Cancer - Types, Causes, Diagnosis and Treatment
Oct 18, 2022, 16:45 IST
Cancer is the most feared diseases found in the world, and in India alone, more than 11 thousand people fall ill with it every year. In worldwide, more than 10 million people succumb to this disease every year. Let's explore what cancer is, causes of cancer, diagnosis, symptoms, and treatment of the cancer.
In human beings, cell differentiation and proliferation are highly manipulated and regulated by the cell division machinery. Uncontrolled cell division occurred when a process called contact inhibition fails. In healthy organisms, during this process, cell replication stops when cells come into contact with other cells. As a result, contact inhibition becomes a powerful anticancer mechanism that is lost in cancer cells. So most types of cancer have tumors (except blood cancers).
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Definition of Cancer
Cancer is a disease in which somebody's cells grow uncontrollably and then spread to the other parts of the body. It can form anywhere in the human body, consisting of multiple cells. Usually, human cells grow and multiply (through cell division) and make new cells as the body needs them. When cells age or become damaged, they die and then form new cells.
Sometimes this process breaks down, and abnormal or damaged cells grow and multiply when they shouldn't. These cells can form tumors, which are lumps of tissue. Tumors can be cancerous or non-cancerous (benign). Cancerous tumors spread to or invade the nearby tissues and then travel to distant places in the body to form new tumors (metastasis). Cancerous tumors can also be called malignant tumors. Many cancers include solid tumors, but blood cancers such as leukemias generally do not.
Benign tumors don't spread or invade the nearby tissues. Benign tumors usually do not grow back after removal, while the cancerous tumors sometimes do. However, benign tumors can sometimes be quite large. Some can cause severe or life-threatening symptoms, such as benign brain tumors.
Types of Cancer
Types of cancer are generally named after the organs or tissues where cancer forms. For e.g., lung cancer starts in the lungs, and brain cancer starts in the brain. Cancers can also be described by the type of cell that created them, such as an epithelial or a squamous cell.
Below are the some categories of cancers that begin in specific types of cells:
- Carcinoma
Carcinomas cancer is the most common type of cancer. They are made up of epithelial cells, which are the cells that cover the inner and outer surfaces of the body. When viewed under a microscope, many types of epithelial cells often have a columnar shape.
- Sarcoma
Sarcomas are the most common cancers that form in bone and soft tissue, including muscle, fat, blood vessels, lymph vessels, and connective tissue (such as tendons and ligaments). Osteosarcoma is the most common bone cancer. The common types of soft tissue sarcoma are leiomyosarcoma, Kaposi's sarcoma, malignant fibrous histiocytoma, liposarcoma, and dermatofibrosarcoma protuberans.
- Leukemia
Cancers that form in the blood tissue of the bone marrow are known as leukemias. These cancers do not form solid tumors. Instead of the large numbers of abnormal white blood cells (leukemic cells and leukemic blast cells) accumulate in the blood and the bone marrow, crowding out normal blood cells. Low levels of normal blood cells can make it harder for the body to get oxygen to tissues, fight infections or control bleeding.
There are mainly four common types of leukemia, which are grouped by how quickly the disease progresses (chronic or acute) and on the type of blood cells in which the cancer begins (lymphoblastic or myeloid). Acute forms of leukemia grow quickly and chronic forms more slowly.
- Lymphoma
Lymphoma is cancer in the lymphocytes (T cells or B cells). These are disease-fighting white blood cells that are part of the immune system. In lymphoma, abnormal lymphocytes accumulate in lymph nodes and vessels, as well as in other body organs.
- Multiple Myeloma
Multiple myeloma is cancer that began in plasma cells, another type of immune cell. Abnormal plasma cells, called myeloma cells, accumulate in the bone marrow and form tumors in bones throughout the body. Multiple myeloma is also called plasma myeloma and Kahler's disease.
- Melanoma
Melanoma is cancer that forms in cells that become melanocytes, which are specialized cells that make melanin (the pigment that gives a skin its color). Most melanomas form on the skin, but melanomas can also form in other pigmented tissues, such as the eye.
Types of Tumour
- Benign Tumour
These tumors are located in a particular place in the body. In addition, it does not spread to other body parts and is generally harmless. However, when a benign tumor occurs in areas such as the brain, it can become fatal. The treatment often involves surgery, and it does not grow back.
- Malignant Tumour
These tumors are cancerous – meaning they will grow quickly and spread to other normal tissues in the body. This ability to spread is called metastasis. Usually, cancer cells metastasize when they enter the bloodstream or lymph nodes and form secondary tumors in various places in the body.
- Premalignant Tumour
This type of tumor may be benign but is observed to have characteristics of a malignant tumor. It may not have metastasized yet, but it can potentially become cancerous. In other words, a premalignant tumor is a type of tumor that has an increased risk of becoming cancer. Benign tumors become premalignant and eventually malignant.
Causes of Cancer
Many factors are responsible for causing cancer. The factors include are:
- Physical factors: ionizing radiation, such as X-rays and gamma rays
- Chemical factors: such as smoke and tobacco
- Biological factors: proto-oncogenes, viral oncogenes, and cellular oncogenes
Diagnosis of Cancer
The diagnosis and detection of cancer are most important before it spreads to other body parts. Identification of cancer genes is pivotal to preventing cancer.
following are the methods to detect cancer –
- Biopsy
- Histopathological studies of tissue
- Radiography technique
- Computed tomography
- Magnetic resonance imaging
- Molecular biology techniques
Treatment of Cancer
Generally, there are three types of treatment available for cancer.
- Surgery: surgically removing localized cancerous mass (Effective for benign tumors)
- Radiation therapy: In this therapy, radiation is used to kill cancer cells.
- Chemotherapy: chemotherapeutic drugs are used to kill cancer cells.
Many chemical drugs have side effects in a cancer patients, like hair loss. Therefore, interferons are injected into cancer patients to develop immunity against these side effects.
Frequently Asked Question (FAQs)
Q1. What are the three most common cases of cancer?
Ans. The most common cancer on the list is breast cancer, with 290,560 new cases expected in the United States in 2022. The following most common cancers are prostate cancer and the lung cancer. Because both colon and rectal cancers are often referred to as "colorectal cancers," these two cancer types are combined for the list.
Q2. Who gets cancer the most?
Ans. You are more likely to get cancer as you get older. Age is the most significant risk factor for the disease. More than 9 out of 10 cancers are diagnosed in human beings 45 and older. Seniors who is older than 74 make up almost 28% of all the new cancer cases.
Q3. What is the rarest form of cancer?
Ans. A few lists of rare cancers are:
- Childhood acute lymphoblastic leukemia.
- Anal cancer
- Merkel cell carcinoma
- Thymic carcinoma
- Hepatoblastoma
- Glioblastoma
Q4. What is used in treatment of cancer?
Ans. The most common treatments for cancer are chemotherapy, surgery, and radiation. Other options include targeted therapy, immunotherapy, laser, hormonal therapy, and others.
Q5. Which cancer is most common in females?
Ans. Some of the common cancers that most often affect women are colorectal, endometrial, breast, lung, cervical, skin, and ovarian cancers.
