Rectal neoplasms

Gastroenterology (12%) Core Clinical Conditions

1B The Physician Associate is able to identify the condition as a possible diagnosis: may not have the knowledge/resources to confirm the diagnosis or to manage the condition safely, but can take measures to avoid immediate deterioration and refer appropriately.

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Definition Aetiology Pathophysiology Risk factor Sign and Symptoms Investigations Management

Rectal neoplasms, also known as rectal tumours, refer to abnormal growths that develop within the rectum. The rectum is the final part of the large intestine, connecting it to the anus. Neoplasms can be either benign (non-cancerous) or malignant (cancerous). Malignant rectal neoplasms, commonly referred to as rectal cancer, are a significant health concern due to their potential to grow, spread, and invade nearby tissues or organs. These tumours typically develop from the inner lining of the rectum and may go through various stages of progression.

• Age: Advanced age is a significant factor in the development of rectal neoplasms, with the risk increasing after the age of 50.

• Family history and genetic factors: Individuals with a family history of colorectal cancer or certain genetic conditions, such as Lynch syndrome or familial adenomatous polyposis (FAP), have a higher risk of developing rectal neoplasms.

• Personal history of colorectal polyps or cancer: Individuals who have previously had colorectal polyps or cancer are at an increased risk of developing rectal neoplasms.

• Lifestyle choices: Certain lifestyle choices can contribute to the development of rectal neoplasms. These include a diet high in red and processed meats, low fiber intake, sedentary lifestyle, obesity, smoking, and heavy alcohol consumption.

• Inflammatory bowel disease (IBD): Individuals with long-standing inflammatory bowel diseases, such as ulcerative colitis or Crohn's disease, are at an increased risk of developing rectal neoplasms.

• Radiation exposure: Previous radiation therapy directed at the pelvis or rectum, especially during childhood, increases the risk of rectal neoplasms.

• Human papillomavirus (HPV) infection: Certain subtypes of HPV have been associated with an increased risk of rectal neoplasms, particularly in cases of anal cancer.

• Diabetes and insulin resistance: Studies have shown a potential link between diabetes and an increased risk of developing rectal neoplasms.

• Ethnicity and race: Some population groups, such as African Americans and Ashkenazi Jews, have a higher incidence of rectal neoplasms compared to other ethnicities.

Rectal neoplasms usually originate from the lining of the rectum and progress through a series of stages, from early abnormal growth to invasive cancer. The key stages in the pathophysiology of rectal neoplasms include:
1. Hyperplasia and Dysplasia: Initially, abnormal cell growth occurs within the lining of the rectum, resulting in hyperplasia (increased cell numbers) and dysplasia (abnormal cell structure). These changes are often asymptomatic and can be detected through screening tests.
2. Adenoma Formation: Over time, hyperplastic and dysplastic cells can cluster to form adenomas or polyps. Adenomas may vary in size and shape and can be sessile (flat) or pedunculated (with a stalk). While most adenomas remain benign, certain high-risk types may progress to cancer.
3. Invasive Cancer: If an adenoma progresses to invade the deeper layers of the rectum, it becomes an invasive cancer. This involves the penetration of cancerous cells through the muscular layers of the rectal wall and potential spread to nearby lymph nodes and distant sites (metastasis).

Clinical Manifestations

The clinical manifestations of rectal neoplasms depend on the stage and location of the tumour. Early-stage rectal neoplasms may remain asymptomatic or present with nonspecific signs, such as rectal bleeding, changes in bowel habits, abdominal discomfort, or unintentional weight loss.
As the tumour grows and progresses, patients may experience more specific symptoms, including persistent rectal bleeding, anaemia due to chronic blood loss, tenesmus (a constant feeling of needing to pass stools), bowel obstruction, and palpable lumps in the rectum.

