How Cancer Is Treated

Treatment options for cancer depend on the specific type and stage of cancer and individual factors such as your age, possible side effects, and other conditions you may have. Local treatments include surgery and radiation therapy, targeting a specific tumor. Systemic treatments target cancer that has spread or may spread, and include chemotherapy, targeted therapies, hormonal therapies, and immunotherapy. The treatment approach will be chosen with your goals in mind. These may be eradicating the cancer, reducing the risk of recurrence, extending your life, or palliative care that improves the quality of your life.

Surgeries and Specialist-Driven Procedures


With a few exceptions, such as blood-related cancers like leukemia, surgery offers the best chance to cure a cancer or at least significantly reduce the chance that it could recur. The goal of surgery may be to:

  • Diagnose cancer: A surgical biopsy may remove part of a tumor, or a cancer may be removed entirely, in order to determine a precise diagnosis.
  • Stage cancer: Staging a cancer is determining how large a cancer is and how far it has spread. It is extremely important in choosing the best treatments for cancer. Many factors go into staging a cancer, but measuring the size of a tumor after surgery is one of these factors. Surgery may also be done to look for the spread of the cancer for the purpose of staging, for example, via an axillary lymph node dissection with breast cancer or mediastinoscopy with lung cancer.
  • Cure cancer: When solid cancers are caught at an early stage, surgery may be used in an attempt to cure the cancer. This may be followed by other treatments such as chemotherapy or radiation therapy in order to reach any cancerous cells that were not removed at the time of surgery.
  • Debulk a tumor: You may wonder why surgery is not used more often for large cancers which have spread. After all, isn't it a good idea to at least reduce the size of a tumor as much as possible? With most advanced tumors, such as stage IV breast cancer, surgery is not recommended, as treatments such as chemotherapy are more effective. There are exceptions in which "debulking" or cytoreduction surgery may have more benefits than risks. For example, with some ovarian cancers, debulking surgery may reduce the amount of tumor present, allowing chemotherapy to be more effective before the tumor becomes resistant to these drugs.
  • Palliate cancer: Surgery may be done for palliative reasons as well. For example, surgery may remove part of a tumor which is causing pain, an obstruction, or interfering with other processes in the body.
  • Prevent cancer: For cancers which have a precancerous stage or if it's thought that someone may develop a cancer in a region of the body, surgery may be done to remove the organ before cancer can develop. For example, some people who have a very high genetic risk for developing breast cancer may elect to have a preventive mastectomy.

Risks and Side Effects of Surgery for Cancer: As with other treatments for cancer, surgery carries risks, and it's important to make sure these risks are outweighed by the possible benefits of treatment. These risks vary considerably depending on the type of tumor and location, but may include bleeding, infection, and complications of anesthesia.

Special surgical techniques: Advances in surgical techniques, such as the option of lumpectomy versus the radical mastectomy of the past, are allowing surgeons to remove tumors with fewer complications and a faster recovery time. The term minimally invasive surgery is used to describe these techniques which offer the same ability to remove a tumor, but with less damage to normal tissue. An example is the use of video-assisted thoracoscopic surgery to remove lung cancer, in contrast to the thoracotomies done routinely in the past. Robotic surgery is another example of a special surgical technique that may be used. There are many other special surgical techniques. Laser surgery entails the use of high-energy radio waves to treat cancer. Electrosurgery is done with the use of high energy electron beams, and cryosurgery uses a cold source like liquid nitrogen to freeze tumors.


Chemotherapy refers to the use of chemicals (medications) to rid the body of cancer cells.These drugs work by interfering with the reproduction and multiplication of rapidly growing cells, such as cancer cells.

Since these drugs are designed to treat rapidly growing cells, they are most effective for rapidly growing—or aggressive—tumors. The forms of cancer which were historically the most aggressive and rapidly fatal are sometimes now the most treatable and possibly curable with the use of chemotherapy. In contrast, chemotherapy is less effective for slow-growing, or "indolent" tumors.

