Rectal Cancer

Introduction

What is the Rectum? Where is it located?

The rectum is the final straight portion of the large intestine. It is about 12 cm to 15 cm long. It is a long, hollow, muscular tube that connects the large intestine to the anus. Rectum stores our waste before defecation. It helps move waste products of digestion (stool) to the anus for excretion. An intact anal sphincter or muscles is required for holding the waste (feces) till defecation.

What is rectal cancer?

Tumors of this portion of large bowel are relatively common. Rectal cancer begins in the cells that line the inside of the rectum. It usually begins as small, noncancerous (benign) clumps of cells called polyps that form on the inside of the rectum. Over time some of these polyps can become cancers. Most common type of cancer is adenocarcinoma. Rare tumors like melanomas, gastro-intestinal stromal tumor (GIST) and lymphomas are also seen in rectum.

Types

Symptoms

Often there are no early symptoms of rectal cancer. Screening methods are available that can detect colonic and rectal cancer before symptoms appear. When detected early, these cases can be cured with much simpler surgery. As the cancer advances, rectal cancer symptoms may become more persistent and severe. Some common symptoms of rectal cancer are:

  • Rectal bleeding may make the stool bright red. A bleeding tumor may also change the color of the stools, sometimes making the stool very dark or tarry looking black colour.
  • Change in bowel habits, such as diarrhea, constipation, or narrow stools, that lasts for more than a few days
  • Feeling of incomplete emptying of bowel- feeling like you need to have a bowel movement, that is not relieved by going to the toilet
  • Cramping or abdominal (belly) pain
  • Weakness and fatigue
  • Unexplained weight loss

Risks

Factors that may increase your risk of rectal cancer include:

  • Older age: Rectal cancer can be diagnosed at any age, but the risk increases after age 50. The rates of colon cancer in people younger than 50 have been increasing.
  • History of colorectal cancer or polyps: If you’ve already had colon or rectal cancer or noncancerous colon polyps, you have a greater risk of rectal cancer in the future.
  • Inflammatory intestinal conditions: Chronic inflammatory diseases of the colon and rectum such as ulcerative colitis and Crohn’s disease can increase risk of rectal cancer.
  • Inherited syndromes due to genetic mutation: Some gene mutations passed through generations of the family can increase risk of rectal cancer significantly. Most common inherited syndromes that increase rectal cancer risk are familial adenomatous polyposis (FAP) and Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC).
  • Family history of colorectal cancer: You’re more likely to develop rectal cancer if you have a blood relative who has had the disease. If more than one family member has colon cancer or rectal cancer, your risk is even greater.
  • Low-fiber, high-fat diet: Colon cancer and rectal cancer may be associated with a typical Western diet, which is low in fiber and high in fat and calories. There is an increased risk of rectal cancer in people who eat diets high in red meat and processed meat.
  • Sedentary lifestyle: People who are inactive are more likely to develop rectal cancer. Getting regular physical activity may reduce your risk of rectal cancer.
  • Diabetes: People with diabetes or insulin resistance have an increased risk of rectal cancer.
  • Obesity: Obese people have increased risk of colorectal cancer and an increased risk of dying of rectal cancer.
  • Smoking: People who smoke may have an increased risk of rectal cancer.
  • Alcohol: Heavy use of alcohol increases your risk of rectal cancer.

Diagnosis Tests

In addition to a physical examination, the following tests may be used to diagnose colorectal cancer. Not all tests listed below will be used for every person

  • Sigmoidoscopy/ Colonoscopy: Colonoscopy allows the doctor to look inside the entire rectum and colon while a patient is sedated. A colonoscope is a thin long flexible tube with a camera at its tip, which helps the doctor to see the rectum and entire colon for any growth, tumour or polyp.
  • Biopsy: Biopsy is the removal of a small amount of tis sue for examination under a microscope. Biopsy can make a definite diagnosis of colorectal cancer. A biopsy may be performed during a colonoscopy, or it may be done on any tissue that is removed during surgery. Sometimes, a needle biopsy is done which removes tissue through the skin with a needle that is guided into the tumor.
  • Blood tests: Colorectal cancer often bleeds into the large intestine or rectum, so people with the disease may become anemic. Complete blood count (CBC), can indicate that bleeding may be occurring.
  • Carcinoembryonic antigen (CEA): High levels of CEA may indicate that a cancer has spread to other parts of the body. A CEA test is most often used to monitor colorectal cancer for people who are already receiving treatment. It is not useful as a screening test.
  • Computed tomography (CT or CAT) scan: A CT scan takes pictures of the inside of the body. It can be used to measure the tumor’s size. Special dye called a contrast medium is given before the scan to provide better images. This dye can be injected into a patient’s vein or given as a pill or liquid to swallow. In a person with colorectal cancer, a CT scan can check for the spread of cancer to the lungs, liver, and other organs.
  • Magnetic resonance imaging (MRI): An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. MRI can be used to measure the tumor’s size. MRI of the pelvis is the best investigation to assess cancer of the rectum.
  • Ultrasound: An ultrasound uses sound waves to create a picture of the internal organs to find out if cancer has spread.
  • Chest x-ray: X-ray of the chest can help doctors find out if the cancer has spread to the lungs.
  • Positron emission tomography (PET) or PET-CT scan.  PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into the patient’s body. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. A scanner then detects this substance to produce images of the cancer.
Stages

