Conceptual image for viral ethiology of prostate cancer
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German study data show that creating a small flap in the peritoneum during prostate cancer surgery can substantially reduce the rate of lymphoceles, a common post-operative complication where lymphatic fluid collects in the pelvis.

The procedure is “safe, easy and inexpensive and should therefore be considered the new standard of care,” said urology specialist Manuel Neuberger from University Medical Centre Mannheim and Heidelberg University.

Neuberger, who presented the findings at the 2023 European Association of Urology (EAU) annual Congress in Milan, Italy, explained that up to 30% of patients develop asymptomatic lymphoceles following robotic-assisted radical prostatectomy (RARP) and approximately 10% develop symptomatic lymphoceles.

Patients who develop lymphoceles can experience pain and discomfort, serious infections, and compression of the internal iliac vein, which in turn may lead to deep venous thrombosis and, in the worst case, pulmonary embolism.

Draining a lymphocele can take from 3 days to 3 weeks, with treatment complete only when the fluid is no longer accumulating. For some patients, this requires a stay in hospital.

The idea of using peritoneal flaps to prevent lymphoceles after RARP was first published by Lebeis et al in 2016 and was followed by a limited number of publications with retrospective data. To provide better quality evidence for the value of the procedure, Neuberger and colleagues set up the Phase III PELYCAN trial in the second half of 2019.

The study included 551 patients undergoing laparoscopic RARP with pelvic lymph node dissection. They were randomly assigned to receive the surgery with (n=277) or without (n=274) the creation of peritoneal flaps.

The intervention technique involves creating a small flap in the peritoneum and attaching it down into the pelvis. This creates a route for lymphatic fluid to escape from the pelvis into the abdomen where it can be more easily absorbed.

Neuberger and colleagues found that, after 6 months of follow-up, 6.4% of participants had symptomatic lymphoceles overall. The rate was significantly lower among the patients who received a peritoneal flap than among those who did not, at 3.7% versus 9.1%, with the difference corresponding to a significant 62% lower likelihood of developing the complication among people in the intervention arm.

The intervention also significantly lowered the chances of developing asymptomatic lymphoceles by from 60% to 69% at both discharge and after six months. At discharge, 7.4% of patients who received a peritoneal flap had asymptomatic lymphoceles compared with 16.8% of those with no flap. At 6 months, the rates were 10.3% and 27.2%, respectively.

Neuberger said that the operating time was 11 minutes longer in the intervention group than in the control group, which, statistically speaking, is a significant difference. However, “in our opinion the extra surgical step of creating peritoneal flaps does not add surgical difficulty to the operation,” he remarked.

The researchers also asked study participants to complete the EORTC-Q30 questionnaire on quality of life, a validated questionnaire on lower lymph edema, and other follow-up questions such as experience of incontinence at six months post-surgery. They are currently analyzing this data, which will be published at a later date.

Neuberger notes that the PELYCAN trial is the first trial involving peritoneal flap creation as part of prostate cancer surgery that showed a significant reduction in lymphoceles across a mixed cohort with both regional and extended pelvic lymph adenectomy. Three other recently published studies only included patients with extended pelvic lymph node dissection.

“Additionally, our study was the one with the most patients and the only one that used a stratification for lymphocele risk factors in addition to the randomization,” he remarked.

The investigator concluded: “In our opinion the creation of peritoneal flaps should be the new standard of care and as a consequence from the PELYCAN trial we adopted this surgical step (the peritoneal flap) as a new standard in all RARPs at our department.”

Nonetheless, he believes that more time, “and probably a review and meta-analysis of [similar] studies” is needed “until other centers will hear of that technique and might discuss adopting it.”

Professor Jochen Walz, from the EAU Scientific Congress Office and the Institut Paoli-Calmettes Cancer Center in Marseille, France said: “Most problems in these operations are linked to the lymph node removal, rather than the prostate surgery itself. Removal of the lymph nodes allows us to see if the cancer has spread, so it’s important to do, particularly as surgery is now mainly used in higher risk patients. Creating a peritoneal flap is a simple, small, easy, and quick procedure that takes about five minutes to complete. It is totally safe, and this trial has shown it can substantially reduce complications, so there’s no reason why surgeons should not now do this as standard.

“Randomized control trials to evaluate technical changes in surgery are notoriously difficult to do—but this study has shown that they are both possible and effective. That’s good news for surgeons and for patients, who will benefit from better outcomes as a result.”

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