What is cancer? – Symptoms, Types, Diagnosis, Stages & Treatment

Cancer refers to any one of a large number of diseases characterized by the development of abnormal cells that divide uncontrollably and have the ability to infiltrate and destroy normal body tissue. Cancer often has the ability to spread throughout your body.

Cancer is the second-leading cause of death across the world. But survival rates are improving for many types of cancer, due to improvements in cancer screening, treatment, and prevention.

What are the stages of cancer?

Most cancers have Four Stages. The specific stage is determined by a few different factors, including the size and location of the tumor:

  •  Stage I: Cancer is localized to a small area and hasn’t spread to lymph nodes or other tissues.
  •  Stage II: Cancer has grown, but it hasn’t spread.
  •  Stage III: Cancer has grown larger and has possibly spread to lymph nodes or other tissues.
  •  Stage IV: Cancer has spread to other organs or areas of your body. This stage is also referred to as metastatic or advanced cancer.

Though stages I through IV are the most common, there is also stage zero. This earliest phase describes cancer that is still localized to the area in which it started. Cancers that are still in stage zero are usually easily treatable and are considered pre-cancerous by most doctors.

How is the stage of cancer determined?

Your doctor will perform tests to determine the extent and severity of your cancer. A number will then be assigned to your diagnosis. The higher the number, the more cancer has spread.

What are the 5 types of cancer?

There are five main types of cancer. These include:

  •  Carcinoma. This type of cancer affects organs and glands, such as the lungs, breasts, pancreas, and skin. Carcinoma is the most common type of cancer.
  •  Sarcoma. This cancer affects soft or connective tissues, such as muscle, fat, bone, cartilage, or blood vessels.
  •  Melanoma. Sometimes cancer can develop in the cells that pigment your skin. These cancers are called melanoma.
  •  Lymphoma. This cancer affects your lymphocytes or white blood cells.
  •  Leukemia. This type of cancer affects the blood.

How common is cancer in India?

According to the National Cancer Registry Programme report, Indians suffer from various types of cancer every year. The rise in urban pollution has led to an increased rate of obesity, tobacco, and alcohol consumption. As a result, the rate of cancer is growing in India. The Indian Council of Medical Research (ICMR) studies predict a possible 12% rise in cancer rate in India by the next five years. 

How does cancer start in the body?

Cancer occurs when your genes stop controlling the way your cells divide. For example, instead of old cells dying, they grow and form abnormal cells.

How dangerous is cancer?

Cancer is potentially fatal. Currently, it’s the leading cause of death worldwide. However, fatality rates largely depend on the type of cancer and how far it has spread. Many types of cancer are successfully treated with prompt care.

Why is cancer so deadly?

When cancer cells develop, they can disturb proper organ function. This can result in reduced oxygen supply and a buildup of waste products. If vital organ function is impaired, it can lead to death.

What causes cancer?

Cancer is caused by changes (mutations) to the DNA within cells. The DNA inside a cell is packaged into a large number of individual genes, each of which contains a set of instructions telling the cell what functions to perform, as well as how to grow and divide. Errors in the instructions can cause the cell to stop its normal function and may allow a cell to become cancerous.

How do smoking and tobacco play a role in causing cancer?

Harmful chemicals in cigarette smoke affect the entire body and smoking causes at least 15 different cancer types. There is no safe level of smoking - stopping completely is the best thing you can do for your health. Following are some of the cancer types that are caused due to smoking and tobacco.

Lung cancer: Lung cancer is a type of cancer that begins in the lungs. People who smoke have the most significant risk of lung cancer, though lung cancer can also occur in people who have never smoked. The risk of lung cancer increases with the length of time and number of cigarettes you've smoked. If you quit smoking, even after smoking for many years, you can significantly reduce your chances of developing lung cancer.

Oral cancer: Oral cancer (mouth cancer) is the most common form of head and neck cancer. It typically affects people aged 60 and older. Oral cancer affects your lips and the first parts of your tongue, mouth roof, and floor. It also affects your oropharynx — the last part of your tongue and roof of your mouth, your tonsils, and the sides and back of your throat. Approximately 63% of people with oral cavity cancer are alive five years after diagnosis.

Laryngeal cancer: Laryngeal cancer is cancer of the larynx, part of the throat. Cancer happens when specific cells grow uncontrollably. As the cells multiply, they invade and damage the body. In laryngeal cancer, these cancerous (malignant) cells start in the larynx (voice box).