Stage 0 & I (T1/2N0M0)

At this stage, cancer is limited to the inner layers of rectum i.e. mucosa and muscle layer. This is a early stage. It may be detected by chance without any symptom or signs. Additional tests are required to confirm the stage. Surgery is the best treatment for this stage. The curative treatment involves surgery to remove cancer along with a normal segment of rectum and clearance of lymph nodes (small nodular structures that are present in the body that clear the tissue fluids). Additional treatments are not usually needed. Aggressive surgery to remove all of the cancer offers a great potential for cure. The five-year survival rate for stage I cases is more than 90%

Stage II (T3/4N0M0)

At this stage, cancer has reached the outer layer of rectum beyond the muscle layer into the surrounding fat and may have invaded the surrounding structures. However the lymph nodes are not involved yet. Surgery is the best treatment for this stage. Chemotherapy may also be given to selected patients precaution against cancer recurrence.

Stage III (TanyNpositiveM0)

Stage III includes locally advanced cancers where the tumour has involved one or more lymph nodes. Treatment of choice is still surgery. At this stage, patients will need chemotherapy after the surgery to achieve best possible result. Sometimes chemotherapy and radiation may need to be given before the surgery to shrink the size of the tumour.

Stage IV (TanyNanyM1)

Stage IV is when the cancer is spread to other organs like liver and lung. At this stage disease is treated with chemotherapy or symptomatic and supportive care, as indicated. Surgery, when performed, is often used to relieve or prevent blockage of the rectum or to prevent bleeding. A curative surgery may be considered in selected cases where all the tumor tissue can be surgically removed (limited number of liver & lung spread). When surgery is possible, the five-year survival rate can be upto 50%. If surgery is not feasible the survival is poor. When surgery is not possible, other options include destroying them with microwaves or heat (radiofrequency ablation) or giving chemotherapy directly into the liver used with embolization (chemoembolization), etc.

Treatments

SURGERY: The only treatment that can cure rectal cancer is surgery. All other forms of treatment like chemotherapy and radiotherapy can only reduce risk of recurrence of cancer after surgery, but cannot cure the cancer. A number of different surgical procedures are available to treat tumours of the rectum. The choice of particular surgery depends upon the location and size of the tumour.

Abdomino-Perineal Resection (APR): APR is the standard surgery performed for rectal cancer. It is done when the cancer is located close to the anus. In this operation, the entire rectal cancer, adjacent normal rectum, rectal sphincter or anus, and surrounding lymph nodes are removed. The cut end of the large intestine is attached to an opening in the abdominal wall, called a permanent colostomy. This opening is covered with a bag on the abdominal wall to collect waste. With present day technique and technology, we can avoid permanent colostomy with same cure rates. (Figure9)

Sphincter-Sparing Treatment: Avoiding permanent colostomy

The rectal sphincter is the circular muscle that controls defecation. If damaged, patients lose control of bowel function. The greatest fear of patients suffering from rectal cancers is loss of anus and the need to have a permanent stoma. Sphincter-sparing treatment refers to cancer therapy that avoids removal of the anal sphincter for rectal cancers that lie close to the anus. This changes the self image. Colostomy changes the way patient leads life.  Because of the inconvenience of a colostomy, Dr. Aditya Kulkarni is using sphincter-sparing treatments that allow the patient to preserve function of the anus. Sphincter-sparing treatment for rectal cancer involves limited surgery, often followed by a combination of chemotherapy and radiation therapy. We are able to save the anus by using specialized techniques called inter-sphincteric dissection and ultra low anterior dissection with colo-anal anastomosis. These surgeries are performed with better results using robotic surgery than with other approaches. Robotic surgery is preferred for the rectal cancers which are very close to the anus.

