Laparoscopic surgery minimizes the surgical manipulation of isolated tumor cells leading to decreased metastasis compared to open surgery for colorectal cancer

Purposes: We focused on the possible benefits of laparoscopic surgery to protect against isolated tumor cells (ITC) generated by surgical manipulation in comparison to open surgery. Methods: We performed conventional open surgery and laparoscopic surgery for 25 and 8 cases of colorectal cancer (CRC), respectively. We compared the presence of ITC in the peripheral blood (PB) immediately after surgery via quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) for a representative epithelial marker, carcinoembryonic antigen (CEA). Results: In the 25 patients who underwent open surgery, 8 of the 10 cases with metastasis were positive for ITC in PB, while 13 of the 15 cases without metastasis were negative for ITC. Therefore, we validated that there was a significant clinical usefulness for the detection of ITC in the prediction of metastasis (p=0.0024). We limited our subsequent analysis to the CRC cases with a Dukes stage of B or C to avoid differences due to the background, and we found that the positive ITC rate for metastasis was higher in the 19 patients who underwent open surgery (42.1%) than in the 8 who underwent laparoscopic surgery (37.5%). Conclusions: The short observation period, especially in the laparoscopic surgery group, and the inadequate number of cases limit the ability to draw any definitive conclusions; however, laparoscopic surgery appears to minimize the surgical manipulation, thus leading to reduced ITC from primary CRC compared with open surgery.