Plane of excision in total mesorectal excision
Around the time the TME technique was introduced, several randomized trials explored the effect of radiotherapy (RT) on local recurrence to define the optimal biologically effective dose, fractionation, and time point (before or after surgery) for RT in rectal cancer. In these trials without TME surgery, RT reduced the frequency of local recurrence by half, from around 25 % to 11–14 %. An equivalent benefit was also observed in trials combining RT and TME. RT reduces the relative risk of local recurrence by 50–70 %, and RT combined with the correct plane of surgery almost abolishes the risk of local recurrence. RT for rectal cancer is best given before surgery. The effects on tumor downsizing, local recurrence rate, and survival are similar for the highly fractionated schedule with 5 Gy × 5 (short-course RT) and the conventionally fractionated schedule with 1.8–2 Gy × 25–28, often combined with concomitant chemotherapy. The addition of chemotherapy to preoperative RT enhances local control, but a significant survival gain has only been observed in locally advanced cancers.
26.2.3 Revised Abdominoperineal Excision
Observational studies and clinical trials have shown superior oncologic outcomes of anterior resection with TME compared with abdominoperineal excision (APE), which was associated with a higher risk for positive CRM, intraoperative perforation, and an inadequate plane of resection. The concept of extralevator APE was introduced to improve the outcome in low, locally advanced rectal cancer. The abdominal part of the procedure is carried out in the TME plane, but the mesorectum is not dissected off the levator muscles. The patient is then turned into a prone position to complete the perineal excision by resecting the anus, the lower rectum, and the levator muscles en bloc. This technique results in a cylindrical specimen, which avoids the characteristic “waist” at the anorectal junction of specimens after conventional APE (Fig. 26.2).
Plane of resection in intersphincteric, extralevator, and ischioanal abdominoperineal excisions. Blue line = abdominal part, Red line = perineal part
26.2.4 Extensive Surgery for Locally Advanced or Recurrent Rectal Cancer
Uncontrolled pelvic tumor growth has a disastrous impact on a patient’s life, and median survival for locally recurrent rectal cancer treated with supportive care is limited to only a few months. Extensive surgery including multivisceral resection (pelvic exenteration), sacral resection, and hemipelvectomy procedures is used to achieve tumor clearance in advanced or recurrent rectal cancer. Radical resection with negative resection margins (R0) is a strong predictor of outcome in this group, and 5-year survival reached 50 % in selected series. The Beyond TME Collaborative published a consensus statement for staging and treatment of this group of patients with complex presentation of rectal cancer diseases.
26.2.5 Organ Preservation
The first results of a wait-and-see policy in patients with low rectal cancer without detectable cancer growth (complete clinical response) after chemoradiotherapy were published in 2004. Several pilot studies confirmed that standard rectal resection did not enhance survival in these select patients. The evidence regarding patient selection, use of (chemo-)RT in early cancers (T2), response assessment and follow-up is limited and currently restricts the general application of this treatment option. Patients so treated should be entered into a registry such as the International Watch & Wait database (www.iwwd.org)
Chemotherapy is the weakest treatment modality for rectal cancer and is based on 5-fluorouracil, described in 1957, or capecitabine, an oral prodrug of 5-fluorouracil. Newer drugs, such as oxaliplatin or irinotecan, and a growing number of biological agents have been shown to improve survival in patients with systemic disease. The value of adjuvant chemotherapy for stage III or perceived-high-risk stage II disease, advised by many oncologists in analogy to colon cancer treatment, is unproven; however, about 20–25 % of these patients develop systemic disease despite local control in the pelvis. Postoperative chemotherapy in patients treated with preoperative (chemo-)RT is not based on strong evidence. Current trials are investigating the effect of preoperative RT and full-dose preoperative chemotherapy.
26.3 Modern Rectal Cancer Treatment and Care
26.3.1 Clinical Presentation
The most common clinical signs of rectal cancer are rectal bleeding, altered bowel habit, and tenesmus; however, symptoms are often nonspecific early in the course of disease. Constipation and large-bowel obstruction are uncommon below the rectosigmoid junction because of the larger diameter of the rectum compared with the (left) colon. The clinical symptoms listed here are often reported at the time of diagnosis:
Hematochezia (rectal bleeding)
Change in stool caliber, tenesmus, urgency, painful or incomplete defecation
Anemia, fatigue, unexplained weight loss
Symptoms of overgrowth to urogenital organs or the lumbosacral plexus
Patients with such complaints should undergo proctologic evaluation with digital rectal examination and rectoscopy. Patients with persistent hematochezia and normal proctologic examination, persistent hematochezia after treatment of protologic conditions, two or more of the above symptoms of rectal cancer, or a family history of CRC should have full endoscopic evaluation.
