Systemic chemotherapy uses anti-cancer drugs that are injected into a vein or given by mouth. These drugs travel through the bloodstream to all parts of the body. In contrast to topical chemotherapy, systemic chemotherapy can attack cancer cells that have spread to lymph nodes and other organs.

One or more chemotherapy drugs may be used to treat squamous cell carcinoma or Merkel cell carcinoma that has spread to other organs. Chemotherapy drugs such as cisplatin, doxorubicin, fluorouracil (5-FU), and mitomycin are given intravenously, usually once every few weeks. They can often delay the spread of these cancers and relieve some symptoms. In some cases, they may shrink tumors enough so that other treatments such as surgery or radiation therapy may be used.

Chemotherapy drugs work by attacking cells that are dividing quickly, which is why they work against cancer cells. But other cells in the body, such as those in the bone marrow, the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemotherapy, which can lead to side effects.

The side effects of chemotherapy depend on the type and dose of drugs given and the length of time they are taken. These side effects may include:

• hair loss
• mouth sores
• loss of appetite
• nausea and vomiting
• lowered resistance to infection (due to low white blood cell counts)
• easy bruising or bleeding (due to low blood platelets)
• fatigue (due to low red blood cells)

These side effects are usually short-term and go away once treatment is finished.

Be sure to talk with your cancer care team about any side effects you have because there are often ways to lessen them. For example, drugs can be given to help prevent or reduce nausea and vomiting.