Abstract:

Autologous hematopoietic stem cell transplantation (AHSCT) is one of the effective treatments for highly aggressive and relapsed/refractory lymphoma, which can bring survival benefits to patients. In recent years, with the advent of new drugs such as small molecule targeted drugs, monoclonal antibodies, cell therapy and immunotherapy, more choices are provided for lymphoma patients, however, AHSCT still occupies an important position in the treatment of lymphoma. This paper summarized the indications eligible for AHSCT and its timing, and introduced the treatment process, post transplantation management and precautions of AHSCT in detail. The indications and timing of AHSCT are closely related to disease subtypes, risk stratification and disease status before transplantation. Before AHSCT, patients need to undergo pre-transplant induction and efficacy evaluation. The induction scheme varies according to different lymphoma subtypes, which can be selected according to the recommendations of corresponding guidelines. Currently the widely used clinical efficacy evaluation standard is imaging remission (CT /MRI evaluation) and metabolic remission (PET/CT evaluation). Every step of the AHSCT process is closely related to posttransplant outcome and prognosis. The overall process includes stem cell mobilization and collection, pretreatment prior to transplantation, stem cell reinfusion, comorbidity management and implantation evaluation. Formulating a good mobilization strategy to ensure the smooth development of transplantation is the most critical step. It is reasonable to choose stem cell mobilization regimen according to disease status after induction therapy, which is beneficial to improve mobilization success rate. Referring to the experience of hematopoietic stem cell mobilization abroad, steady-state mobilization is preferred in patients with stable disease, such as patients with CR1/CR2; in terms of stem cell collection, previous clinical experiences domestically and abroad mostly recommend that the optimal target collection of peripheral blood stem cells (PBSC) is 5×10 ⁶ CD34 ⁺ cells/kg. A recently published study suggests that a PBSC of 4.5×10 ⁶-8×10 ⁶ CD34 ⁺ cells/kg in myeloma patients generates significantly better survival, and the optimal PBSC threshold for lymphoma patients needs further study. The evaluation of autograft is now evolving from only CD34 ⁺ cells model, and studies have shown that autograft absolute lymphocyte count (A-ALC) can be introduced in autograft evaluation. Myeloablative pretreatment should be used before AHSCT, BEAM (carmustine, etoposide, cytarabine and melphalan) regimen is commonly used in AHSCT pretreatment of lymphoma. For stem cell reinfusion, preparations should be made in advance to avoid cell aggregation. Clinical quality control and management should be strengthened during infusion, and targeted treatment should be carried out in time in case of adverse events. After implantation, the complete blood count and other indicators were monitored regularly until 100 days after the transplantation to evaluate engraftment. After transplantation, patients with certain lymphoma subtypes need maintenance treatment to reduce the risk of recurrence and treatment failure, and to improve survival rate. Different maintenance treatment schemes can be adopted for different lymphoma subtypes. For patients at high risk of recurrence after transplantation, a variety of new drugs with different action mechanisms such as BTK inhibitors and immunomodulators have been launched into the market. At present, the research on the efficacy and safety of new drugs is also under further exploration. It takes a certain amount of time for lymphoma patients to get hematopoiesis recovery after AHSCT treatment. After transplantation, measures should be taken to avoid complications. After successful engraftment, curative effect evaluation and follow-up should be performed regularly. Lymphoma patients eligible for transplantion should be transferred to transplantion centers for AHSCT treatment at an early stage, to avoid missing the best AHSCT timing.

Key words: Lymphoma, Autologous hematopoietic stem cell transplantation, Clinical practice