A group of 91 colorectal patients treated in a single institution was involved into the study. Only the patients with tumors located in the rectum or left side colon were included. The term left colon was defined as the left 1/3 of transverse colon and all the colon parts distally from this point. None of the colon cancer patients received preoperative chemotherapy, while 5 of the rectal cancer patients received preoperative radiotherapy and two preoperative radiochemotherapy. There were 42 women and 49 men, the mean age 64,7 (SD - standard deviation 10,2). The bone marrow biopsy was performed on the day of surgery after the induction of general anesthesia from posterior superior iliac spine. The 5ml sample of the bone marrow was collected to plastic tubes containing EthyleneDiamineTetraacetic (EDTA). Patients received postoperative chemotherapy if indicated, regardless of their DTC status. All the patients were followed up at least for 5 years or until death.
The incidence of DTC was not related to the depth of infiltration (T feature) being similar in T1-2 and T4 patients. There was no statistically significant difference between the incidence of DTC in N- and N+ patients. The 5 years survival rate for the DTC patients was 59,5% while for the DTC negative patients was 53%.
