rectal cancer surgery

What is rectal cancer?

Rectum or rectal cancer is a type of cancer that develops in the distal end of colon (large intestine), called rectum. It usually starts as small, non-cancerous growths called polyps, which can become cancerous over time.

Are rectal cancer symptoms different from colon cancer?

Colon cancer  and rectum cancer are both types of colorectal cancer, and they can have similar symptoms. However, there are some symptoms that are more commonly associated with rectal cancer, including:

  • Changes in bowel habits: Diarrhea, constipation, or a feeling of incomplete bowel movements.

  • Tenesmus: Urge to have a bowel movement even after just having one .

  • Rectal bleeding: Blood may appear in the stool or on toilet paper after wiping. The blood may be bright red or dark.

  • Pain or discomfort in the rectum: Pain or discomfort in the rectal area, including the anus and lower abdomen.

  • Narrowing of the stool: As the rectal tumor grows, it can narrow the rectum and make it difficult for stool to pass through. This can result in thinner stools, sometimes referred to as a “pencil-thin” appearance.

What are the risk factors?

Similar with colon cancer, some common risk factors for rectal cancer include:

  • Age (the risk of cololorectal cancer increases after the age of 50)
  • Personal or family history of colorectal cancer or polyps
  • Inflammatory bowel disease (such as ulcerative colitis or Crohn’s disease)
  • A diet high in red or processed meats and low in fruits and vegetables
  • Smoking and tobacco use
  • Certain inherited genetic syndromes, such as Lynch syndrome or familial adenomatous polyposis (FAP).

How to diagnose rectal cancer?

Colonoscopy is considered the gold standard for diagnosing rectal cancer due to its high accuracy and reliability. In addition to visual examination, your doctor may also take a small tissue sample (biopsy) from any suspicious areas for further examination under a microscope.

Occasionally, a sigmoidoscopy maybe performed if the cancer is too large to allow further inspection of rest of the colon.

After a diagnosis of rectal cancer is confirmed, additional investigations may be conducted to determine the extent or stage of the cancer. These investigations may include:

Computed Tomography (CT): This imaging test is commonly used to stage rectal cancer. It is mainly used to determine  any distant spread of the disease, such as to the liver or lungs.

Magnetic Resonance Imaging (MRI): MRI is a valuable diagnostic tool that allows for detailed visualization of soft tissue surrounding the rectum. It provides crucial information regarding the size, location, and extent of the tumor, as well as the involvement of surrounding structures and lymph nodes, which is essential for planning the most effective treatment strategy. In cases where the rectal tumor has advanced and invaded surrounding organs or lymph nodes, treatment such as radiotherapy and chemotherapy may be necessary before surgical intervention. 

Positron Emission Tomography (PET): PET scan is an alternative staging test to CT scan for rectal cancer. It is more sensitive in detecting metabolic activity of cancers, but it can produce false-positive results due to uptake of the tracer in non-cancerous tissues or inflammation.

Carcinoembryonic antigen (CEA) blood test: CEA is a protein that may be secreted by crectal cancer into the bloodstream. However, not all rectal cancers produce CEA, and other factors such as smoking or inflammation may also increase CEA levels. Therefore, CEA levels should be interpreted with caution.

What are the stages of rectal cancer?

There are four stages:

Stage I, the cancer has grown through the inner lining of the rectum and into the middle layers but has not spread beyond the rectal wall.

Stage II, the cancer has grown through the rectum wall and may have invaded nearby tissues or organs but has not spread to the lymph nodes.

Stage III, the cancer has spread to nearby lymph nodes.

Stage IV, the cancer has spread to other parts of the body, such as the liver or lungs.

How to treat rectal cancer?

Treatment typically involves a combination of three main modalities: radiation therapy, chemotherapy, and surgery. This approach provides the best chance of a positive outcome for patients.

For early-stage rectal cancer, surgery is often the only necessary treatment. However, for more advanced cases, neoadjuvant chemoradiation therapy (a combination of chemotherapy and radiation therapy) may be required before surgery to reduce the size of the tumor and lower the risk of cancer recurrence.

In cases where the cancer has metastasized, both chemotherapy and radiation therapy can be used to relieve symptoms and improve the patient’s quality of life. Overall, the specific treatment plan for rectal cancer will depend on the individual patient’s case and will be determined by surgeon.

What are the surgical approach for rectal cancer?

Surgery aims to remove the cancerous tumor and nearby lymph nodes while preserving healthy tissue and bowel function. Previously, open laparotomy via a long midline incision was the standard approach, but now minimally invasive laparoscopic surgery is more common. However, open surgery may still be necessary for specific patient groups, such as those with multiple previous surgeries or obstructed rectal cancer.

Laparoscopy involves a few small incisions in the abdomen, resulting in less pain, faster recovery, and minimal blood loss.

Robotic-assisted surgery, using the da Vinci system, may be utilized for more complicated cases, as it can enhance surgical precision. This approach is extremely useful for low rectal cancer surgery where the tumor is located deep inside the narrow pelvis.

Rectal cancer surgery may require the creation of a stoma or ostomy, which is more likely in cases where the cancer is located very low in the rectum and requires neoadjuvant chemoradiation therapy before surgery. Other factors that increase the likelihood of needing a stoma include poor anal sphincter function and significant co-morbidities. Stoma can be temporary or permanent, and the decision to create one is based on the patient’s individual case, including the stage of the rectal cancer and their overall health. This decision should be carefully considered and discussed with the surgeon to ensure the best possible outcome for the patient.

What are the potential complications of rectal cancer surgery?

Rectal cancer surgery is a significant procedure that carries some potential risks. Here are some of the possible complications:

  • Bleeding: There is a risk of bleeding from the resection site or at the anastomosis.
  • Infection: Patients undergoing rectal cancer surgery are at risk of developing intra-abdominal infections and superficial wound infections.
  • Anastomotic leak: The new connection between two ends of the bowel may not heal properly, leading to stool leakage into the abdomen. This is a serious complication that may require further surgery. Occasionally, a stoma is created to minimized the consequences of anastomotic leak.
  • Damage to nearby organs: During the surgery, there is a risk of accidentally damaging nearby organs, such as the bladder, ureter, or small intestine.
  • Blood clots: There is a risk of developing blood clots, such as deep vein thrombosis (DVT), which can lead to more serious complications if the clots dislodge and travel to the lung, causing pulmonary embolism.
  • Bowel obstruction: There is a risk of bowel adhesions forming after the surgery, which can lead to bowel obstruction in the future.

Related Topics

Consult Us

Dr LEE Kuok Chung

Senior Consultant General Surgeon
Subspeciality interest: Colorectal, Advanced Endoscopy and Robotic Surgery

Dr TAN Wee Boon

Senior Consultant General Surgeon
Subspeciality interest: Thyroid, Hernia and Endocrine Surgery

Kim guowei, UGI surgeon, Stomach specialist

Dr KIM Guowei

Senior Consultant General Surgeon
Subspeciality interest: Upper Gastrointestinal, Bariatric and Robotic Surgery

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