This mechanism of action also accounts for the well-known side effects of chemotherapy. There are several "normal" types of cells in the body which grow rapidly as well, such as those in the hair follicles, digestive tract, and bone marrow. Since chemotherapy attacks any rapidly growing cells, this accounts for the well-known side effects of hair loss, nausea, and bone marrow suppression.

The goal of chemotherapy may be:

  • To cure cancer: With blood-related cancers such as leukemias and lymphomas, chemotherapy may be used with the intent to cure the cancer.
  • Adjuvant chemotherapy: Adjuvant chemotherapy is chemotherapy given after surgery in effect to "clean up" any cancer cells that have traveled beyond the tumor but are not yet detectable on imaging tests we now have. These wayward cells which are too small to be detected are referred to as micrometastases. Adjuvant chemotherapy is designed to lower the risk of recurrence of a cancer.
  • Neoadjuvant chemotherapy: Neoadjuvant chemotherapy may be given prior to surgery to decrease the size of a tumor. If a tumor is unable to be operated on due to its size or location, chemotherapy in this setting may decrease the size of the tumor enough so that surgery is possible.
  • To extend life: Chemotherapy may be used to prolong life.
  • Palliative chemotherapy: Palliative chemotherapy refers to the use of chemotherapy to decrease the symptoms of cancer, but not to cure cancer or extend life.

There are several different types of chemotherapy medications, which differ in both their mechanisms of action and the part of the cell cycle they disrupt. Most often chemotherapy drugs are used in combination—something termed combination chemotherapy. Individual cancer cells are all at different points in the process of reproducing and dividing. Using more than one drug helps to treat cancer cells at whichever point they are at in the cell cycle.

Chemotherapy may be given by vein (intravenous chemotherapy), orally, via a pill or capsule, directly into the fluid surrounding the brain, or into the fluid present in the abdominal cavity.

Risks and side effects of chemotherapy: Most people are familiar with the common chemotherapy side effects, such as hair loss. Thankfully, in recent years treatments have been developed for managing many of these side effects. For example, many people now have minimal or no nausea or vomiting relative to in the past. These side effects vary depending on the drug's use, the dosages, and your general health, but may include:

Most of these side effects resolve shortly after your final chemotherapy session, but there are sometimes long-term side effects of chemotherapy. Examples include heart damage with some of these drugs and a slightly increased risk of secondary cancers (such as leukemia) with others. The benefits of therapy often far outweigh any of these potential concerns, but having an awareness may help you discuss all options thoroughly with your doctor.

Radiation Therapy

Radiation therapy is a treatment which uses high-energy X-rays (or proton beams) to destroy cancer cells. Significant improvements have been made in these therapies in recent years, minimizing the damage to normal tissues around a cancer.

Radiation may be given externally, in which radiation is delivered to the body from an outside similar to an X-ray machine, or internally (brachytherapy) in which radioactive material is either temporarily or permanently injected or implanted in the body.

As with other cancer treatments, radiation therapy is used for different reasons and with different goals. These goals may be:

  • To cure the cancer: Stereotactic body radiotherapy (SBRT) may be used, for example, in an attempt to cure a small cancer that can otherwise not be reached with surgery, or to completely remove an isolated metastasis.
  • As adjuvant therapy: Radiation therapy may be used after surgery to treat any cells that are left over after surgery. This may be done either externally or internally. An example is the use of radiation therapy to the chest wall after a mastectomy.
  • As neoadjuvant therapy: Radiation therapy may be combined with chemotherapy to reduce the size of a tumor before surgery. For example, radiation therapy—usually combined with chemotherapy—may be used to decrease the size of an inoperable lung cancer so that surgery can then be done.
  • Preventively: An example of preventive therapy is giving radiation therapy to the brain to prevent brain metastases in people with small cell lung cancer.
  • Palliative radiation therapy: Palliative radiation therapy refers to the use of radiation to address the symptoms of cancer but not to cure a cancer. It may be used to decrease pain, reduce pressure, or relieve obstructions caused by a cancer.

