.png "Cancer Disease | Definition, Types, and Symptoms (Part 1)")
Introduction
Cancer is a complex and multifaceted disease that affects millions of people worldwide. It is characterized by the uncontrolled growth and spread of abnormal cells in the body. These cells can form tumors, invade nearby tissues, and spread to other parts of the body through the bloodstream and lymphatic system. There are over 100 types of cancer, each with its own unique characteristics and behaviors. Understanding the basics of cancer is the first step in the fight against this formidable disease. In this article we will talk about the definition of cancer, its development, spread, types and symptoms.
Definition of Cancer
Cancer is a disease that happens when cells in the body start to grow out of control. Normally, cells grow and divide to form new cells as the body needs them. When cells get old or damaged, they die, and new cells take their place. However, when cancer develops, this orderly process breaks down.
In simple terms, cancer is like having a garden where weeds start growing uncontrollably and crowding out the healthy plants. These "weeds" are abnormal cells that multiply rapidly and can form lumps or tumors. Not all tumors are cancerous; some are benign and don't spread to other parts of the body. But malignant tumors are cancerous and can invade nearby tissues or spread to other parts of the body through the blood and lymph systems.
Term Origin "Cancer"
The term originates from the ancient Greek (καρκίνος), which denotes both 'crab' and 'tumor'. Hippocrates and Galen, notable Greek physicians, observed the resemblance between crabs and certain tumors characterized by swollen veins. The term entered the English language in its modern medical context around 1600.
Development of Cancer
Cancer develops and spreads in the body through a complex process involving changes at the cellular level. Here's an overview of how it happens:
1- Cellular Changes (Mutation):
- Cancer begins with genetic mutations in a cell's DNA. These mutations can be caused by various factors, including environmental exposures (e.g., tobacco smoke, radiation), inherited genetic factors, and random errors during cell division.
- Mutations may affect genes that regulate cell growth and division, such as oncogenes (which promote cell growth) and tumor suppressor genes (which inhibit cell growth).
2- Uncontrolled Cell Growth:
- When mutations occur in critical genes, cells may start to grow and divide uncontrollably, forming a mass of abnormal cells called a tumor.
- Not all tumors are cancerous. Benign tumors do not spread to other parts of the body, while malignant tumors are cancerous and can invade nearby tissues.
3- Angiogenesis:
- Cancer cells can stimulate the growth of new blood vessels (angiogenesis) to supply the tumor with oxygen and nutrients, which are essential for its growth and survival.
Spread of Cancer (Metastasis)
1- Invasion:
- Cancer cells can invade surrounding tissues by breaking through the basement membrane, a barrier that separates the tumor from nearby tissues.
- This invasion is facilitated by enzymes produced by cancer cells that degrade the extracellular matrix and other structural components of tissues.
2- Intravasation:
- Cancer cells can enter the bloodstream or lymphatic system, a process known as intravasation. This allows them to travel to other parts of the body.
3- Circulation:
- Once in the bloodstream or lymphatic system, cancer cells can circulate throughout the body. However, many cancer cells die in this hostile environment due to immune system attacks or physical stress.
4- Extravasation:
- Surviving cancer cells can exit the bloodstream or lymphatic system and enter distant tissues, a process known as extravasation.
5- Colonization:
- In the new location, cancer cells can begin to grow and form secondary tumors, known as metastases. The ability to establish new tumors in distant organs is what makes cancer particularly dangerous.
Types of Cancer
There are more than 100 types of cancer, and they can be broadly categorized based on the tissue or organ where they originate. These are some common types:
- Carcinomas: These cancers arise in epithelial cells that cover the body's surfaces and line internal organs. Examples include breast cancer, lung cancer, prostate cancer, and colorectal cancer.
- Sarcomas: Sarcomas develop in connective tissues such as bones, muscles, and cartilage. Types include osteosarcoma (bone cancer) and leiomyosarcoma (smooth muscle cancer).
- Lymphomas: Lymphomas affect the lymphatic system, which is part of the body's immune system. They include Hodgkin lymphoma and non-Hodgkin lymphoma.
- Leukemias: Leukemias originate in blood-forming tissues like the bone marrow and cause abnormal blood cell production. Examples are acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL).
- Central Nervous System (CNS) Cancers: These cancers affect the brain and spinal cord. Gliomas, meningiomas, and medulloblastomas are examples.
- Melanomas: Melanomas arise in the cells that produce pigment in the skin (melanocytes).
