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  Diet  a 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 Cancer research UK. Bowel cancer  Colon Cancer Canada. Fast facts on colorectal cancer Colon Cancer Canada. Fast facts on colorectal cancer  Colorectal cancer: symptoms, diagnosis and treatment. National Institute of Health magazine. 2009; Volume 4 Number 2 Colorectal cancer: symptoms, diagnosis and treatment. National Institute of Health magazine. 2009; Volume 4 Number 2  Merck Manuals Professional Edition. Colorectal cancer Merck Manuals Professional Edition. Colorectal cancer  British Medical Journal (BMJ). Best practice British Medical Journal (BMJ). Best practice  Kumar and Clark's Clinical Medicine, 8th Edition