Cancer begins in cells, the building blocks that form tissues. Tissues make up the organs of the body.
Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place.
Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor.
Tumors can be benign or malignant:
- Benign tumors are not cancer:
- Benign tumors are rarely life-threatening.
- Generally, benign tumors can be removed, and they usually do not grow back.
- Cells from benign tumors do not invade the tissues around them.
- Cells from benign tumors do not spread to other parts of the body.
- Malignant tumors are cancer:
- Malignant tumors are generally more serious than benign tumors. They may be life-threatening.
- Malignant tumors often can be removed, but sometimes they grow back.
- Cells from malignant tumors can invade and damage nearby tissues and organs.
- Cells from malignant tumors can spread (metastasize) to other parts of the body.
Cancer cells spread by breaking away from the original (primary) tumor and entering the bloodstream or lymphatic system. The cells can invade other organs, forming new tumors that damage these organs. The spread of cancer is called metastasis.
To plan the best treatment for cancer, the doctor needs to know the extent (stage) of your disease. For most cancers (such as breast, lung, prostate, or colon cancer), the stage is based on the size of the tumor and whether the cancer has spread to lymph nodes or other parts of the body.
Before starting treatment, you may want a second opinion about your diagnosis and treatment plan. Many insurance companies will cover a second opinion if your doctor requests it. It may take some time and effort to gather medical records and arrange to see another doctor. Usually it is not a problem to take several weeks to get a second opinion. In most cases, the delay in starting treatment will not make treatment less effective. But some people with cancer need treatment right away. To make sure, you should discuss this delay with your doctor.
The treatment plan depends mainly on the type of cancer and the stage of the disease.
Doctors also consider the patient's age and general health. Often, the goal of treatment is to cure the cancer. In other cases, the goal is to control the disease or to reduce symptoms for as long as possible. The treatment plan may change over time.
Most treatment plans include surgery, radiation therapy, or chemotherapy. Some involve hormone therapy or biological therapy. In addition, stem cell transportation may be used so that a patient can receive very high doses of chemotherapy or radiation therapy.
Some cancers respond best to a single type of treatment. Others may respond best to a combination of treatments.
Treatments may work in a specific area (local therapy) or throughout the body (systemic therapy):
Your doctor can describe your treatment choices and the expected results. You and your doctor can work together to decide on a treatment plan that is best for you.
Because cancer treatments often damage healthy cells and tissues, side effects are common. Side effects depend mainly on the type and extent of the treatment. Side effects may not be the same for each person, and they may change from one treatment session to the next.
*Information from National Institutes of Health (NIH)