Cancer surgery

The principle of cancer surgery is to remove the tumor completely with histologically proven margins and the lymph nodes that drain the tumor. Histologically, completeness of tumor clearance from the resection margins is classified R0, R1and R2. An R0 resection is defined as one where all margins are histologically free of tumor. An R1 resection is defined as one in which microscopic residual disease has been left behind. An R2 resection is defined as incomplete resection with macroscopic residual disease.

Subtotal gastrectomy

Indication: gastric cancer situated in the distal part of stomach, complicated gastric ulcer disease.

Area resected: the distal half to two thirds of stomach with the surrounding lymph nodes.

Main blood vessels divided: left and right gastric arteries, right gastroepiploic artery.

Reconstruction: historically, the continuity was usually reconstructed by carrying out a simple gastrojejunostomy. This can result in significant biliary reflux which can cause anastomotic ulcerations. A roux-en-Y reconstruction negates biliary reflux and is generally the preferred option of reconstruction (Figures 21.1A, 21.1B).

Figure 21.1 (A) Partial gastrectomy, resection margins; (B) partial gastrectomy, reconstruction.

Postoperative barium appearance: barium passes from the stomach into the drainage roux loop. Reflux of barium may occur at the jejunojejunostomy.

Total gastrectomy

Indication: gastric cancer located in the proximal part or body of the stomach.

Area resected: whole stomach and surrounding lymph nodes.

Main blood vessels divided: left and right gastric arteries, right and left gastroepiploic arteries and short gastric arteries.

Reconstruction: A roux-en-Y reconstruction with or without a neogastric pouch. This is akin to a J-shaped ileoanal pouch (see ileoanal pouch) (Figures 21.2A, 21.2B and 21.3A, 21.3B).

Figure 21.2 (A) Total gastrectomy, resection margins; (B) total gastrectomy, roux-en-Y reconstruction.

Figure 21.3 (A) Roux-en-Y, gastric bypass (note resection margins A and B); (B) roux-en-Y reconstruction. Resection margin ‘A’ forming a jejunojejunostomy; resection margin ‘B’ anastomosed to gastric pouch.

Postoperative barium appearance: barium will flow from esophagus into a small gastric pouch and down the roux limb.

Benign surgery

Antireflux procedures

Indication: Gastro-esophageal reflux disease including repair of hiatus hernia.

Procedure: Performed laparoscopically, this procedure essentially consists of two parts:

1. to reduce the hiatus hernia (if present) and repair the diaphragmatic hiatal defect

2. to create an antireflux mechanism using the fundus of the stomach.

Antireflux surgery has a number of variations; however, the two gold standard procedures were described by the German surgeon Rudolph Nissen (1896–1981) and the French surgeon Andre Toupet born in 1915. Nissen’s fundoplication is a complete (360 degrees) wrap with the fundus round the lower esophagus and Toupet’s fundoplication is one where the fundus wraps the posterior aspect of the lower esophagus, variations suggest between 180 and 270 degrees (Figures 21.4 A–F).

Figure 21.4 (A) Wide diaphragmatic hiatus (1–2), gastric herniation (3); (B) gastric herniation reduced and the hiatus repaired. A retro-esophageal tunnel is created to allow for fundoplication; (C) gastric fundus pulled through to the right of the esophagus; (D) the Nissen 360 degrees wrap created by suturing points ‘A’ and ‘B’; (E) Nissen wrap at barium swallow; (F) the alternative Toupet 270 degrees wrap can be created by suturing points ‘A’ and ‘B’ to the sides of the esophagus.

Main blood vessel divided: the short gastric vessels may be divided.

Postoperative barium appearance: the lower esophagus is slightly narrowed by the wrap and the esophagus may have a bird’s beak appearance. Barium often has a slight delay before passing into the stomach.

Ileocecectomy

Indication: Crohn’s disease or other pathology affecting the distal terminal ileum such as radiation enteritis, benign tumors of the cecal pole, terminal ileum or appendix, conditions which mimic Crohn’s disease such as tuberculosis.

Bowel resected: distal ileum (depending on the extent of ileal pathology) and cecal pole.

Main blood vessel divided: ileocecal artery (Figure 21.7).

Figure 21.7 Ileocecal resection margins.

Postoperative barium appearance: ileum will run straight into colon with no cecal pole and no appendix apparent

Right hemicolectomy

Indication: colorectal cancer in the right side of the colon, inflammatory bowel disease, diverticulum, cecal volvulus.

Bowel resected: last 5–10 cm terminal ileum, cecum, right colon and hepatic flexure.

Blood vessels divided: ileocolic artery, right colic artery ± right branch of middle colic artery (Figure 21.8).

Figure 21.8 Right hemicolectomy margins.

Postoperative appearance: ileum will run straight into colon with no cecal pole or appendix. Anastomosis will lie anywhere from right side of abdomen to upper midline

Extended right hemicolectomy

Indication: most commonly a tumor of the mid to distal transverse colon or splenic flexure.

Bowel resected: last 5–10 cm terminal ileum, cecum, hepatic flexure, transverse colon and splenic flexure.

Main blood vessels divided: ileocolic artery, right colic artery, middle colic artery (Figure 21.9).

Figure 21.9 Extended right hemicolectomy margins.

Postoperative appearance: ileum will run straight into colon with no cecal pole or appendix. Anastomosis may lie on left side of abdomen. Only left colon will remain.

Left hemicolectomy

Indication: less common than other resections. It is usually performed for a descending colon tumor. An extended right hemicolectomy is an alternative and will increase lymph node harvest but the left hemicolectomy preserves a greater length of large bowel.

Bowel resected: distal transverse colon, splenic flexure and descending colon.

Main blood vessel divided: left colic artery (Figure 21.10).

Figure 21.10 Left hemicolectomy margins.

Postoperative appearance: shortened colon. The landmarks of the splenic flexure may no longer be apparent.

Sigmoid colectomy

Indication: tumor of sigmoid colon, sigmoid diverticular disease, Crohn’s disease or volvulus.

Bowel resected: sigmoid colon.

Main blood vessel divided: sigmoid branch of inferior mesenteric artery (IMA) (Figure 21.11).

Figure 21.11 Sigmoid colectomy margins.

Postoperative appearance: this depends on whether the operation was elective or emergency. In the emergency situation, where there may be a lot of fecal contamination, e.g. stercoral perforation (a pressure ulcer that can develop in the colon and lead to a perforation), or perforated sigmoid diverticular disease, a Hartmann’s procedure may be performed. This is where bowel continuity is not restored, the rectal stump is over sewn and the descending colon is brought out as an end colostomy. Occasionally, a track might be deliberately formed from the bowel distal to the defunctioning stoma; this track (a mucus fistula) leads to a second stoma and produces only mucus.

There is little indication for imaging after this procedure. If the procedure was elective or there was no peritoneal fecal contamination, a primary anastomosis will be performed. In this case, postoperative imaging will show a shortened left colon. The sigmoid colon will no longer be present and the left colon will appear less tortuous.

High and low anterior resections

An anterior resection is a resection of the sigmoid and upper rectum.

High anterior resection

Indication: tumor of distal sigmoid colon or upper rectum or severe sigmoid diverticular disease.

Bowel resected: sigmoid colon and upper rectum.

Main blood vessel divided: inferior mesenteric artery (IMA) at its origin (Figure 21.12).

Figure 21.12 (A) High anterior resection margins; (B) fluoroscopic image of a high anterior resection; (C) leak fistulating from a high anterior resection.

Postoperative appearance: shortened left colon. The sigmoid colon will no longer be present and the left colon will appear less tortuous. A stapled anastomosis is likely and will be seen in the region of the pelvic brim but may be higher or lower depending on rectal anatomy (Figure 21.12B).

