Colorectal cancer is one of the most common types of cancer in the Western world. Each year,
- in Germany, according to 2018 cancer registry data, and around 59,000 people
- in Switzerland, 4,500 people
are diagnosed with colon or rectal cancer. Together with malignant tumors of the sigmoid colon, rectal cancer accounts for more than 60% of all malignant colorectal tumors. Men are affected slightly more often than women. Overall, colorectal cancer is the third most common cancer among men and the second most common among women.
On average, patients are over 60 years old at the time of diagnosis. In rare cases, however, significantly younger individuals may develop the disease if they have a family history of the condition.
Possible location of rectal cancer © bilderzwerg | AdobeStock
Like other types of cancer, rectal cancer is classified into stages.
Stage I represents the earliest form, in which the tumor affects only the superficial layers of the intestinal mucosa. Higher stages reflect the extent of the spread. Stage IV means that the tumor has already formed distant metastases in more distant organs.
The tumor usually grows very slowly. The earlier the stage, the better the chances of recovery. The goal is therefore early diagnosis so that it can be treated while still in the early stages.
Up to 90% of all cancers in the intestine are so-called adenocarcinomas. This means that they develop from the glands of the intestinal mucosa.
Just like colon cancer, rectal cancer usually develops from colorectal polyps—benign growths on the lining of the intestinal wall. Colorectal polyps are therefore considered a precursor to possible colorectal cancer later on.
Illustration of colorectal polyps (shown here in the colon) © tussik | AdobeStock
One of the most important risk factors for the development of colorectal cancer is age. While colorectal cancer is still extremely rare at age 30, the risk increases significantly with age. In fact, more than 90% of all rectal carcinomas develop after the age of 50.
However, genetic predisposition also plays an important role—it can increase the risk of colorectal cancer by up to three times. For this reason, during patient consultations, healthcare providers always ask about cases of colorectal cancer among first-degree relatives. In the case of rare hereditary conditions, there is a high risk of developing colorectal cancer even at a young age.
In addition, there is a slightly increased risk in cases of chronic inflammatory bowel diseases. These include, for example,
These risks cannot be influenced. However, there are also so-called lifestyle risk factors that are within everyone’s control:
- Smoking
- excessive alcohol consumption
- a diet that is too high in fat and low in fiber, with a high proportion of red meat or processed meats
- Lack of exercise
- Being overweight
A healthy and balanced diet is an important factor in good health, even when it comes to cancer © sonyakamoz | AdobeStock
For most people affected, the tumor causes little or no symptoms for a long time. In the early stages, it is therefore usually discovered by chance, for example during a routine examination.
Cancer screening plays a crucial role in early cancer detection. In Germany, these screenings are covered by statutory health insurance starting at age 50. In Switzerland, basic health insurance also covers the costs of cancer screenings for people between the ages of 50 and 69.
If symptoms do occur, they are usually nonspecific at first. Those affected often either fail to notice them or ignore them. These include bowel irregularities such as frequent bowel movements or alternating constipation and diarrhea.
Visible blood in the stool can also indicate rectal cancer. In addition, patients often suffer from
- nausea,
- a feeling of fullness,
- bloating,
- pain during bowel movements, or
- cramps.
Nonspecific general symptoms of cancer include
- weight loss,
- severe night sweats,
- fever, and
- reduced physical performance.
Later, gradual blood loss through the stool often leads to anemia, which manifests as
- pallor,
- fatigue, and
- increased susceptibility to infections
.
In addition to other nonspecific symptoms, rectal cancer can also cause night sweats © kolotype | AdobeStock
As the tumor progresses, it increasingly constricts the bowel. This can lead to changes in stool consistency, resulting in what are known as “pencil-thin stools.” In the worst-case scenario, bowel obstruction may even occur. This is usually accompanied by severe, cramping pain.
In later stages, the tumor can also spread beyond the intestine and invade neighboring organs.
Metastases may also form in other organs. In this process, cancer cells are carried via the blood and lymphatic systems to other organs, where they can form secondary tumors.
In rectal cancer,
- for tumors in the upper and middle thirds of the rectum, primarily the liver;
- for tumors in the lower third of the rectum, primarily the lungs
are primarily affected.
Even though a wide range of technical examination options are now available, the digital rectal exam remains an essential part of the diagnostic process. Up to 10% of rectal tumors are detected this way.
Colonoscopy is the gold standard for confirming a diagnosis. During the procedure, tissue samples are taken, allowing the diagnosis to be confirmed. In addition to a rectal examination, a complete colonoscopy should always be performed, as so-called secondary tumors may be present in up to 7% of cases. In addition to colonoscopy, a tissue sample can also be taken from the intestinal mucosa to definitively confirm a diagnosis of rectal cancer.
If the diagnosis of rectal cancer is confirmed, further evaluation of the tumor stage is conducted. This allows physicians to assess the extent of the tumor and the surrounding tissue.
This includes
The search for distant metastases is performed using ultrasound of the upper abdominal organs and X-rays of the lungs, or alternatively using computed tomography.
The measurement of so-called tumor markers (CEA and CA 19-9) is particularly important for follow-up care. A baseline value is therefore determined at the time of initial diagnosis.
Screening tests play a crucial role in early diagnosis. An early diagnosis significantly improves the chances of recovery. In this context, preventive colonoscopy plays a key role. It allows rectal cancer to be detected before it causes symptoms. Additionally, colorectal polyps—which are precancerous lesions—can be removed before they become malignant.