Radiation therapy may be given in several different ways as well:

  • External beam radiation therapy: External beam radiation is used often and involves directing a beam of radiation locally to the site of a tumor.
  • Intensity-modulated radiation therapy (IMRT): IMRT is a method of more precisely directing radiation to a site, allowing a higher amount of radiation to be given with less damage to surrounding cells.
  • Brachytherapy: Brachytherapy, or internal radiation, is a method in which radioactive seeds are placed in the body either temporarily or permanently.
  • Stereotactic body radiotherapy (SBRT): SBRT, also known as cyberknife or gamma knife, is not a surgery, but actually a method of directing a high dose of radiation to a small area of tissue, with the intent to completely destroy an early stage cancer much as surgery would. It may be used to treat "oligometastases"—isolated or few metastases to an area such as the lung, liver, or brain from another cancer.
  • Proton therapy: Proton therapy uses proton beams—atomic particles that are more easily controlled than x-rays—to treat irregularly shaped tumors which are difficult to treat with conventional radiation.
  • Systemic radiation therapy: Systemic radiation is a method in which radiation is delivered throughout the body through the bloodstream. An example is the use of radioactive iodine to treat some types of thyroid cancers.

Risk and side effects of radiation therapy: The risks of radiation therapy depend on the specific type of radiation as well as the location where it is delivered and the doses used. Short-term side effects of radiation therapy often include redness (like a sunburn), inflammation of the area which receives radiation, such as radiation pneumonitis with radiation to the chest, and fatigue. Cognitive symptoms are also common in people who receive whole brain radiation. Long-term side effects of radiation therapy may include scarring in the region where it is used as well as secondary cancers.

Stem Cell Transplants

Stem cell transplants, in contrast to a solid organ transplant like a kidney transplant, replace stem cells in the bone marrow. These hematopoietic stem cells are the beginning cells which can differentiate into all of the blood cells of the body including red blood cells, white blood cells, and platelets.

In this procedure, high doses of chemotherapy drugs plus radiation are given to destroy cells in the bone marrow. Following this, stem cells are replaced in one of two ways. In an autologous stem cell transplant, a person's own stem cells are removed prior to chemotherapy and then replaced. In an allogeneic stem cell transplant, stem cells from a matched donor are used to replace the cells in the bone marrow. Stem cell transplants are most often used for leukemias, lymphomas, myeloma, and germ cell tumors.

Clinical Trials

There are many myths about clinical trials, but the truth is that every single treatment that is now available for cancer was once studied in a clinical trial. It's important to note that, with the advances in cancer research, clinical trials have been changing as well. Whereas in the past a phase I trial (the first trials in which a treatment is tried in humans) was often a "last-ditch" approach and unlikely to help individual people with cancer, these same trials may now sometimes offer the only available effective treatment for a cancer. The difference is that many of these new treatments are carefully designed to target specific molecular abnormalities present in some cancer cells. According to the National Cancer Institute, people with cancer should consider clinical trials as they make decisions about their cancer care.

An example is worth a thousand words. In 2015, there were six new drugs (targeted therapies and immunotherapy drugs) approved for the treatment of lung cancer. These drugs were approved as they were found superior to the best treatments we had at the time. One year earlier, in 2014, the only people who could receive these newer and better treatments were those who were involved in clinical trials.


Cancer therapy can include many specialized medications, and this is an area undergoing many new developments.

Targeted Therapies

Targeted therapies are medications that are designed to target cancer cells specifically, and in such are often less harmful to normal cells. Many of the recently approved drugs for cancer are targeted therapies, and more are being evaluated in clinical trials. In addition to being called targeted therapies, these treatments may also be referred to as "molecularly targeted drugs" or "precision medicine."

