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How Stem Cell and Bone Marrow Transplants Are Used to Treat Cancer

How Stem Cell and Bone Marrow Transplants Are Used to Treat Cancer

Stem cell

All blood cells in your body, including white blood cells, red blood cells, and platelets, begin as immature (young) cells called hematopoietic stem cells. Hematopoietic refers to the process of making blood. These are immature cells that haven’t fully matured. Despite the fact that they all start out the same, stem cells can grow into any form of blood cell, depending on what the body requires at the time.

The majority of stem cells reside in the bone marrow (the spongy centre of certain bones). They split here to produce new blood cells. Blood cells leave the bone marrow and enter the circulation after they have matured. A tiny percentage of immature stem cells make their way into the circulation. 

What is the significance of stem cells?

Red blood cells, white blood cells, and platelets are all produced by stem cells. All of these types of blood cells are required to keep us alive. You need enough of each of these blood cells in your blood for them to fulfill their tasks.

Red blood cells are the cells that makeup blood (RBCs)

Red blood cells transport oxygen from the lungs to all of the body’s cells. They transport carbon dioxide from cells to the lungs, where it is expelled. A hematocrit test determines how much of your blood is made up of RBCs. For adults, the typical range is between 35 and 50 percent. Anemia affects those whose hematocrit is less than this. They may seem pale and feel weak, fatigued, and short of breath as a result of this.

White blood cells are the cells that make up the blood (WBCs)

White blood cells aid in the fight against bacteria, viruses, and fungal illnesses. WBCs come in a variety of shapes and sizes.

Neutrophils are the most essential form of white blood cell in the fight against infections. When a damage occurs or when pathogens enter the body, they are the first cells to respond. When they’re low, you’re more susceptible to illness. The quantity of neutrophils in your blood is measured by the absolute neutrophil count (ANC). Neutropenia occurs when your ANC falls below a specific threshold. The lower the ANC, the higher the infection risk.

Another type of white blood cell is lymphocytes. T lymphocytes (T cells), B lymphocytes (B cells), and natural killer (NK) cells are three types of lymphocytes. Antibodies are produced by certain lymphocytes to aid in the fight against infections. Lymphocytes help the body detect its own cells and reject cells that don’t belong there, such as invading pathogens or cells transplanted from another person.

Platelets are a kind of platelet that is (thrombocytes)

Platelets are little cells that help blood clot and close broken blood arteries, both of which are critical for stopping bleeding. A normal platelet count ranges from 150,000 to 450,000 per cubic millimetre, depending on the facility that does the test. Thrombocytopenia is a condition in which a person’s platelet count falls below normal, causing them to bruise more readily, bleed longer, and experience nosebleeds or bleeding gums. If a person’s platelet count falls below 20,000/mm3, spontaneous bleeding (bleeding without apparent cause) can occur. If bleeding develops in the brain or blood begins to flow into the intestines or stomach, this can be hazardous.

Where do transplantable stem cells come from?

There are three types of stem cells that can be used for transplants, depending on the type of transplant:

  • Bones marrow (from you or someone else)
  • The bloodstream (peripheral blood from you or another person)
  • Blood from infants’ umbilical cords
  • Marrow from the bones

The spongy liquid substance in the core of certain bones is called bone marrow. It contains a large number of stem cells, and its primary function is to produce blood cells that circulate throughout the body. The pelvic (hip) bones have the most marrow and are home to a significant number of stem cells. As a result, cells from the pelvic bone are frequently utilised in bone marrow transplants. 

The pelvic (hip) bones have the most marrow and are home to a significant number of stem cells. As a result, cells from the pelvic bone are frequently utilised in bone marrow transplants. To obtain a large quantity of healthy stem cells, enough marrow must be removed.

While the donor is under general anaesthesia (drugs used to put the patient into a deep slumber so they don’t feel pain), the bone marrow is collected (removed). A big needle is inserted into the rear of the hip bone and into the skin of the lower back. The needle is used to extract the thick liquid marrow. This process is continued until all of the marrow has been extracted.

