Stem Cell Transplant for Lymphoma and Leukemia in the Era of Precision Medicine
Hematologic cancers, such as lymphoma and leukemia, are conditions that concern many people—not only because of their complexity, but also due to the treatment process, potential side effects, and quality of life after therapy. However, today, the management of hematologic cancers has entered a new era, offering a broader range of treatment options.
This special edition features an in-depth survey of a hematopoietic stem cell transplantation, also known as bone marrow transplantation, from its underlying principles and patient selection to the evolving treatment landscape in the era of precision medicine, gleaned from an exclusive interview with Asst. Prof. Dr. Udomsak Bunworasate, an oncologist specializing in Hematology and Hematopoietic Stem Cell Transplantation at the Light of Day Oncology Center, MedPark Hospital.
Hematologic Cancers: More Complex Than They Appear
Hematologic cancers are a group of diseases arising from disorders of the blood-forming tissues or immune system, primarily involving the blood cells, bone marrow, or the lymphatic system. They disrupt the body’s ability to produce functional blood cells. Common forms include lymphoma and leukemia. Although collectively referred to as hematologic cancers, their characteristics, disease progression, and treatment approaches can vary significantly in individual patients.
Asst. Prof. Dr. Udomsak explains the distinction between the two conditions: “Lymphoma typically originates in the lymph nodes, whereas leukemia arises within the bone marrow.”
In current practice, the treatment of hematologic cancers generally begins with standard regimens, including chemotherapy and targeted therapy. Depending on the individual patient, physicians may also consider additional therapeutic options.
“Most patients begin with chemotherapy as first-line treatment. However, certain patients may require stem cell transplantation, particularly in cases of disease relapse, uncontrolled disease, or a high risk of recurrence. In such situations, physicians may also consider further options, including stem cell transplantation or immunotherapy.”
Widening Options for Patients at Risk of Relapse
Asst. Prof. Dr. Udomsak explains the criteria for stem cell transplantation, noting that while many patients with hematologic malignancies respond well to standard, first-line treatments, a subset may experience disease relapses or are at higher risk. Such cases may require more intensive therapeutic strategies to improve the likelihood of durable disease control.
“In lymphoma, two main groups of patients may benefit from hematopoietic stem cell transplantation. The first includes those whose disease has relapsed after conventional therapy but remains responsive to chemotherapy. In these patients, high-dose chemotherapy followed by hematopoietic stem cell transplantation can significantly improve the likelihood of durable disease control. The second group comprises patients who are in remission but have a high risk of relapses, such as those with aggressive subtypes or advanced-stage disease. In these cases, physicians may opt to proceed with stem cell transplantation soon after remission, to reduce the risk of recurrence and improve long-term outcomes.”
Stem Cell Transplantation: More Than a Treatment; It Restores the Hematopoietic System.
“The fundamental principle of stem cell transplantation is the administration of high-dose chemotherapy to eradicate malignant cells, followed by reinfusion of previously collected healthy stem cells into the patient’s body, restoring the bone marrow and hematopoietic system.”
Stem cell transplantations are of two principal types:
- Autologous stem cell transplantation, which utilizes the patient’s own stem cells
- Allogeneic stem cell transplantation, which involves stem cells from a compatible donor
Asst. Prof. Dr. Udomsak noted that the selection of the most appropriate treatment strategy depends on several key factors, including the type of disease, the site of malignant cells, and the patient’s overall clinical condition.
“For lymphoma, autologous stem cell transplantation is most commonly employed. In contrast, leukemia originates in the bone marrow, often necessitating stem cells from a healthy, disease-free donor with a compatible tissue match.”
Peripheral Blood Stem Cell Collection: The First Step in Transplant Preparation
Stem cells are collectable from the peripheral blood. This method differs significantly from traditional bone marrow transplantation, which requires general anesthesia and aspiration of bone marrow from the pelvic bone. Following a comprehensive physical evaluation, the patient receives a granulocyte colony-stimulating factor (G-CSF) injection to stimulate the bone marrow to mobilize stem cells into the bloodstream. Stem cells are selectively collected using specialized apheresis technology. These cells are preserved for subsequent reinfusion into the patient after the completion of high-dose chemotherapy.
