We want to test whether robotic-assisted laparoscopic surgery is as good, or even better, at removing rectal cancers as standard laparoscopic surgery (actually Robotic-assisted laparoscopic surgery is used as standard of care in rectal cancer patients at University of California, Irvine Medical Center). We also want to investigate whether using robotic-assisted laparoscopic surgery reduces the number of times a laparoscopic operation needs to be converted to an open operation, and see whether using a robotic system can also shorten the length of time patients need to stay in hospital and if it reduces the number of complications patients may have during and after their operation.