Cancer is a disease in which there is a development of cells abnormally that divide uncontrollably and have the ability to penetrate & destroy normal body tissue. Cancer cells have the ability to spread throughout your body. It is the second leading cause of death in the world. It can start anywhere in the human body.
- Normal process: Cells grow and multiply to form new cells in the body. When these cells grow old, they die and are replaced by new cells.
- In cancerous cells: Sometimes this normal cell growth process breakdown and abnormal or damaged cells grow and multiply. These cells form a lump of tissue which is a tumor. These tumors can be cancerous or non-cancerous (Benign).
The most common cancers are- Breast cancer, lung cancer, and prostate cancer.
How does cancer begin?
Cancer begins when genetic changes interfere with the normal growth process. These genetic changes are known as Mutations. Genetic changes that cause cancer:
- Errors during cell division.
- Damage occurs to DNA- due to harmful substances in the environment, such as chemicals in tobacco and ultraviolet rays from the sun.
- Inherited from your parents.
Normally body destroys the damaged cells from our body before they become cancerous. But as age advances, this ability goes down, and the risk of cancer increases later in life.
Types of genes are involved in causing cancer:
3 main types of genes are involved:
1. Proto-oncogenes 2. Tumor suppressor gene & 3. DNA repair gene.
- Proto-oncogenes: they are made up of protein. It is responsible for the stimulation of cell division and cell growth. They are required for the normal growth, development, and maintenance of organs and tissue. When a mutation of these proto-oncogenes occurs, they are known as oncogenes and cause cancerous changes in our bodies. Due to mutation, these genes change their function and grow exponentially. They cause the growth of cancer cells and the whole cell cycle is destroyed.
- Tumor suppressor genes: these genes inhibit cell growth and tumor development. During mutation, these genes are lost or inactivated. The body lost the ability to prevent cell growth. So cells continue to grow, accumulate and form tumors.
- DNA repair genes: In our body, every day thousands of DNA damage process occurs and our DNA repair system prevents that. Effective DNA repair is the backbone of cancer-free survival. Defects in DNA repair genes affect the primary DNA structure and changes in chromosomal parts like deletion or duplication of parts. These mutations make the cells cancerous.
These 3 mutations are mostly found in every cancer. But there are other specific mutations contributing to different cancers.
What is the reason for cell mutation?
The mutation that you are born with: Some genetic mutations that you inherited from your parents. These mutations include very small percentages of cancers.
Mutations that occur after birth (Acquired mutation): These mutations are not inherited. There are a number of factors responsible that causing mutation—sunlight (UV rays), X-rays; Chemicals like cigarette smoke, nitrate or nitrite preservatives, benzoyl peroxide; Infections like human papillomavirus (HPV), H.pylori.
Differences between normal cells & cancerous cells:
|Undergo apoptosis (a signal that normally tells cells to stop dividing or to die)
|No contact inhibition
|Stay in specific organ
|Ability to metastasize
|Even appearance and nuclei
|Variable appearance and variable-shaped nuclei
|No organized arrangement
|Mature into functional cell
|Do not mature into functional cell
|Mortal (die after 50 divisions)
|Immortal (divide indefinitely)
|Stay bound together
|Can easily detach from each other
How does the cancer spread?
The process is known as Metastasis. The cancer cells break from the original site, enter the bloodstream or lymphatic system and form new tumors in another part of the body. Cancer formed at the other site is known as Metastatic cancer.
The cancers spread in 3 ways:
- The cells grow directly into the tissue surrounding the tumor.
- The cancer cells travel through the bloodstream to other organs in your body.
- The cells can travel through the lymphatic system to nearby or distant lymph nodes.
The most common sites of metastatic cancer are the lungs, liver, bones & brain. Others are the adrenal gland, lymph nodes, skin, and other organs.
We can stop metastasis by early detection of cancer in earlier stages. Systemic treatment is given in addition to surgery. In some cases, treatment reduces the growth of cancer cells, prolongs the lives of people and it may reduce the chances of metastasis.
Risk factors for the development of cancer
- Age- Cancer takes so many years to develop and causes any symptoms. So cancer is mostly diagnosed after the age of 60 years or more. So it is more common in older age but can also be seen at any age.
- Habits/ Addiction– Smoking, and drinking addiction increase the risk of developing cancer. You can change the habit and lower the risk of cancer.
- Family history– As cancer has a genetic role in development, family history plays a very important part. Genetic mutations are inherited from parents and can develop cancer at an early age.
- Food habits- Hot and spicy food consumption increases the chances of developing gastric cancers.
Harmful chemicals, dyes, certain persistent infections, continuous radiation exposure, UV exposure, and workplace- these factors also play an important part in developing cancer.
What are the usual symptoms associated with cancer?
- Weight changes; unexplained weight loss or gain
- Trouble breathing and persistent cough
- Difficulty in swallowing
- Lump or thickening felt under the skin
- Persistent indigestion and discomfort after eating
- Bleeding or bruising
- Persistent sore especially in the mouth, on lips, or tongue
See your doctor if any of these symptoms are persistent & unexplained. If you have any family history of cancer and are worried about it, go and consult your doctor. Go under necessary testing and screening procedures to rule out any cancerous growth.
What are the main types of cancer?
There are more than 100 types of cancers. It is usually named according to the organs from where cancer starts.
Tumor growth can be classified into two types according to its nature: Benign & Malignant tumors.
Benign tumors do not spread to other organs. It can be treated and does not grow back. In some organs like the brain, it produces serious symptoms and can be proven life-threatening.
