**Abstract**

This chapter deals with the emergency treatment of transverse colon cancer. The main complications that classify transverse colon cancer in an emergency setting are obstruction, perforation accompanied by localized or generalized peritonitis, and hemorrhage which may be occult or cataclysmic with hemorrhagic shock. We present the technical principles of radical surgical resection using embryological, anatomical, and oncological concepts. In this chapter we also discuss the principles of lymphadenectomy associated with complete excision of the mesocolon with high vascular ligation, in particular with T3 or T4 cancers requiring D2/D3 lymphadenectomy. The use of infrapyloric, gastro-epiploic, and prepancreatic lymphadenectomy is recommended due to the frequent metastases in these regional lymph nodes.

**Keywords:** transverse colon cancer, emergency, transverse cancer, colon cancer, large bowel obstruction

#### **1. Introduction**

The incidence of transverse colon cancer in an emergency setting is approximately 77–80%. Five percent of all colon cancer are located at the level of transverse colon, hepatic flexure cancer represents 3% whilst splenic flexure represents 2% [1, 2]. The complications associated with transverse colon cancer are represented by large bowel obstruction, tumor perforation, or more commonly diastatic perforation and hemorrhagic syndrome [3].

Based on embryological and anatomical considerations, the colonic frame can be divided into the proximal ("right") colon represented by the cecum, the ascending colon and the proximal or right 2/3 of the transverse colon, and the distal ("left") colon represented by the distal 1/3 of the transverse colon, the descending colon, the sigmoid colon, the rectum and the proximal 2/3 of the anal canal [4–7].

Since the proximal colon is derived from the midgut the incidence of transverse colon cancer is higher in females. Thus, mucinous tumors are more common, which present an increased risk of genetic mutations ↑ CIMP, ↑ BRAF, ↑ MSI, ↑ CMS1, ↑ CMS3, ↑ KRAS, and where survival has a limited prognosis compared to distal colon cancers [8–10].

The recommended surgical technical principles for proximal colon cancer complications are simple and are represented by resection and anastomosis in the first intent in most scenarios, while in the case of distal colon cancer complications, surgeons perform resections and colostomies (terminal or loop colostomy) or in rare cases of hemodynamically stable patients, per-primam anastomoses.

The majority of transverse colon tumors and their complications follow the general characteristics of colorectal cancers. Thus, in an emergency setting, patients have already developed complications the disease is generally found in advanced stages (T3-T4) [11]. Due to the presence of complications at the time of diagnostic, radical intent surgery is most of the time impossible; surgeons cannot perform a radical D2 or D3 lymphadenectomy, due to local cancer spread and the technical impossibility to remove the tumor together with the anterior and posterior sheets of the visceral peritoneum. To follow Hohenberger principles introduced in 2009 [12] to completely resect the mesocolon and perform high vascular ligature, in the case of complicated transverse colon cancer becomes impossible in most cases [12, 13].

Embryologically, the small intestine starting from D3, the cecum, the ascending colon, and the proximal or right 2/3 of the transverse colon derive from the midgut. The vascular supply is represented by ileocolic vessels, right colic artery, and middle colic artery, all derivative from superior mesenteric vessels. The parasympathetic innervation of these segments of the intestine is represented by the vagus nerve.

For the distal third (or left third), the descending colon, sigmoid, rectum, and the proximal 2/3 of the anal canal the embryological origin are represented by the hindgut and the vascular supply by the left colic branches of the inferior mesenteric vessels. The parasympathetic innervation is represented by the pelvic splanchnic nerves S2-S4. The transition zone from the parasympathetic vagal to the sacred is called the Cannon-Bohm point [14]. This corresponds to Griffith's point where Drummond's marginal arch anastomoses with the ascending branch of the middle colic artery [15].

## **2. Anatomical particularities**

The proximal colon is anatomically the most dilated segment in the colonic frame, having the largest diameter at the level of the cecum (8 cm), while the ascending colon being is 6 cm in diameter and the transverse colon 5 cm. The transverse colon is the longest segment of the colic frame, having a length of about 50 cm as well as being the most mobile segment of the colon [16].

The arterial sources of the ascending colon are represented by the branches of the superior mesenteric artery. They are the ileocolic artery, the right colic artery which may be inconsistent, the middle colic artery with the right and left branches, the left colic artery with the ascending branch which has its origin in the inferior mesenteric artery. In addition to these arterial sources for each segment, some anastomoses from the marginal artery of Drummond (MA) – the marginalis colic artery (arteria marginalis coli), the anastomotic source between the superior and inferior mesenteric artery [14, 17]. Another important anastomotic arterial source, also the anastomosis between the two important arterial sources, is represented by Riolan's arch, also called Moskowitz's arch or meandering mesenteric artery. An important aspect of this marginal arch is present in the splenic flexion, the so-called Griffith area in which there is the possibility to interrupt this arterial anastomosis, thus having direct implications in resections of the transverse colon or splenic flexure [14].

Thus, colon resections regardless of the region are segmental resections. This principle was introduced and accomplished with the sigmoid colon segment by Jean-Francois Reybard in 1833. Later this type of resection extended to the transverse colon, becoming a transversectomy. Also related to the name of this surgeon, Reybard is also linked with the first right hemicolectomy, performed in 1832.
