Cancer of the small intestine and the anus (anal carcinoma) is rare. Colorectal cancer is a malignant tumor of the large intestine (colon cancer) and the rectum (rectal cancer). These types of cancer are also known as colorectal carcinomas. Colorectal cancer can develop in any section of the large intestine and rectum. However, it most commonly occurs in the lower 30–40 centimeters. Benign, often mushroom-like growths—known as colorectal polyps—are frequently precursors to colorectal cancer.
The primary treatment for colorectal cancer is surgery. This involves removing the affected section of the large intestine along with the surrounding lymphatic vessels and blood vessels. If the cancer is advanced and there is no prospect of a cure, doctors usually do not perform colorectal cancer surgery. Unless, that is, they need to prevent complications such as an intestinal obstruction. Colon cancer surgery is not considered an emergency procedure (except in cases of intestinal obstruction), so there is sufficient time for diagnosis and treatment planning. This helps prevent complications and improves the chances of a cure.
Following a diagnosis of colon cancer (colorectal carcinoma), surgery is performed immediately in most cases @ Emil /AdobeStock
Colon cancer surgeries are performed in many hospitals and specialized colorectal centers. Colorectal centers are hospitals that are particularly well-suited to caring for patients with colon cancer. The primary goal of colon cancer surgery is the complete removal of the tumor and, thereby, a cure for the cancer.
In addition to removing the colorectal tumor, colorectal cancer surgery also includes:
- Removal of metastases (secondary tumors, e.g., in the lungs and liver)
- Inspection of the abdominal cavity and its organs, as well as
- The removal of lymph nodes for diagnostic purposes (to check for possible spread beyond the colon)
The evaluation of the lymph nodes is important for staging. Staging is the classification of cancer into stages. This information allows doctors to plan treatment and assess the prognosis. Furthermore, colorectal cancer surgery may be necessary if adhesions pose a risk of intestinal obstruction (impaired bowel passage).
Colon cancer surgery is considered curative (healing) when doctors are able to remove all of the tumor tissue (including metastases in lymph nodes and organs). During colorectal cancer surgery, doctors remove not only the directly affected section of the colon but also surrounding healthy tissue. This is intended to reduce the risk of the tumor returning (recurrence). Since individual cancer cells may have spread to the regional lymph nodes, doctors remove these as well.
In palliative colorectal cancer surgery, on the other hand, doctors aim to alleviate tumor-related complications and symptoms. This type of surgery is used for patients with more advanced colorectal cancer (e.g., with metastases), for whom there is no longer any prospect of a cure. If the tumor grows into the intestine, it can obstruct the passage of intestinal contents. This can lead to a life-threatening intestinal obstruction. The colorectal surgeon attempts to reduce the size of the tumor enough to clear the blockage.
Palliative colorectal cancer surgeries also include:
Before colorectal cancer surgery, doctors must assess the condition and location of the tumor in the bowel, as well as its extent. This is done using comprehensive diagnostic procedures.
Common tests include:
- Digital rectal examination: Palpation of the lowermost part of the rectum to assess the extent of the tumor and to evaluate whether sphincter function can be preserved after colorectal cancer surgery
- Abdominal ultrasound (abdominal sonography): To assess whether the tumor has spread beyond the organ
- Chest X-ray: To rule out or detect lung metastases
- Determination of CEA levels before colorectal cancer surgery: To assess the prognosis and as a basis for follow-up monitoring after colorectal cancer surgery.
- Rectoscopy (rectal endoscopy): To determine the extent of rectal cancer
- Endosonography (endoscopic ultrasound): To assess the depth of infiltration of rectal cancer
- Colonoscopy: To thoroughly examine the entire large intestine in order to detect any additional colorectal polyps or tumors
Colonoscopy is the most important medical examination for the early detection of colorectal cancer @ Graphicroyalty /AdobeStock
Before and during colorectal cancer surgery, the bowel is thoroughly cleansed with a special solution that acts as a laxative. The patient takes this solution orally. The patient is also given an antibiotic to prevent infections, as bacteria in the gut flora can cause dangerous infections in the abdominal cavity. Shaving the area where the incision will be made is also necessary. Thrombosis prophylaxis is equally important.
Colon surgeons generally distinguish between two techniques for colorectal cancer surgery.
- In radical colorectal cancer surgery, doctors remove not only the tumor but also surrounding healthy tissue from the body.
- In local colorectal cancer surgery, on the other hand, they remove only the tumor itself, along with a safety margin. The surrounding tissue is preserved.
Depending on the extent and severity of the tumor, colorectal cancer surgery can be performed as open surgery via laparotomy (open abdominal surgery) or as minimally invasive surgery.
For small tumors that do not extend into deeper layers of the colon, doctors can remove the tumor during a colonoscopy. If there is any doubt as to whether tumor tissue remains, doctors will follow up with standard colorectal cancer surgery.
