January 16, 2025

Katelyn Tran 

11th Grade

Fountain Valley High School

Introduction

Despite affecting numerous individuals across varying demographics each day, cancer has yet to be met with an effective cure. Even among currently available treatments, cancer patients often have limited choices, and in the case of blood cancer patients, bone marrow transplants may be an effective option but come with difficulties of their own. It is often challenging for patients to find a suitable donor, and even then, allogeneic transplants come with the risk of complications resulting from a host’s rejection. Used in conjunction with chemotherapy and sometimes additional radiation, autologous stem cell transplants have become a growing treatment option to help blood cancer patients reach long-term remission in a more safe, reliable way.

The History of Autologous Stem Cell Treatments

Originally, autologous stem cell treatment sprung from pivotal research on stem cell cryopreservation. After World War II, researchers began pursuing methods to prevent the deaths of the inhabitants of Hiroshima and Nagasaki as a result of radiation from the atomic bombs that were dropped. A variety of studies were conducted on how bone marrow could be extracted, preserved at low temperatures, and regrafted into animals first, and this ultimately transitioned into human application. 

Eventually, this work extended into the field of cancer treatment in 1976; however, it was initially intended to primarily serve as a means of maximizing the dosage of chemotherapy drugs and radiation that could be used on a patient to improve its effectiveness. Over time, it has evolved to utilize only stem cells instead of actual marrow and work in synergy with the aforementioned treatment options to help patients achieve long term remission.

Cancer and Stem Cells

In relation to cancer treatment, stem cells are particularly significant due to their ability to not only self-replicate but also differentiate; depending on the type, they can form into various other kinds of tissue and blood cells. This makes them critical in facilitating the recovery of cancer patients, as treatments like chemotherapy and radiation not only kill off cancerous cells but have proven to be destructive to necessary, functional cells as well. In particular, chemotherapy uses strong chemical components in a drug that is meant to kill off quickly reproducing cells; while cancer cells fall into this category, many body cells do as well, which is why autologous transplants are necessary to restore a patient back to health after treatment. Stem cells can allow for the production of new, healthy cells that assist patients’ recovery from treatment and carry out necessary bodily functions.

How Autologous Stem Cell Transplants Work

The process of receiving an autologous transplant effectively follows three main stages: the collection of stem cells, the process of cancer treatment, and the reinfusion of the healthy cells back into the blood. Prior to extraction, patients are given drugs containing growth factors that promote the reproduction of stem cells in the body, in addition to drugs that facilitate mobilization, the movement of stem cells from the bone marrow into the bloodstream. This makes the actual extraction of the stem cells easier, as blood can simply be drawn from one vein, filtered through a centrifuge that collects the stem cells, and returned to the body in another vein.

After the cells have been harvested, they are frozen and preserved. The conditioning process will begin, which is when a patient undergoes aggressive forms of conventional cancer treatment, chemotherapy and sometimes radiation. Once the full course treatment has concluded, re-infusion of the preserved bone marrow may commence.

Re-infusion is done through either an intravenous or a central venous catheter. Then, the stem cells will travel back into the bone marrow in a process called engraftment; until this process is fully completed, patients are immunocompromised due to a deficit of white blood cells. For this reason, visitors are often restricted, as patients are highly susceptible to developing severe infections.

A Brighter Future With Autologous Transplants

Because some cases of cancer are so severe and thus require intense treatment for patients to reach remission, bone marrow or stem cell transplants are often needed to ensure patients can safely undergo high-dosage treatments of chemotherapy and radiation. With autologous transplants, this type of care is more accessible, being both more cost effective and eliminating the need to search for a suitable donor. When compared to allogeneic transplants, or those requiring a donor, autologous transplants have seen reduced mortality numbers resulting from treatment as well. This is because engraftment takes much less time with autologous transplants, as the stem cells being reintroduced are the patient’s own; additionally, this eliminates the possibility of the patient developing graft-versus-host disease, in which the stem cells are often incompatible and attack the patient’s cells.

While autologous transplant patients do still have a higher incidence of relapse after treatment compared to those who underwent allogeneic transplants, research continues by the day to optimize safety and effectiveness. Relapse occurs more frequently with autologous transplants because it does not provide patients with the graft-versus-tumor effect in which stem cells recognize and attack cancerous cells in the body. However, the absence of this effect comes with the aforementioned benefit of removing the risk of a graft-versus-host disease. As a result, autologous stem cell transplants are still being built upon and improved, with scientists working hard to help cancer patients achieve the best outcome possible.