Rectal cancer is a malignant tumor arising from the inner wall of the final part of the large intestine, the rectum.
The rectum is part of the digestive system. Once food nutrients have been absorbed by the small intestines, the waste is moved by muscular contractions into the large intestine (bowel).
Water is removed and the waste is temporarily stored in the rectum, which comprises the last 20cm or so of the bowel.
From the rectum, wastes pass out of the body through the anus. The rectum’s lining (epithelium) secretes mucus that helps to lubricate the faeces through the anus.
Rectal Cancer or Cancer of the rectum begins as cellular changes in the topmost layer of the epithelium. Rectal cancer tends to affect people over the age of 50 years, with men more at risk than women.
Some people have an increased risk due to genetic factors, and may develop the disease sometime after the age of 40 years. If treated in its earliest stages, rectal cancer is highly curable. If untreated, stray cancer cells can migrate around the body via the lymphatic system and develop secondary cancers.
Although colon cancer and rectal cancer share many features, there are important differences between these two diseases including, especially, the tendency for rectal cancer — but not colon cancer — to recur locally. Local recurrence of rectal cancer is common (15-45%) after standard surgery and is often catastrophic. It is difficult to cure, and the associated symptoms are debilitating.
Risk factors for Rectal Cancer
Risk factors for rectal cancer include heredity (family history), colorectal polyps, and long-standing ulcerative colitis. Most cancers of the rectum, like those in colon, develop from polyps. Polyp removal can thus prevent rectal cancer. Polyps and early cancer can have no symptoms so regular screening is important.
Diagnosis of rectal cancer can be made by protoscopy or by colonoscopy with biopsy confirmation of the cancer.
Factors that may increase a person’s risk of rectal cancer include:
- Advancing age
- Family history of colon cancer
- Polyps in the rectum
- Pre-existing inflammatory bowel disease, such as ulcerative colitis
- High fat, low fiber, low calcium diet
Rectal Cancer Symptoms or Rectal Cancer Signs
The Rectal cancer symptoms or the sign of rectal cancer include:
- A change in previous bowel habits, such as constipation or diarrhea
- Feeling that the bowel does not empty completely
- Urgency to pass bowel motions
- Bleeding from the anus
- Abdominal pain.
- A change in bowel habits.
- Blood (either bright red or very dark) in the stool.
- Stools that is narrower than usual.
- General abdominal discomfort
- Frequent gas pains,
- Bloating, fullness or cramps.
- Weight loss for no known reason.
- Weakness or Tiredness.
It should be noted that other conditions also may cause these symptoms.
Rectal Cancer Treatment
Cancer of the rectum is a highly treatable and often curable disease when localized. Rectal cancer treatment depends on its stage, but may include:
- Surgery – is the primary treatment and results in cure in approximately 45% of all patients. The cancer associated rectal tissue and nearby lymph nodes is removed either through the anus or via an abdominal incision through surgery. The rectum is then sewn back together. If a large amount of tissue is removed, it may not be possible to close the rectum and a colostomy will be needed, either temporarily or permanently.The standard surgical procedure is called total mesorectal excision. Preoperative chemo radiotherapy has been found to reduce the risk of local recurrence and to cause fewer long-term toxic effects than if the chemo radiotherapy is given postoperatively.
- Radiation therapy – high doses of precisely targeted radiation are used to kill cancer cells.
- Chemotherapy – cancer-killing drugs are administered by intravenous injection or by mouth.
Sometimes, so much tissue is removed that the rectum can’t be sewn back together or reattached to the anus. In this case, the bowel is diverted from the anus to a small hole in the abdomen (stoma) and a colostomy bag fitted.
A colostomy bag is made from plastic and is stuck to the stoma with special glue. Wastes are passed into the bag, which is then thrown away and replaced with a fresh one. A temporary colostomy bag may sometimes be needed while a successfully remodelled rectum heals properly.
The work-up (evaluation) for patients with a rectal tumor begins with a medical history, physical examination, biopsy and a pathology review of the specimen, colonoscopy, CEA blood levels, CT scans of the abdomen and pelvis, a chest x-ray, and an endorectal ultrasound or endorectal MRI examination.
Further treatment depends on the doctor’s estimate of the stage, depending on what the physical examination and imaging tests show.
Accordingly, preventing local recurrence is one of the main treatment goals with rectal cancer.
Rectal Cancer Prognosis and Rectal Cancer Survival Rate
Rectal cancer prognosis (outlook) and rectal cancer survival rate is clearly related to the degree of penetration of the tumor through the bowel wall and the presence or absence of lymph node involvement.
These two characteristics form the basis for all staging systems developed for this disease. Rectal cancer causes disabling symptoms and is difficult to treat.
Prognosis by stage
As with many other types of cancer, the outcome of rectal cancer depends on how advanced it is when it is diagnosed. In other words, the stage of rectal cancer.
Of all those diagnosed with rectal cancer, roughly 5 out of every 10 people (50%) live for at least 5 years after they are diagnosed. This has improved a lot over the past 20 years. The statistics below relate to people having surgery. About 80% of people with rectal cancer have surgery intended to cure them. But the cancer comes back in about half of these people.
Stage 1: As this is a very early stage cancer, it has a high cure rate. After surgery, more than 8 out of 10 patients (80%) will live for more than 5 years. Unfortunately, at the moment only about 1 out of every 10 patients (10%) diagnosed with rectal cancer have stage 1.
Stage 2: This means that the cancer has grown into the muscle layer of the rectal wall. About 35 out of every 100 people (35%) with rectal cancer are diagnosed at this stage. With surgery, about 6 or 7 out of every 10 people (60 to 70%) with rectal cancer can expect to live longer than 5 years.
Stage 3: This means that the cancer has spread into the lymph nodes surrounding the rectum. Roughly 25 out of every 100 people (25%) with rectal cancer have spread to their lymph nodes when diagnosed. After surgery, about 3 to 6 out of every 10 people (30 to 60%) with Stage 3 rectal cancer will live for at least 5 years after their diagnosis.
Stage 4: This means that the cancer has spread from the rectum to another part of the body. Roughly 3 out of 10 people (30%) with rectal cancer will already have cancer spread to another part of their body when they are diagnosed. For this advanced cancer the survival rates are lower. With this stage about 15 people out of every 100 (15%) will live for at least 2 years after they are diagnosed.