Treatments for poorly differentiated carcinoma of unknown primary

The following are treatment options for poorly differentiated carcinoma of unknown primary (CUP). Your healthcare team will suggest treatments based on your needs and work with you to develop a treatment plan.

When deciding which treatments to offer for poorly differentiated CUP, your healthcare team will consider:

  • whether it is favourable-risk or poor-risk CUP
  • where and how many different places cancer is found
  • prognosis
  • performance status
  • where the cancer may have started (called the primary site)
  • your overall health
  • your age
  • your preferences for treatment


Chemotherapy may be offered for poorly differentiated CUP. Researchers are still looking for the best chemotherapy combinations for this type of cancer.

Extragonadal germ cell tumours

When poorly differentiated CUP is found in adults under the age of 40, doctors usually think that the original tumour was an extragonadal germ cell tumour. This type of tumour starts in the germ cells. Germ cells are usually found in the testicles or ovaries, but extragonadal germ cell tumours start in germ cells that are outside of the testicles or ovaries.

Chemotherapy for testicular cancer may be offered to younger men with a poorly differentiated CUP.

Chemotherapy for ovarian germ cell tumours may be offered to young women with a poorly differentiated CUP.

Other poorly differentiated CUPs

For other types of poorly differentiated CUP found in adults over the age of 40 where it isn’t certain where the primary site is, your healthcare team will offer chemotherapy drugs that they think will work best. This is referred to as empirical chemotherapy. Usually 2 or more drugs will be used. Most combinations include at least one of the following:

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

If you can’t have or don’t want cancer treatment

You may want to consider a type of care to make you feel better rather than treat the cancer itself. This may be because the cancer treatments don’t work anymore, they’re not likely to improve your condition or they may cause side effects that are hard to cope with. There may also be other reasons why you can’t have or don’t want cancer treatment.

Talk to your healthcare team. They can help you choose care and treatment for advanced cancer.

Clinical trials

You may be asked if you want to join a clinical trial for cancer of unknown primary. Find out more about clinical trials.

Expert review and references

  • American Cancer Society. Cancer - Unknown Primary. Atlanta, GA: 2014:
  • 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 . Cancer of unknown primary site: improved patient management with molecular and immunohistochemical diagnosis. 2013 ASCO Educational Book. Alexandria, VA: American Society of Clinical Oncology;
  • 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 . Neoplasms of unknown primary site. Hong WK, Bast RC Jr, Hait WN, et al (eds.). Holland Frei Cancer Medicine. 8th ed. People's Medical Publishing House; 2010: 120: 1713-1722.
  • 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.
  • Kim KW, Krajewski, KM, Jagannathan JP, et al . Cancer of unknown primary sites: what radiologists need to know and what oncologists want to know. AJR: American Journal of Roentgenology. The American Roentgen Ray Society; 2013.
  • National Cancer Institute. Carcinoma of Unknown Primary Treatment (PDQ®) Health Professional Version. 2015.
  • National Comprehensive Cancer Network. Occult Primary (Cancer of Unknown Primary [CUP]) (Version 3.2014).
  • Pavlidis N, & Pentheroudakis G . Cancer of unknown primary site. Lancet. Elsevier; 2012.
  • Stella GM, Senetta R, Cassenti A, Ronco M, & Cassoni P . Cancers of unknown primary origin: current perspectives and future therapeutic strategies. Journal of Translational Medicine. 2012: