Background: The current study was conducted to clarify the frequency of systemic circulating tumor cells (CTCs) appearing after surgery for renal cell carcinoma and to evaluate the differences in postoperative CTCs between different surgical procedures.
Methods: This prospective, cohort study included 60 consecutive patients who underwent laparoscopic radical nephrectomy (RN) (n = 22), laparoscopic partial nephrectomy (PN) (n = 19), open RN (n = 8), or open PN (n = 11). In this study CTCs were measured by the FISHMAN-R system, and CTCs drawn from a peripheral artery were collected just before and immediately after surgery. The number of pre- and postoperative CTCs and the perioperative changes in CTCs were measured for each surgical method.
Results: Six patients were excluded from the current analyses. Preoperative CTCs did not differ significantly by surgical approach (laparoscopic RN: 3.4 ± 4.2; laparoscopic PN: 3.4 ± 4.1; open RN: 7.7 ± 6.8; open PN: 6.0 ± 7.6; P = 0.19). Open RN resulted in a significantly greater number of postoperative CTCs (laparoscopic RN: 4.8 ± 3.7; laparoscopic PN: 7.9 ± 9.1; open RN: 22.5 ± 26.3; open PN: 6.4 ± 6.3; P < 0.001) and perioperative changes in CTCs (laparoscopic RN: 1.3 ± 5.3; laparoscopic PN: 4.5 ± 9.6; open RN: 14.7 ± 25.0; open PN: 0.4 ± 6.3; P < 0.001). No significant differences in these were observed among the three groups except in the open RN group. In the multivariate analysis, the surgical approach was significantly correlated with the number of postoperative CTCs (P = 0.016) and the perioperative change in CTCs (P = 0.01).
Conclusions: This proof-of-concept study indicated that after surgery, more cancer cells can be expelled into the bloodstream, especially after open RN. Sufficient and careful follow-up assessment for the emergence of distant metastases is needed for patients undergoing open RN.