Chemotherapy for cancer of unknown primary

Chemotherapy uses anticancer, or cytotoxic, drugs to destroy cancer cells. Many people with cancer of unknown primary (CUP) will have chemotherapy. Your healthcare team will consider the type of CUP that you have, how it responds to treatment and your personal needs to plan the drugs, doses and schedules of chemotherapy. They will also consider if it is favourable-risk CUP or poor-risk CUP when they are planning chemotherapy. You may also receive other treatments.

Chemotherapy is given for different reasons. You may have chemotherapy to:

  • destroy cancer cells in the body
  • destroy cancer cells left behind after surgery
  • relieve pain or control the symptoms of advanced CUP (called palliative chemotherapy)

Your healthcare team may decide that chemotherapy isn’t the best treatment option if you are in poor health or if you have a type of CUP that likely won’t respond to chemotherapy.

Chemotherapy is sometimes used as part of chemoradiation to treat squamous cell CUP that is found in lymph nodes in the neck. Chemoradiation is treatment that combines chemotherapy with radiation therapy. These treatments are given during the same time period and are used to make each treatment more effective.

Chemotherapy drugs used for CUP

Chemotherapy is usually a systemic therapy. This means that the drugs travel through the bloodstream to reach and destroy cancer cells all over the body.

Different combinations of chemotherapy drugs are used for different types of CUP. Usually 2 or more drugs are used. Most combinations include at least one of the following:

  • a platinum drug – either cisplatin (Platinol AQ) or carboplatin (Paraplatin, Paraplatin AQ)
  • a taxane drug – either paclitaxel (Taxol) or docetaxel (Taxotere)

Other drugs that are combined with the platinum or taxane drug include:

  • etoposide (Vepesid, VP-16)
  • bleomycin (Blenoxane)
  • vincristine (Oncovin)
  • gemcitabine (Gemzar)
  • 5-fluorouracil (Adrucil, 5-FU)
  • irinotecan (Camptosar)
  • oxaliplatin (Eloxatin)
  • capecitabine (Xeloda)
  • streptozocin (Zanosar) – for neuroendocrine CUP

Side effects

Side effects can happen with any type of treatment for CUP, but everyone’s experience is different. Some people have many side effects. Other people have few or none at all.

Chemotherapy may cause side effects because it can damage healthy cells as it kills cancer cells. Side effects can develop any time during, immediately after or a few days or weeks after chemotherapy. Sometimes late side effects develop months or years after chemotherapy. Most side effects go away on their own or can be treated, but some side effects may last a long time or become permanent.

Side effects of chemotherapy will depend mainly on the type of drug, dose, how it’s given and your overall health. Some common side effects of chemotherapy drugs used for CUP are:

Tell your healthcare team if you have these side effects or others you think might be from chemotherapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Information about specific cancer drugs

Details on specific drugs change quite regularly. Find out more about sources of drug information and where to get details on specific drugs.

Questions to ask about chemotherapy and other drug therapies

Find out more about chemotherapy and side effects of chemotherapy. To make the decisions that are right for you, ask your healthcare team questions about chemotherapy.

Expert review and references

  • American Cancer Society. Cancer - Unknown Primary. Atlanta, GA: 2014:
  • Cancer Care Ontario. Drug Formulary. Toronto, ON: Cancer Care Ontario;
  • Fizazi K, Greco FA, Pavlidis N, et al . Cancers of unknown primary site: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology. Oxford University Press; 2011.
  • Greco FA & Hainsworth JD . Cancer of unknown primary site. DeVita VT Jr, Lawrence TS, & Rosenberg SA. Cancer: Principles & Practice of Oncology. 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2015: 113:1720-1737.
  • Hainsworth JD, Greco FA . Chemotherapy of carcinoma of unknown primary site. Perry MC, Doll DC, Freter CE. Perry's The Chemotherapy Source Book. 5th ed. Lippincott Williams Wilkins; 2012: Chapter 37.
  • Lee J, Kim D-W, Kim, J, et al . Evaluation of survival benefits by platinums and taxanes for an unfavourable subset of carcinoma of unknown primary: a systematic review and meta-analysis. British Journal of Cancer. Nature Publishing Group; 2013.
  • National Comprehensive Cancer Network. Occult Primary (Cancer of Unknown Primary [CUP]) (Version 3.2014).