Esophageal cancer: Esophageal cancer is cancer that occurs in the esophagus — a long, hollow tube that runs from your throat to your stomach. Your esophagus helps move the food you swallow from the back of your throat to your stomach to be digested. Esophageal cancer usually begins in the cells that line the inside of the esophagus. Esophageal cancer can occur anywhere along the esophagus. More men than women get esophageal cancer.

What is the first sign of cancer?

Cancer symptoms can vary significantly for each person. However, there are a few things that could indicate the early signs of disease. Schedule an appointment with your healthcare provider if you experience:

  •  Unexplained weight loss.
  •  Chronic tiredness.
  •  Persistent pain.
  •  Fever that occurs mostly at night.
  •  Skin changes.

What are common symptoms of cancer? 

Here are some of the more common signs and symptoms that may be caused by cancer. However, any of these can be caused by other problems as well.

  •  Fatigue or extreme tiredness that doesn’t get better with rest.
  •  Weight loss or gain of 10 pounds or more for no known reason
  •  Eating problems such as not feeling hungry, trouble swallowing, belly pain, or nausea and vomiting
  •  Swelling or lumps anywhere in the body
  •  Thickening or lump in the breast or other part of the body
  •  Pain, especially new or with no known reason, doesn’t go away or gets worse
  •  Skin changes such as a lump that bleeds or turns scaly, a new mole or a change in a mole, a sore that does not heal, or a yellowish color to the skin or eyes (jaundice).
  •  Cough or hoarseness that does not go away
  •  Unusual bleeding or bruising for no known reason
  •  Change in bowel habits, such as constipation or diarrhea, that doesn’t go away or a change in how your stools look
  •  Bladder changes such as pain when passing urine, blood in the urine, or needing to pass urine more or less often
  •  Fever or nights sweats
  •  Headaches
  •  Vision or hearing problems
  •  Mouth changes such as sores, bleeding, pain, or numbness

How does cancer spread (metastasis)?

Metastasis is a word used to describe the spread of cancer. Unlike normal cells, cancer cells have the ability to grow outside of the place in your body where they originated. When this happens, it’s called metastatic cancer, advanced cancer, or Stage IV cancer. 

Metastatic tumors (metastases) can occur in three ways:

  1. They can grow directly into the tissue surrounding the tumor.
  2. Cancer cells can travel through your bloodstream to distant locations in your body.
  3. Cancer cells can travel through your lymph system to nearby or distant lymph nodes.

How is cancer diagnosed?

Diagnosing cancer at its earliest stages often provides the best chance for a cure. Your doctor may use one or more approaches to diagnose cancer.

  • Physical exam. Your doctor may feel areas of your body for lumps that may indicate cancer. During a physical exam, your doctor may look for abnormalities, such as changes in skin color or enlargement of an organ that may indicate the presence of cancer.
  • Laboratory tests. Laboratory tests, such as urine and blood tests, may help your doctor identify abnormalities that can be caused by cancer. For instance, a common blood test called complete blood count may reveal an unusual number or type of white blood cells in people with leukemia.
  • Imaging tests. Imaging tests allow your doctor to examine your bones and internal organs in a non-invasive way. Imaging tests used in diagnosing cancer may include a computerized tomography (CT) scan, bone scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scan, ultrasound, and X-ray, among others.
  • Biopsy. During a biopsy, your doctor collects a sample of cells for testing in the laboratory. There are several ways of collecting a sample. Which biopsy procedure is right for you depends on your type of cancer and its location. In most situations, a biopsy is the only way to definitively diagnose cancer.

In the laboratory, doctors look at cell samples under the microscope. Normal cells look uniform, with similar sizes and orderly organization. Cancer cells look less orderly, with varying sizes and without apparent organization.

How is cancer treated?

Cancer treatment is the use of surgery, radiation, medications, and other therapies to cure cancer, shrink cancer or stop the progression of cancer.

Many cancer treatments exist. Depending on your particular situation, you may receive one treatment or you may receive a combination of treatments.

