Objective: To investigate the influences of natural orifice specimen extraction surgery (NOSES) on postoperative recovery and immune function in patients with rectal cancer.    
Methods: The clinical data of 98 patients with rectal cancer treated from February 2015 to December 2016 were retrospectively analyzed. Of the patients, 49 cases underwent radical rectal cancer resection with the NOSE approach (observation group), and the other 49 cases underwent conventional laparoscopic radical rectal cancer resection (control group). The main clinical variables and the pre- and postoperative levels of stress factors and immune function parameters of the two groups of patients were analyzed. 
Results: In observation group compared with control group, the time to postoperative gas passage was significantly reduced (2.62 d vs. 3.31 d, P<0.05), while the operative time, intraoperative blood loss and number of resected lymph nodes showed no significant differences (all P>0.05). There were no significant differences in the levels of E-selectin, endothelin (ET), soluble vascular cell adhesion molecule 1 (sVCAM-1), matrix metalloproteinases 9 (MMP-9) and immunoglobulins between the two groups before operation (all P>0.05), but the postoperative levels of E-selectin, ET, sVCAM-1 and MMP-9 were significantly lower and the postoperative levels of immunoglobulins were significantly higher in observation group than those in control group (all P<0.05). the incidence of complications in observation group was lower than that in control group (8.16% vs. 18.37%), but it did not reach a statistical significance (P>0.05).
Conclusion: NOSE radical rectal cancer resection can achieve the equivalent oncologic outcomes of the traditional procedures, and it can also reduce the expressions of stress factors, exert less impact on immune function, and accelerate the recovery of the patients.