For many years the treatment of rectal cancer has involved removal of the rectum and the mesorectal envelope through a laparotomy, an operation commonly known as total mesorectal excision (TME).1 For surgeons performing this procedure, the main surgical consideration was whether to preserve the sphincter and restore continuity of the bowel or remove the entire rectum and anal canal leaving the patient with a permanent colostomy. In recent years, an improved understanding of the biology of rectal cancer and the causes of local recurrence,2,3 coupled with advances in imaging,4 surgical techniques,5,6 and the use of radiation and systemic chemotherapy7 have expanded the available surgical options. Selection between the different surgical therapies is based predominately on the stage and location of the tumor. Other factors such as patient age, overall health, functional status, and personal wishes and expectations also need to be taken into consideration when deciding on an appropriate surgical approach.
Treatment decisions in patients with rectal cancer can be influenced by the presence of synchronous tumors, by the locoregional extension of the disease, and by the presence of distant metastasis. Therefore, every patient should undergo a complete evaluation before outlining a treatment plan.
A complete colonoscopy is important to exclude synchronous polyps and cancers, but locoregional staging is essential to guide the initial therapy. A digital rectal examination (DRE) provides useful information because the mobility of the tumor in relation to the rectal wall is an indication of the depth of tumor invasion. The DRE is particularly useful in assessing the relationship of the tumor to the levator muscle and the external anal sphincter, and deciding between the different treatment options. A proctoscopic examination is the best method to assess the distance of the tumor from the anal verge, the only anatomical landmark that can be seen simultaneously with the distance marks of the rigid scope.
In addition to a thorough clinical examination, every rectal cancer patient should undergo adequate local and regional staging with the help of the best available imaging technology.4 Endorectal ultrasound (ERUS) is a useful technique for staging early rectal cancer as it provides detailed images of the different layers of the rectal wall and demonstrates the disruption of those layers by the tumor. Magnetic resonance imaging (MRI) is most useful for staging locally advanced rectal cancer because it provides a broader view of the pelvis and the best images of the fascia propria of the rectum. The new-generation computed tomography (CT) scanners also provide high-resolution cross-sectional images of the rectum, the mesorectum, and surrounding pelvic structures, and can be used for the locoregional staging of rectal cancers when high-quality MRI is not available. A chest x-ray and a CT scan of the abdomen and pelvis are also commonly included in any patient assessment to diagnose metastatic disease. Occasionally, other tests such ...