Same as aetiology (see above)

1. Rectal bleeding: One of the most noticeable symptoms of rectal neoplasms is rectal bleeding. This can manifest as bright red blood in the stool, blood on toilet tissue after wiping, or blood in the toilet bowl. Although occasional rectal bleeding can have other causes, persistent or recurrent bleeding should be evaluated by a medical professional.
2. Changes in bowel habits: Individuals with rectal neoplasms often experience changes in their usual bowel habits. They may notice a persistent change in the consistency and shape of their stool, such as thinning or pencil-like stools. There may also be alterations in the frequency of bowel movements, including constipation, diarrhea, or a feeling of incomplete emptying.
3. Abdominal pain or discomfort: Some individuals with rectal neoplasms may experience abdominal pain or discomfort. This can range from mild cramping to more persistent and severe pain. The pain may be localized to the lower abdomen or the rectal area and can be accompanied by bloating or a feeling of fullness.
4. Unexplained weight loss: Unintended weight loss without any apparent cause can be a sign of various underlying health conditions, including rectal neoplasms. If a person loses a significant amount of weight without diet or lifestyle changes, it's essential to consult a healthcare professional to determine the cause.
5. Fatigue and weakness: Rectal neoplasms can sometimes lead to chronic fatigue and weakness. This can be due to various factors, including the presence of cancer cells, anaemia caused by chronic bleeding, or the body's immune response to the tumour. Fatigue may be persistent and not alleviated by rest.
6. Anaemia: Chronic or recurrent rectal bleeding can lead to iron deficiency anaemia. Anaemia can cause symptoms of weakness, fatigue, shortness of breath, and pale skin. If an individual experiences these symptoms, it is important to have their blood count checked to determine if anaemia is present.
7. Changes in stool colour: In some cases, rectal neoplasms can cause noticeable changes in stool colour. The stool may appear darker than usual, tarry, or black in color. This change in colour, known as melena, is an important sign that should not be ignored.
8. Feeling of rectal pressure: As rectal tumours grow, they can cause a sensation of rectal pressure. This sensation may lead to discomfort, an urge to have a bowel movement, or a feeling that the rectum is not empty even after passing stool.

1. History Taking and Physical Examination:

During history taking evaluate risk factors, symptoms, and family history of cancer. During the physical examination, you may perform a digital rectal examination (DRE) to check for any abnormalities or masses in the rectal area.

2. Imaging Tests:

• Colonoscopy: This is considered the gold standard for diagnosing rectal neoplasms. A flexible, thin tube with a camera called a colonoscope is inserted through the anus to examine the rectum and the entire colon. Tissue samples, or biopsies, can be taken during this procedure for further analysis.

• Magnetic Resonance Imaging (MRI): An MRI scan provides detailed images of the rectum and surrounding structures. It helps evaluate the extent of the tumour, invasion into adjacent organs, and potential spread to distant organs.

• Computed Tomography (CT) Scan: A CT scan may be performed to further assess the extent of the tumour, especially to look for distant metastasis.

3. Lab Tests:

• Full Blood Count (FBC): To assess overall blood cell counts and detect anaemia or abnormal cell populations.

• Liver Function Tests (LFTs): These tests are used to assess liver function, which can be affected if the tumour has spread to the liver.

• Carcinoembryonic Antigen (CEA) Test: CEA is a tumour marker that may be elevated in cases of rectal neoplasms. Serial CEA measurements can help monitor treatment response and detect recurrence.

4. Biopsy and Pathological Examination:

Biopsy is essential for obtaining a definitive diagnosis. During a colonoscopy or surgery, a tissue sample from the rectal tumor is collected and sent to a pathology laboratory. There, pathologists examine the tissue under a microscope to determine the type of rectal neoplasm, grade, and other characteristics. This information helps guide treatment decisions.

5. Staging:

Once a diagnosis has been established, the extent of the tumor needs to be determined to plan the appropriate treatment. Staging may involve additional imaging, such as positron emission tomography (PET) scans or bone scans, to evaluate the presence of distant metastasis.

1. Surgery:

• Local Excision: For early-stage tumours confined to the rectal wall, endoscopic mucosal resection or trans-anal local excision may be sufficient.

• Other techniques involve removal of the rectum and if necessary reconstruction.

2. Radiation Therapy.

3. Chemotherapy.

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