Low Anterior Resection Surgery (LAR): Low anterior resection (LAR) is a common treatment for rectal cancer when the cancer is located well above the anus. During a LAR, the entire rectal cancer, adjacent normal rectal tissue and surrounding lymph nodes are removed. After the cancer is removed, the cut ends of the rectum are joined back together. The passage of stool from the large intestine through the anus is therefore preserved. If the cancer is lower in the rectum, the cut end of the large bowel may be attached directly to the anus, known as colo-anal anastomosis. When LAR surgery is performed, some surgeons will create a temporary stoma in order to protect the delicate surgical connection of the large intestine to the anus. After the patient has recovered from the surgery, the temporary stoma is removed and stool is again passed normally through the large intestine. Figure 10

Surgery Techniques

Open surgery: It involves large cuts or incisions on the patient’s body to make a big opening through which the surgery is done. It is highly painful; there is chance of increased blood loss, infection and prolonged recovery. (Figure 11)

Minimal invasive surgery: In these surgeries, the entire procedure is performed using small keyhole incisions, which leads to less pain, less blood loss, faster recovery of the patient. These can be done with laparoscopic or robotic techniques. (Fig 12)

Using minimal invasive technique, colon cancer surgery can be performed with improved comfort. Colectomy when performed by laparoscopy or robotic surgery avoids most of the complications which are mainly related to wound. Patients will have faster recovery, with less blood loss, less chances of infection and less chances of hernia later on. 

Robotic surgery for rectal cancer: The surgeon operates several precision-guided robotic arms that hold and manipulate miniaturized instruments that are inserted through keyhole-sized incisions. A small video camera provides surgeons with magnified 3D images of the operating site. The robotic arms, which can rotate 360 degrees, enable surgical instruments to be moved with greater precision, flexibility and range of motion than in standard minimally invasive laparoscopy. (Figure 13)

Most procedures take two to three hours under general anesthesia. Patients typically experience only minimal blood loss, and blood transfusions are rarely needed. Depending on the surgery, patients often only spend few nights in the hospital and are usually discharged as soon as their laboratory tests are acceptable, their pain is controlled and they are able to retain liquids.

Improved Sphincter-Sparing Treatments: Because of the inconvenience of a colostomy, physicians are using sphincter-sparing treatments that allow patients with low-lying rectal cancers to keep the anus. Improved methods to select patients who can be treated with limited surgery followed by adjuvant chemotherapy and radiation therapy are being developed. More aggressive use of preoperative (neoadjuvant) chemoradiation may allow more patients with larger low-lying rectal cancers a chance to maintain anal function.

Chemotherapy: Chemotherapy uses drugs to destroy cancer cells. For rectal cancer, chemotherapy might be recommended after surgery to kill any cancer cells that might remain. Chemotherapy combined with radiation therapy might also be used before an operation to shrink a large cancer so that it’s easier to remove with surgery. Chemotherapy can also be used to relieve symptoms of rectal cancer that can’t be removed with surgery or that has spread to other areas of the body.

Radiation therapy: Radiation therapy uses powerful energy sources, such as X-rays and protons, to kill cancer cells. In people with rectal cancer, radiation therapy is often combined with chemotherapy that makes the cancer cells more likely to be damaged by the radiation. It can be used after surgery to kill any cancer cells that might remain. Or it can be used before surgery to shrink a cancer and make it easier to remove.

Combined chemotherapy and radiation therapy: Combining chemotherapy and radiation therapy (chemoradiotherapy) makes cancer cells more vulnerable to radiation. The combination is often used for larger rectal cancers and those that have a higher risk of returning after surgery.

Chemoradiotherapy may be recommended:

•            Before surgery. Chemoradiotherapy may help shrink the cancer enough to make a less invasive surgery possible. The combined treatment may increase the chance that your operation will leave the anal area intact so waste can leave the body normally after surgery.

•            After surgery. If surgery was your first treatment, your doctor may recommend chemoradiotherapy afterward if there’s an increased risk that your cancer may return.

•            As the primary treatment. Your doctor may recommend chemoradiotherapy to control the growth of cancer if your rectal cancer is advanced or if surgery isn’t an option.

Treatments for complications

Stent: Relieving rectal obstruction. If cancer has narrowed the lumen, a surgeon may use an endoscope and special tools to place a metal tube (stent) to hold it open. Other options include surgery to make a stoma above the level of the blockage

Rectal cancer surgery carries a risk of serious complications, such as infection, bleeding and leakage from the area where the remaining ends of colon or small bowel are reattached. It is considered to be a major cancer surgery. However, the outcome of this surgery is more likely to be successful if performed by a qualified and experienced GI cancer surgeon (Figure 14).

Dr. Aditya Kulkarni is the best colorectal cancer surgeon, advanced laparoscopic cancer surgeon and robotic surgeon in Pune, Maharashtra, who is qualified and experienced in gastrointestinal cancer surgery.

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The information provided on this website is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images and information, contained on or available through this website is for general information purposes only. We make no representation and assume no responsibility if the information, contained on or available through this website, is taken without Dr. Aditya Kulkarni’s consult and consent.