| Objective: To discuss the feasibility and reliability of detecting micrometastases in patients with early stage colorectal cancers using RT-PCR, according to the results of analysis of clinical data about colorectal cancers and the results of experiments. Meanwhile the clinical value of micrometastasis was evaluated.Methods: (1). Six hundred and ninety-three patients with colorectal cancers were treated in department of abdominal surgery in cancer hospital of former Shanghai Medical University during the period of 1991-2000. Of all cases 307 were on stage A, the rate was 44.3%. The number of stage B was 386, the rate was 55.7%. The data were collected and analyzed. Relative factors such as clinical and pathological features which were correlated with postoperative recurrence and metastasis in colorectal cancers were analyzed. Also the significance of micrometastasis detection and necessity of actively adjuvant treatment for patients with early stage colorectal cancers were discussed. (2). During the period of Oct. 2001 to Mar.2002, six hundred and eighteen lymph nodes from 42 colorectal cancer patients undergoing radical operation were collected, including 370 lymph nodes from 25 cases which were histologically diagnosed to be node-negative. The nodes were submitted to RT-PCR examination. A specific marker GCC mRNA was used , together with CEA and CK20mRNA. All these cases were followed-up for 6-26 months. (3). Blood samples from eighty-three patients with colorectal cancers were tested fromAugust to November in 2003. Each sample contained 5ml peripheral blood from which the total RNAs were extracted. Then GCC mRNA and CEA mRNA was detected by reverse transcriptase polymerase chain reaction. Forty-seven controlled cases were tested, too. @. The significance of detecting micrometastasis in colorectal cancers was discussed theoretically, on the base of which the principles of treatment for colorectal cancers were discussed, too.Results: ?. Of all cases 22 endured postoperative recurrence, the rate was 3.2%, and the risk of recurrence was related with tumor location and invasive depth. Forty-three out of 693 cases suffered from postoperative metastases, the rate was 6.2%, the risk of metastases was correlated with invasive depth, pre- and postoperative radiotherapy, and postoperative chemotherapy. The 1-, 3-, 5-year overall survival were 94.51%, 89.18%, 83.34%, respectively. The 1-, 3-, 5-year disease-free survival were 94.35%, 88.62%, 81.88%, respectively. Log-rank test showed that the disease-free survival was influenced by patients' age, tumor invasive depth, nerve involvement and blood transfusion. According to the Cox model analysis, the differences on patients' age, rumor invasive depth and tumor location were absolute factor related with disease-free survival. (2). Twenty-five out of 42 cases were determined to be of Dukes' stage A or B, while the others belonged to Dukes' C. Within the cases on Dukes' stage A or B, GCC, CEA and CK20mRNA were detected in 12.16%, 42.16% and 41.62% of 370 lymph nodes, respectively. Fourteen out of 25 cases histologically diagnosed to be node-negative had GCC-positive nodes, of these 14 cases 2 cases suffered from local recurrence and other 2 cases suffered from liver metastases. The sensitivity and specificity of this diagnostic trial was 100% and 52.38%. There was a significant association between mRNA levels and distant recurrence or metastasis. ?. Within 83 cases with CRCs, fifty-seven samples were tested to be GCC mRNA positive, the rate was 68.7%. In the controlled group the positive rate was 21.3%, the difference between CRCs group and controlled group was significant, p=0.000. Of all 83 cases with CRCs, sixty-nine cases had primary tumors and 14 developed recurrent tumors or tumor metastases. Of 69 cases with primary CRCs 44 cases were tested to be GCC mRNA positive, the rate was 63.8%. |
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