With a high anterior resection, it is not necessary to perform a defunctioning loop ileostomy; however, this may be done if there are doubts about the anastomosis. If this is the case, it is usual to perform water-soluble (Gastrografin) enema postoperatively to check the integrity of the anastomosis prior to closing the ileostomy (Figure 21.12C).

Low anterior resection

Indication: mid to low rectal tumor.

Bowel resected: sigmoid colon and entire rectum down to pelvic floor. This is what is known as a total mesorectal excision (TME).

Main blood vessel divided: inferior mesenteric artery (IMA) at its origin (Figure 21.13).

Figure 21.13 Low anterior resection margins.

Postoperative appearance: shortened left colon. The sigmoid colon will no longer be present and the left colon will appear less tortuous. A stapled anastomosis is almost certain unless a hand-sewn colo-anal anastomosis has been performed and will be seen just above the pelvic floor (Figures 21.14A, 21.14B).

Figure 21.14 (A) Low anterior resection; (B) low anterior resection.

These operations are almost always defunctioned with a loop ileostomy and again it is usual to perform a water-soluble contrast enema postoperatively to check the integrity of the anastomosis prior to stoma closure.

Subtotal colectomy

Indication: acute fulminant colitis, inflammatory bowel disease (IBD), infective or ischemic colitis, synchronous colorectal tumors, some colorectal cancer syndromes.

Bowel resected: distal 5–10 cm of ileum and entire colon to top of rectum.

Main blood vessels divided: ileocolic, right colic, middle colic, left colic, sigmoid arteries (Figure 21.15).

Figure 21.15 Subtotal colectomy margins.

Postoperative appearance: depends on whether bowel continuity has been restored. In the emergency situation, e.g. acute fulminant colitis, an end ileostomy will be fashioned and the rectal stump will remain in situ. There is little indication for imaging postoperatively unless there is doubt about the integrity, health or length of rectal stump. If bowel continuity has been restored, an ileorectal anastomosis will have been performed in which case the ileum will be anastamosed directly to the top of the rectal stump (Figures 21.16A, 21.16B).

Figure 21.16 (A) Ileorectal anastomosis, lateral view; (B) ileorectal anastomosis, anterior view.

Ileoanal pouch

Indication: familial adenomatous polyposis (FAP), ulcerative colitis.

Bowel resected: the entire colon is resected from distal ileum to pelvic floor. In the case of FAP, all colonic mucosa needs to be removed down to the dentate line. In order to restore bowel continuity, the distal ileum is fashioned into a pouch or neo-rectum, which is anastamosed to the top of the anal canal either via a circular stapler or a hand-sewn anastomosis (Figures 21.17, 21.18A, 21.18B and 21.19).

Figure 21.17 Ileoanal pouch. A loop of ileum is looped back on itself in a U-shape and sutured or stapled to form a pouch.

Figure 21.18 (A) Ileoanal pouch; (B) ileoanal pouch.

Figure 21.19 Ileoanal pouch; leak from ileoanal anastomosis with drain.

Postoperative appearance: a ring of staples may be seen at the top of the anal canal. The appearance of the pouch depends on its configuration. The commonest type is a stapled J pouch, followed by a hand-sewn W.

Abdominoperineal resection (AP resection, APR, APER)

Indication: tumors of the lower rectum/anal canal where there is not enough normal colon distally to restore bowel continuity.

Bowel resected: accessed via the abdomen and from around the anus, the sigmoid, rectum and anal canal are removed and the descending colon is fashioned into an end colostomy.

Type of anastomosis

Anastomoses can be performed using staplers or hand-sewn with sutures. For distal anastomoses of high or low anterior resections, a circular staple gun is used which fires a ring of staples that can be clearly seen on x-ray (see Figures 21.12B, 21.14A). In the pelvis, circular staplers allow anastomoses to be performed that would be impossible or extremely difficult to perform with sutures.

