Colorectal Cancer (Colon Carcinoma): Surgical Therapy

Colon carcinoma

Procedure for pT1 carcinoma (according to current S3 guideline).

  • If histologic examination of an endoscopically R0-removed polyp reveals a pT1 carcinoma, oncologic resection should be omitted if the situation is low-risk with a histologically carcinoma-free polyp base (R0; curative resection). In the high-risk situation, radical surgical treatment should be performed even if the lesion has been completely removed.
  • In the case of incomplete ablation of a low-risk pT1 carcinoma, complete endoscopic or local surgical resection should be performed. If an R0 situation is not achievable or there is doubt about the presence of a pT1 situation, oncologic surgical resection should be performed.
  • Endoscopic local follow-up should be performed after complete removal (R0) of low risk (pT1, low grade (G1, G2, L0)) Carcinomas should be performed after half a year. A complete colonoscopy should be performed after 3 years.

The greatest importance in the treatment of colon carcinoma (colorectal cancer) has surgery. The following principles must be observed (according to current S3 guideline):

  • Surgical therapy of colon carcinoma should include complete mesocolic excision (CME).The mesocolon includes the lymph nodes on the supplying arteries as a bilateral sheath.
  • Complete mesorectal excision for carcinoma of the middle and lower thirds of the rectum and partial mesorectal excision for carcinoma of the upper third of the rectum by sharp dissection along anatomical structures between the fascia pelvis visceralis and parietalis (total mesorectal excision – TME)Note: 12 or more lymph nodes should be removed and examined.
  • The maintenance of an appropriate safety distance.
  • Usually en bloc resection of tumor-adherent organs (mutivisceral resection) to avoid local tumor cell dissemination
  • The sparing of the autonomic pelvic nerves (hypogastric nerves, inferior and superior hypogastric plexus).

The following forms of colon resection are distinguished:

  • Hemicolectomy right – removal of the right colon.
  • Hemicolectomy left – removal of the left colon.
  • Transversum resection – removal of the transverse colon.
  • Sigmoid resection – removal of the sigmoid colon.

Due to the length of the colon (large intestine), the loss of a section of intestine usually does not mean any impairment of function. It is simply removed the tumorous portion and the ends are sutured or stapled back together. Provided metastases (daughter tumors) have not yet formed, the chances are very good that this will result in a permanent cure.

Rectal Cancer

In rectal cancer (rectal cancer), complete surgery (rectal resection) is also the primary goal. Modern surgical methods make it possible to preserve the sphincter (sphincter muscle) in most cases. A minimally invasive procedure called “TAMIS” is used for this purpose. This stands for transanal minimally invasive surgery, “TME” refers to total mesorectal excision (removal of the mesorectum; fatty tissue surrounding the rectum is referred to. It contains the local ducts as well as regional lymph nodes). This procedure spares the autonomic nervous system for sexual and bladder function and has led to a significant improvement in the quality of life for affected patients. Today, TME represents the gold standard of surgical therapy for rectal cancer [guideline: S3 guideline]. Laparoscopic TME (lapTME) is now considered equivalent to open surgery.Furthermore, the goal of resection is the complete removal of the tumor with tumor-free margins of deposition (R0) aborally, i.e. toward the sphincter, orally and circumferentially (described with CRM, “circumferential margin).The prerequisite for this is that the tumor has not infiltrated (grown into) the sphincter. If infiltration has occurred, an anus praeter (artificially created intestinal outlet) or stoma must be created. Note: Patients who have undergone sphincter-preserving surgery suffer from “Low Anterior Resection Syndrome” (LARS) in 40-80% of cases.This describes impaired bowel function associated with high stool frequency, fractional voiding, urge to defecate, diarrhea (diarrhea), and incontinence problems.Education should be provided about these facts!Therapy for rectal cancer in UICC stage II or III involves the following standard treatment steps:

  1. Radiochemotherapy (RCT; e.g., fluorouracil/oxaliplatin; radiation therapy at 50.5 Gy) – aimed at reducing tumor mass prior to surgical removal of the tumor.
  2. Surgery*
  3. Chemotherapy (3 cycles of fluorouracil, leucovorin and oxaliplatin) – with the aim of destroying any micrometastases in the body.

