Rectal Cancer

Rectal cancer usually develops through a combination of genetic changes, chronic damage to the intestinal lining, and lifestyle or environmental factors. In many cases, it develops step by step from benign changes in the mucosa. This often includes adenomatous polyps. Over several years, genetic mutations and problems in cell regulation can build up. As a result, an initially benign change may develop into an invasive tumor.

The most important risk factors include genetic and family-related factors. Well-known hereditary tumor syndromes include familial adenomatous polyposis, or FAP, Peutz-Jeghers syndrome, and hereditary non-polyposis colorectal cancer syndrome. This is also known as HNPCC or Lynch syndrome. A family history of colorectal cancer can also clearly increase the risk.

Diet and lifestyle also play an important role in the development of rectal cancer. A high-fat and low-fiber diet may increase the risk. The same applies to a high intake of red or processed meat, smoking, regular alcohol use, and obesity. Chronic inflammation, changes in the gut microbiome, and contact between the intestinal lining and carcinogenic substances may also be involved.

Important risk factors include:

• Older age, especially from around age 40 to 50
• Colorectal adenomas or intestinal polyps
• A family history of colorectal cancer
• Hereditary tumor syndromes such as FAP or HNPCC
• Chronic inflammatory bowel diseases such as ulcerative colitis or Crohn’s disease
• Smoking
• Regular alcohol use
• Obesity
• Lack of physical activity
• A high-fat and low-fiber diet
• High intake of red or processed meat
• Type 2 diabetes mellitus
• Links with other cancers, such as breast cancer, ovarian cancer, or stomach cancer

Chronic inflammatory bowel diseases are an important risk factor. This is especially true when they last for many years and cause strong inflammatory activity. Repeated inflammation can damage the intestinal lining over time. This may support the development of malignant cell changes.

There are also factors that may have a protective effect. Physical activity, a high-fiber diet with plenty of fruit and vegetables, and a diet lower in meat may be linked to a lower risk of rectal cancer or colorectal cancer. Faster intestinal passage may also have a possible protective effect. This may reduce the time harmful substances stay in contact with the intestinal lining.

The symptoms of rectal cancer, a malignant tumor of the rectum, often develop slowly. In early stages, they can be hard to link to rectal cancer. Many symptoms are non-specific at first. They can also occur with benign bowel conditions, such as hemorrhoids or inflammation. For this reason, typical warning signs should be checked by a doctor early.

The symptoms depend partly on the size, location, and spread of the tumor. Sudden changes in bowel habits are especially common. Symptoms may also arise from changes in intestinal passage or bleeding in the rectal area.

Typical rectal cancer symptoms and warning signs include:

• Blood in the stool
• Changes in bowel habits
• Alternating diarrhea and constipation
• Frequent urge to pass stool
• Pencil-thin or narrow stool
• Pain or pressure in the rectal area
• Abdominal pain or cramps
• Unintentional weight loss
• Reduced performance and tiredness
• Anemia due to chronic blood loss

Blood in the stool is one of the most important warning signs. This applies whether it is visible or hidden. It should be checked by a doctor, regardless of age. Smaller chronic bleeds are not always visible. Sometimes they only become noticeable through tiredness, exhaustion, or anemia caused by iron deficiency.

In advanced stages, stronger pain may occur. Problems with bowel movements or signs of bowel obstruction may also appear. Depending on tumor spread, nearby structures may be affected. These can include the bladder, prostate, or surrounding nerves. This may cause additional symptoms, such as changes in bladder function or pelvic pain.

Early stages of rectal cancer may cause no noticeable symptoms for a long time. This makes colorectal cancer screening especially important. Regular screening can detect precancerous changes or early tumors before clear symptoms or invasive forms develop.

Rectal cancer diagnosis usually includes several steps. These include a clinical examination, endoscopic procedures, tissue sampling, and imaging. The aim is not only to confirm the tumor. Doctors also assess its exact location, spread, and possible metastases. Treatment planning for rectal cancer depends strongly on tumor height, local invasion, and tumor stage. Accurate diagnosis is therefore very important.

At the beginning, doctors usually take a detailed medical history and perform a physical examination. A digital rectal examination is especially important. During this examination, the doctor carefully feels the rectum with a finger. In fact, up to about 10% of colorectal cancers can already be felt this way. The doctor can also assess sphincter function. In low rectal tumors, this may help estimate whether nearby structures are already affected.

