What is Cancer?

Cancer is a disease characterized by the uncontrolled growth and spread of abnormal cells in the body. These cells can form tumors and interfere with normal body functions.

Cancer can be classified and categorized in different ways, depending on the specific type of cancer and its characteristics.

One common way to classify cancer is based on the type of cells that the cancer originates from. The main categories are:

• Carcinoma: cancer that begins in the skin or in tissues that line or cover internal organs.

Carcinoma: This is cancer that originates in the cells that make up the skin or the lining of organs, such as the lungs, liver, or intestines.

• Sarcoma: cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.

Sarcoma: This is cancer that originates in the cells that make up the body’s connective tissues, such as bones, muscles, cartilage, and fat.

• Leukemia: cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the bloodstream.

Leukemia: This is cancer that originates in blood-forming cells, such as those found in the bone marrow.

• Lymphoma and myeloma: cancers that begin in the cells of the immune system.

Lymphoma: This is cancer that originates in the cells of the immune system, particularly the lymphocytes.

• Central nervous system cancers: cancers that begin in the tissues of the brain and spinal cord.

Another way to classify cancer is by its stage, which describes how advanced the cancer is and how far it has spread. The stages of cancer are typically numbered from 0 to 4, with higher numbers indicating more advanced disease.

Other factors that may be used to categorize cancer include the location of the cancer, the specific genetic mutations or alterations present in the cancer cells, and the presence or absence of specific biomarkers or other molecular features.

The symptoms of cancer can vary depending on the type and stage of the cancer, as well as the location in the body where the cancer is present. However, some common symptoms of cancer include:

• Fatigue
• Unexplained weight loss
• Pain or discomfort in a specific part of the body
• Skin changes, such as yellowing or darkening
• Changes in bowel or bladder habits
• Persistent coughing or hoarseness
• Difficulty swallowing or persistent indigestion
• Persistent headaches

Stage 0 cervical intraepithelial neoplasia (CIN) is a pre-cancerous condition that affects the cervix. It does not usually cause symptoms, but may be detected during routine cervical cancer screening tests.

The symptoms of cancer in stage 1 can vary depending on the type of cancer, but may include a small tumor or lump, pain in the affected area, or other changes in the affected part of the body.

As cancer progresses to stage 2, the tumor may grow larger and symptoms may become more severe. For example, a person with stage 2 breast cancer may notice a lump or swelling in the breast, while a person with stage 2 lung cancer may experience shortness of breath or chest pain.

As cancer progresses to stages 3 and 4, the tumor is larger and may have spread to other parts of the body. Symptoms may become more severe and may include pain, fatigue, weight loss, and other changes in bodily function. The exact symptoms will depend on the type and location of the cancer.

The time it takes for cancer to progress from stage 0 to stage 1 can vary depending on the type of cancer, as well as individual factors such as genetics and lifestyle. Similarly, the time it takes for cancer to progress from stage 1 to stage 4 can also vary widely depending on these factors. Without treatment, cancer can progress more quickly.

Cancer is a complex disease that can be caused by a variety of genetic and environmental factors. There are many genes that can contribute to the development of cancer, and the specific genes that are involved can vary depending on the type of cancer.

Some of the genes that have been identified as playing a role in cancer growth and development include:

1. Tumor suppressor genes: These genes normally help to prevent the development of cancer by regulating cell growth and division. Mutations in these genes can lead to uncontrolled cell growth and the development of tumors.
2. Oncogenes: These genes normally help to regulate cell growth and division, but when they become mutated or overactive, they can promote the development of cancer by causing cells to grow and divide uncontrollably.
3. DNA repair genes: These genes help to repair damaged DNA, which is important for preventing mutations from accumulating and leading to cancer. Mutations in these genes can increase the risk of developing cancer.
4. Epigenetic genes: These genes help to regulate gene expression, which can impact the development of cancer. Changes in epigenetic regulation can lead to alterations in gene expression that promote cancer growth.
5. Inherited cancer susceptibility genes: Some people may inherit mutations in genes that increase their risk of developing certain types of cancer, such as BRCA1 and BRCA2 mutations, which are associated with an increased risk of breast and ovarian cancer.

The specific genes that contribute to cancer can vary depending on the type of cancer and the individual’s genetic makeup. There is ongoing research to better understand the genetic basis of cancer and to develop targeted therapies that can be tailored to an individual’s specific genetic profile.

Some of the top 10 cancer conditions with the highest mortality rate include:

1. Lung cancer
2. Colorectal cancer
3. Breast cancer
4. Pancreatic cancer
5. Prostate cancer
6. Liver cancer
7. Stomach cancer
8. Ovarian cancer
9. Esophageal cancer
10. Bladder cancer

Some of the top 10 cancer conditions with high cure rates include:

1. Testicular cancer
2. Hodgkin’s lymphoma
3. Prostate cancer
4. Breast cancer
5. Skin cancer
6. Thyroid cancer
7. Cervical cancer
8. Melanoma
9. Childhood leukemia
10. Colorectal cancer

Newer cancer treatments for stage 3 and 4 cancers include targeted therapies, immunotherapy, and combination therapies. These treatments are designed to attack cancer cells directly, while minimizing damage to healthy cells.

The most common treatments for cancer stage 1 and stage 2 include:

1. Surgery: This is the primary treatment for many stage 1 and stage 2 cancers. Surgery involves removing the tumor and any surrounding tissue that may contain cancer cells.
2. Radiation therapy: Radiation therapy uses high-energy radiation to kill cancer cells. This may be used before or after surgery to reduce the risk of the cancer returning.
3. Chemotherapy: Chemotherapy uses drugs to kill cancer cells. It may be used alone or in combination with other treatments.
4. Hormone therapy: This is used for certain types of breast and prostate cancers that are hormone-sensitive. Hormone therapy blocks the hormones that help these cancers grow.

As for novel drugs that can be used to prevent cancer, there are several ongoing studies and trials for new drugs that can help prevent cancer. Some examples include:

1. Immunotherapy drugs: These drugs help the immune system recognize and attack cancer cells.
2. Targeted therapy drugs: These drugs target specific proteins or genes in cancer cells to stop their growth.
3. PARP inhibitors: These drugs block the PARP enzyme, which helps repair damaged DNA. Cancer cells with damaged DNA cannot survive without this enzyme.
4. Aspirin: Studies have shown that long-term use of aspirin can lower the risk of developing certain types of cancer, such as colorectal cancer.

The most common screening tests used to early detect or diagnose cancer include:

1. Mammograms: This is a type of X-ray used to detect breast cancer in women.
2. Pap test: This is a test used to detect cervical cancer in women.
3. Colonoscopy: This is a test used to detect colon cancer.
4. PSA test: This is a blood test used to detect prostate cancer in men.
5. CT scan: This is an imaging test that can be used to detect various types of cancer.

It is important to note that not all cancers can be detected early with screening tests, and not all cancers need to be screened for. Screening recommendations vary depending on age, gender, and other risk factors.

It is important to talk to your doctor about which screening tests are appropriate for you.

 

Verified by: Rami Diab (May 5, 2023)

Citation: Rami Diab. (May 5, 2023). What is Cancer? Classification, Types, Novel Cancer Therapies. Medcoi Journal of Medicine, 6(2). urn:medcoi:article22235.