What is cancer?

Cancer is a group of over 100 diseases which are characterized by the uncontrolled growth and development of cells, generally abnormal cells, in one’s body. In all types of cancer, cells begin to divide uncontrollably without replacing old cells and infiltrate, or spread, into the neighboring tissues.

Typically, cells in the human body grow and divide in a regulated manner as the body needs them. When cells die or become damaged, new cells replace them. When cancer develops, the normal regulated cell process (growth, division, and replacement, or new cells replacing old cells) breaks down. Old or damaged cells remain when they should not and new cells grow and divide when the body does not need them. This uncontrolled process of cell growth and development is characterized by the term, cancer.


Stages of Cancer Explained

So what are the stages of cancer and what do they mean? The majority of cancers have stages I (1) through IV (4) with the exception of certain cancers having a stage zero (0). Below, the stages of cancer are explained by Cancer.Net [2].

Stage 0- This stage describes cancer in situ, which means “in place.” Stage 0 cancers are still located in the place they started and have not spread to nearby tissues. This stage of cancer is often highly curable, usually by removing the entire tumor with surgery.

Stage I- This stage is usually a small cancer or tumor that has not grown deeply into nearby tissues. It also has not spread to the lymph nodes or other parts of the body. It is often called early-stage cancer.

Stage II & III- In general, these 2 stages indicate larger cancers or tumors that have grown more deeply into nearby tissue. They may have also spread to lymph nodes but not to other parts of the body.

Stage IV- This stage means that the cancer has spread to other organs or parts of the body. It may also be called advanced or metastatic cancer.

The stage of cancer is derived or calculated by what is referred to as the TNM results or descriptions. The “T” stands for tumor and looks to see where the tumor is located in the body and what its size is. The “N” stands for node and looks to see if the cancer has spread to any lymph nodes in the body. Lastly, the “M” stands for metastasis and aims to find out if the cancer has metastasized, or spread, to another location or locations in the body and if so, how much and where exactly has is metastasized to.


Some Differences Between Normal Cells and Cancer Cells

The key difference between normal cells and cancer cells is that normal cells regulate their processes of growth, development and replacement, while cancer cells grow and divide uncontrollably without replacing old or damaged cells [3]. The over-accumulation of cells is what can go on to construct tumors.

Unlike normal healthy cells, cancer cells do not mature to specialize into a distinct cell/tissue type. The lack of specialization is what allows the cancer cells to move around the body via the blood and lymph systems. The absence of adhesion molecules on the cancer cells (the property that keeps cells near similar cell types together) is what gives the cancer cells the ability to metastasize, or spread to other tissues [4].

When examining cells under a microscope, there are clear differences between normal, healthy cells and cells that are cancerous. An obvious difference is that of variability in the size of the cells. Depending on the type of cancer, cells can be larger or smaller than what is typical of that specific cell type [4]. Furthermore, research has shown that it is typical of cancer cells to have an abnormal shape, both the cell shape as well as the shape and size of the nucleus. The larger size of the nucleus can be attributed to the excess amount of DNA in cancer cells [4].

Types of Cancer

As reported by the National Institutes of Health, there are over 100 types of cancer. Cancer types are named by the cells, organs or tissues that are affected in the body. Some of the categories of cancer are explained below.

Sarcoma: cancer of the connective tissue(s), (nerves, muscles, joints, bone, fat, blood vessels)

Carcinoma: cancer of the skin’s epithelial cells or the lining of the internal organs

Leukemia: cancer of the blood-forming tissues (blood and/or bone marrow)

Lymphoma: cancer of the lymphocytes (infection fighting cells)

Melanoma: cancer of the melanin-forming cells

Multiple Myeloma: cancer of the plasma cells

For more information and/or resources regarding any type of cancer, visit the Cancer Treatment Centers of America website here.


Treatment Options

Treatment options are dependent on many factors. While there are many types of treatment options, some cancers can be treated with one option, and other cancers can be treated with a combination of options. Treatment can be very unique to the individual and should be discussed with one’s oncologist.

Some treatment options are:

  • Chemotherapy
  • Immunotherapy
  • Targeted Therapy
  • Hormone Therapy
  • Radiation
  • Precision Medicine
  • Surgery
  • Stem Cell Transplant

To learn more about treatment options, click here.


Reduce Your Risk

While there is no absolute way to completely reduce your risk of getting cancer, decades of scientific research have indicated that there are modifiable behaviors, or lifestyle choices, that can reduce your risk of getting cancer. Some of those modifiable behaviors are as follows:

  • Schedule regular cancer screening exams
  • Do not smoke, or stop smoking
  • Eat a healthy and balanced diet
  • Maintain a healthy and ideal weight for your body type
  • If you choose to drink alcohol, drink in moderation
  • Exercise regularly
  • Avoid excessive sun (UV) exposure
  • Discuss immunizations with your healthcare provider
  • Reduce or eliminate exposure to known toxins, both chemical and environmental

The American Cancer Society provides detailed explanations of some of the behaviors brought up above. To learn more click here.


  1. [youtube] https://www.youtube.com/watch?v=LEpTTolebqo
  2. https://www.cancer.net/navigating-cancer-care/diagnosing-cancer/stages-cancer
  3. https://www.cancer.gov/about-cancer/understanding/what-is-cancer
  4. https://www.verywellhealth.com/cancer-cells-vs-normal-cells-2248794
  5. [picture] https://www.verywellhealth.com/cancer-cells-vs-normal-cells-2248794
  6. https://www.cancercenter.com
  7. [picture] http://gallbladdecancer.weebly.com/cancer-ribbons-and-theyre-meanings.html