TME (Total mesorectum excision) is the golden standard of radical resection for mid-low rectal cancer. However, the damage of pelvic autonomic nerve following with TME principle will lead to high incidence of urinary and sexual function disorder. PANP (pelvic autonomic nerve preservation) surgery played a role in decreasing incidence of urinary and sexual function disorder. However, 32%-44% patients still suffered from urinary and sexual function disorder when underwent open (O-PANP-TME) or laparoscopic PANP TME surgery (L-PANP-TME).

In the early stage of work, the investigators performed preservation of Denovilliers' fascia in L-PANP-TME to discuss the protection of urinary and sexual function of male mid-low rectal cancer patients. The results showed that preservation of Denovilliers' fascia in L-PANP-TME significantly decreased incidence of urinary and sexual function disorder. In order to further confirm the early work, the investigators design a multicenter randomized controlled clinical trial to compare differences in urinary and sexual function protection and long-term outcomes between preservation and excision of Denovilliers' fascia in L-PANP-TME.

Inclusion Criteria:

1. Male, 20 < age (years) < 71, informed consent;
2. Pathological diagnosis of rectal adenocarcinoma;
3. Tumors from anal edge 6 ~ 12 cm (measured by rigid proctoscope);
4. Preoperative staging T1-4 (T1-2 for anterior rectal wall) N0-2M0 rectal cancer (AJCC- 7th);
5. R0 TME surgical results is expected;
6. Preoperative ECOG physical status score 0/1;
7. Preoperative ASA grade I ~ III;
8. Normal urinary function (Bladder residual urine<100ml), normal erection function (IIEF-5>21) and ejaculation function grading as I level.

Exclusion Criteria:

1. Complicated with acute ileus, perforation or hemorrhage;
2. Tumors with extensive invasion of surrounding tissues, TME not applicable; Imaging examination in regional integration intumescent lymph nodes (maximum diameter 3 cm or higher);
3. With other malignant diseases or with other malignant disease within 5 years; With other diseases need surgery;
4. A history of abdominal and pelvic major operation;
5. People with severe mental illness, or cannot be evaluated due to cultural or psychological factors;
6. No sexual life;
7. Critical organ dysfunction, unbearable surgery;
8. Unstable angina, myocardial infarction, cerebral infarction or hemorrhage within 6 months;
9. Systemic corticosteroids or immunosuppressive medication history within 1 month;
10. Pre-existent true incontinence or severe stress urinary incontinence.

Exit criteria:

1. Confirmed as M1 during or after operation;
2. Conversion to abdominoperineal resection (APR)
3. Postoperatively confirmed as invading rectal intrinsic fascia, or T3 for anterior rectal wall;
4. Intraoperative confirmed regional lymph node fusion conglobation cannot ensure R0 resection;
5. Infiltrating major blood vessel and unresectable;
6. Intraoperative finding other diseases need simultaneous surgery;
7. Preoperative emergent severe complications, cannot carry out the study treatment;
8. Emergency surgery is needed;
9. Into this study, at any stage of the initiative exit or discontinue treatment; Prove to implement the healer violates this research plan.