A “standard” colorectal cancer surgery can be performed as follows:
- Minimally invasive using keyhole technology (laparoscopy) or
- Open abdominal surgery (laparotomy)
For colorectal cancer in more advanced stages, a laparotomy is performed due to the extent of the disease. Otherwise, laparoscopic tumor removal is now an established procedure for patients with colorectal cancer. Although it is widely used, it should be performed by an experienced surgeon.
It yields results comparable to those of open colorectal cancer surgery. A major advantage is that the procedure is less invasive, allowing patients to recover more quickly.
- Radical colorectal cancer surgery
Cancer cells in colorectal cancer tend to break away from the primary tumor and settle elsewhere in the body. There, they form metastases (including in the lymph nodes). During radical colorectal cancer surgery, doctors remove these metastases along with a wide margin of healthy tissue.
The surrounding healthy tissue and the associated lymph nodes, lymphatic vessels, and blood vessels are also removed.
Radical surgery is crucial for successful tumor removal and for preventing recurrence. However, it is often only during the operation that doctors can determine exactly what needs to be removed.
To prevent tumor cells from spreading during surgery, doctors ligate the blood and lymph vessels connected to the tumor. They also separate the tumor-bearing section of the intestine from the healthy intestine.
Without touching the tumor (no-touch technique), they extract the section along with the lymph and blood vessels and lymph nodes.
The no-touch technique is intended to prevent the tumor from breaking apart and thus prevent the spread of tumor cells.
If the tumor is large enough to have invaded neighboring organs, experienced surgeons perform a radical en-bloc resection. They then remove not only the large tumor but also the affected organs as a single unit (en bloc). Here, too, they avoid damaging or touching the tumor.
In local colorectal cancer surgery, doctors remove only the tumor itself along with a safety margin. This procedure can only be performed on small, early-stage tumors, and the following methods are generally used:
- Colonoscopy and polypectomy (for colon cancer)
- Laparotomy or laparoscopy (for colon cancer) or
- Polypectomy or transanal endoscopic microsurgery (for rectal cancer)
Doctors do not perform radical colorectal cancer surgery if:
- No tumor cells are detectable in the histological examination
- There is a low risk of recurrence
An artificial bowel outlet (stoma or anus praeter) is a connection between the healthy bowel and the abdominal wall. This allows bowel contents to pass to the outside. This connection may be permanent or temporary. In cases of colon cancer, doctors rarely need to create a permanent stoma. In difficult cases, a temporary stoma may be necessary to relieve pressure on the bowel or the surgical incision after colon cancer surgery.
In the past, when treating rectal cancer, doctors had to remove the rectal segment and the sphincter muscle. This was necessary for tumors located near the anus. Today, the sphincter muscle is preserved in most cases.
For experienced rectal surgeons, maintaining a 1 cm safety margin from the anus is sufficient to prevent the need for a stoma.
Doctors create a temporary colostomy during colorectal cancer surgery to relieve pressure on the bowel with the fresh suture.
The stoma directs bowel contents outward, allowing the bowel and the surgical incision to heal undisturbed. This stoma is also called a diversion stoma.
A temporary stoma is usually created as a double-lumen stoma. Doctors pull the intestine (small intestine or large intestine) through the abdominal wall to the outside. They make an incision at the top and turn it inside out so that two intestinal openings are visible. After 2–3 months, they restore the natural digestive tract and close the artificial stoma. They then close the opening in the abdominal wall.
About 70 percent of all ostomates have cancer @ Zane /AdobeStock
- Permanent artificial bowel opening
If the tumor is located close to the sphincter muscle, the anus cannot be preserved. Doctors must then remove the rectum and the sphincter muscle. This type of colorectal cancer surgery involves the creation of a permanent, end-stoma. With an end-stoma, doctors bring the lowest, healthy portion of the large intestine out through an opening in the abdominal wall. There, they suture it to the skin.
After a period of adjustment and with proper guidance, most patients cope well with a permanent stoma. Even regular bowel movements are possible. Special adhesive patches or stoma caps are available for water sports (e.g., swimming) and sauna visits. Furthermore, there are virtually no restrictions for stoma patients regarding their chosen profession or the type of sports they participate in.
Like any other surgery, colorectal cancer surgery carries risks and dangers. Serious complications of colorectal cancer surgery can include, for example, bleeding in the abdominal cavity, wound healing problems, and infections.
Other risks and complications following colorectal surgery include:
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Anastomotic leakage: An anastomosis is the connection between two anatomical structures. The ends of the intestine that have been sutured together, or the suture between the intestine and the skin at the colostomy site, can leak or tear open. Intestinal contents can enter the abdominal cavity and cause peritonitis (inflammation of the peritoneum).
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Digestive problems: Since the absorption of nutrients is already largely complete in the large intestine, large intestine surgeries are less problematic for nutrient absorption than small intestine surgeries. However, water reabsorption takes place in the large intestine. Therefore, the consistency of the stool may be disrupted. This results in diarrhea of varying severity. Many patients, especially those with ostomies, complain of digestive problems such as bloating, constipation, and foul odors. Patients then alter their diet, which can lead to nutritional imbalances.
