Detection of disseminated tumor cells in bone marrow in patients with colon cancer

Colon cancer is one of the most common cancer in the Netherlands. The most
important predictor of survival is the presence of lymph node or distant
metastasis.
Still, in 30-45% of the patients with curatively resected colon cancer with no
lymph node involvement, local regional recurrence or distant metastasis will
occur.
A plausible explanation could be the dissemination of tumor cells via blood or
lymphatic system.
A method for detection of disseminated tumor cells is RT-qPCR. With RT-qPCR it
is possible to detect specific genetic markers on tumor cells. In colon
carcinoma, the expression of the genetic markers CK-20 and CEA are often
elevated.
Since metastasis occur mainly via blood stream and the lymphatic system, tumor
cells can be found in blood and bone marrow.

To determine the feasiblity of the detection of disseminated tumor cells in
bone marrow with RT-qPCR

During surgery, two bone marrow needle aspiration are performed, when the
patient is under full anesthesia. The puncture site is the spina illiaca
anetrior superior. The first punction will be performed during surgey, when the
tumor has not yet been resected. The second puncture will be performed as soon
as the specimen is out of the patient.
The aspirated bone marrow will be conserved in a special medium en be brought
to the laboratory. Here, the RT-qPCR will be performed and the aspirated bone
marrow will be analysed for the presence of tumor cells.

The bone marrow aspiration will be performed during surgery by the operating
surgeon under a sterile environment. The actual surgery will not take extra
time. Also, the risk of infection is minimalised by performing the procedure
under sterile conditions.
After an needel aspiration, there's a risk of hemorrhage. This risk is no
greater than after an arterial punction. After aspirating bone marrow, the
aspiration site will be compressed and a pressure bandag will be applied.