
BMT Program
BMT is a term that refers to the use of immature cells (stem cells) derived
from the bone marrow or blood as part of the therapy of cancer and some other
serious medical conditions. The stem cells used in BMT can be obtained from
the patient (autologous BMT) or from a donor (allogeneic BMT).Which type
of BMT is performed will depend largely upon the patient's diagnosis and
clinical history.
The stem cells used are ultimately derived and may be collected
directly from bone marrow; although most commonly, they are collected from
the blood using a process called "mobilization." Mobilization
involves the administration of medications that temporarily move some of
the bone marrow stem cells into the blood stream where they can be more easily
collected. When stem cells are collected in this manner, the procedure is
usually not painful and general anesthetic is not necessary. However, a catheter
accessing a central vein is usually needed.
For both autologous and allogeneic
BMTs, the patient receives special preparative treatment for approximately
1-6 days. This is also called the "conditioning" regimen. For autologous
transplants the conditioning regimen is administered after completion of
the mobilization and cell collection phase. For allogeneic transplants the
conditioning regimen is often administered to the patient while the donor
is undergoing mobilization/cell collection. The conditioning regimen provides
anti-cancer therapy and for allogeneic BMT also prevents rejection of the
donor's cells. This conditioning regimen caused the
blood counts to be severely reduced for several days. The period during which
the patient's white blood
cell count is very low is usually called the "neutropenic" period. This is
a time during which the patient is highly susceptible to infections and must
be monitored closely.
Once the conditioning regimen is completed, the stem
cells are infused into a large vein like a blood transfusion. This is usually
done through a special venous cathether. These cells find their own way to
the bone marrow and typically start to manufacture blood cells there a few
days later. This results in recovery of the white blood cell count typically
by about 10-15 days after the stem cell infusion. During the neutropenic
period the patient usually requires blood and platelet transfusions and also
usually receives prophylactic antibiotics to prevent infection. Once the
patient's white blood cell count
is recovered the risk of infection decreases. However, the patient may still
be susceptible to unusual infections for some time thereafter and continued
precautions/medications may be necessary.
Generally, patients undergoing
an allogeneic transplant are at risk for infections for longer than patients
undergoing allogeneic transplantation. They are also susceptible to immune
complications like graftversus- host disease (GVHD) and rejection of the
graft which typically do not occur after autologous transplants. Thus, patients
undergoing allogeneic transplants usually require longer periods of close
monitoring and also take medications which prevent infection, GVHD and graft
rejection for several months (and occasionally longer).
Most patients eventually recover from their transplant and manage to come
off all medications -
returning to a normal quality of life. Also, as BMT is a potentially curative
treatment for many conditions, we expect many patients to achieve a normal
life-span. Patients continue to be monitored for some time for possible recurrence
of their cancer and also for the development of second cancers. Our patients
are often referred from outside oncologists or other specialists. Although
our patient's care
is primarily the responsibility of the BMT team during the transplant phase
of their treatment, we work closely with your referring physician (if you
have one) to manage your long term care.