Group 2 patients have 14% (14/70) early and 6% (4/70) late relapse rate. No treatment-related deaths occurred.

Early relapse rate was significantly higher in Group 2 if the patient had initially high LDH (Group 1 – 3,1% (1/32), Group 2 – 15,8% (9/57)) - tα = 2,21 (p = 0.014865); more than one initial extranodal site (Group 1 – 3,3% (1/30), Group 2 – 17,0% (9/53)) - tα = 2,23 (p = 0.014257). MYC and BCL-2 coexpression was statistically significant in terms of both early (Group 1 – 6,6% (1/15), Group 2 – 38,4% (5/13)) - tα = 2,13 (p = 0.0214) and all relapses (Group 1 – 6,6% (1/15), Group 2 – 46,1% (6/13)) - tα = 2,59 (p = 0.007761). The early relapse rate in Group 2 was significantly higher if the combination of initially high LDH, more than 1 extranodal site, MYC and BCL-2 coexpression were present (Group 1 – 12,5% (1/8), Group 2 – 55.5% (5/9)) - tα = 2,12 (p = 0.025547).

Conclusion
 

1. CR rate significantly increased for DLBCL NOS pts with stage IV, IPI ≥2 treated by upfront HDCT with auto-HSCT.

2. Upfront HDCT with auto-HSCT significantly decreases early relapse rate for DLBCL NOS pts with stage IV, IPI ≥2 if high LDH, more than one extranodal site, and MYC and BCL-2 coexpression are present.

Keyword(s): Autologous hematopoietic stem cell transplantation, Diffuse large cell lymphoma, High risk