Removal of a colorectal polyp during a colonoscopy © phonlamaiphoto | AdobeStock
Nowadays, the treatment of rectal cancer is no longer the responsibility of a single medical specialty but should be approached in an interdisciplinary manner. Therefore, every case of a patient with rectal cancer should be discussed in an interdisciplinary tumor board meeting. During this meeting, the appropriate treatment for the cancer stage is determined, taking all findings into account. In addition to surgery, treatment often includes radiation therapy and chemotherapy. This combination can shrink the tumor, thereby facilitating the surgical procedure.
After treatment—whether surgery and/or chemotherapy—the patient is re-evaluated, and the next steps are determined. This ensures that every patient remains under the care of an interdisciplinary team at all times. This approach is mandatory for all certified colorectal cancer centers.
Treatment for rectal cancer depends on its location, the depth of invasion, and the presence of lymph node involvement or distant metastases.
Local Treatments
The prerequisites for the direct surgical removal of rectal cancer are
- a very early stage of cancer
- spread limited to the upper layer of the submucosa (the layer directly beneath the mucosa)
- the tumor’s location in the lower two-thirds of the rectum
The tumor can be removed
- be performed during a colonoscopy, a procedure known as endoscopic mucosal resection (EMR),
- through the anus using transanal endoscopic microsurgery (TEM), or
- a conventional transanal tumor resection
.
Surgical Treatment
A rectal carcinoma that has a greater depth of invasion than described above but does not yet show wall-penetrating growth or lymph node metastases can be treated with radical surgery.
Nowadays, this procedure is usually performed using a minimally invasive approach—that is, laparoscopically with the aid of a camera through several small incisions. A surgical robot may also be used. Whether the sphincter can be preserved depends on whether it has already been invaded by the tumor.
Furthermore, for tumors located just above the sphincter, it is important to consider that pre-existing incontinence may worsen after surgery.
Even when the sphincter was preserved, it was often necessary in the past to create a colostomy as part of the surgery. This significantly impairs the quality of life for those affected. Today, modern surgical techniques can often avoid the need for a colostomy.
TME (Total Mesorectal Excision)
The goal is to remove the tumor along with its lymphatic drainage pathways and thus its primary routes of metastasis.
The TME technique involves removing the rectal cancer along with its surrounding fatty tissue and the surrounding layer (mesorectal fascia). This can be performed using a minimally invasive approach or via an open abdominal incision.
The intestinal continuity is then restored using a special stapler or sutures. This connection is also called an anastomosis. In cases of very deep anastomoses, a temporary colostomy is often created to allow the intestinal suture to heal properly.
This can usually be closed in a subsequent minor surgery after three months.
In some cases, rectal cancer surgery is performed using a minimally invasive approach (example photo of a minimally invasive procedure) © Kadmy | AdobeStock
Preoperative Treatment with Radiation and Chemotherapy
If the tumor has already invaded the surrounding fatty tissue or if the surrounding lymph nodes are already enlarged, a combination of radiation therapy and chemotherapy is administered before surgery.
Chemotherapy is also administered following the surgery. This approach is called neoadjuvant treatment. Its goal is to shrink the tumor before surgery and reduce the risk of tumor recurrence.
Postoperative Care / Fast-Track Protocol
Postoperative care in the hospital is provided, whenever possible, according to a defined protocol (fast-track protocol / ERAS protocol). The goal here is to help patients regain their independence as quickly as possible.
The protocol includes adequate pain management, a rapid return to a normal diet, and early mobilization with the help of physical therapy.
Palliative Chemotherapy
Chemotherapy is also typically used for locally inoperable tumors or advanced metastasis. It cannot cure the cancer, but it can prolong life and improve quality of life.
After successful surgery and treatment, follow-up care is essential. The goal is to detect and treat any recurrence of the tumor or newly developed distant metastases as early as possible.
For rectal cancer, follow-up care is highly structured and defined in so-called guidelines. It includes the
- clinical examination,
- blood tests,
- regular colonoscopies, and
- imaging via ultrasound and CT
over a period of five years.
Today, we are able to cure 60% of patients with rectal cancer. However, the chances of a cure depend largely on the tumor stage.
While 95% of patients with Stage I cancer survive for the next five years, the survival rate drops sharply in Stage IV. In recent years, changes in treatment approaches have significantly improved survival rates even in the presence of isolated distant metastases.
If all of these can be removed, there is a realistic chance of a cure today.
1. What is rectal cancer (rectal carcinoma)?
Rectal cancer, also known as cancer of the rectum or rectal carcinoma, is a malignant tumor in the final section of the intestine. It is one of the most common forms of colorectal cancer. In the early stages, the tumor usually grows slowly and often causes no symptoms, which underscores the importance of early detection.
2. What symptoms indicate rectal cancer?
Typical symptoms include blood in the stool, changes in bowel habits (e.g., diarrhea, constipation, or pencil-thin stools), abdominal pain, and bloating. General symptoms such as weight loss, fatigue, or night sweats may also occur. Since these symptoms are nonspecific, a screening exam starting at age 50 is strongly recommended.
3. How is rectal cancer diagnosed?
The most important diagnostic method is a colonoscopy, during which tissue samples are taken. In addition, imaging techniques such as MRI, CT, or ultrasound are used to determine the extent of the tumor. Tumor markers in the blood play a role primarily in follow-up care.
4. What treatment options and chances of recovery are available?
Treatment depends on the stage and location of the tumor. Surgery is usually performed, often in combination with radiation therapy or chemotherapy. Thanks to modern treatment approaches, about 60% of patients can now be permanently cured—and in the early stages, the chances of recovery are as high as 95%.
