Tests to Help Choose Chemotherapy

July 25, 2011

To help doctors give their patients the best possible care, the American Society of Clinical Oncology (ASCO) developed evidence-based recommendations on the usefulness of laboratory tests (called assays) to find out if a cancer might be resistant or sensitive to a specific chemotherapy treatment before it is offered to a patient. In 2011, this guideline was reviewed due to new research; this research continued to support the 2004 recommendations. This guide for patients is based on ASCO's most recent recommendations.

Key Messages

  • Chemotherapy sensitivity and resistance assays are laboratory tests that have been studied to help predict how well chemotherapy may work.
  • However, these tests should not be used to determine treatment options for an individual patient.
  • Instead, the choice of chemotherapy should be based on the research on the drugs being considered and the patient's health and treatment preferences.


Chemotherapy is the use of drugs to kill cancer cells, usually by stopping the cancer cells' ability to grow and divide. Chemotherapy sensitivity and resistance assays are tests done in a laboratory on the cells from part of the tumor removed during surgery or biopsy. These tests have been looked at in research studies as a way to predict whether chemotherapy will help treat the tumor or if the tumor is resistant to chemotherapy, meaning that the chemotherapy will not help treat the tumor.


Very few research studies suggest that tests to help choose chemotherapy improve treatment. In addition, there are no tests available for many types of cancer. Therefore, ASCO recommends the following for using chemotherapy sensitivity and resistance assays:

  • Chemotherapy sensitivity and resistance assays should not be used to select chemotherapy for patients who are not participating in a clinical trial.
  • Chemotherapy should be recommended based on research on the specific drug(s) and a patient's health and treatment preferences.

What This Means for Patients 

The type of chemotherapy your doctor recommends for you depends on several factors, including how well that chemotherapy has been shown to work for the type of cancer you have and your overall health. It's important to talk with your doctor about all treatment recommendations and why specific treatments are being recommended.

Questions to Ask the Doctor

  • What type of cancer do I have? What is the stage?
  • What are my treatment options?
  • Do you recommend chemotherapy?
  • What type of chemotherapy do you recommend?
  • How do you determine the type of chemotherapy that is best for me?
  • What clinical trials are open to me?