Malignant tumors can spread to other organs. It may have the tendency to reoccur after treatment and surgical removal. They all are life-threatening.
Types of cancer that begin from a specific type of cells:
- Carcinomas- It usually arises from different epithelial cells. It affects various organs and glands. This term includes squamous cell carcinomas, adenocarcinomas, basal cell carcinomas & transitional cell carcinomas that affect different organs.
- Sarcomas– Rare type of malignant tumor that develops in bone and soft tissues such as fat, blood vessels, cartilage, muscles, and tissue surrounding bones and joints.
Bone sarcomas are-
- Ewing’s sarcoma
Soft tissue sarcomas are-
- Synovial sarcoma
3. Lymphomas– This is the cancer of lymphocytes and white blood cells. This term includes Non-Hodgkins lymphomas which is a group of blood cancers that develop in the lymphatic system. It affects the B & T lymphocytes of our immune system. Nowadays people living with this condition have longer life spans due to newly developed treatment options.
B-cell lymphomas are-
- Diffuse large B cell lymphoma (DLBCL)
- Mental cell lymphoma
- Lymphoblastic lymphoma
- Burkitt’s lymphoma
- T cell lymphomas
- NK cell lymphomas
4. Leukemias– This cancer affects the blood. This uncontrolled growth takes place in the bone marrow, from where blood production starts. It is usually immature white blood cells. It may also affect red blood cells and platelets. It does not diagnose by imaging like an x-ray or CT scan unless it affects bone or any organs. It is usually diagnosed via CBC (complete blood count), blood cell examination (flow cytometry), and bone marrow biopsy.
- Acute lymphocytic leukemia
- Acute myelogenic leukemia
- Chronic lymphocytic leukemia
- Chronic myelogenic leukemia
5. Melanomas- It is a serious type of skin cancer. It develops from a skin cell called a melanocyte. It is the most invasive with a high risk of death. It may arise in any area of your body. It grows quickly and rapidly spread to other organs. It may appear as a mole on the skin. They have a 99% of cure rate if diagnosed and treated in the early stages. The main risk factor for this type of cancer is UV exposure, which causes a rapid rise in the number of cases.
Various diagnostic methods for cancer detection:
- Physical examination– Your doctor does a physical examination by feeling areas of lumps or abnormal skin changes. Palpate various organs for any abnormal growth.
- Laboratory tests– It includes blood and urine tests. It is the most commonly used method to know any presence of Lymphomas & Leukemias.
- Imaging tests– It is a non-invasive way to see your organs, soft tissues, and bones. It includes X-ray, Computed tomography scan, MRI, PET (positron emission tomography), Ultrasonography & many others.
- Biopsy– It is an invasive procedure. The doctor collects a sample of cells for testing. This procedure depends on the type of cancer and its location. It is the only way to accurate diagnosis of cancer.
Common staging of cancer:
- Stage 0– Cancer cells remain in the same place where they started. This may also be called cancer-in-situ, which means it has not grown or spread.
- Stage 1– Cancer has not grown into nearby tissues or lymph nodes.
- Stage 2– Cancer has grown into nearby tissues and possibly nearby lymph nodes.
- Stage 3– Cancer has grown deeper into nearby tissues and may have spread to nearby lymph nodes, but not to distant parts of the body.
- Stage 4– Cancer has spread to other parts of the body or the other organs. This is also called Metastatic or Advanced cancer.
Some cancers may also be described using a grading system, that describes how different cancerous cell looks in comparison to a normal cell. Cells in low-grade tumors do not much differentiate from healthy cells, while in high-grade tumors look very different from normal healthy cells and may spread very quickly.
Treatment options are not always curable in the case of cancer. It reduces growth and decreases the chances of metastasis.
- Surgery: Surgical removal of tumor growth reduces the chances of metastasis
- Chemotherapy: Drugs are used to kill cancer cells.
- Radiation therapy: High-power energy rays such as X-rays & protons are used to kill cancer cells.
- Bone marrow transplant: It is also known as a stem cell transplant. Bone marrow is the liquid present in the cavity in the center of the bone, which produces different blood cells. This treatment method replaces diseased bone marrow.
- Palliative care: It is meant to improve the quality of life of cancer patients who have life-threatening diseases. It can be given with or without curative care. The goal is to prevent and treat the disease, in addition to related psychological, social, and spiritual problems.
Other treatment options are Immunotherapy, Hormone therapy, and targeted drug therapy.
Recurrence of cancer
Cancer returns after a period of remission, that is recurrence. Some cells of cancer remained after treatment which is responsible for repeat growth and symptoms of cancer.
Sometimes a new type of cancer occurs in people who have a history of cancer. This type of cancer is known as the second primary cancer.
Different types of recurrences:
- Local recurrence– When cancer occurs at the same or near the original site.
- Regional recurrence– When cancer grows into lymph nodes or tissues near original cancer.
- Distant recurrence– Cancer has spread to organs or tissues far from the original site.
How do I recognize cancer before it starts to cause serious health problems?
Some cancers cause early symptoms, but others do not express symptoms until they are advanced. Many symptoms are unrelated to cancer. The best way for early detection is to report unusual, persistent symptoms to a doctor. So your doctor advises you for further testing. Common symptoms are described above.
Can cancer be cured?
When cancer treatment starts to work, we can say that cancer is cured. The partial cure is when cancer growth is slowed down but it doesn’t disappear. A complete cure is when there is no sign of cancer at present.