Cost-effectiveness of biological mesh closure of the pelvic floor after rectal cancer surgery.

De kosten-effectiviteit van een biologische mat voor het sluiten van de bekkenbodem na operatie voor laag gelegen endeldarm kanker.

Approximately 800 abdominoperineal resections (APR) are performed for rectal cancer each year in the Netherlands. The extralevator approach (eAPR) reduces the rate of positive margins and improve oncological outcome in distal rectal cancer.
However, wider excisions increase wound healing problems and development of perineal hernia. This has resulted in a
progressive increase of the use of musculocutaneous flaps and biological meshes associated with a substantial increase of costs, which is not supported by proper data.
The aim of this study is to determine the cost-effectiveness of pelvic floor reconstruction using a biological mesh after
standardized eAPR with neo-adjuvant (chemo)radiotherapy.



HYPOTHESIS:

It is hypothesized that the use of a biological mesh will improve primary perineal wound healing and prevent secondary perineal
hernia formation compared to primary closure of the perineum.



STUDY DESIGN:

This is a multicenter study in which patients undergoing an eAPR are randomized between standard care using primary closure
of the perineum and the experimental arm with assisted closure using a biological mesh.



STUDY POPULATION:

Patients with a clinical diagnosis of primary rectal cancer who are scheduled for eAPR after neo-adjuvant (chemo)radiotherapy.



INTERVENTION:

The intervention in the experimental arm consists of suturing an acellular biological mesh derived from porcine dermis in the
pelvic floor defect, followed by perineal closure similar to the control arm.



OUTCOME MEASURES:

The primary endpoint is the percentage of uncomplicated perineal wound healing (Souphampton wound score less than II on
day 30). Secondary endpoints are hospital stay, incidence of perineal hernia, quality of life, and costs.



SAMPLE SIZE CALCULATION/DATA ANALYSIS:

A total number of 104 patients (52 per group) is needed in order to be able to detect an absolute 25% improvement in perineal wound healing (from 60% to 85%).



COST-EFFECTIVENESS ANALYSIS/ BUDGET IMPACT ANALYSIS:

Costs per uncomplicated wound healing and the costs per quality adjusted life-year will be determined. The budget impact will
be determined by balancing the additional costs of a biological mesh against decreased costs related to in hospital and home nursing wound care and less treatment of perineal hernia.



TIME SCHEDULE:

Patient inclusion untill 22 months, followed by 12 month of follow-up and 2 month of data analysis and reporting.

It is hypothesized that the use of a biological mesh will improve primary perineal wound healing and prevent secondary perineal hernia formation compared to primary closure of the perineum.

At 7 and 30 days, 3, 6, 9 and 12 months.

The perineal phase of the APR will be performed according to the principles of an extralevator APR. Preferably, an omental plasty is positioned in the pelvic cavity following resection.



The intervention in the experimental arm consists of suturing an acellular biological mesh derived from porcine dermis in the pelvic floor defect (Strattice™, 6x10 cm). The mesh will be sutured at each side of the coccyx or distal sacrum with Prolene or PDS to the discretion of the surgeon. Laterally, the mesh is attached to the remainings of the levator complex and, anteriorly, to the transverse perineal muscle or posterior vaginal wall. A suction drain will be inserted and positioned on top of the mesh. The perineal subcutaneous fat and skin will be subsequently closed in layers similar to primary simple closure as performed in the standard arm.