Perioperative isolation of circulating tumor cells in patients with open or laparoscopically resected colorectal carcinoma

Background/Purpose: Laparoscopic resections in colorectal carcinoma (CRC) have been performed for over twenty years. Apart from many perioperative parameters, which are superior in laparoscopic procedures compared to open surgery, oncological equivalence is still being discussed. In the context of this discussion, the influence of circulating tumor cells (CTCs) as a possible surrogate parameter for oncological results in non-metastatic CRC patients remains unclear. Methods: At first a retrospective analysis of 420 patients who were treated laparoscopically (n = 226) and open (n = 194) was performed, with respect to metastasis-rate, diseasefree and overall survival. Furthermore, CTCs were isolated preoperatively and postoperatively in a prospective study for 119 patients who were resected laparoscopically (n = 81) or open (n = 38). Results: In the retrospective study cohort, the laparoscopic procedure showed significantly superior results with respect to metastasis-free (p = 0.004) and overall survival (p = 0.013). The prospective study cohort showed lower postoperative CTC counts in laparoscopically resected patients (p = 0.013), especially in non-metastatic carcinomas (p = 0.042). In addition, the 3-year overall survival rate for the laparoscopically resected group was higher (71.6% vs. 61.6%, p = 0.145). Conclusions: The results show that the difference in CTC numbers after laparoscopic resection was significantly lower than after open surgery. CRC patients with laparoscopic resection presented less frequently with metachronous metastases and had a longer metastasis-free and overall survival. This may be an indication of an oncological advantage of the laparoscopic procedure, which may be caused by less immunological impairment and thus better tumor cell control.