Cancer treatment options include:

  • Surgery - The goal of surgery is to remove the cancer or as much of cancer as possible.
  • Chemotherapy - Chemotherapy uses drugs to kill cancer cells.
  • Radiation therapy -  Radiation therapy uses high-powered energy beams, such as X-rays or protons, to kill cancer cells. Radiation treatment can come from a machine outside your body (external beam radiation), or it can be placed inside your body (brachytherapy).
  • Bone marrow transplant - Your bone marrow is the material inside your bones that makes blood cells from blood stem cells. A bone marrow transplant, also knowns as a stem cell transplant can use your own bone marrow stem cells or those from a donor.
  • A bone marrow transplant allows your doctor to use higher doses of chemotherapy to treat your cancer. It may also be used to replace diseased bone marrow.
  • Immunotherapy - Immunotherapy, also known as biological therapy, uses your body's immune system to fight cancer. Cancer can survive unchecked in your body because your immune system doesn't recognize it as an intruder. Immunotherapy can help your immune system "see" cancer and attack it.
  • Hormone therapy -  Some types of cancer are fueled by your body's hormones. Examples include breast cancer and prostate cancer. Removing those hormones from the body or blocking their effects may cause the cancer cells to stop growing.
  • Targeted drug therapy - Targeted drug treatment focuses on specific abnormalities within cancer cells that allow them to survive.
  • Cryoablation. This treatment kills cancer cells with cold. During cryoablation, a thin, wandlike needle (cryoprobe) is inserted through your skin and directly into the cancerous tumor. Gas is pumped into the cryoprobe in order to freeze the tissue. Then the tissue is allowed to thaw. The freezing and thawing process is repeated several times during the same treatment session in order to kill the cancer cells.
  • Radiofrequency ablation - This treatment uses electrical energy to heat cancer cells, causing them to die. During radiofrequency ablation, a doctor guides a thin needle through the skin or through an incision and into the cancer tissue. High-frequency energy passes through the needle and causes the surrounding tissue to heat up, killing the nearby cells.
  • Clinical trials - Clinical trials are studies to investigate new ways of treating cancer. Thousands of cancer clinical trials are underway.

Other treatments may be available to you, depending on your type of cancer.

What are the side effects of cancer treatment? 

Cancer treatments and cancer can cause side effects. Side effects are problems that occur when treatment affects healthy tissues or organs. Speak up about any problems you have. Your health care team can treat and/or talk with you about ways to reduce these side effects, so you feel better. 

  • Anemia
  • Appetite Loss
  • Bleeding and Bruising (Thrombocytopenia)
  • Constipation
  • Delirium
  • Diarrhea
  • Edema (Swelling)
  • Fatigue
  • Fertility Issues in Boys and Men
  • Fertility Issues in Girls and Women
  • Flu-Like Symptoms
  • Hair Loss (Alopecia)
  • Infection and Neutropenia
  • Lymphedema
  • Memory or Concentration Problems
  • Mouth and Throat Problems
  • Nausea and Vomiting
  • Nerve Problems (Peripheral Neuropathy)
  • Immunotherapy and Organ-Related Inflammation
  • Pain
  • Sexual Health Issues in Men
  • Sexual Health Issues in Women
  • Skin and Nail Changes
  • Sleep Problems 
  • Urinary and Bladder Problems
  • Keep in mind that side effects vary from person to person, even among people receiving the same type of cancer treatment.

How can I manage the side effects of cancer treatment?

If you’re undergoing cancer treatment, talking with your healthcare provider can help you manage your side effects. Many people find that maintaining a healthy diet helps them feel better and stay stronger. You may also benefit from incorporating exercise into your daily routine. Clear any dietary changes and activities with your healthcare provider first.

How long does it take to recover from cancer treatment?

Because cancer treatments vary significantly, the answer to this question is different for each person. Ask your healthcare provider what to expect in terms of your recovery timeline.

How can a person reduce the risk of cancer? 

Though cancer can’t be prevented altogether, there are certain things you can do to reduce your risk. For example:

  • Don’t smoke or use other tobacco products.
  • Stay physically active.
  • Eat a healthy diet.
  • Practice safe sex.
  • Use proper daily sun protection.
  • Get vaccinated.
  • When should someone meet an oncologist? 

If you’re undergoing cancer treatment, it’s important to bring any issues to the attention of your healthcare provider. Call your oncology team if you notice:

  • A fever of 101° or higher.
  • Severe headaches.
  • Chills.
  • Persistent cough.
  • Shortness of breath (dyspnea).
  • Sores on your lips or in your mouth.
  • Sudden weight loss of over five pounds.
  • Excessive vomiting (three times an hour for three hours or more).
  • Blood in your pee or poop.
  • Excessive bleeding or bruising.