Targeted therapies differ from chemotherapy in a few important ways. Unlike chemotherapy which attacks any rapidly dividing cells whether normal or cancerous, targeted therapies specifically target cancer cells. Chemotherapy drugs are also usually cytotoxic, meaning that they kill cells, whereas targeted therapies are often cytostatic, which means they stop the growth of cancer but do not kill the cancer cells. There are two basic types of targeted therapies:

  • Small molecule drugs: Small molecule drugs are able to travel to the inside of a cancer cell and target proteins involved in cell growth. They are then able to block the signals which tell the cells to divide and grow. These medications are identified by the suffix “ib” such as erlotinib.
  • Monoclonal antibodies: Monoclonal antibodies are similar to the antibodies our bodies make in response to exposure to viruses and bacteria. Unlike those antibodies, however, monoclonal antibodies are "man-made" antibodies, and instead of fighting off viruses and bacteria, they target a specific molecular target (proteins) on the surface of cancer cells. These medications carry a suffix “mab” such as bevacizumab.

There are four primary ways in which these targeted therapies work against cancer. They may:

  • Interfere with the growth of new blood vessels. These drugs referred to as angiogenesis inhibitors, essentially starve a tumor by disrupting its blood supply.
  • Block signals inside or outside of the cell which tell the cell to divide and grow.
  • Deliver a toxic "payload" to the tumor.
  • Stimulate the immune system to get rid of cancer cells.

Risks and side effects of targeted therapies: While targeted therapies are often less harmful than chemotherapy drugs, they do have side effects. Many of the small molecule drugs are metabolized by the liver and can cause inflammation of that organ. Sometimes a protein is present in normal cells as well. For example, a protein known as EGFR is overexpressed in some cancers. EGFR is also expressed by some skin cells and digestive tract cells. Drugs which target EGFR may interfere with the growth of the cancer cells, but also cause diarrhea and an acne-like rash on the skin. Angiogenesis inhibitors, since they limit the formation of new blood vessels, may have the side effect of bleeding.

When you are diagnosed, your doctor may do molecular profiling (gene profiling) in order to know if a tumor is likely to respond to one of these treatments.

Hormonal Therapy

Cancers such as breast cancer and prostate cancer are often influenced by the level of hormones in the body. For example, estrogen can fuel the growth of some breast cancers (estrogen receptor positive breast cancer) and testosterone may stimulate the growth of prostate cancer. In this way, hormones act like gasoline on a fire to fuel the growth of these cancers. Hormone treatments—also called endocrine therapy—block this stimulating effect of the hormones to stop the growth of a cancer. This may be done through an oral pill, via an injection, or through a surgical procedure with a goal to:

  • Treat cancer: Hormone therapy may be used to stop or slow the growth of hormone sensitive tumors. Both estrogen and progesterone help to drive the growth of some breast cancers and testosterone can drive the growth of some prostate cancers.
  • Prevent cancer: An example of cancer prevention would be the use of Tamoxifen in someone at high risk of developing breast cancer with the hope that the treatment will reduce the risk that cancer will develop in the first place.
  • Decrease the risk of recurrence (lessen the chances that a cancer will come back)
  • Treat the symptoms of cancer

Oral medications may be used to block the production of a hormone, or to block the ability of the hormone to attach to cancer cells. Surgery may also be used as a hormonal therapy. For example, surgical removal of the testicles may significantly reduce the production of testosterone in the body and removal of the ovaries (oophorectomy) may inhibit the production of estrogen. The following articles explore hormonal therapy for cancer in greater depth:.

Risks and side effects of hormonal therapy: Many of the side effects from these treatments, such as anti-estrogens, androgen deprivation therapy, and surgery, are related to the absence of the hormones ordinarily present in our bodies. For example, removing the ovaries, and thus decreasing estrogen, can result in hot flashes and vaginal dryness.


Immunotherapy is an exciting new approach to treating cancer and was labeled the Association for Clinical Oncology advance of the year in 2016. There are many different types of immunotherapy, but the commonality is that these drugs work by either altering the body's immune system or by using products of the immune system to fight cancer.

