Colorectal Cancer
Labels Colorectal Cancer
- Definition .
- Description .
- Demographics .
- Causes and Symptoms .
- Diagnosis .
- Treatment .
- Prognosis .
- Prevention .
- The Future .
Showing posts with label Colorectal Cancer. Show all posts
Showing posts with label Colorectal Cancer. Show all posts
Labels Colorectal Cancer
Definition
Colorectal cancer develops in the colon (the first 4–5 feet [0.6–0.9
meter] of the large intestine) or the rectum (the last few inches of the
large intestine).
meter] of the large intestine) or the rectum (the last few inches of the
large intestine).
Description
Colorectal cancer affects the lower part of the digestive tract. It
occurs most often in people over 50 but may develop in younger adults
with a family history of colorectal cancer. Most colorectal cancers
develop out of polyps, tissue growths that arise out of the tissue that
lines the large intestine. Most polyps are benign, but some undergo
changes in their genetic makeup that cause them to eventually become
cancerous.
Colorectal cancer usually develops over a period of several years. In
many cases the patient has no symptoms but is diagnosed as the result
of screening for the disease. About half of patients go to their doctor
because they have abdominal pain; a third notice a change in bowel
habits; and 15 percent have an obstruction (blockage) in their intestines.
In some cases these patients may notice that their bowel movements are
unusually thin in shape. As a rule, the larger the cancer and the closer it is
to the anus, the more likely the patient is to have noticeable changes in
bowel habits.
Good Grief, Charlie Brown!
Charles Schulz (1922–2000), the creator of Peanuts,
one of the most beloved comic strips of the
twentieth century, died of colon cancer only 60
days after being diagnosed with the disease in
November 1999. The diagnosis made headlines
because Schulz had originally entered the hospital
for surgery for another disorder. He announced
his retirement from cartooning on December 14
and died in his sleep on February 12, 2000.
Schulz’s mother died of cancer when he was a
young man, but he apparently was unaware of or
ignored his own increased risk of developing the
disease, as well as some early warning symptoms.
He said in a radio interview shortly after his diagnosis,
“I never dreamed that this [cancer] would
happen to me. I always had the feeling that I
would stay with the strip until I was in my early
eighties, or something like that. But all of sudden
it’s gone. I did not take it away. This has been
taken away from me.”
occurs most often in people over 50 but may develop in younger adults
with a family history of colorectal cancer. Most colorectal cancers
develop out of polyps, tissue growths that arise out of the tissue that
lines the large intestine. Most polyps are benign, but some undergo
changes in their genetic makeup that cause them to eventually become
cancerous.
Colorectal cancer usually develops over a period of several years. In
many cases the patient has no symptoms but is diagnosed as the result
of screening for the disease. About half of patients go to their doctor
because they have abdominal pain; a third notice a change in bowel
habits; and 15 percent have an obstruction (blockage) in their intestines.
In some cases these patients may notice that their bowel movements are
unusually thin in shape. As a rule, the larger the cancer and the closer it is
to the anus, the more likely the patient is to have noticeable changes in
bowel habits.
Good Grief, Charlie Brown!
Charles Schulz (1922–2000), the creator of Peanuts,
one of the most beloved comic strips of the
twentieth century, died of colon cancer only 60
days after being diagnosed with the disease in
November 1999. The diagnosis made headlines
because Schulz had originally entered the hospital
for surgery for another disorder. He announced
his retirement from cartooning on December 14
and died in his sleep on February 12, 2000.
Schulz’s mother died of cancer when he was a
young man, but he apparently was unaware of or
ignored his own increased risk of developing the
disease, as well as some early warning symptoms.
He said in a radio interview shortly after his diagnosis,
“I never dreamed that this [cancer] would
happen to me. I always had the feeling that I
would stay with the strip until I was in my early
eighties, or something like that. But all of sudden
it’s gone. I did not take it away. This has been
taken away from me.”
