Cancer causes uncontrollable division of the cells. This can lead to tumours, immune system damage, and other fatal disability.
According to a 2018 report from the American Cancer Society, an estimated 15.5 million people with a history of cancer have lived in the United States as of January 1, 2016.
In this article, we examine cancer types, how the disease develops and the many treatments that help improve the quality of life and rates of survival.
What is cancer?
Cancer is a descriptive term. This explains the disease that occurs when changes in the cells cause excessive growth and cell division.
Many cancers cause rapid growth of the cells while others cause cells to grow and divide at a slower rate.
Some forms of cancer lead to noticeable growths called tumors, while others, including leukemia, don’t.
Most cells within the body have specific functions and set lifetime. Cell death is part of a natural and beneficial phenomenon called apoptosis, although it may sound like a bad thing.
A cell receives instructions to die so that it can be replaced by a newer cell that works better. Cancer cells do not have the components which instruct them to stop dividing and die.
As a result, they build up in the body, consuming oxygen and nutrients which would normally feed other cells. Cancer cells can form tumors, damage the immune system and cause other changes that prevent the body from regularly functioning.
Cancerous cells can show up in one area and then spread through the lymph nodes. These are clusters of body-wide immune cells.
Many cancer causes and some can be prevented.
For example, according to data reported in 2014, more than 480,000 people die from smoking cigarettes each year in the United States.
Apart from smoking, cancer risk factors include:
- heavy alcohol intake
- excess body weight
- physical inactivity
- poor nutrition
Certain cancer causes are not preventable. The most significant unpreventable risk factor nowadays is age. According to the American Cancer Society, in people aged 50 years or older, doctors in the U.S. treat 87 per cent of cancer cases.
Is cancer genetic?
Genetic factors can be contributing to cancer development.
Genetic code of a person informs his or her cells when to divide and expire. Variations in the genes can lead to incorrect instructions, and can result in cancer.
Genes also affect protein production in the cells, and proteins hold many of the cell growth and division instructions.
Many genes alter proteins normally restoring damaged cells. That can result in cancer. If a parent has these genes, the altered instructions may be passed on to his offspring.
Some genetic changes occur after birth, and the risk may be increased by factors such as smoking and sun exposure.
Certain changes that can cause cancer occur in the chemical signals that dictate how specific genes are deployed by the body, or “say.”
Eventually, a person can inherit a predisposition to a type of cancer. A physician may refer to this as having an inherited cancer syndrome. Inherited genetic mutations contribute significantly to the development of 5–10% of cases of cancer.
Innovative science has stimulated the development of new drugs and technology for treatment.
Physicians usually recommend medications based on the type of cancer, its diagnostic stage, and overall health of the individual.
Examples of cancer treatment strategies are given below:
- Chemotherapy aims at destroying cancer cells with drugs that attack rapidly dividing cells. The drugs may also help to reduce tumors, but the side effects may be severe.
- Hormone therapy involves taking drugs that alter the functions of certain hormones or interfere with the ability of the body to manufacture them. Like with prostate and breast cancers, this is a common strategy when hormones play a significant role.
- Immunotherapy uses medications and other therapies to improve and enable the immune system to fight cancerous cells. Checkpoint inhibitors and adoptive cell transfer are two examples of these therapies.
- A modern, evolving approach is precision medicine, or personalized medicine. This involves using genetic testing to determine the best treatments for the cancer appearance specific to a patient. Nevertheless, researchers still have to prove that it can handle all types of cancer effectively.
- To kill cancer cells, radiation therapy uses high-dose radiation. A doctor may also recommend using radiation to shrink a tumor before surgery, or to reduce symptoms associated with the tumor.
- For people with blood-related cancers such as leukemia or lymphoma, stem cell transplantation can be particularly beneficial. It involves the removal of cells that have damaged chemotherapy or radiation, such as red or white blood cells. Then laboratory technicians repair the cells and return them to the body.
- When a person has a cancerous tumor, surgery is often part of a treatment plan. A physician may also cut lymph nodes for order to reduce or avoid the spread of the disease.
- Targeted medications perform cancer cell functions to avoid multiplication. We can improve the immune system as well. Small-molecule medications and monoclonal antibodies are two examples of these therapies.
Sometimes, physicians employ more than one type of treatment to optimize efficacy.
According to the National Cancer Institute, breast cancer is the most common type of cancer in the U.S., followed by lung and prostate cancers which excluded nonmelanoma skin cancers from these findings.
Each year over 40,000 people across the country are diagnosed with one of the following cancer types:
- colon and rectal
- non-Hodgkin’s lymphoma
Other forms are less common. According to the National Cancer Institute, there are over 100 types of cancer.
Cancer development and cell division
Doctors classify cancer by:
- its location in the body
- the tissues that it forms in
Sarcomas grow in bones or soft tissues, for example, while carcinomas form in cells that cover internal or external surfaces within the body. In the skin, basal cell carcinomas develop, while in the breast adenocarcinomas may form.
The medical term for this is metastasis, as cancer cells spread to other parts of the body.
A person may also suffer from more than one type of cancer at a time.
Improvements in cancer detection, increased awareness of smoking risks, and a reduction in cigarette consumption have led to a year-on-year decrease in the number of cases and deaths from cancer.
The global cancer death rate declined by 26 per cent between 1991 and 2015, according to the American Cancer Society.
When a person has cancer, the outlook depends on whether the disease has spread and the type, nature and location of that disease.
Cancer causes uncontrollable division of the cells. It also stops them from dying in their life cycle, at the natural point.
Genetic factors and lifestyle choices, such as smoking, can help the disease grow. The forms DNA interacts with cells and controls their division and death are influenced by various elements.
Breast cancer is the most common form in the U.S. after the nonmelanoma skin cancer. Lung cancer, however, is the leading cause of death in relation to cancer.
Treatments are getting steadily stronger. Current methods include chemotherapy, radiation therapy and surgery as examples. Many people are taking advantage of new options, such as stem cell transplantation and precision medicine.
The rates of cancer diagnosis and death are dropping annually.
How do I recognize cancer before it starts to cause serious health problems?
Some cancers cause early symptoms, but others do not exhibit symptoms until they are more advanced. Many of these symptoms are often from causes unrelated to cancer.
The best way to identify cancer early is to report any unusual, persistent symptoms to your doctor so they can advise you on any further testing that may be needed.
Yamini Ranchod, PhD, MS
Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.