Minimally Invasive vs Open Surgery in Pancreatic Cancer

CHICAGO — Patients with resectable, early-stage pancreatic cancer can safely undergo minimally invasive distal pancreatectomy (MIDP) as an alternative to traditional open surgery, suggest results from the international DIPLOMA study.

In the trial, around 260 patients were randomly assigned to undergo either open surgery or minimally invasive laparoscopic or robot-assisted surgery. Rates of complete tumor removal were comparable between the groups.

In addition, the disease-free and overall survival rates at 3 years were nearly identical.

“For pancreatic cancer, we have proven for the first time that minimally invasive distal pancreatectomy is as good as open surgery,” commented principal investigator Mohammad Abu Hilal, MD, PhD, surgical director at the Instituto Ospedaliero Fondazione Poliambulanza in Brescia, Italy.

“Our research provides reassurance for surgeons and can help patients by giving them the information they need to have a conversation with their doctor about how they want to be treated,” he added.

Hilal was speaking at a press briefing ahead of the American Society of Clinical Oncology (ASCO) 2023, where the study will be presented (abstract 4163) on June 5.

The study was not able to show that there was a benefit in terms of shorter hospital stays or greater functional recovery with the minimally invasive approach, Hilal noted, but he suggested that this could be due to differences in postoperative procedures between the participating centers.

He told Medscape Medical News that minimally invasive surgery is becoming “very common all over the world,” particularly in the United States, and that randomized controlled trials are “always the last step” in convincing people to use the technique.

He also emphasized that the “the best results are obtained in high-volume centers where surgeons do more than at least 50 pancreatic resections a year,” because the minimally invasive approach is “quite complex and difficult,” more so than open surgery.

“This confirmatory study proves that minimally invasive surgical techniques are a safe and effective option for resectable pancreatic cancer,” commented ASCO expert Jennifer F. Tseng, MD, chair of surgery at Boston Univesrity School of Medicine and surgeon-in-chief at the Boston Medical Center. It may also “provide benefits like faster recovery time and less infection risk, without increasing cancer risk.”

The results from this trial “will help both surgeons and patients feel comfortable that minimally invasive surgery, in expert hands, is not inferior to open surgery,” she commented in a statement.

Minimally Invasive Surgery

Only around 12% of patients with pancreatic cancer are diagnosed when the disease is at an early enough stage for surgical resection to be a possibility, Hilal noted. Minimally invasive pancreatectomy, particularly the distal procedure, was introduced around 25 years ago, but it was initially used only for benign tumors or borderline malignancies.

It took another 10 years before it was considered in cases of confirmed malignancies, “and the main reason for this delay were concerns about the oncological efficiency” of MIDP in terms of its ability to achieve radical resection and an adequate lymph node yield. At the same time, some concerns about minimally invasive surgery for cancer were raised because of results from randomized trials in other cancer types, such as hysterectomy for cervical cancer. Some studies showed worse survival after minimally invasive surgery than after open surgery.

In recent years, use of minimally invasive techniques for pancreatic cancer has become an increasingly “hot topic in many surgical forums,” Hilal said.

So his team set out to investigate the approach in a phase 3 noninferiority trial. The investigators focused on patients who had an indication for elective distal pancreatectomy plus splenectomy due to proven or highly suspected pancreatic ductal adenocarcinoma in the pancreatic body or tail.

Patients from 35 centers in 12 countries were recruited between May 2018 and May 2021 and were randomly assigned to undergo either MIDP or open distal pancreatectomy.

Patients, nurses, and pathologists were blinded to the surgical procedure by covering of the abdominal wall.

None of the patients underwent adjuvant or neoadjuvant chemotherapy.

Following the procedure, the patients were followed up at 2 weeks and at 1, 3, 6, and 12 months, and a CT scan was performed at 12 months. A range of assessments were performed at each visit, including quality of life measures.

From 1146 patients initially screened, 261 patients were included.

A few patients withdrew; 131 patients underwent MIDP, and 127 underwent open surgery and were included in the intention-to-treat analysis. Of those, 129 and 125, respectively, were included in the follow-up analysis.

The results confirmed the noninferiority of MIDP compared with open surgery, with a rate of R0 radical resection (defined as ≥1 mm distance between the tumor and the surgical margin) of 73% vs 69% (P = .039).

In addition, the lymph node yield was comparable between the two approaches, at an average of 22 nodes for MIDP vs 23 for open surgery (P = .89), and the time to functional recovery was identical, at 5 days for both (P = .22).

The rate of intraperitoneal recurrence was found to be 41% with MIDP, compared with 38% for patients who underwent open surgery.

Hilal also showed that the rate of serious adverse events, such as bleeding or organ damage, was similar between the two procedures, at 18% with minimally invasive surgery vs 22% for the open procedure.

Turning to the survival curves, he noted that it is “very clear” that the two procedures achieved near-identical results, at a hazard ratio of 0.99 (P = .94) for overall survival and 0.97 (P = .88) for disease-free survival when comparing MIDP with open surgery.

The researchers will continue to follow up the patients for 3 to 5 years and will analyze the lymph nodes retrieved to determine whether removal of the spleen is necessary.

The study was funded by Medtronic and Ethicon. Hilal has relationships with Ethicon and Medtronic. Tseng has relationships with Aegerion, Amgen, AstraZeneca, Bristol-Myers Squibb, Cubist, Curadel Surgical Innovations, Daiichi Sankyo/Lilly, GlaxoSmithKline, Intarcia Therapeutics, Merck, MyoKardia, PanTher Therapeutics, Pfizer, Quest Diagnostics, Sanofi, Vertex, Zeus.

American Society of Clinical Oncology 2023 Annual Meeting: Abstract 4163. To be presented June 5, 2023.

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