Demographics
Colorectal cancer is the fourth most common cancer in the United States.
According to the American Cancer Society (ACS), about 112,000 people
are diagnosed with colon cancer annually; about 41,000 new cases of rectal
cancer are diagnosed each year; and about 57,000 persons die each year
from colorectal cancer. According to the World Health Organization
(WHO) there are about 940,000 new cases of and 500,000 deaths from
colorectal cancer reported worldwide each year.
Colorectal cancer is most common in older adults; the average age at
the time of diagnosis is 72. Colon cancer in teenagers or young adults is
unusual. Rates are equal for men and women. African Americans appear
to have higher rates of colon cancer than members of other racial groups
in the United States, but the reasons are unclear.
The lifetime risk of developing colon cancer in the United States
is about 7 percent. Researchers at the National Cancer Institute
have identified several factors that increase a person’s risk of colon
cancer:
According to the American Cancer Society (ACS), about 112,000 people
are diagnosed with colon cancer annually; about 41,000 new cases of rectal
cancer are diagnosed each year; and about 57,000 persons die each year
from colorectal cancer. According to the World Health Organization
(WHO) there are about 940,000 new cases of and 500,000 deaths from
colorectal cancer reported worldwide each year.
Colorectal cancer is most common in older adults; the average age at
the time of diagnosis is 72. Colon cancer in teenagers or young adults is
unusual. Rates are equal for men and women. African Americans appear
to have higher rates of colon cancer than members of other racial groups
in the United States, but the reasons are unclear.
The lifetime risk of developing colon cancer in the United States
is about 7 percent. Researchers at the National Cancer Institute
have identified several factors that increase a person’s risk of colon
cancer:
- Age over 50.
- A family history of colorectal cancer. Parents, siblings, or children
of a person diagnosed with colon cancer have an increased
risk of developing it, particularly if the relative was diagnosed at
a young age. - Having either of two specific genes that increase the risk of colon
cancer. These genes are associated with 3 percent of all colon cancers,
and can lead to colon cancer by age forty. They can be
detected by genetic testing. - In women, a personal history of breast cancer.
- A history of ulcerative colitis or Crohn’s disease.
- A history of polyps in the colon or rectum. Polyps are growths that
develop along the inner wall of the colon or rectum, most often in
people over fifty. Most are benign (not cancerous), but some may
develop into cancerous tumors. - A diet high in fat and low in fiber.
- A history of heavy smoking or alcohol consumption.
- Obesity and diabetes.
- Gigantism and other disorders involving growth hormone.
- Previous radiation treatment for cancers elsewhere in the
abdomen.
Causes and Symptoms
The cause of most cases of colorectal cancer is the change in normally
benign intestinal polyps to cancerous tumors. There are several different
types of intestinal polyps, but only two carry a risk of developing into
cancers. These two types can be removed during screening tests for colorectal
cancer. The triggers that cause some polyps to become cancerous are
not completely understood.
In addition to changes in bowel habits, abdominal cramping, and
signs of intestinal blockage, patients with colorectal cancer may have the
following symptoms:
benign intestinal polyps to cancerous tumors. There are several different
types of intestinal polyps, but only two carry a risk of developing into
cancers. These two types can be removed during screening tests for colorectal
cancer. The triggers that cause some polyps to become cancerous are
not completely understood.
In addition to changes in bowel habits, abdominal cramping, and
signs of intestinal blockage, patients with colorectal cancer may have the
following symptoms:
- General tiredness, unexplained weight loss, and lack of appetite
- Bleeding from the rectum or blood or mucus on the stools
- Anemia
- Pain when passing a bowel movement
- Nausea and vomiting
- A feeling that the bowel hasn’t completely emptied following a
bowel movement
Diagnosis
Doctors may use several methods to screen for colorectal cancer. The
simplest are a digital rectal examination (DRE) and a fecal occult blood
test (FOBT). In a DRE, the doctor inserts a gloved finger into the lower
part of the rectum to feel for tumors. The FOBT requires the patient to
take a kit home from the doctor’s office and collect a stool sample, which
is then returned to the doctor or a laboratory to be tested for occult
(hidden) blood. Patients must avoid eating rare meat and other foods
that can affect the test results before using the kit.