The most important diagnostic test is a full colonoscopy with tissue sampling, known as a biopsy. It is considered the gold standard for detecting colorectal polyps and cancers. The removed tissue is then examined under a microscope. In most cases, rectal cancer is an adenocarcinoma. This means it develops from the glandular lining of the rectum. Other tumor types are much rarer. One example is squamous cell carcinoma near the anocutaneous line. This is the transition between the rectal mucosa and the outer skin.

Adenocarcinomas of the colon and rectum can sometimes occur in more than one place. Therefore, doctors usually perform a full colonoscopy. This helps rule out further tumors or precancerous changes in the rest of the large intestine.

After a confirmed diagnosis, staging is performed. This means assessing how far the carcinoma has spread. The TNM classification is the basis for staging. It assesses local tumor spread, possible lymph node involvement, and distant metastases. This is especially important for treatment planning and prognosis. Basic diagnostics also include an abdominal ultrasound, a chest X-ray, and measurement of the tumor marker CEA before treatment starts. If findings are unclear, or if metastases or organ invasion are suspected, further imaging may be used. This can include CT scans of the abdomen, pelvis, and chest.

All rectal cancers are also examined with rigid rectoscopy. This test can measure the exact distance between the tumor and the anocutaneous line. In rectal cancer, this tumor height is very important. It strongly affects surgical planning, possible sphincter preservation, and later continence. A standard flexible colonoscopy often cannot assess this distance accurately enough.

Pelvic MRI is also especially important for local staging of rectal cancer. It can assess the distance between the tumor and the mesorectal fascia. This is important for surgery and for the decision about neoadjuvant therapy. In locally limited tumors, rectal endosonography may also be used. It can assess how deeply the tumor has grown into the bowel wall.

Rectal cancer treatment depends mainly on the tumor stage. It also depends on the exact tumor location in the rectum, lymph node involvement, distant metastases, and general health. Doctors mainly distinguish between localized, non-metastatic tumors and metastatic forms. The aim of treatment is to remove the tumor as completely as possible. Treatment also aims to prevent local recurrence and improve long-term prognosis.

In non-metastatic rectal cancer, surgical removal of the tumor is usually the main treatment. Different surgical procedures may be used, depending on tumor height and spread. Complete removal of the tumor is especially important. This includes the surrounding mesorectal fat and lymph tissue. In lower tumors, sphincter preservation and continence are especially important. Depending on the tumor stage, neoadjuvant chemoradiotherapy is often given before surgery. The aim is to shrink the tumor, improve local tumor control, and reduce the risk of later recurrence. Surgery is then performed. In some cases, additional adjuvant chemotherapy may be needed.

In metastatic rectal cancer, treatment depends strongly on the spread and location of the metastases. Systemic therapies are usually used. These include chemotherapy, targeted therapies, or immunotherapies. Determining the mutation status is important for choosing the right treatment. In some cases, individual metastases, such as in the liver or lungs, can be removed surgically or treated locally.

Complementary medicine and holistic medicine approaches are also often used as supportive care. These include acupuncture, methods from traditional Chinese medicine, nutritional concepts, intestinal cleanse, and oncological hyperthermia. The main aim is to support quality of life. These approaches may also help relieve treatment-related symptoms such as fatigue, nausea, loss of appetite, sleep disorders, or general exhaustion.

Acupuncture is used especially to support patients with nausea, sleep problems, or treatment-related discomfort. Hyperthermia may also be considered as another complementary method. Controlled heating is intended to influence metabolic processes, blood flow, and the sensitivity of tumor cells to certain therapies.

The gut microbiome is also playing a growing role in intestinal health, inflammation control, and the prevention of colorectal tumors. Experts discuss whether a high-fiber diet, enough physical activity, prebiotics, and probiotics may support healthy gut flora. They may also help stabilize the intestinal lining and positively influence inflammatory processes.

The chances of recovery from rectal cancer depend especially on the tumor stage at diagnosis. Rectal cancers that are found early and are still localized can often be treated successfully. In some cases, cure may be possible. If lymph nodes or distant metastases are already widely affected, the prognosis is generally worse. Even so, the prognosis of rectal cancer has improved in recent years. This is due to modern surgical methods, multimodal treatment concepts, and better oncological treatment options.

Screening plays a very important role. A fecal occult blood test, or FOBT, can detect hidden blood in the stool. Colonoscopy is also considered the most important screening test. It can detect early tumors. It can also remove intestinal polyps as possible precancerous changes. Regular screening therefore helps detect colorectal cancer early and may reduce the risk of cancer developing from polyps.

The information listed contains relevant topics and serves to improve understanding.