“Stem cells are now primarily collected from the peripheral blood, as this approach allows faster recovery. Before transplantation, the medical team conducts a comprehensive evaluation of the patient’s physical condition, including detailed cardiac, pulmonary, hepatic, and renal function, as well as any underlying comorbidities. Patients with conditions such as diabetes, chronic kidney disease, or hypertension may still be eligible for transplantation, provided these conditions are well controlled before treatment.”
For younger patients who may have concerns about future fertility, Asst. Prof. Dr. Udomsak further explained that patients are encouraged to have a fertility consultation before initiating treatment for oocyte or sperm cryopreservation to maximize the chances of parenthood. It is particularly important as high-dose chemotherapy may adversely affect ovarian or testicular function.
The Critical First 100 Days: A Countdown to the Body’s “System Reset”
Asst. Prof. Dr. Udomsak explained that following stem cell transplantation, patients enter a crucial phase during which the body begins to regenerate the hematopoietic and immune systems. The first 100 days are considered a critical period requiring close monitoring for complications and infections. Although blood cell counts may return to normal, the immune system has not yet fully recovered and remains functionally immature.
“During the first 10–14 days, stem cells begin to engraft and generate new blood cells. The immune system is still profoundly suppressed. Patients are therefore cared for in positive-pressure rooms with controlled air quality and stringent infection control measures. A dedicated multidisciplinary team, including hematologists, infectious disease specialists, and transplant nurses, provides close, 24-hour monitoring and care. In the early recovery phase, most patients who are not overly fatigued can watch movies, listen to music, work with a computer, and engage in light activities.”
After discharge, family members and close contacts should continue to exercise caution when interacting with the patient. Although blood counts may have normalized, the immune system typically requires an additional three months to recover fully. As such, even a common cold in otherwise healthy individuals can pose a significant risk to the patient.
Graft-versus-Host Disease (GVHD): When the New Immune System Has Yet to Recognize the Patient’s Body
One of the key complications requiring close surveillance following allogeneic stem cell transplantation is graft-versus-host disease (GVHD). It occurs when donor-derived immune cells perceive the patient’s tissues as foreign and initiate an immune response against them. While this may sound concerning, established strategies exist for close monitoring, management, and prevention.
Asst. Prof. Dr. Udomsak explained, “All patients who receive stem cells from a donor are pre-treated with prophylactic medications and closely monitored from the early stages of treatment. Over time, the newly established immune system gradually adapts and learns to coexist harmoniously with the patient’s body. As a result, some patients may be able to reduce or even discontinue immunosuppressive therapy. It differs from solid organ transplantation, where lifelong immunosuppression is necessary.”
CAR-T Cell Therapy and BiTEs: New Treatment Strategies in the Era of Precision Medicine
In the era of precision medicine, doctors tailor treatment strategies to the specific disease, the characteristics of cancer cells, and each patient’s overall clinical profile. Targeted therapy and immunotherapy, in particular, have become integral to modern cancer care, especially for patients who are refractory to standard treatments or at high risk of relapse.
Asst. Prof. Dr. Udomsak highlighted the key advantages of this treatment, stating: “The major trend in treating hematologic malignancies is personalized therapy tailored for each patient. This approach considers the disease type, the patient’s response to prior therapy, and their overall clinical condition. Because today, we are no longer limited to just a single treatment option.”
Emerging technologies that are gaining increasing attention include:
- CAR-T Cell Therapy (Chimeric Antigen Receptor T-cell therapy): This approach involves collecting a patient’s own T cells and genetically engineering them in the laboratory to enhance their ability to recognize and precisely target cancer cells. The modified cells are then reinfused into the patient to eliminate malignant cells.
- BiTEs (Bispecific T-cell Engagers): These are a class of antibody-based immunotherapies designed to bind to both cancer cells and T cells. It facilitates more efficient immune-mediated destruction of tumors without the need for genetic modification of the patient’s T cells, as is required in CAR-T cell therapy.
Life After Treatment and the Gradual Return of Smiles
While a stem cell transplant is a complex therapeutic process that demands a long recovery period, once the body and immune system fully recuperate, patients can return to their daily routines. They can work, exercise, and even participate in their favorite sports, enjoying a normal quality of life.
Asst. Prof. Dr. Udomsak concluded with a warm gaze, with a glimpse of hope.
“The future of medicine is moving toward precision and personalized care. Our goal is to broaden access to advanced and sophisticated treatments for all Thais, ensuring that patients with hematologic malignancies have greater treatment options and renewed hope for returning to a full and meaningful life.”