Post on 09-Dec-2015
description
COLON CANCER
• Definition• Signs & symptoms
• Treatment• Root of the disease
What is the colon?
Colon or commonly known as the large bowel is made up of the colon ascending, transverse, descending & sigmoid colon
It is approximately 5 feet long and together with the rectum & anus it is referred to as colorectal
Colorectal cancer (CRC) CRC is the third most common cancer in Canada but is the
second commonest cause of death from cancer in both men and women Around 423 Canadians are diagnosed with CRC each week
while 175 die each week from this disease During life time of a Canadian
One in 14 in men and one in 15 women is expected to develop CRC
Colon cancer has been found to be more common in women while in men, rectal cancer is more common
Age is considered as a major risk factor for the development of CRC The condition is rare before the age of 40 years but the risk
increases with age with a peak of incidence seen between the ages 60-70
Colorectal cancer (CRC)
Staging of CRC provides a guide on the best treatment option for that particular patient and also helps in to evaluate the prognosis.
Colorectal cancer (CRC) Several staging systems exist but most common ones are
TNM method - primary tumour (T), the status of regional lymph nodes (N), and the presence or absence of distant metastases (M) – used commonly
Dukes’ classification
Signs & symptoms CRC patients may present in three ways
Patient complaining of clinical features suggestive of CRC During screening of high risk patients Emergency admission from features of CRC e.g. – intestinal
obstruction Signs and symptoms of CRC is non specific in most of the
patients Early symptoms mimic variety of other diseases of the large
intestines Some patients may present initially with features of metastatic
disease (spread out of the colon) e.g. – enlarged liver, ascites
Signs & symptoms Some of the common presenting symptoms are as follows
Abdominal pain A change in the normal bowel habit e.g. – diarrhoea,
constipation or both Blood in stools Abdominal distension Weight loss Feeling of incomplete evacuation of bowel weakness
Physical findings may include: Abdominal lump Palpable mass, blood on digital rectal examination Metastatic features – enlarged liver, ascites
Signs & symptoms
Treatment Surgical resection of the tumour remains the best treatment
method for localised disease Type of surgery depends on the stage of the disease
Chemotherapy, immunotherapy (both given systemically), radiotherapy (local) Carried out for CRC which has spread beyond the colon
Surgery may sometime be combined with chemotherapy and radiotherapy or both modalities This can be done before the surgery or after the surgery Used to reduce the progression of disease after surgery and
to improve overall survival Sometimes used to reduce the size of the tumour before
surgery
Treatment
Root of the disease How does a cancer develop?
Normal cells in the body respond to various extracellular stimuli & these in turn activates genes that stimulate cell growth
Cancer arises when a normal cell, for variety of reasons escapes the normal restrictions placed on its growth and begins to divide in an abnormal fashion
These extracellular stimuli can be divided in to genetic and environmental
Root of the disease Colon cancer can be described as an multifactorial disease in
which more than one stimuli is responsible for the cause of the disease
Around 80% of cases are sporadic The following are considered as causes of colon cancer
Genetic factors (about 20% have an inheritable component) A family history of CRC, specially if a single first degree
relative is affected the risk is increased 2-3 folds while if 2 are affected the risk increases to 3-4 fold
People with polyps e.g. - familial adenomatous polyposis (FAP) has an almost 100% risk of developing colon cancer by age 40 years
People with a family history of other cancers e.g. – breast, uterine ovarian
Polyps
Root of the disease Environmental factors
Dieta lot of red meat and processed meats increases bowel
cancer risk (Poultry meat doesnt increase the risk). Alcohol Fiber containing diet (fruits, vegetables, cereals etc),
calcium and dairy has a protective effect Obesity (high BMI)
Inflammatory conditions of the colon e.g. Ulcerative colitis or Crohn;s disease
Colorectal cancer (CRC) Majority of CRC develops from a growth called polyps which
overtime may turn into a cancer Normal colonic epithelium changes into adenomatous
polyps which later transforms into invasive colorectal cancer
Previously mentioned stimuli are responsible for this transformation
Colorectal cancer (CRC)
References Cancer research UK. Bowel cancer Colon Cancer Canada. Fast facts on colorectal cancer Colorectal cancer: symptoms, diagnosis and treatment. Nationa
l Institute of Health magazine. 2009; Volume 4 Number 2
Merck Manuals Professional Edition. Colorectal cancer British Medical Journal (BMJ). Best practice Kumar and Clark's Clinical Medicine, 8th Edition