Introduction: Insulin like growth factor binding protein-3 (IGFBP-3), which binds IGF and induces apoptosis independently, inhibits the growth of many tumors, including colon cancer. Low blood levels have been shown to be a poor prognostic factor for several human cancers. It is the intact IGFBP-3 protein, rather than the degraded form which has the tumor inhibitory properties. It has been documented that open colorectal resection (OC), significantly more so than laparoscopic-assisted resection (LC), is associated with a significant decrease in the plasma IGFBP-3 levels early after surgery that can persist for up to 3 days. This study's purpose was to assess and compare intact plasma IGFBP-3 levels in colorectal cancer patients undergoing hand assisted laparoscopic resection (HAL), LC, or OC.
Methods: Intact IGFBP-3 levels of HAL, LC, and OC cancer patients (pts) were determined preoperatively (PO) and on POD#2 using a combination of ELISA and Western blot analysis. The HAL, OC, and LC IGFBP-3 results were then compared.
Results: A total of 54 pts were studied: HAL, 12 pts; OC, 19 pts; LC, 23 pts. The mean incision sizes for the three groups were OC-21.9cm (range=12-37), LC-5.4cm (range=3-11), and HAL-10.7cm (range=7-15). In the OC group there was a significant decrease in intact plasma IGFBP-3 levels from PO (1749ng/ml +/- 1366ng/ml) to POD#2 (393.8ng/ml +/- 345.8ng/ml, vs. PO; p=0.0002). In contrast, no significant change was noted in the LC group from PO (1148ng/ml +/-779.6ng/ml) to POD#2 (896ng/ml +/- 625.2ng/ml, vs. PO- p=NS). The HAL's pts showed a significant drop in their IGFBP-3 levels on POD#2 (POD#2-979.8ng/ml +/- 717.7 vs. PO-1441ng/ml +/-696.3ng/ml ; p=0.0425). However, the HAL POD#2 levels were significantly higher than OC POD#2 levels (HAL-979.8ng/ml +/- 717.7ng/ml vs. OC-393.8ng/ml +/- 345.8ng/ml; p=0.0084). No difference was found between the LC and the HAL POD#2 levels.
Conclusion: Intact plasma IGFBP-3 levels fall significantly after HAL and OC, however, after LC a non-significant decrease occurs. The HAL POD2 levels, although decreased are significantly greater than the OC results. There is an indirect relationship between length of incision and postop IGFBP-3 levels; this decrease may be related to the extent of abdominal trauma. The clinical importance of the IGFBP-3 decrease noted after OC and HAL has not yet been established, in theory, this depletion may be detrimental for cancer pts with retained tumor cells after surgery.