Oncologist-approved cancer information from the American Society of Clinical Oncology
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Tests to Help Choose Chemotherapy

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?
Helpful Links

Read the entire clinical practice guideline at www.asco.org/guidelines/csra.

Understanding Chemotherapy

Tests and Procedures

About ASCO's Guidelines

To help doctors give their patients the best possible care, ASCO asks its medical experts to develop evidence-based recommendations for specific areas of cancer care, called clinical practice guidelines. Due to the rapid flow of scientific information in oncology, new evidence may have emerged since the time a guideline or assessment was submitted for publication. As a result, guidelines and guideline summaries, like this one, may not reflect the most recent evidence. Because the treatment options for every patient are different, guidelines are voluntary and are not meant to replace your physician's independent judgment. The decisions you and your doctor make will be based on your individual circumstances. These recommendations may not apply in the context of clinical trials.

The information in this patient guide is not intended as medical or legal advice, or as a substitute for consultation with a physician or other licensed health care provider. Patients with health-related questions should call or see their physician or other health care provider promptly and should not disregard professional medical advice, or delay seeking it, because of information encountered in this guide. The mention of any product, service, or treatment in this guide should not be construed as an ASCO endorsement. ASCO is not responsible for any injury or damage to persons or property arising out of or related to any use of this patient guide, or to any errors or omissions.


The best cancer care starts with the best cancer information. Well-informed patients are their own best advocates, and invaluable partners for physicians. Cancer.Net (www.cancer.net) brings the expertise and resources of ASCO, the voice of the world's cancer physicians, to people living with cancer and those who care for and care about them. ASCO is composed of nearly 35,000 members globally who are the leaders in advancing cancer care. All the information and content on Cancer.Net was developed and approved by the cancer doctors who are members of ASCO, making Cancer.Net an up-to-date and trusted resource for cancer information on the Internet. Visit Cancer.Net to find guides on more than 120 types of cancer and cancer-related syndromes, clinical trials information, coping resources, information on managing side effects, medical illustrations, cancer information in Spanish, videos, podcasts, the latest cancer news, and much more. For more information about ASCO's patient information resources, call toll free 888-651-3038.

© 2005-2014 American Society of Clinical Oncology (ASCO). All rights reserved worldwide.

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