Other tests that may be used to diagnose colorectal cancer include:
simplest are a digital rectal examination (DRE) and a fecal occult blood
test (FOBT). In a DRE, the doctor inserts a gloved finger into the lower
part of the rectum to feel for tumors. The FOBT requires the patient to
take a kit home from the doctor’s office and collect a stool sample, which
is then returned to the doctor or a laboratory to be tested for occult
(hidden) blood. Patients must avoid eating rare meat and other foods
that can affect the test results before using the kit.
Other tests that may be used to diagnose colorectal cancer include:
- Blood tests for tumor markers, substances that can be analyzed to
detect the presence of cancer. - Barium enema. Barium in enema form is given to coat the lining
of the colon and rectum. Air is then blown into the colon in order
to fill it. The resultant x-ray can be used to detect precancerous
polyps as well as cancerous tumors. - Sigmoidoscopy. A sigmoidoscope is a flexible lighted tube that can
be inserted into the rectum and used to examine the last 2 feet
(0.6 meter) of the colon. It can be done in a doctor’s office but
does not provide a view of the entire colon. If a polyp or tumor
is found, the doctor will recommend a colonoscopy in order to
check the upper part of the colon. - Colonoscopy. A colonoscope is a long flexible tube attached to a
video camera and monitor that allows the doctor to examine the
entire length of the patient’s colon and rectum. The patient must
take a laxative the night before to cleanse the bowel and may be
given a sedative in the doctor’s office to make them more comfortable.
The doctor can remove polyps during a colonoscopy or take
tissue samples for analysis. - Virtual colonoscopy. This technique uses computed tomography
(a CT scan) to take images of the patient’s colon but is not yet
available in all medical centers. Although virtual colonoscopy does
not involve inserting a tube into the patient’s rectum, the patient
must still take a laxative the night before to empty the bowel
Treatment
The first step in treating colorectal cancer is called staging. Staging
describes the location of the cancer, its size, how far it has penetrated into
healthy tissue, and whether it has spread to other parts of the body. Colorectal
cancers are classified into five stages:
colorectal cancers are first treated by some type of surgery.
to lower the risk of recurrence. Chemotherapy is often used to treat
patients with Stage III or Stage IV cancer for a period of six to eight
months after surgery. Radiation therapy is used more often to treat Stage
III rectal cancer, although it may also be given to patients with colon
cancer to relieve pain or to shrink tumors before surgery.
describes the location of the cancer, its size, how far it has penetrated into
healthy tissue, and whether it has spread to other parts of the body. Colorectal
cancers are classified into five stages:
- Stage 0: The cancer has not grown beyond the lining of the colon
or rectum. - Stage I: The cancer has penetrated through the lining of the colon
or rectum into the underlying tissues but has not spread beyond
the colon wall. - Stage II. The cancer has grown through the wall of the colon or
rectum but has not yet spread to nearby lymph nodes. - Stage III. The cancer has spread to nearby lymph nodes but has
not yet affected other organs. - Stage IV. The cancer has spread to other organs. This process of
spread is called metastasis. The most common locations of metastases
from colorectal cancer are the liver, the lungs, the inside of
the abdomen, or the ovaries.
colorectal cancers are first treated by some type of surgery.
- Small Stage 0 cancers may be completely removed during a colonoscopy.
