Oncologist-approved cancer information from the American Society of Clinical Oncology
Printer Friendly
Download PDF

Chemotherapy Doses for Obese Patients With Cancer

To help doctors give their patients the best possible care, the American Society of Clinical Oncology (ASCO) developed evidence-based recommendations on giving doses of chemotherapy that are based on a patient's actual weight. This guide for patients is based on ASCO recommendations and is intended for people who are obese.

Key Messages

  • Research on patients with cancer who are obese (extremely overweight) shows that they are more likely to die from cancer than those who are not obese, which may be partially due to how chemotherapy doses are determined.
  • Giving chemotherapy based on actual weight for patients who are obese often increases the dose, which makes treatment more effective without causing additional side effects.

Chemotherapy is a type of treatment commonly used for many types of cancer. It is the use of drugs to kill cancer cells, usually by stopping the cancer cells' ability to grow and divide. Systemic chemotherapy is often delivered through the bloodstream (called intravenously or IV) to reach cancer cells throughout the body. Some chemotherapy is given orally (by mouth) as a pill. A patient may receive one drug at a time or combinations of different drugs at the same time.

Chemotherapy doses are often based on ideal body weight, which is an estimate of a patient's body surface area (the size of the outside of the patient's body), rather than the patient's actual body weight and body surface area. Because of this approach, patients who are obese (determined by using a body mass index or BMI calculator) may be getting less chemotherapy for their actual weight and height than patients who are not obese. This is often because of concerns that higher doses of chemotherapy may cause more side effects. Studies estimate that up to 40% of patients who are obese do not receive doses based on actual body weight, which may affect their survival and risk of the disease worsening. Furthermore, studies show that higher doses do not cause more severe side effects.

Research has shown that patients with cancer who are obese are more likely to die from the disease than those who are not obese. Although the suspected causes of this difference in prognosis (chance of recovery) are complex, doses of chemotherapy that are not based on a patient's actual weight may contribute.

Recommendations for Giving Chemotherapy to Obese Patients

ASCO recommends that patients with cancer who are obese should receive chemotherapy doses based on their actual weight when the goal of treatment is to cure the cancer. However, because of possible side effects from specific drugs, ASCO recommends considering fixed (not based on weight) doses of a few drugs, such as carboplatin (Paraplat, Paraplatin) and bleomycin (Blenoxane). Also, no more than 2 milligrams (mg) of vinicristine (Oncovin) is recommended when used in the chemotherapy regimen called CHOP (cyclophosphamide [Clafen, Cytoxan, Neosar], doxorubicin [Adriamycin], vincristine, prednisone [multiple brand names]) or the regimen called CVP (cyclophosphamide, vincristine, prednisone).

What This Means for Patients

If you are obese, receiving chemotherapy based on your actual weight means that you'll receive more chemotherapy than if the dose is based on an ideal weight or a limited estimate. A higher dose based on your weight may help the chemotherapy work better to treat the cancer, and the research shows that receiving such a dose does not necessarily increase the side effects from treatment. Whatever dose you receive, your doctor will monitor your side effects closely. It's important to talk with your health care team about the specific type of chemotherapy recommended for you, how much of each drug you will receive, and how and when it will be given.

Questions to Ask the Doctor

Consider asking the following questions of your doctor:

  • What type of cancer do I have?
  • What is the stage? What does this mean?
  • What are my treatment options?
  • What treatment plan do you recommend? Why?
  • Will chemotherapy be a part of this plan?
  • If so, what are the goals of chemotherapy, and how do you determine the dose that is best for me?
  • Have you given me a dose based on my actual weight or a standard dose?
  • What are the side effects of treatment, and how can they be managed?
  • Will you monitor my side effects and decrease my dose if I have side effects?
  • Will you return to the original dose after my side effects go away?
  • If I'm worried about managing the costs related to my cancer care, who can help me with these concerns?
Helpful Links

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

Understanding Chemotherapy

Managing the Cost of Care

Managing Side Effects

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 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.

Connect With Us: