Chemotherapy for Anal Cancer

Chemotherapy (chemo) is treatment with anti-cancer drugs that can be swallowed in pill form or injected into a vein. The drugs travel through the bloodstream to reach most parts of the body.

When is chemotherapy used for anal cancer?

Most people with anal cancer will need chemo, but it might be used at different times:

• Before surgery (neoadjuvant chemotherapy): Chemo combined with radiation therapy (known as chemoradiation) is often the first treatment for most anal cancers. This can often successfully treat the cancer without the need for surgery.
• If the cancer comes back in the groin lymph nodes (recurrence): Chemotherapy might be given alone or sometimes with radiation, if radiation was not given before
• For anal cancer that has spread (metastasized) : If anal cancer has spread to distant parts of the body, such as the liver or lungs, chemo with or without immunotherapy can help keep the cancer under control or relieve symptoms it's causing.

Chemotherapy drugs used to treat anal cancer

In most cases, two or more drugs are used at the same time to shrink the cancer.

• The main drug combination used to treat anal cancer is 5-fluorouracil (5-FU) and mitomycin.
• The combination of 5-FU and cisplatin can also be used, especially in people who can't get mitomycin or for advanced anal cancer.
• In certain people who may be older or can’t tolerate two chemotherapy drugs, 5-FU alone may be given with radiation.

The 5-FU infusion is given in a vein (IV) 24 hours a day for 4 days. It's put in a small pump that you can take home with you. The other drugs are given more quickly on certain other days in the treatment cycle. Sometimes, the oral drug capecitabine might be given in place of 5-FU.

Radiation is given 5 days a week for at least 5 weeks. Talk to your treatment team about your treatment plan and how and where you will get chemo.

For advanced anal cancer or anal cancer that has already been treated with 5-FU and mitomycin, other chemo options include:

• Carboplatin with paclitaxel (Taxol)
• FOLFOX regimen: Oxaliplatin, leucovorin, and 5-FU
• FOLFCIS regimen: Cisplatin, leucovorin, and 5-FU
• 5-FU with cisplatin
• DCF regimen: Docetaxel (taxotere), cisplatin, and 5-FU

Possible side effects of chemo for anal cancer

Chemo drugs can cause side effects depending on the type and dose of drugs given and how long they are taken. Some common side effects include:

• Nausea and vomiting
• Loss of appetite or weight changes
• Hair loss
• Diarrhea
• Mouth sores

Chemo can also damage the blood-producing cells of the bone marrow, which can result in:

• A greater chance of infection (from low white blood cell counts)
• Easy bleeding or bruising (from low blood platelet counts)
• Fatigue or shortness of breath (from low red blood cell counts)

Along with the risks above, some chemo drugs can cause other, less common side effects.

Cisplatin, paclitaxel, oxaliplatin, or docetaxel might cause nerve damage (called peripheral neuropathy). This can lead to numbness, tingling, sensitivity to cold, or pain in the hands and feet. 

Most side effects get better once treatment stops, but some can last a long time or even be permanent. If you're going to get chemo, be sure to discuss the drugs that will be used and their possible side effects.

Tell your doctor or nurse about any side effects as soon as you notice them so they can be treated promptly. For example, drugs can be used to help control nausea and vomiting. In some cases, changing the treatment dosage or delaying or stopping treatment may keep the side effects from getting worse.