autologous blood and marrow transplantation - Blog Science ...

Moss et al. 271
0 3 6 12 18 24 30 36 42
Months Post -ASCT
Figure 3. Survival curve comparing the disease-free survival of patients with tumor colon
in the PBPC vs. those with no colony growth.
DISCUSSION
Studies have shown that approximately 3-22% of patients with stage IV breast
cancer will have contamination of the PBPC product, 1-5
compared with the presence
of breast cancer cells in 36-82% of marrow specimens. 1
- 6
' 7
Little, however, is
known about the clinical significance of these occult micrometastatic cells.
In this study, we demonstrate that the presence of detectable tumor in blood and
marrow stem cell collections at the time of transplant is highly predictive of a poor
clinical outcome. Patients with both PBPC and marrow positive for breast cancer
cells had a 100% relapse rate. On the other hand, patients whose marrow and stem
cell product were negative for tumor cells had the best clinical outcome. This is one
of the first studies to show that the presence of breast cancer cells in the reinfusion
product is predictive of posttransplant outcome.
The clonogenic and ICC assays provide complementary prognostic information.
In approximately 10% of cases, tumor colonies will grow despite a negative ICC
due to extremely low levels of tumor contamination, poor cell viability, or other
factors. In approximately 30-40% of cases, an ICC-positive patient will not grow
tumor colonies. All of the positive patients will do poorly. This indicates that the
presence of tumor cells in the collection may be a biologic marker of highly
resistant disease. Consequently, these patients may be very poor transplant
candidates and should be considered for alternative therapy.
Another important consideration is the determination of the growth potential for
tumor cells in the marrow and stem cell product. One such method is the use of cell