* The laparoscopic approach is now considered an alternative to open surgery. In one study, the complete histopathological response of the tumor was increased by 10% compared to the standard approach (see above) when treatment was performed in the following steps: first radiochemotherapy (RCT), then chemotherapy and finally surgery. For locally advanced adenocarcinoma (cT3/4 and/or cN+) of the middle and lower thirds of the rectum, the S3 guideline continues to recommend neoadjuvant radiochemotherapy (therapy used to reduce tumor mass before planned surgery) or short-term radiotherapy (recommendation grade A, “level of evidence” 1b, agreement > 75-95%). However, as expert consensus (agreement > 95%) added:

  • “In the following exceptional cases, primary resection may be performed in patients with UICC stage II/III rectal cancer: cT1/2 tumors in the lower and middle thirds with questionable lymph node involvement on imaging; cT3a/b tumors in the middle third with only limited infiltration into perirectal adipose tissue on MRI (cT3a: < 1 mm, cT3b: 1-5 mm) and without imaging suspicion of lymph node metastasis or extramural vessel invasion (EMVI-) with adequate quality assurance of MRI diagnosis and TME surgery (due toTME see above).”

Colon carcinoma and acute abdomen

In about 20% of all cases, colon carcinoma is diagnosed due to acute abdomen. In approximately 80% of cases, this involves blockage of the intestinal passage. This usually necessitates emergency surgery, otherwise the intestinal wall would rupture. In one study, instead of emergency surgery, physicians restored the continuity of intestinal passage by endoscopic placement of a stent (“vascular support”) in half of the patients, thus postponing the actual cancer surgery to a later time. By this procedure, this group of patients required an anus praeter in only 45% of cases. In the case of emergency surgery, an artificial bowel outlet was required in 69% of cases. The mortality rate (death rate) was the same in both groups at 1 year.

Stoma creation

  • A temporary deviation stoma (anus praeter) should be placed upstream during radical surgery for rectal cancer with TME (total mesorectal excision) and deep anastomosis.
  • As deviation stoma colostoma (artificial intestinal outlet of the colon) and ileostoma (artificial intestinal outlet of the small intestine) are equivalent.

Isolated liver metastases (daughter tumors in the liver) should also be surgically removed – if possible.Simultaneous resection of liver metastases is unlikely to affect long-term survival compared with a two-stage approach if patients are appropriately selected (current S3 guideline). Further references

  • With appropriate selection and surgeon expertise, laparoscopic surgery results in the same oncologic outcomes as the open procedure [1, 2, 3). For minimally invasive procedures, overall mortality rates during hospital stay were significantly superior to open surgery (1.8% vs. 4.7%); length of stay was usually shorter after minimally invasive procedures (10-15 days vs. 15-19 days after open surgery).
  • After R1 resection (macroscopically, the tumor was removed; however, in histopathology, smaller tumor components are detectable in the resection margin) of adenocarcinomas of the rectum, the problem is not local recurrence (local recurrence) of the tumor, but the occurrence of distant metastases (daughter tumors; lung metastases 77%, liver metastases 32%).
  • Preoperative mechanical bowel cleansing in combination with oral antibiotic therapy resulted in a significantly lower rate of wound infection 30 days after surgery compared with procedures without either precaution (3.2% versus 9.0%). Anastomotic insufficiency (rupture or leakage of the intestinal end connection) also occurred significantly less frequently (2.8% versus 5.7%).
  • The results of a population-based study in the Netherlands suggest that patients with stage IV colorectal cancer appear to live longer with primary resection as the initial intervention than with systemic therapy: 24% in the primary resection (surgical removal) group compared with only 14% in the systemic therapy group. The median survival after surgery as initial therapy was 17.2 months (95% confidence interval between 16.3 and 18.1 months) and 11.5 months (95% confidence interval between 11.0 and 12.0 months) in the comparison group….
  • Watchful Waiting demonstrated an additional caused 2-3% risk of tumor death in patients with rectal cancer without metastases responding with clinically complete remission to neoadjuvant radiochemotherapy (RCTX). This thus appears to be an appropriate therapeutic strategy. This was a prospective cohort study of 100 patients (further studies are awaited).