Q: What is chemotherapy, and what is its role in cancer treatment?

A: Every cancer diagnosis is different, and the type of treatment you receive depends on the type of cancer. Many people use "chemotherapy" as a blanket term for all cancer treatments; however, you have numerous options for treatment, including radiation, chemotherapy, surgery, or a combination of these.

Chemotherapy is a medication-based remedy that uses drugs to interfere with cancer cells' ability to multiply. Chemotherapy medications are typically injected, entering the bloodstream and treating the entire body, including large tumors or individual cancer cells.

Chemotherapy is useful for treating late-stage cancers, such as advanced breast and lung cancers, metastatic colon cancer, lymphoma, leukemia, and blood cancers. It also can be used to prevent a recurrence. However, in addition to slowing cancer cell growth, chemotherapy also slows the growth of healthy cells, which can cause nausea, hair loss, and fatigue.

Radiation uses X-rays, gamma rays, and other charged particles to treat localized cancers, such as breast cancer. About half of all cancer patients receive some type of radiation therapy during treatment, according to the National Cancer Institute.

Radiation can also be used to shrink a tumor before surgery and to reduce the risk of recurrence after surgery. Following surgery, the affected area can appear cancer-free; however, one cancer cell can trigger regrowth. Radiation can help kill those lingering cells. In large part, radiation is used in combination with other treatments to increase effectiveness.

Radiation therapy may cause fatigue, skin irritation, nausea, vomiting, and loss of appetite; however, much of this depends on the part of the body that is irradiated.

Surgery is an effective option for treating cancer that is limited to one part of the body, such as prostate, breast, and early-stage colon cancers. Physicians can also use surgery to diagnose cancer and identify what areas of the body are affected.

Recently, immunotherapy has become an increasingly effective remedy for treating lung, skin, kidney, liver, and blood cancers. In some cases, cancer cells can lull your body's immune system to sleep. Immunotherapy helps awaken your body's immune system to kill tumor cells.

During treatment, blood tests and scans can help your physician gauge how well your regimen is working. Throughout the course of treatment, your physician may recommend several different options until you find the one that is right for you.

Rajan Singla, M.D., is a hematologist and medical oncologist at Nazareth Hospital and an assistant clinical professor of oncology at Thomas Jefferson University.