The circular stapled anastomosis can be an end to end or end to side which can cause some confusion in interpreting postoperative images as there is often a ‘dog-ear’ to the side of the join which may be misinterpreted as a leak.

In other parts of the colon, staples and sutures are interchangeable as it is technically as easy to hand sew as it is to staple. The only benefit is that it is arguably quicker to use a stapling device and the join between the two pieces of bowel is usually larger. However, stapling is more expensive. If a hand-sewn anastomosis is performed, this is not visible on x-ray. However, staples are visible and the anastomosis is usually performed in a side-to-side configuration.

Stomas

It is worth mentioning stomas, as the radiographer or radiologist may sometimes be asked for a contrast study via a stoma. Stomas are either ileostomies or colostomies. In general, an ileostomy is fashioned in the right iliac fossa (although it could be anywhere on the abdomen) and contains liquid stool in the bag and is spouted.

A colostomy is usually in the left iliac fossa, contains more solid stool and is flush with the skin (Figure 21.20).

Figure 21.20 End colostomy. Colon is sutured flush with abdominal wall.

Stomas are performed for various reasons:

There are loop or end stomas (Figure 21.21A). Temporary defunctioning stomas are almost always loop stomas. It is possible to intubate either limb for imaging. In a loop ileostomy, the spouted end will be proximal (Figure 21.21B); in a loop colostomy, the passage of stool usually indicates which end is proximal. Temporary stomas can be closed any time after 6 weeks, but this depends on the fitness of the patient and integrity of the anastomosis on postoperative imaging.

Figure 21.21 (A) End ileostomy. Ileum is spouted onto the abdominal wall to prevent bowel contents excoriating abdominal wall. (B) Loop ileostomy. A loop of bowel is brought up to the abdominal wall. The proximal (afferent) limb is spouted to protect the abdominal wall. The distal (efferent) limb is sutured flush with the abdominal wall.

Laparoscopic colorectal surgery

Laparoscopic surgery is minimally invasive surgery where the bulk of the operating is performed using a laparoscope and laparoscopic instruments, inserted through very small incisions. This replaces traditional surgery, which is performed through a midline or transverse incision. The technique was first perfected with laparoscopic cholecystectomy with the benefits of reduced pain and earlier return to normal activities. However, laparoscopic resection has been slower to evolve as a technique for colorectal cancer surgery because it is technically demanding and time consuming, especially when the surgeon is on a learning curve. Early in its evolution there was concern about a high morbidity of up to 21%, which deterred surgeons from adopting the technique (Berends et al., 1994). The incidence of port site metastases led to concern about cancer outcomes and whether laparoscopic surgery was oncologically equivalent to traditional open surgery.

An early British study (the CLASICC trial) reflected the learning curve of surgeons with conversion rates to open surgery of 29%, but there were no differences in mortality, postoperative complications or the number of positive circumferential resection margins (Guillou et al., 2005). Since then, there have been other randomized controlled trials and meta-analyses which have demonstrated short-term benefits from laparoscopic surgery for colon and rectal cancer in terms of reduced blood loss, less pain, earlier return of bowel function and earlier tolerance of a normal diet. Oncologically, the surgery appears to be equivalent in terms of positive circumferential resection margins for rectal cancer, complete resection for colon cancer and numbers of lymph nodes harvested in the specimen (Breunkink et al., 2006; Wexner and Cera, 2006; Aziz et al., 2006).

Reports of longer-term outcomes suggest similar results for both open and laparoscopic surgery for colorectal cancer (Reza et al., 2006), but long-term oncological outcomes in terms of local recurrence, disease-free survival and cancer-related mortality are eagerly awaited by the surgical community. There is also expectation that laparoscopic surgery will reduce the rate of postoperative adhesional obstruction and incisional hernia. After initial scepticism, the National Institute for Clinical Excellence (NICE) has now ruled that laparoscopic resection can be recommended as an alternative to open surgery in England and there is wide uptake of the laparoscopic technique within the confines of supervised training (NICE, 2006).