Some types of immunotherapy include:

  • Monoclonal antibodies: Monoclonal antibodies work like the antibodies we make to attack viruses and bacteria, but instead of attaching to these microorganisms, they attach to specific point (antigens) on cancer cells. In doing this they may block a signal to the cancer cell telling it to grow, "tag" the cancer cell so that other immune cells can find it and attack, or instead, they may be attached to a "payload"—a chemotherapy drug or particle of radiation designed to kill the cancer cell.
  • Immune checkpoint inhibitors: Our immune systems largely know how to fight off cancer cells. Immune checkpoint inhibitors work by essentially taking the brakes off of the immune system so that it can do the job it is intended to do—fight cancer.
  • T cell therapies: These treatments work by taking the small army of T cells you have available to fight a specific cancer, and multiplying them.
  • Oncolytic viruses: Unlike the viruses that attack our bodies and cause symptoms such as the common cold, these viruses are designed to enter cancer cells and act like dynamite, destroying the cancer cell.
  • Cancer vaccines: Unlike the vaccines you have received to prevent tetanus or the flu, cancer vaccines are made using either tumor cells or substances made by tumor cells to treat a cancer which is already present.
  • Cytokines: The first immunotherapy agents to be used, cytokines, including interleukins and interferons, create an immune response to any foreign invader, including cancer cells.

Risks and side effects of immunotherapy: Common side effects of immunotherapy are often what you would expect from having an overactive immune system. Allergic reactions are common with some of these drugs, and medications to limit these reactions are often used simultaneously with the infusion of the drug. Inflammation is common, and there is a saying that the side effects of immunotherapy drugs are often things that end with "itis." For example, pneumonitis refers to an inflammation of the lungs related to these drugs.

Over-the-Counter (OTC) Therapies

Your medical team may recommend various over-the-counter products for the relief of symptoms or side effects of your medications. For example, OTC pain relievers would be the first choice before prescription medications.

It is always important that you report any OTC medications, supplements, and herbal remedies to your health care team. There is a risk of interactions with your prescription medications and other forms of treatment (such as bleeding if aspirin is taken before surgery). Some products will also not be advised during radiation or chemotherapy as they may increase side effects.

Home Remedies and Lifestyle

A healthy diet and moderate exercise can improve well-being, and sometimes even improve survival with cancer. Unfortunately, some of the treatments available for cancer can add to—rather than reduce—your ability to get good nutrition, and you might find it hard to get motivated to exercise.

Whereas in the past nutrition was widely ignored in oncology, many oncologists now consider a good diet a part of cancer treatment. Good nutrition can help people tolerate treatments better and may possibly have a role in outcomes. Only recently it's been noted that cancer cachexia, a syndrome involving weight loss and muscle wasting, may be responsible for 20% to 30% of cancer deaths. This reinforces the importance of a healthy diet.

Talk to your doctor about your nutritional needs during your treatments. Some cancer centers have nutritionists on staff who can assist you, and some offer classes on nutrition and cancer as well. Most oncologists recommend getting the nutrients you need primarily through food sources and not supplements. While some cancer treatments may cause vitamin deficiencies, there is the concern that some vitamin and mineral supplements may interfere with cancer treatments.

Staying active while you go through treatment can be a challenge, but it has significant benefits in for many conditions. Simply going for a walk, swimming, or taking an easy bike ride will help.

Complementary Alternative Medicine (CAM)

Many cancer centers provide integrative therapies for cancer, but what role can they play in the management of your cancer? There is little evidence to suggest that any of these treatments can cure cancer or slow its growth, but there is positive evidence that some of these may help people cope with the symptoms of cancer and cancer treatments. Some of these integrative therapies include:

Again it should be noted that there are no alternative treatments that have been found effective in treating cancer directly and that their purpose should be to treat the symptoms of cancer.

A Word From Verywell

With the multitude of options now available to treat cancer, it can be challenging to choose the treatments that are uniquely best for you. Reach out to your family and friends and accept help. In asking for help you not only lessen your own load but address this need of your loved ones to help you as well. Seek support from others who are facing a similar diagnosis, either in your community or online. They can share their experience with various treatments.

Most importantly, hang on to hope. Cancer treatments—and survival rates—are improving. It's estimated that there are 15 million cancer survivors in the United States alone, and that number is growing. Not only are more people surviving cancer, but many are thriving, with a new sense of purpose and appreciation of life after cancer.

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