Definition
The treatment of patients requires intensive cooperation between the specialist departments of surgery, internal medicine, radiotherapy and pain therapy. During the therapy, the preceding tumor staging (assessment of the tumor extent) is used as an essential decision-making aid. For each tumor stage there are corresponding therapy guidelines that are taken into account.
What are the treatment options?
As one of the most common types of cancer in adults, colorectal cancer therapy is a major topic in medical research and is constantly being improved through new discoveries. The therapy of colorectal cancer rests on three pillars: surgical removal of the tumor, chemotherapy and radiation (which, however, is only used when the rectum is affected), which can be used alone or in combination. Which method or combination is ultimately used for the individual patient is usually discussed in a panel of experts, the clinical-pathological conference.
Here, surgeons, radiologists, pathologists and oncologists consult with each other based on the patient’s findings, current guidelines and the current state of medical research. There are two different approaches to the therapeutic procedure: On the one hand, there is the curative approach, which aims at complete healing. The palliative approach is to be distinguished from the curative approach, in which, due to low chances of cure, the focus is on alleviating the tumor symptoms without the direct aim of a cure.
Therapy types
Surgical therapy is the most important pillar of colorectal cancer therapy, as it allows in the best case a total removal of the tumor and thus a cure. Here, care is taken to remove as much of the tumor mass as possible, including a safe distance from healthy tissue, so that no tumor cells are left behind. Lymph nodes into which the tumor may have spread are also removed.
The extent of the operation depends on the location of the tumor, whereby usually only the affected intestinal section is removed. The two remaining ends of the intestine are then sutured together again, which is called anastomosis. A special situation is rectal cancer (cancer of the rectum), since, depending on the location of the tumor, the sphincter muscle may have to be removed as well, which may make it necessary to create an artificial anus praeter.
In some high-risk patients it is recommended to remove the bowel completely (colectomy). Patients with long-standing ulcerative colitis and patients with familial poliposis coli are eligible for this procedure. In this prophylactic operation, the sphincter muscle is always preserved, so that the stool continence is maintained.
In order to imitate the storage function of the rectum, a reservoir is formed from the connected piece of small intestine. All these procedures can be performed either by opening the abdominal cavity through a large abdominal incision or laparoscopically, whereby a camera and instruments are inserted into the abdominal cavity through several small incisions. Surgery can also help patients who have no chance of recovery due to advanced disease, for example by removing or bridging intestinal sections overgrown by the tumor to spare the patient unnecessary suffering.
All these procedures can be performed either by opening the abdominal cavity through a large abdominal incision or laparoscopically, whereby a camera and instruments are inserted into the abdominal cavity through several small incisions. Surgery can also help patients who have no chance of recovery due to advanced disease, for example by removing or bridging intestinal sections overgrown by the tumor to spare the patient unnecessary suffering. Chemotherapy is a pillar of colorectal cancer therapy.
Here, different preparations are usually used in combination with each other, which aim to kill the rapidly dividing tumor cells (cytostatic drugs). Chemotherapy can be used in addition to surgery or alone if surgery is not (any longer) possible or not desired. In combination, chemotherapy can be administered before surgery as so-called neoadjuvant chemotherapy.This is intended to reduce the tumor mass in order to return non-operable tumors to an operable stage or reduce the extent of surgery.
In addition, neoadjuvant chemotherapy helps to reduce the risk of a later recurrence of the tumor. Chemotherapy can also be used after surgery, which is then referred to as adjuvant. The aim is to combat the cancer cells still remaining in the body and to treat small micrometastases that may have already formed but are not yet visible in imaging.
Most chemotherapeutic agents are directed non-specifically against fast-dividing cells and therefore often have unpleasant side effects, as they affect not only cancer cells but also other fast-dividing tissues. Common side effects include nausea, vomiting, diarrhea, loss of hair and limited production of blood cells, which leads to anaemia and a tendency to infection, as the immune system is also weakened. Chemotherapy is usually administered on an outpatient basis, so no inpatient stay is necessary.
Depending on the therapy schedule, the drugs are administered through the vein on one or two consecutive days. This procedure is usually repeated every 14 days, which is called a cycle that is repeated several times. Radiotherapy is still a possible treatment option for rectal tumors.
Here, high-energy rays, which are either secreted by radioactive substances or generated by special equipment, are used to destroy tumor cells. This is done with the highest possible precision so that the tumor receives the majority of the harmful radiation dose. Unfortunately, however, it is not entirely possible to prevent surrounding tissue from being affected, which can lead to inflammation, nerve damage and thrombosis in the adjacent vessels.
Like chemotherapy, radiotherapy can also be used adjuvantly or neoadjuvantly. However, radiation therapy is not suitable for intestinal tumors above the rectum, since the position of the tumor inevitably varies due to intestinal movements in the abdominal cavity and therefore targeted radiation is not possible. In this case, antibodies (the body’s own defense substances) are used, which are directed against various structures of the cancer cell and thus prevent it from growing.
These antibodies are administered in combination with cytostatic drugs. If a curative therapy can no longer be carried out, palliative therapy of colorectal cancer is usually considered. This therapy aims primarily at alleviating the symptoms and improving the patient’s quality of life.