CHICAGO – Though it's not optimal in some other cancer types (such as pancreatic and cervical), the minimally invasive method of laparoscopic surgery in colorectal cancer (CRC) with liver metastases vs. the more dramatic "open" surgery leads to the same rate of survival. That's according to findings unwrapped at the American Society of Clinical Oncology (ASCO) annual meeting, where attendees heard results from the randomized study called Oslo-Comet determining that patients lived more than 6.5 years after surgery, regardless of whether it was laparoscopic or open.

From February 2012 to January 2016 at Oslo University Hospital in Norway, investigators randomly assigned 280 CRC patients with liver metastases to either laparoscopic, also known as keyhole surgery, or open surgery. The operations were performed with a liver-sparing technique, wherein surgeons remove only the tumors and a minimal amount of surrounding liver tissue. One-hundred thirty-three people received laparoscopic surgery, while 147 people underwent the open method. About half of the patients received chemotherapy before or after their surgery following standard Norwegian guidelines, which included the use of chemo drugs 5-fluorouracil plus leucovorin (folinic acid) and oxaliplatin (Eloxatin, Sanofi SA).

Based on ongoing outcomes (patients enrolled in 2015-2016 have not yet reached the five-year observation mark), the researchers found a number of comparable, non-statistically significant results. People who had the laparoscopic procedure lived a median of 80 months after surgery compared to 81 months for those who had open surgery. For those who had a laparoscopic procedure, median recurrence-free survival was 19 months compared to 16 months for those who had open surgery. After a minimum of three years of follow-up (the last patients were enrolled in early 2016), the researchers were able to estimate that 56% of people who had open surgery would be alive five years after their procedure compared to 57% of those who had a laparoscopic procedure. An estimated 31% of patients with open surgery would have no recurrence of disease five years later compared to 30% of those who had laparoscopy. Considering solely the surgical process, no difference emerged between the groups in terms of the rate of complete tumor removal, or the amount of tissue removed beyond the observable cancer.

Patients reported improved health-related quality of life after laparoscopy, which also brought fewer postoperative complications (19% with laparoscopy vs. 31% with open surgery). The researchers found that the monetary costs for either type of surgery were comparable, though they conceded that disparities in costs may hold sway in other countries.

Pick one, but get resected

"This is news and this is important," said ASCO expert Nancy Baxter, a colorectal surgeon. "Standard surgery is still safe and effective," she said, but patients ought to consider laparoscopic surgery if they can find a center where such operations are done routinely. "You certainly want to make sure that the entire surgical team is familiar with laparoscopic surgery, that the surgeon performs a significant number of cases and has adequate training," she said, adding that "not every single liver resection can be done laparoscopically, so if your surgeon is telling you [the procedure] is best done open, listen to your surgeon."

Bjørn Edwin, of the Oslo hospital, leads the research effort. He said centralized laparoscopic efforts can make the prospect much more inviting to patients. "High-volume centers usually come out OK" in terms of successful operations, he said. "We do this every day, and that certainly makes us more confident."

The study, Baxter concluded, emphasizes the importance of research vs. hunches. "We assumed that [laparoscopic surgery] was going to be effective for cervical cancer because it is for endometrial cancer" but the idea didn't prove out, she said. "Just like a different drug or a different mechanism for delivering a drug, it needs to be tested before we just get on the bandwagon. This is an excellent example of good quality evidence that's going to allow us to drive care to benefit patients." She added that "everybody who has the opportunity to have their metastatic disease resected for cure" should take advantage of it. "To me, that's much more important than the surgical approach taken."

Similar studies are not common but also not unheard of. In 2009, Annals of Surgery published results of one such comparison between open hepatectomy (OH) and laparoscopic hepatectomy (LH). Two groups composed of 60 patients each were obtained from two specialized liver units performing either OH or LH as their primary modality. Cohorts of 215 LH cases and 1,783 OH were used to establish the study population. Patients were compared on an intention to treat basis using nine preoperative prognostic criteria, including sex, age, primary tumor localization, number of tumors, diameter of tumor, distribution of metastases, presence of extrahepatic disease, initial respectability, and the use of pre-hepatectomy chemotherapy. Overall survival and disease-free survival were compared between OH and LH for a follow-up of 36 months. The median follow-up for the LH group is 30 months and 33 months for the OH group (p=0.75). One-, three- and five-year patient survival for LH was 97%, 82% and 64%, and for OH was 97%, 70% and 56%, respectively (p=0.32). One-year, three-year and five-year disease-free survival was 70%, 47% and 35% and 70%, 40% and 27% (p=0.32), respectively, for the two groups. The study concluded that, "in a highly specialized center, first-line application of laparoscopic liver resection in selected patients can provide comparable oncologic results to treatment with open liver resection for patients with colorectal liver metastases."