26.3.2 Workup of Rectal Lesions
Workup of rectal lesions includes three steps – “name it, stage it, treat it” – and should provide morphological verification and classification according to the American Joint Committee on Cancer’s TNM-based criteria:
Medical history, physical examination, and venous blood sample (blood count, liver and renal function, carcinoembryonic antigen)
Proctologic evaluation with digital rectal examination, rectoscopy, and biopsy to assess anal sphincter function, distance between the anal verge and the distal extent of the lesion, mobility against adjacent pelvic structures, and morphological verification
Complete colonoscopy to exclude synchronous lesions
Computed tomography of chest and abdomen to assess lymph nodes, liver, and lungs
Magnetic resonance imaging (MRI) of the pelvis to assess tumor growth in relation to the mesorectal fascia, nodal disease in and outside the mesorectum, extramural vascular invasion, and invasion of other pelvic structures/organs
Endoanal ultrasound may be useful to assess the depth of invasion in stage 1 tumors
Correct sequencing and timing of multimodal treatment of rectal cancer is essential and is the reason for multidisciplinary team discussion between colorectal surgeons, radiologists, pathologists, oncologists, and specialized nurses. Liver and thoracic surgeons are involved in cases of suspected systemic disease, which may be identified in up to 20 % of patients during primary workup.
26.3.3 Tailored Treatment of Primary Rectal Cancer (Localized or Regional Disease)
18.104.22.168 Preoperative Treatment
Curative treatment for primary rectal cancer should aim for a risk of residual disease in the pelvis less than 5 % and a specimen with >1 mm of CRM in resected patients. The expected gains of additional treatments such as RT, chemotherapy, and more extensive surgery should be balanced against the increased morbidity (Table 26.1).
Tailored treatment for primary rectal cancer stage I–III
Clinical tumor and nodal stage
T1 sm1(−2?) N−
Complete with resection (or CRT) if sm ≥2, high grade, or vascular invasion
T3a/b N+, mrf−, EMVI−
T3a/b N−, mrf−, EMVI−
Complete with Cx or CRT if CRM+ or pN2
T1-2 N−, mrf−, EMVI−
T3 N+, mrf−, EMVI+
Preoperative RT/CRT and standard resection
Limited T4a N−
T3 N+, mrf−, EMVI+
Limited T4a N−
T3 mrf+, T4, lateral nodes+
Preoperative CRT and extended resection; alternatively, preoperative RT and delayed extended resection if Cx not tolerated
22.214.171.124 Bowel Preparation
A Cochrane review from 2011 found no advantage for mechanical bowel preparation regarding anastomotic leakage or surgical site infections in colorectal surgery. By contrast, the only randomized controlled trial related to rectal cancer surgery found an advantage of mechanical bowel preparation regarding infectious morbidity and a trend toward decreased anastomotic leakage. Three large cohort studies from the United States published in 2015 showed a marked reduction in surgical site infections and anastomotic leaks if mechanical bowel preparation was combined with preoperative oral antibiotics in patients with colonic and rectal resections. These results suggest that a combination of preoperative oral antibiotics and mechanical bowel preparation should be used for patients without an imminent risk for bowel obstruction.
126.96.36.199 Local Excision
Local excision of rectal lesions includes a localized, full-thickness resection of the rectal wall to obtain a specimen that allows differentiation between T1 and T2 cancers. Transanal endoscopic microsurgery and transanal minimally invasive surgery (are preferred over transanal excision because of the decreased risk for incomplete resection. Local excision is applicable in early rectal cancer limited to the mucosa and less than 3 cm in diameter without evidence for nodal disease and extramural venous invasion on MRI. The presence of adverse pathological features such as involved margin, level 3 submucosal invasion, lymphovascular/perineural invasion, or mucinous/signet cell components should prompt salvage rectal resection after wound healing. The risk of nodal involvement is 0–12 %, and the proportion with local recurrence at 5 years is 0–24 % for T1 cancers, which has implications for the follow-up of these patients.
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188.8.131.52 Standardized Procedures for Rectal Resection
The two standardized surgical procedures for the resection of rectal cancers are low anterior resection and abdominoperineal excision. Many colorectal surgeons and patients regard preservation of bowel continuity while saving the anal sphincter as a marker of the quality of surgery for rectal cancer. Patients without a history of fecal incontinence or signs of anal sphincter dysfunction may be evaluated for low anterior resection (Table 26.2).
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