Some larger polyps can also be removed by inserting surgical
instruments through the abdominal wall in a procedure called
a laparoscopy. - Stage I or Stage II cancers may be treated by removing the section
of the colon that contains the tumor and then reconnecting the cut
ends of the bowel. If reconnection is not possible, or if the cancer
is at the lower end of the rectum, the doctor may have to perform a
colostomy, in which an opening called a stoma is made in the wall
of the abdomen and a portion of the remaining colon is attached
to the stoma. The person’s body wastes pass through the stoma
and are collected in a special bag attached to the outside of the
body. - If the cancer is advanced, surgery is unlikely to cure it. However,
the surgeon can remove some of the tumor in order to relieve pain
and bleeding. - If the colorectal cancer has spread only to the liver and the
patient’s health is otherwise good, the surgeon can remove the cancerous
part of the liver with the colorectal tumor.
to lower the risk of recurrence. Chemotherapy is often used to treat
patients with Stage III or Stage IV cancer for a period of six to eight
months after surgery. Radiation therapy is used more often to treat Stage
III rectal cancer, although it may also be given to patients with colon
cancer to relieve pain or to shrink tumors before surgery.
Prognosis
In spite of progress in early identification and treatment of colorectal
cancer, it remains the third leading cause of death from cancer in the
United States. Prognosis for recovery depends on the stage at which the
disease is detected and treated. If it does not reappear (recur) within five
years, it is considered cured. Stage I, II, and III colorectal cancers are considered
potentially curable, but most doctors do not consider Stage IV
cancer to be curable.
According to the NCI, 93 percent of colon cancer patients and
93 percent of rectal cancer patients who were diagnosed with Stage I
cancer are still alive five years after diagnosis, but only 39 percent of colorectal
cancers are detected at this early stage. The five-year survival rate
drops to 8 percent for those diagnosed with Stage IV cancer.
cancer, it remains the third leading cause of death from cancer in the
United States. Prognosis for recovery depends on the stage at which the
disease is detected and treated. If it does not reappear (recur) within five
years, it is considered cured. Stage I, II, and III colorectal cancers are considered
potentially curable, but most doctors do not consider Stage IV
cancer to be curable.
According to the NCI, 93 percent of colon cancer patients and
93 percent of rectal cancer patients who were diagnosed with Stage I
cancer are still alive five years after diagnosis, but only 39 percent of colorectal
cancers are detected at this early stage. The five-year survival rate
drops to 8 percent for those diagnosed with Stage IV cancer.
Prevention
Screening tests for colon cancer in adults over age 50 are good preventive
measures. The death rate for colon cancer has dropped since 1990, in
part because of increased awareness and screening by colonoscopy. Colon
cancer can almost always be caught in its earliest and most curable stages
by colonoscopy.
People who have either of the two genes for early colorectal cancer,
which can be identified by genetic testing, should have colonoscopies
during their late teens and have their colons removed when they are in
their 20s to prevent getting colorectal cancer.
Although further research is needed to find out how large a role diet
plays in the development of colorectal cancer, people should consider
lowering the amount of fat and increasing the amount of fiber in their
diets to lower their risk of this type of cancer.
measures. The death rate for colon cancer has dropped since 1990, in
part because of increased awareness and screening by colonoscopy. Colon
cancer can almost always be caught in its earliest and most curable stages
by colonoscopy.
People who have either of the two genes for early colorectal cancer,
which can be identified by genetic testing, should have colonoscopies
during their late teens and have their colons removed when they are in
their 20s to prevent getting colorectal cancer.
Although further research is needed to find out how large a role diet
plays in the development of colorectal cancer, people should consider
lowering the amount of fat and increasing the amount of fiber in their
diets to lower their risk of this type of cancer.
The Future
It is likely that the survival rate for patients with colorectal cancer will continue
to rise over the next few decades. The introduction of more effective
screening techniques, the development of new drugs to treat cancer, and
further advances in surgical technique should all be beneficial.
to rise over the next few decades. The introduction of more effective
screening techniques, the development of new drugs to treat cancer, and
further advances in surgical technique should all be beneficial.
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