Abdominoperineal resection performed for anorectal tumors leaves a large pelvic and perineal defect causing a high rate of morbidity of the perineal wound (40 - 60 %). Biological meshes offer possibility for a new standard of perineal wound reconstruction. Perineal filling with biological mesh is expected to increase quality of life by reducing perineal morbidity.

Perineal wound problems after abdominoperineal resection (APR) in the context of cancer are frequent. These types of resection problems occur because of wound complications caused by large perineal defects. Indeed, perineal wound complications, perineal abscess, wound dehiscences, chronic fistulas and sinuses lengthen the hospital stays. Futhermore, the standardization of the surgery since the late 2000s and the extralevator technique lead a larger defect and increase i perineal complications.

Several strategies are used to decrease the complication rate. Closure by direct approximation of the pelvic muscles leads to a rate of major complication up to 57% depending on the series. Musculocutaneous flaps help to reduce this rate (16- 65%) but they generate their own morbidity, require experience and increase the costs of care. Finally, the use of biologic meshes since the beginning of 2010 seems to have improve the healing process. However, results are still variable and the only randomized study comparing direct closure and mesh closure showed no significant results at one year. Another ongoing randomized trial is comparing gluteus maximus flap to mesh closure and focusing on physical performances.

This increase in post-operative complications and their consequences causes an increase in costs. In addition, they affect the patients' quality of life and lead to a loss of productivity. From an oncological point of view, perineal scarring problems can cause a delay in the adjuvant therapeutic sequence. Few studies have highlighted the efficiency of perineal wound complications, using cost-effectiveness analyses. In order to clarify the best strategy comparing primary and mesh closure in term of cost effectiveness on perineal healing after ELAPE, we designed this randomized controlled trial.

Inclusion Criteria:

• Age ≥ 18

• Eastern Cooperative Oncology Group performance status score of 2 or less

• Histologically proven rectal adenocarcinoma or anal canal epidermoïd carcinoma

• Abdominoperineal resection indication after multidisciplinary team discussion:

  • for rectal adenocarcinoma: circumferential MRI margin equal or less than 1 mm from closest tumoral structure and a striated muscular layer (levator ani or external anal sphincter)
  • for epidermoid carcinoma: residual or recurrent tumour after chemoradiotherapy.

• Voluntary written informed consent

• Patients with social security insurance or equivalent social protection

Exclusion Criteria:

• T4 tumour needing a surgical extensive resection with reconstruction by a musculocutaneous flap
• Metastasis disease deemed unresectable with curative intent
• Previous pelvic radiotherapy for another disease than the rectal or anal cancer
• Immunosuppressive drugs treatment
• Uncontrolled diabetes (glycosylated hemoglobin (HbA1c) > 8 % despite adequate therapy)
• Patient under juridical protection.
• Sensitivity to porcine derived products.
• Enrolment in trial with overlapping primary endpoint.
• Pregnant women
• Breastfeeding women