Cancers are a large family of diseases involving abnormal cell growth and differentiation, with the potential of unlimited growth and invasion of organs of the body. Cancers are a subset of tumors, but while not all tumors are malignant (harmful), all cancers are malignant.
Tumor cells that are cancers have the six following features:
Cell growth and differentiation in the absence of growth signals from the body
No programmed cell death
Ability of constructing its own blood vessels
Limitless cell division
Continuous growth and division
Invasion of bodily organs and spread to far and wide areas of the bodies.
Cancer is one of the major challenges faced by modern day medicine. It is an epidemic of enormous proportions, undermining social and economic advances throughout the world. Every year, more than 8 million people die of cancer.
In 2012, there were 6.1 million new cancer cases in developed countries compared to 8 million new cancer cases in developing countries. The number of new cases in developing countries is predicted to rise to 13.1 million by 2030.
CAUSES OF CANCER
The most common type of cancer on the list is breast cancer, with more than 255,000 new cases expected in the United States in 2017. The next most common cancers are lung cancer and prostate cancer.
Cancer is caused by changes to the DNA within cells, which is also referred to as mutations. The DNA inside a cell is packaged into a large number of individual genes, each of which contains a set of instructions telling the cell what functions to perform, as well s when and how to grow, divide, and die. Errors in the instructions can cause the cell to stop its normal functioning and become cancerous.
Genetic mutations cause normal cells to acquire abnormal behaviors. It increases the cell division potential to many times the normal limit, which creates an increased number of abnormal cells very quickly, that all have the same mutation.
Not only do cancerous cells divide and grow at an increased level, they also alter the death mechanism that is inherent to individual cells. This allows them uncontrolled growth and proliferation potential.
Normal cells have repair genes within the DNA itself that takes care of any errors the DNA might make along the way. A mutation in a DNA repair may also lead to a cell becoming cancerous, by inhibiting the repair mechanism, hence, allowing the DNA to continue on with numerous errors within the genetic make up.
Genetics and cancer:
The gene mutations you are born with and those that you acquire throughout life can interfere and work together to cause cancer.
RISK FACTORS OF CANCER
The majority of cancers have no specific risk factors; however, some of the risk factors for certain types of cancers are well known:
Social habits: Certain behaviors such as smoking, excessive drinking, excessive exposure to sun, obesity, consuming large, regular amounts of preservatives and canned food, are documented risk factors that are associated with specific cancers.
Family history: A small number of cancers are due to inherited mutations. Cancers with a genetic background include breast cancer, colo-rectal cancers, and pancreatic cancers.
Environmental factors: Environmental factors such as inhaling secondhand smoke and chemicals in everyday home or workplace products, such as asbestos and benzene, also are associated with an increased risk of cancer.
SIGNS AND SYMPTOMS OF CANCER
Signs and symptoms caused by cancer will vary depending on what part of the body is affected.
Some general signs and symptoms associated with, but not specific to, cancer, include:
- Lump or area of thickening that can be felt under the skin
- Weight changes, including unintended loss or gain
- Skin changes, such as yellowing, darkening or redness of the skin, sores that won’t heal, or changes to existing moles
- Changes in bowel or bladder habits
- Persistent cough or trouble breathing
- Difficulty swallowing
- Persistent indigestion or discomfort after eating
- Persistent, unexplained muscle or joint pain
- Persistent, unexplained fevers or night sweats
- Unexplained bleeding or bruising
Advances in care are allowing patients to live longer, better quality lives. Survival has improved substantially as knowledge of the biology and etiology of cancer has increased, offering the promise of precision oncology. However, these remarkable achievements come at a price—the cost of care is outpacing national budgets, the numbers of cancer patients and survivors are putting greater pressures on health-care systems, and increasing numbers of vulnerable patients from less traditional demographics, such as children and younger adults, require different clinical solutions that have yet to be fully conceived.