occurring in 4% to 26% of cases.101,102 In addition to causing patient suffering, SSIs lengthen hospital

stay and increase costs.103 The institutional rate of SSI after colorectal surgery is now an important

quality metric for several benchmarking programs. A number of federal and state-wide initiatives aimed

at improving surgical care recommend implementing measures to reduce the rate of SSI and other

complications in patients undergoing elective colorectal surgery.104,105

Figure 68-7. Staging modalities for colorectal cancer. A: Obstructing colon cancer at colonoscopy. B: Polypoid colonic tumor at

colonoscopy. C: Cecal circumferential tumor with regional lymphadenopathies. D: Liver metastases of colorectal origin.

The colon has the largest concentration of bacteria in the human body. A gram of feces contains 1011

polymicrobial bacteria, mostly gram negatives and anaerobes.106 Oral mechanical bowel preparation

using polyethylene glycol to reduce the bacterial load and risk of intraoperative fecal spillage has been

considered an axiom in colon and rectal surgery. However a number of prospective trials have failed to

demonstrate benefit from mechanical bowel cleansing in preventing SSIs.107,108 These results were

confirmed by a Cochrane systematic review of 5,805 patients; the authors concluded that there is no

statistically significant evidence that patients benefit from mechanical bowel preparation or the use of

rectal enemas.109 Another recent systematic review by the Agency for Health Care Research and Quality

reached similar conclusions. Oral mechanical bowel preparation appeared to be protective, compared to

no preparation, for peritonitis or intra-abdominal abscess, but the evidence was weak. The study could

not draw any conclusion on potential harms, such as dehydration and electrolyte imbalances, related to

use of oral mechanical bowel preparation.110 Despite the lack of solid data, many surgeons still

recommend oral mechanical bowel preparation because manipulation and suturing is easier with a clean

colon.

High-quality evidence indicates that antibiotics covering aerobic and anaerobic bacteria, delivered

orally or intravenously (or both) prior to elective colorectal surgery, reduce the risk of postoperative

surgical wound infection by as much as 66%.111 Oral antibiotics, neomycin- and erythromycin-based, are

delivered the day before surgery, in combination with the oral mechanical bowel preparation. For

patients without penicillin allergy, a second-generation cephalosporin (cefotetan or cefoxitin) is

administered intravenously within 30 minutes of the surgical incision, with re-dosing during the

procedure as required according to the half-life of the drug and the duration of surgery. For penicillinallergic patients, metronidazole or clindamycin combined with either ciprofloxacin or gentamicin is

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acceptable, as are aztreonam and fluoroquinolones.112 Ertapenem, a long-acting carbapenem active

against gram negatives and anaerobes, is an accepted alternative to second-generation cephalosporins

for prophylaxis in CRC. Ertapenem has a long life and does not require re-dosing in prolonged

procedures, but has been associated with increasing risk of Clostridium difficile infection.113 Other

measures that prevent SSI include tight glucose control in diabetic patients, smoking cessation, clipping

rather than shaving the skin of the abdominal wall, and maintaining normothermia and adequate

oxygenation during anesthesia.114

Patients undergoing surgery for CRC are also at risk of deep venous thrombosis and pulmonary

embolism, and should have thromboembolic prophylaxis with unfractionated heparin or low-molecularweight heparin during the peri- and postoperative periods.115

As the incidence of CRC increases with age, many patients have cardiovascular or respiratory

conditions requiring medical clearance before surgery. While technical advances have made CRC

operations safer, optimal outcomes require special effort to ensure that the patient’s overall health is

optimal at the time of surgery. Many CRC patients have other comorbid conditions such as diabetes,

hypertension, and coronary artery disease requiring medical evaluation before undergoing surgery.

Comorbidities can impact decision-making and affect short- and long-term outcomes. Patient clinical and

performance status should be optimized to reduce the risk of perioperative complications. Fertility

options should be discussed with all individuals of child-bearing potential.

Patients who may require a stoma should be seen before surgery by an enterostomal therapist.