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Fecal incontinence, bladder dysfunction, and sexual dysfunction (erectile dysfunction in men): Surgery on the rectum can irritate and damage nerves in the surgical area. With modern colorectal cancer surgery techniques, however, the risk is low.
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Adhesions: Adhesions are usually harmless and painless, but occasionally they can be painful and dangerous due to restricted bowel motility and obstruction.
Only regular follow-up care can detect metastases (secondary tumors) or recurrences (the reappearance of a tumor at the original site) at an early stage.
After successful colorectal cancer surgery, the following follow-up examinations are available, among others:
- Regular colonoscopies
- Measurement of the CEA tumor marker
- Ultrasound examination of the abdomen
- X-ray of the lungs
- CT scans of the lungs and abdomen
For nutritional reasons, patients do not need to make significant changes to their eating and drinking habits after colorectal cancer surgery. However, due to digestive symptoms (bloating, diarrhea, constipation, odors), you should take steps to regulate your bowel movements.
To avoid an unbalanced diet, you should follow these dietary tips:
- Eat about 5 to 6 smaller meals a day. You should avoid large portions.
- Drink plenty of fluids between meals.
- You should eat slowly and chew your food thoroughly.
- Avoid very hot and very cold foods.
- Make sure to eat at regular intervals and avoid crash diets.
- Eat enough food—that is, underweight people should eat a little more, and overweight people a little less.
- Steaming and poaching are gentle methods of food preparation.
- Avoid fatty, sweet, and gas-causing foods. Also eliminate foods that have been seared, grilled, or deep-fried from your diet. Avoid foods that have caused you digestive problems on multiple occasions.
Surgery is the most important and often the most effective treatment for colorectal cancer. The goal of treatment is to completely remove the colorectal tumor or carcinoma and thereby achieve the best possible chances of recovery. Whether surgery is necessary depends on various factors, including the size of the tumor, its exact location in the colon, and the presence of metastases. The prognosis is particularly good when colon cancer is detected early and the disease is still confined to the colon’s mucous membrane or a limited section of the colon.
During surgery, the surgeon removes not only the tumor itself but also, as a rule, adjacent tissue and the associated lymph nodes. If the colorectal tumor has already invaded neighboring structures, a more extensive procedure may be necessary. However, thanks to modern surgical techniques, minimally invasive procedures are now often possible, which can reduce the burden on patients. In some cases, surgery is supplemented with chemotherapy or radiation therapy to combat any remaining cancer cells and lower the risk of recurrence.
For people with colorectal cancer, treatment at a specialized clinic is particularly important, as experienced specialists and surgeons work closely together there. The individualized treatment plan takes into account both the extent of the cancer and the patient’s overall health. Overall, the earlier colorectal cancer is diagnosed and treated, the better the long-term chances of recovery. Regular screening exams and early colonoscopy play a crucial role in detecting changes in the colon lining in a timely manner and enabling successful treatment.
How is colorectal cancer surgery performed?
During colorectal cancer surgery, the tumor is removed along with a safety margin and the associated lymph nodes. The surgery itself is usually performed under general anesthesia. Depending on the location in the colon, rectum, or in the case of rectal cancer, the surgeon removes the affected section of the intestine and then connects the ends of the intestine via an anastomosis. The goal is to remove the tumor as completely as possible.
When is surgery necessary for colorectal cancer?
In most cases, surgery for colorectal cancer is necessary as soon as the diagnosis has been confirmed. Surgical removal of the tumor is the most important treatment, particularly for colon cancer. Surgery may also be required if colorectal cancer is suspected or if there is an intestinal obstruction. Patients with colorectal cancer often benefit from early treatment.
Is a colostomy necessary after colorectal cancer surgery?
Not every colorectal cancer surgery requires a colostomy. In certain situations, however, it may be necessary to create a temporary colostomy to support the healing of the bowel. Some patients have a temporary colostomy or stoma created. Only rarely is a permanent colostomy or anus praeter necessary.
What are the chances of recovery after colorectal cancer surgery?
The chances of recovery depend on the stage of the cancer. If colorectal cancer is detected at an early stage and the tumor is completely removed, the prognosis is often very good. In cases of advanced colorectal cancer or existing metastases, additional treatments such as chemotherapy or radiation therapy may be necessary. Treatment for colorectal cancer is tailored individually to the patient’s specific findings.
What complications can occur after surgery?
Like any surgical procedure, colorectal cancer surgery carries risks. Possible complications include bleeding, infections, problems at the anastomosis site, or the need for a repeat surgery. For tumors in the rectum or near the sphincter muscle, temporary changes in sexual function or bowel function may also occur. However, modern surgical techniques and care at a specialized clinic help minimize these risks.
