3603 - TMLI and Skin Irradiation as Conditioning Regimens for Allogeneic Hematopoietic Cell Transplant in T-Cell Lymphoma Patients
Presenter(s)
H. Gilbertson1, A. Wen1, C. Hao2, C. J. Ladbury3, P. Frankel4, O. Okunowo5, J. Y. C. Wong3, G. Shouse6, C. Querfeld5, M. Niedzwiedz5, M. Iwata5, N. Zovigian5, C. Han3, A. Braun5, A. Herrera6, P. Wang3, N. Khan6, J. Zain7, M. Al Malki6, and S. V. Dandapani3; 1City of Hope Cancer Center, Duarte, CA, 2Johns Hopkins Medical School, Baltimore, MD, 3Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, 4Department of Information Sciences, City of Hope National Medical Center, Duarte, CA, 5City of Hope, Duarte, CA, 6Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, 7Memorial Sloan Kettering Cancer Center, New York City, NY
Purpose/Objective(s): Allogeneic Hematopoietic Cell Transplantation (HCT) offers a promising therapeutic option for patients with high risk T-Cell Lymphomas (TCL); however, disease relapses remain the major cause of treatment failure. Advancements in conditioning regimens, including total marrow and lymphoid irradiation (TMLI) aim to minimize off target toxicity while reducing disease burden prior to HCT. The addition of total skin radiation such as total skin electron therapy (TSET) controls skin disease in a subset of TCL: i.e. cutaneous TCL (CTCL). In this study, we describe the safety, feasibility and efficacy of TMLI and total skin radiation prior to HCT in patients with TCL.
Materials/Methods: We retrospectively analyzed TCL patients who were treated with radiation prior to HCT at City of Hope between February 2012 and September 2024. The primary endpoint was overall survival (OS), and secondary endpoint was local control. Adverse events were assessed using CTCAE v5.0 criteria.
Results:
21 patients (median age 56 [range 24-77] years) with TCL (PTCL, peripheral T cell lymphoma, n=14; CTCL, n=7) were treated with radiation (median 12 Gy [range 2-20Gy]) prior to HCT. Patients received focal radiation (median 12 Gy; n=2), TBI (median 2 Gy; n=2), TMLI (median 12 Gy; n=11), TSET (median 12 Gy; n=2), or a combination of TMLI and total skin radiation (median 12 Gy each, n=4). All transplants were matched donors. Graft-versus-host disease (GVHD) prophylaxis was tacrolimus and sirolimus (n=8) or tacrolimus, mycophenolate mofetil, and post-transplant cyclophosphamide (n=13). Median follow up was 20 months (range 1.3-83.7). All patients engrafted. Median OS was 7 years (95% CI, 3.1 years – not reached [NR]) for all patients. All patients treated with TMLI, and total skin radiation (n=4) remain alive (median follow up 2.4 years [range 0.4-4.8]), while 73% (8/11) of patients treated with TMLI alone are still alive (median follow up 1.6 years [range 0.02-7.0]). Six patients (2 CTCL, 4 PTCL) passed away at a median of 8.5 months (range 1.5-90.8) post-transplant from disease progression (n=5) and lung infection (n=1). No grade 3 radiation-related adverse events occurred. 8 patients had post-transplant infections. 10 patients had mild acute or chronic GVHD. Of the CTCL patients, 4/7 had TMLI & total skin irradiation. All 4 remain alive. 3 of those 4 relapsed (in the skin) and remain alive with salvage systemic treatment and focal skin radiation. 2/7 had TSET alone; 1 relapsed in the skin and remains alive with salvage therapy and 1 died from disease in the bone marrow. 1/7 received focal RT alone and died from disease progression.Conclusion: TMLI is well tolerated with an acceptable toxicity profile for high-risk TCL patients. The addition of low dose total skin radiation to myeloablative TMLI resulted in no additional toxicity and shows promise for disease control in CTCL patients. The optimal TSET dose for CTCL transplant patients warrants further investigation.