Cancer is a disease that kills more and more people every year. It is the leading cause of death after heart diseases. It is the number one devastating killer disease that affect both adults and children all over the world.
Cancer in simple terms means uncontrolled growth or division of abnormal cells in part of the body. It is a genetic disease caused by accumulation of harmful and abnormal genome (genes) over the course of a lifetime.

Note: A single mutation (alteration/change) in one’s gene is not sufficient to induce cancer formation.

It is also referred to as tumor. Tumor on the other hand, is the swelling (without inflammation) of a part the body. This swelling is caused by an abnormal growth tissues. It can be benign or malignant.

Cancer can also be referred to as neoplasm. Neoplasm is an abnormal new growth of tissue in some part of the body.

Cancer originated from the Greek word “Karkinos” which means crab, due to the presence of swollen veins along its skin. Cancer cells can metastasized, that is can migrate from its primary site (origin) to a distant organ.

Classification

Cancer can be classified based on tissue they originate from. There are four (4) types namely:

1. Carcinomas: This is cancer of epithelial tissue (tissues found in the internal and external linings of the body). It is further subdivided into;
*  Adenocarsinoma–cancer that developed in an organ or gland e. g. Prostate cancer, Breast cancer, Liver cancer).
*  Squamous cell carcinomas–cancer that develop in the squamous epithelium of organs e. g.  Skin cancer, Lung cancer, cancer of the bladder and cancer of the oesophagus.

2. Sarcomas: Cancer that are found in the bones, tendons, cartilage, fats and muscles.

3. Leukemias: Cancer of the blood, that originates in the bone marrow.

4. Lymphomas: Cancer of the lymphatic system.

Stages of cancer formation

Hyperplasia (increase in the number of cells)——->Dysplasia (abnormal development of nuclei and shape of a cell)———>cancer cells

The Common cancer

Lung cancer: Lung cancer is a fatal disease. It is the leading cause of cancer death. It is one of the most common cancer in men and women. Subtypes includes; non-small cell lung cancer (NSCLC) accounting for 85%, Adenocarsinoma squamous small and large cell carcinoma

Risk factors includes;
Smoking.
Second hand smoking.
Asbestos.
Radioactive ores like uranium and
Inhaled chemicals.

Prevention:
Stop smoking.
Reduce exposure to smoke.

Colon cancer: Colon cancer is the third most common leading cause of death. Early diagnosis can be cured.
Risk factors includes;
Age (over 50years).
Diet- diet high in red meat and low in vegetables. As this will help in emptying the colon.
Lifestyle- obesity, smoking and alcohol drinking.
Inflammatory bowel diseases e. g. Crohn’s disease or ulcerative colitis.
Positive family history- there is double risk if a family member was diagnosed with colon cancer.
Genes- DNA repair genes as KRAS and P53.

Prevention
Diet low in red meat and fat and high in vegetables.

Screening
colonscopies, sigmoidoscopy, double contrast barium enema

Breast cancer
The breast consist of milk producing glands surrounded by fats and connective tissues. The glands connects ducts which carries milk to the nipples. Most of breast cancer are diagnosed early and be treated with radiation and surgery. Subtypes are lobular and nipple cancer.

Risk factors :
Age.
Family history.
Gene (Breast C1 and BCA2).
Dense breast tissue.
Lifestyle- obesity, lack of physical activity, not having children, oral contraceptives, post menopausal therapy and alcohol abuse.

Screening:
Self breast examination (SBE).
Mammogram.

Prevention
No known strategy except prophylactic mastectomy in high risk women.

Possibilities: high fibre diet, low fat diet, physically active and maintaining normal body weight.

Prostate cancer
It is the second leading cause of cancer death in men. It is curable when detected early.

Risk factors:
Age.
Family history.
Diet (high red meat and low in vegetables).

Screening:
Blood test for prostate specific antigen (PSA) in men aged 55-69 and at 40 years for men with positive family history.

Liver cancer
The liver is an important organ in the body. It breaks down the nutrients absorbed from the intestine. It is the one of the most common cancer worldwide. It is a lethal disease because, it is usually diagnosed late. It is generally not detected until it has caused an obstruction to bile or other body organ.

Risk factors:
Sex, it is more common in male than female.
Chronic disease if the liver e.g. viral hepatitis.
Alcohol consumption.
Aflatoxins.
Lifestyle- obesity, anabolic steroid abuse.

Prevention
Cessation of smoking and alcohol drinking.
Treating hepatitis.

Screening
No proven strategies but alpha-fetoprotein via a blood test can be used to diagnose liver cancer.

Stomach cancer
Stomach is a hollow organ situated just below the diaphragm on the left side in the abdominal cavity. It is seen as ulcerating mass in the lining of the stomach. It is extremely common worldwide. It is the leading cause of cancer death, this is because by the time the symptoms develops, it has spread and it is too late to treat with primary therapy such as surgery. Stomach cancer is more common in men, in people over the age of 60 years.

Risk factors
Chronic infection with Helicobacter pylori (which is implicated in stomach ulcer).
Diet high in smoked food, salted fish and meat and prickled vegetables. Food that contain nitrates and nitrites.
Lifestyle- obesity and smoking.
Having a type A blood group.

Prevention
Treating H pylori infection.
Eradicating chronic gastritis and ulcers.
Using refrigeration instead of smoking as method for food preservation.
Maintaining normal body weight.
Avoiding smoking.

Screening

There is no proven strategy for stomach cancer screening.

American Cancer Society (ACS) Guidelines on Nutrition and Physical Activity for Cancer Prevention

ACS Recommendations for Individual Choices
•  Maintain a healthy weight throughout life
•  Balance caloric intake with physical activity
•  Avoid excessive weight gain throughout the life    cycle
•  Achieve and maintain a healthy weight if currently overweight or obese
•  Adopt a physically active lifestyle
•  Adults: engage in at least 30 minutes of moderate to vigorous physical activity, above usual activities, on 5 or more days of the week; 45 to 60 minutes of intentional physical activity are preferable
•  Children and adolescents: engage in at least 60 minutes per day of moderate to vigorous physical activity at least 5 days per week
•  Choose whole grains in preference to processed (refined) grains
•  Limit consumption of processed and red meats If you drink alcoholic beverages, limit consumption. Drink no more than one drink per day for women or two per day for men.