Elsevier

Surgery (Oxford)

Volume 35, Issue 3, March 2017, Pages 145-150
Surgery (Oxford)

Intestinal surgery – I
Surgery for colorectal cancer

https://doi.org/10.1016/j.mpsur.2016.12.003Get rights and content

Abstract

Colorectal cancer surgery represents a major component of the colorectal service workload. A solid understanding of key anatomical and oncological principles is essential for safe practice. In this article we discuss these fundamental aspects of colorectal cancer surgery. The first part of the article will deal with preoperative staging, surgical planning and principles of oncological surgery. The second part will focus on some of the commonest operations. We will describe key intra-operative principles involved in performing a right hemicolectomy, left hemicolectomy, anterior resection and abdomino-perineal resection. Laparoscopic colorectal cancer surgery is increasingly widespread and therefore our perspective will assume this approach by default. In the final section, we discuss the role of radiotherapy in rectal cancers, transanal surgery, resection of colorectal liver metastases and the rationale behind follow-up.

Introduction

Colorectal cancer is the fourth most common cancer in the UK. In 2013, there were approximately 41,000 new cases in the UK; 23,000 (56%) cases in men and 18,000 (44%) in women, giving a male:female ratio of 13:10.1 Geographically, the incidence of colorectal cancer is highest in Western Europe and North America. Multiple risk factors are associated with its development; these include smoking, alcohol, diet (excessive red meat and processed food consumption), obesity and decreased physical activity. Inflammatory bowel disease is also associated with increased risk in proportion to the extent of bowel involvement and duration of disease.

The majority of colorectal cancers are sporadic whereas 5–10% are inherited syndromes, for example hereditary non-polyposis colon cancer (HNPCC) and familial adenomatous polyposis (FAP). There may be some overlap of genetic abnormalities involving sporadic and inherited forms. The risk of colorectal cancer for an individual with a first-degree relative with the disease is three times greater than one who has no family history. Vogelstein proposed a multi-step model identifying key mutations.2 Although colorectal carcinogenesis involves a complex interplay between environmental and genetic factors, key mutations appear to involve APC, KRAS and p53 genes. The most common histopathology for colorectal cancer is adenocarcinoma. The development of colorectal adenocarcinoma is postulated to follow the adenoma–carcinoma sequence. In this model, there may be a natural progression from benign polyps into invasive cancerous lesions. The national bowel cancer screening programme was set up in 2006 based on this model, which is widely accepted.

About 20% of cases present as emergencies and these are associated with a poorer outcome.3 Early presentation is key to improving outcomes for colorectal cancer and the management of pre-invasive lesions. Approximately 30% of cases occur in the rectum and 20% in the sigmoid colon. About 20% develop in the right colon and 10% are found in the transverse or left colon. Approximately 80% of newly diagnosed cases will require surgery. Surgery remains the primary treatment for the majority of cases of colorectal cancer both as treatment with curative intent and as a palliative therapy.

Section snippets

Staging and imaging of colorectal cancer

The single most important factor that determines the outcome is the stage of cancer at presentation. The international standard used for staging is referred to as the TNM classification. Prognosis is intimately linked to the invasiveness of the tumour (T), extent of regional lymph node (N) involvement and the presence of distant extra-intestinal metastases (M). Clinical staging is with colonoscopy, computed tomography (CT) scan of the chest abdomen and pelvis and magnetic resonance imaging

Preoperative considerations

As with all cancer surgery today, a careful multidisciplinary team (MDT) approach should be employed to ensure the best possible decision and outcome for each patient. The first step is to establish whether disease is localized or disseminated. The operative strategy should be based on fundamental principles of oncological surgery, discussed in the next section. Laparoscopic colorectal surgery is gradually becoming the standard of care around the UK rather than something carried out only in

Oncological principles in colorectal cancer surgery

The goal of surgery is to resect the primary tumour en bloc with clear resection margins and include all draining locoregional lymphatics that may contain micrometastases. In order to understand the extent of bowel resection and lymphadenectomy one must have a clear understanding of the anatomical principles behind lymphatic spread.

Longitudinal intramural lymphatic spread in the colon rarely exceeds 2 cm, hence the rationale for 5 cm resection margins proximally and distally. For rectal

Laparoscopic right hemicolectomy

Surgical anatomy

The use of a laparoscopic approach does not imply deviation from fundamental oncologic principles stated above. To reiterate, this includes proximal and distal resection margins, proximal ligation of the main vascular pedicle(s) along with attached mesentery and en bloc resection of locally advanced colorectal tumours. Proximal or ‘high’ ligation at the origin of the feeder vessels is important to ensure the maximum number of lymph nodes within a complete mesenteric specimen

Radiotherapy and rectal cancer

Historically, cancers of the rectum had a higher risk of local recurrence than colon cancers. Reasons for this include the challenging anatomical location and the difficulty of establishing precise dissection planes for total mesorectal excision. For this reason, adjuvant therapies have been investigated intensely over the last few decades. The Swedish Rectal Cancer Trial randomized 1100 cT1-3 patients into two groups between 1987 and 1990.12 One group received short course preoperative

Summary

The last three decades have seen rapid evolution in the surgical treatment of colorectal cancer. The most significant change has been the uptake of laparoscopic techniques. As surgical proficiency and expertise has developed, the number of patients and indications eligible for the laparoscopic approach has increased. Other advances in the field include surgery for locally resectable metastases and more effective adjuvant therapies to improve outlook and survival. Surgery represents the gold

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