The collected marrow is filtered before being frozen in a specific solution. When the marrow is ready to be utilised, it is thawed and then injected into the patient’s bloodstream via a vein, similar to a blood transfusion. The stem cells migrate to the bone marrow, where they engraft (or “take”) and begin the process of producing blood cells. In a few weeks, the patient’s blood tests should show signs of the new blood cells.

Blood from the periphery

In most cases, there aren’t many stem cells in the blood. However, giving stem cell donors growth factors injections a few days before the harvest causes their stem cells to develop quicker and migrate from the bone marrow into the bloodstream.

The stem cells for a peripheral blood stem cell transplant are extracted from the patient’s blood. A catheter (a thin flexible tube) is inserted into a major vein in the donor and connected to tubing that transports the blood to a specific machine. The stem cells are separated from the rest of the blood by the machine, which is then returned to the donor during the same operation.

Umbilical cord blood:

A significant number of stem cells are seen in the blood of newborn infants. The blood left in the placenta and umbilical cord after birth (known as cord blood) can be collected and preserved for use in a stem cell transplant later. Cord blood may be stored in the freezer until it is required. A cord blood transplant makes use of blood that would otherwise be discarded when a baby is born. After the infant is born, cord blood is carefully collected by properly trained members of the health care team. The infant is not in any way injured.

Even while infants’ blood contains a significant number of stem cells, cord blood accounts for only a small portion of that total. As a result, the lesser quantity of stem cells in cord blood might represent a disadvantage. However, each cord blood stem cell may generate more blood cells than a stem cell from adult bone marrow, which helps to balance things out. Cord blood transplants, on the other hand, might take longer to take hold and begin functioning. Like a blood transfusion, cord blood is injected into the patient’s bloodstream.

Bone marrow cancers are cancers that affect the bone marrow.

Some malignancies begin in the bone marrow and spread there, whereas others do not. Cancer affects the bone marrow, leading it to produce too many of some cells, crowding out others, or producing unhealthy cells that don’t function properly. Bone marrow cells must function normally and begin producing new, healthy cells for these malignancies to cease developing.

How a stem cell transplant for cancer treatment works

Stem cell transplants are utilised to restore bone marrow cells that have been damaged by cancer or by chemo and/or radiation treatments.

Different types of stem cell transplantation exist. To destroy cancer cells, they all employ extremely high doses of chemo (often in combination with radiation). However, large dosages can destroy all of a person’s stem cells and cause the bone marrow to cease producing blood cells for a period of time. To put it another way, all of a person’s initial stem cells are purposefully killed. However, because our bodies require blood cells to operate, stem cell transplants are used. 

By replenishing the body’s stem cells that have been killed by therapy, the transplanted stem cells assist to “rescue” the bone marrow. As a result, doctors may use far greater doses of chemotherapy to try to kill all of the cancer cells, and the transplanted stem cells can develop into healthy, mature blood cells that function properly and generate cancer-free cells.

Your cancer care team will weigh the risks associated with the malignancy against the risks associated with the transplant. They may also discuss different therapy choices or clinical trials with you. The disease stage, the patient’s age, the period from diagnosis to transplant, the donor type, and the patient’s general condition are all factors to consider when balancing the benefits and drawbacks.

Here are a few questions to think about. You may need to speak with the transplant team or the individuals who deal with insurance and payments at the doctor’s office and/or the hospital about some of these:

  • Is a transplant the most effective treatment for me? Why? What is the objective?
  • How many transplants do you perform each year for my kind of cancer?
  • Is there anything I should look into in terms of clinical trials?
  • Are there any other treatments I should consider?
  • Which stem cell transplant will I receive? Why?
  • What are your chances of finding a suitable match?
  • How likely is it that the transplant will be successful?
  • How many transplants do you perform each year for my kind of cancer?

Transplantation costs

Stem cell transplants are expensive, and some kinds are more expensive than others. Getting cells from a donor, for example, is more expensive than collecting your own. Furthermore, many chemical and radiation therapies used to destroy bone marrow might be costly. Some transplants require longer hospital time than others, which might impact the cost. Despite the changes, stem cell transplants may be expensive, costing hundreds of thousands of dollars.

Some forms of cancer, particularly solid tumor malignancies, are still deemed experimental, thus insurance may not pay the cost of a transplant (or specific types of transplants).

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