People undergoing surgery for rectal cancer fare just as well whether they have conventional or minimally invasive laparoscopic surgery, suggests a new international comparison involving 1,044 patients. 

However, when the tumor is in the lower rectum, laparoscopic surgery seems better, according to the results in the New England Journal of Medicine.

Overall survival rates were 86.7 percent when the surgery was done with just a few puncture holes in the body versus 83.6 percent when the abdomen was opened up. Just 5 percent of people in both groups had a cancer recurrence within three years.

"This is the largest trial to date and we can now state with evidence that laparoscopic surgery is safe and associated with long-term cancer outcomes that are at least similar to open surgery," Dr. Jaap Bonjer, the lead author, told Reuters Health.

"With laparoscopic surgery, the short-term outcomes are better. What that means is patients experience less pain after surgery, bowel function returns earlier and the post-operative recovery goes more quickly," said Bonjer of the VU University Medical Center in Amsterdam.

But Dr. Heather Yeo, an assistant professor of surgery at Weill Cornell Medical College and New York-Presbyterian Hospital, urged caution because the test involved highly-skilled surgeons operating on specially-selected patients whose tumors had not spread.

And the new findings do not discuss which group was more likely to retain proper bowel and bladder control, or sexual function, an important element for patients, noted Yeo, who was not involved in the study.

About 466,000 people develop rectal cancer worldwide each year. Doctors have begun to favor such "keyhole" surgery because it is so much less invasive.

But there has been lingering concern over whether the gas that was injected in the abdomen to create a working space for laparascopic surgery tools would displace too many cancer cells and transfer those tumor cells to the incisions in the abdominal wall, Bonjer said.

The new study, known as COLOR II, was designed to address that question.

Thirty hospitals in Europe, North America and Asia enrolled patients with adenocarcinoma of the rectum in the study. People whose tumors had spread to other tissues were excluded. Ethicon Endo-Surgery Europe, a subsidiary of Johnson & Johnson, paid for the study.

Yeo said the surgeons in the study "had multiple evaluations of their skill and their experience before they were even enrolled in the trial," so the results show what can happen under ideal conditions.

Although both types of surgery generally gave comparable results, the researchers found that the location of the tumor made a difference.

When the cancer was in the lower rectum, the three-year recurrence rate was 3.8 percent with laparoscopic surgery versus 12.7 percent with traditional surgery.

With conventional open surgery, it can be harder for a surgeon to see deep into the pelvis, Bonjer explained. A laparoscope can get a better view, and the image is magnified, he said, “so the surgeon can operate with greater precision."

Over all, laparoscopic surgery also produced a higher rate of disease-free survival - 64.9 percent versus 52.0 percent - in people with stage 3 disease, where the tumor has spread to adjacent lymph nodes.

The type of surgery did not affect the risk of death, regardless of the stage of the cancer. The risk of distant metastases was also similar in the two groups.

"We only included patients whose cancers had not invaded adjacent organs such as the bladder and ureters," Bonjer said. "With patients who have larger cancers, it needs to be done open because it's too complex to do laparoscopically."

Yeo said, "For patients, I think the important thing is to make sure their surgeon is a high-volume surgeon" with lots of experience in rectal cancer surgery.

"The big question is going to be the functional outcomes," she said, referring to how well patients retain their bowel, bladder and sexual functioning.

"Forty percent to 60 percent have bowel problems; 20 percent to 30 percent have problems with urinary function and probably 30 percent to 40 percent have sexual function problems after rectal cancer surgery," she said. "So those are the kinds of reasons you should go to a specialist."