- Cancers of Unknown Primary (CUP): In some cases, cancer is found but the primary site of origin is unknown. This is referred to as cancer of unknown primary.
Each type of cancer may have subtypes with distinct characteristics and treatment approaches.
Symptoms of Cancer
Cancer symptoms can vary widely depending on the type and location of the cancer. These are common symptoms categorized by cancer type:
1) Breast Cancer
- Lump or mass in the breast or underarm.
- Change in breast shape or size.
- Nipple discharge or inversion.
- Skin changes on the breast, such as dimpling or redness.
2) Lung Cancer
- Persistent cough.
- Chest pain.
- Shortness of breath.
- Wheezing.
- Coughing up blood.
- Unexplained weight loss.
3) Prostate Cancer
- Difficulty urinating.
- Frequent urination, especially at night.
- Weak or interrupted urine flow.
- Blood in urine or semen.
- Erectile dysfunction.
- Pain in the hips, back, or chest.
4) Colorectal Cancer
- Changes in bowel habits (diarrhea or constipation).
- Blood in stool or rectal bleeding.
- Abdominal pain or discomfort.
- Unexplained weight loss.
- Fatigue.
5) Skin Cancer (Melanoma)
- New or changing moles.
- Asymmetrical moles.
- Moles with irregular borders or multiple colors.
- Itching, tenderness, or pain in a mole.
- Non-healing sores.
6) Ovarian Cancer
- Abdominal bloating or swelling.
- Pelvic pain.
- Difficulty eating or feeling full quickly.
- Urinary symptoms (urgency or frequency).
- Fatigue.
- Back pain.
7) Pancreatic Cancer
- Abdominal pain radiating to the back.
- Jaundice (yellowing of the skin and eyes).
- Loss of appetite.
- Unintended weight loss.
- New-onset diabetes.
- Blood clots.
8) Leukemia
- Persistent fatigue.
- Frequent infections.
- Easy bruising or bleeding.
- Fever or chills.
- Unexplained weight loss.
- Swollen lymph nodes, liver, or spleen.
9) Lymphoma
- Swollen lymph nodes (neck, armpit, groin).
- Fever.
- Night sweats.
- Unexplained weight loss.
- Fatigue.
- Itching.
10) Bladder Cancer
- Blood in urine.
- Frequent urination.
- Painful urination.
- Back or pelvic pain.
11) Kidney Cancer
- Blood in urine.
- Pain in the side or lower back.
- Lump in the abdomen.
- Unexplained weight loss.
- Fever.
12) Oral Cancer
- Mouth sores that don't heal.
- Persistent mouth pain.
- Lump in the neck.
- Difficulty swallowing or chewing.
- White or red patches in the mouth.
13) Thyroid Cancer
- Lump in the neck.
- Hoarseness or voice changes.
- Difficulty swallowing.
- Neck pain.
- Swollen lymph nodes.
14) Esophageal Cancer
- Difficulty swallowing.
- Chest pain.
- Unexplained weight loss.
- Hoarseness.
- Chronic cough.
15) Stomach (Gastric) Cancer
- Indigestion or heartburn.
- Abdominal pain.
- Nausea and vomiting.
- Unexplained weight loss.
- Feeling full after small meals.
16) Liver Cancer
- Weight loss.
- Loss of appetite.
- Upper abdominal pain.
- Nausea and vomiting.
- General weakness and fatigue.
- Jaundice.
17) Brain Cancer
- Headaches.
- Seizures.
- Nausea and vomiting.
- Vision problems.
- Balance and coordination issues.
- Personality or behavior changes.
18) Bone Cancer
- Bone pain.
- Swelling and tenderness near the affected area.
- Fractures.
- Fatigue.
- Unintended weight loss.
19) Testicular Cancer
- Lump in either testicle.
- Heaviness in the scrotum.
- Dull ache in the abdomen or groin.
- Sudden fluid collection in the scrotum.
- Pain or discomfort in a testicle or the scrotum.
It's important to note that these symptoms can also be caused by conditions other than cancer.
Conclusion
Cancer remains a formidable challenge globally, affecting millions with its complex manifestations and diverse forms. Understanding its origins, from ancient observations of crab-like tumors to modern genetic insights, underscores the long-standing struggle against this disease. The journey from cellular mutations to metastasis highlights the intricate path cancer takes within the body, necessitating ongoing research and vigilant awareness. With over 100 types identified, each demanding unique approaches to detection and treatment, early recognition of symptoms remains crucial.
Here (Part 1) of this topic ends, continue reading in (Part 2).
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