Adequate marking of the site improves outcomes for patients requiring a stoma. Preoperative teaching

shortens the time patients require to become proficient managing the stoma, and reduces hospital

stay.116

The Enhanced Recovery After Surgery (ERAS) protocols were introduced in open colorectal surgery in

the 1990s, with the aim of speeding patient recovery, improving patient outcomes and satisfaction,

shortening hospitalization, and reducing healthcare costs.117 ERAS protocols span the entire

perioperative period, and attempt to minimize surgical stress and postoperative ileus through patient

education, preoperative hydration and carbohydrate loading, goal-directed intraoperative fluid

management, narcotic sparing for intraoperative and postoperative pain control, and early mobilization

and oral feeding in the postoperative period. A number of prospective trials have indicated that the

implementation of ERAS protocols reduces length of hospital stay, compared to conventional recovery

in patients undergoing open or minimally invasive surgery for CRC.118,119 A recent systematic review

and a meta-analysis confirmed that ERAS protocols resulted in a shorter length of stay and a reduction

in overall complications, with no difference in mortality and surgical complications.120,121 Similar

results have recently been reported from an international registry.122

Principles of Surgical Treatment

The goal for any curative-intent surgery is to remove the tumor-bearing segment of the bowel with

adequate margins, along with en bloc excision of the mesentery containing the feeding vessels and

regional lymph nodes. The location of the primary tumor determines lymphatic drainage and dictates

the extent of the resection. Lymphatic capillaries are primarily located in the submucosal and subserosal

layers of the bowel wall. The lymphatic flow in the colon is primarily circumferential, with longitudinal

spread along the bowel wall thought to be less than 1 cm in each direction. Therefore, a 5-cm margin of

normal bowel on either side of the primary tumor is considered sufficient to avoid anastomotic

recurrence. The length of the terminal ileum resected in patients with rectal cancer does not influence

the risk of anastomotic recurrence. In the rectum, where the longitudinal lymphatic flow is primarily

upward, cancer cells rarely spread distally along the bowel wall farther than 1 cm from the macroscopic

distal end of the tumor. Consequently, a 2-cm margin of normal bowel distal to the tumor, or even less

in patients treated with neoadjuvant therapy, is considered appropriate to an oncologically safe

resection.123

The lymphatic channels in the bowel wall drain to the regional nodes, which are classified in different

groups according to their proximity to the bowel and its blood supply (Fig. 68-8). The “epicolic” nodes

are located in the bowel wall under the peritoneum, usually close to the epiploic appendices. The

“paracolic” lymph nodes are located along the marginal vessels. Next, the “intermediate” nodes are

positioned in the middle of the mesentery. Finally, the “central” or “apical” lymph nodes are located

close to the root of the mesentery, near the origin of the named vessels. While CRC generally spreads

sequentially from the paracolic to the central or apical lymph nodes, nodal metastases skipping one of

the groups are common.124

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The extent of the mesenteric resection is determined by the need to remove all the lymph nodes

draining the corresponding segment of bowel, including the central lymph nodes located at the origin of

the named feeding blood vessels. As most tumors are located between two named vascular pedicles,

both of these should be resected at their origin. When suspected of being involved by tumor, the central

nodes should be marked on the specimen, as they have negative prognostic information. Other lymph

nodes located away from the feeding vessels and suspected of tumor involvement during surgery,

should be removed and analyzed, because in some patients the lymphatic drainage does not follow an

orderly pattern.125,126 If residual metastatic lymph nodes remain after sampling, the resection should be

considered incomplete.

Figure 68-8. Anatomy of the colon. A: Epicolic lymph nodes. B: Paracolic lymph nodes. C: Intermediate lymph nodes. D: Apicalcentral lymph nodes.

While achieving safe oncologic margins and adequate lymphadenectomy are the main considerations

when performing a surgical resection for CRC, ensuring an adequate blood supply to the bowel ends,

and maintaining tension-free anastomosis, are also important in order to avoid anastomotic

complications.

Locally advanced tumors attached to other organs should be removed en bloc with contiguously

involved structures. As it is impossible to distinguish clinically or radiographically between

inflammatory adhesions and tumor infiltration, it is preferable to perform an en bloc resection of any

organ attached to the primary tumor, rather than spilling cancer cells by separating structures infiltrated

by tumor. Intraoperative tumor perforation has negative prognostic implications. It is important to

report the completeness of the resection (R0, R1, or R2), combining clinical and pathologic information,

to determine risk of locoregional recurrence and long-term prognosis.

The concept of the no-touch technique, with initial control of the vascular supply before manipulation

of the tumor to avoid releasing cancer cells into the blood stream, has not been shown to be associated

with improved outcomes.127 However, early vascular control with medial-to-lateral dissection of the

mesentery, before mobilization of the colon, is the preferred approach during minimally invasive

colorectal surgery, because it helps identify all vascular and retroperitoneal structures.

Proper surgical technique is crucial in achieving optimal results in CRC patients. The removal of the

rectum along with its mesorectal envelope, using sharp dissection along normal anatomical planes – an

operation called total mesorectal excision, or TME – is associated with a reduced risk of local tumor

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