Cancer and Complementary

Health Practices

© Rhoda Baer

People with cancer want to do everything they can to combat the 

disease, manage its symptoms, and cope with the side effects of 

treatment. Many turn to complementary health practices, including 

natural products—such as botanical (herbal) and other dietary 

supplements—and mind and body therapies—such as acupuncture, 

massage, and yoga.

This fact sheet provides an introductory overview of these practices, 

including a summary of “what the science says.” The fact sheet is 

mainly for people who have been diagnosed with cancer, and for 

families and friends of people who are being treated for or 

recovering from cancer. This fact sheet also takes a brief look at 

research on some of the dietary supplements that people use in 

hope of preventing cancer.

Key Points 

• There is limited scientific evidence suggesting that some of the 

complementary health practices discussed here may be useful in 

managing some symptoms of cancer and side effects of 

treatment. At present, there is no convincing evidence regarding 

the use of these practices in preventing or curing cancer.

• Before using any complementary health practice, people who 

have been diagnosed with cancer should talk with the health care 

providers who treat their condition—to make sure that all aspects 

of their cancer care work together. Be aware that some dietary 

supplements can interfere with standard cancer treatments.

• Tell all your health care providers about any complementary health 

practices you use. Give them a full picture of what you do to manage 

your health. This will help ensure coordinated and safe care.

About Cancer 

Cancer is a group of related diseases that occur when abnormal cells 

divide without control. Cancer cells can invade and damage nearby 

tissues and spread to distant parts of the body through the blood
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and the lymph systems. Although cancer remains the second leading cause of death in the 

United States, improvements in detection, diagnosis, and treatment have increased the 

survival rate for many types of cancer.

Detailed information on cancer is available from the National Cancer Institute at www.cancer.gov. 

About Complementary Health Practices 

The term complementary health practices refers to a group of diverse medical and health care 

systems, practices, and products that are not generally considered to be part of conventional 

medicine. It includes natural products, such as dietary supplements, herbs, and probiotics, as 

well as mind and body practices, such as meditation, acupuncture, and massage.

Some complementary health practices are beginning to find a place in cancer treatment—not 

as cures but as complementary approaches that may help patients feel better.

Use of Complementary Health Practices for Cancer 

Many people who have been diagnosed with cancer use complementary health practices. In 

2002 and 2007, the National Health Interview Survey (NHIS) included comprehensive questions 

on the use of complementary health practices by Americans. According to the 2007 NHIS, more 

than one-third of adults (about 38 percent) had used some form of complementary health 

practice. A special analysis of 2002 NHIS data found that use was more prevalent among 

people with a prior diagnosis of cancer. About 40 percent of cancer survivors reported using 

these practices; 18 percent had used multiple practices. Rates of use for cancer survivors were 

similar to rates for people with other chronic illnesses such as arthritis, asthma, inflammatory 

bowel disease, irritable bowel syndrome, or ulcers. The most popular practices among cancer 

survivors were herbal and other natural products (20 percent), deep breathing (14 percent), and 

meditation (9 percent).

Other surveys also find that use of complementary health practices is common among people 

who have been diagnosed with cancer, although estimates of use vary widely. Studies have 

found that cancer patients who use these practices usually do not expect them to cure their 

disease. Rather, they hope to boost their immune system, relieve pain, or manage the side 

effects they are experiencing from the disease or its treatment. Few cancer patients say they 

use complementary health practices because they are disappointed with their standard 

treatment. Their motivation is more likely to be a perceived benefit from the practice, a desire 

to feel more in control of their health, or a strong belief in the practice.

Surveys also indicate that use of vitamin and mineral supplements is widespread among 

cancer patients and survivors, but many health care providers are unaware that their cancer 

patients are using these supplements.

What the Science Says 

To date, relatively little is known about the safety and effectiveness of complementary health 

practices that people may use for cancer. However, some of these practices have undergone 

careful evaluation, and many more studies are being carried out every year. In 2009, the Society for 
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Integrative Oncology issued evidence-based clinical practice guidelines for health care providers to 

consider when incorporating complementary health practices in the care of cancer patients.

A comprehensive summary of research on complementary health practices for cancer is 

beyond the scope of this fact sheet. The following sections provide an overview of research 

status, highlighting results from a few reviews and studies in the areas of cancer prevention, 

treatment, and management of symptoms and side effects.

Complementary Health Practices for Cancer Prevention

Although researchers continue to investigate the possible role of vitamin and mineral 

supplements in preventing cancer, available evidence does not support taking these 

supplements for this purpose:

• A 2007 review of clinical trials looking at the effectiveness of multivitamin/mineral 

supplements for cancer prevention found that few such trials have been conducted, and 

that the results of most large-scale trials have been mixed. According to the National 

Cancer Institute, the following supplements have been studied but have not been shown to 

lower the risk of cancer: vitamins B6, B12, E, and C; beta-carotene; folic acid; and selenium.

• Two large-scale studies—the Alpha-Tocopherol, Beta-Carotene (ATBC) Cancer Prevention 

Trial and the Beta-Carotene and Retinol Efficacy Trial (CARET)—found evidence that 

supplements containing beta-carotene increased the risk of lung cancer among smokers.

• An independent review of data from the Selenium and Vitamin E Cancer Prevention Trial 

(SELECT), funded by the National Cancer Institute, the National Center for Complementary 

and Alternative Medicine (NCCAM), and other agencies at the National Institutes of Health 

(NIH), showed that selenium and vitamin E supplements, taken either alone or together, 

did not prevent prostate cancer. A 2011 updated analysis from this trial concluded that 

vitamin E supplements significantly increased the incidence of prostate cancer in healthy 

men. At a median followup of 7 years, the researchers observed that the incidence of 

prostate cancer was increased by 17 percent in men who received the vitamin E 

supplement alone compared with those who received placebo. There was no increased 

incidence of prostate cancer when vitamin E and selenium were taken together.

• A 2003 Agency for Healthcare Research and Quality (AHRQ) review found little evidence of 

cancer prevention benefits from three antioxidants (vitamins C and E and coenzyme Q10).

• A 2008 review of 20 clinical trials found no convincing evidence that antioxidant 

supplements prevent gastrointestinal cancer, but did find indications that some might 

actually increase overall mortality. The review looked at beta-carotene, selenium, and 

vitamins A, C, and E. Selenium alone demonstrated some preventive benefits.

• Higher intake of calcium may be associated with reduced risk of colorectal cancer, but the 

National Cancer Institute has concluded that the available evidence does not support 

taking calcium supplements to prevent colorectal cancer.
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A 2009 review of 51 studies with more than 1.6 million participants found “insufficient 

and conflicting” evidence regarding an association between green tea consumption and 

cancer prevention.

Additional information on cancer prevention is available from the National Cancer Institute at 

www.cancer.gov/cancertopics/pdq/prevention/overview/patient. 

Complementary Health Practices for Cancer Treatment

A 2008 review of the research literature concluded that some botanical supplements used in 

Ayurvedic medicine and traditional Chinese medicine may have a role in cancer treatment. 

However, scientific evidence is limited—much of the research on botanicals and cancer 

treatment is in the early stages. The review also notes that botanicals can have side effects and 

can interact with cancer drugs, blood thinners and other prescription drugs, and each other.

It is unclear whether the use of vitamin and mineral supplements by people who have been 

diagnosed with cancer is beneficial or harmful. For example, taking a daily multivitamin might 

improve the nutritional status of patients who cannot eat a healthful diet, but there is concern 

that some supplements might interfere with cancer treatment or increase the risk of a 

recurrence. Related studies have been inconsistent or inconclusive.

While some research has reported benefits from taking antioxidants for cancer, there is not 

enough scientific evidence to support their use by cancer patients. A 2003 AHRQ review of 

cancer-related research on three antioxidants (vitamins C and E and coenzyme Q10) found 

little scientific evidence of cancer treatment benefits. Patients’ use of antioxidants while 

undergoing chemotherapy or radiation therapy has not been well studied. However, a 2008 

review of published research suggests that antioxidant supplements may decrease the 

effectiveness of chemotherapy and radiation therapy.

Complementary Health Practices for Cancer Symptoms and Side Effects

Studies have found acupuncture to be useful in managing chemotherapy-associated vomiting 

in some cancer patients. Although some early studies have shown beneficial effects, research 

on acupuncture for cancer pain control and for management of other cancer symptoms is 

limited. A 2008 evidence-based review of clinical options for managing nausea and vomiting in 

cancer patients noted electroacupuncture as an option to be considered.

Various studies also suggest possible benefits of hypnosis, massage, meditation, and yoga in 

helping cancer patients manage side effects and symptoms of the disease. For example, a study of 

380 patients with advanced cancer concluded that massage therapy may offer some immediate 

relief for these patients, and that simple touch therapy (placing both hands on specific body 

sites)—which can be provided by family members and volunteers—may also be helpful. The 

study was conducted at 15 hospices in the Population-based Palliative Care Research Network.

A 2008 review of the research literature on botanicals and cancer concluded that although 

several botanicals have shown promise for managing side effects and symptoms such as 

nausea and vomiting, pain, fatigue, and insomnia, the scientific evidence is limited (the 

reviewers did not find sufficient evidence to recommend any specific treatment), and many 
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clinical trials have not been well designed. As with use for cancer treatment, use of botanicals 

for symptom management raises concerns about interactions with cancer drugs, other drugs, 

and other botanicals.

Safety: Some Precautions for Cancer Patients

Some dietary supplements can interfere with cancer treatments; for example, the herb St. 

John’s wort may cause certain anticancer drugs not to work as well as they should, and high 

doses of vitamins (even vitamin C) may affect how chemotherapy and radiation work. There 

are also general safety cautions about dietary supplements to be aware of; for example, some 

products may contain ingredients that are not on the label. Related information is available 

from NCCAM at nccam.nih.gov/health/supplements/wiseuse.htm. 

Complications from acupuncture are very rare, as long as the acupuncturist uses sterile 

needles and proper procedures. Because chemotherapy and radiation therapy weaken the 

body’s immune system, cancer patients who are undergoing these therapies should be sure 

that the acupuncturist follows strict clean-needle procedures. The acupuncturist should use 

new disposable (single-use) needles for each patient.

Although massage therapy appears to be generally safe, cancer patients should consult the 

health care provider who treats their cancer before they have a massage that involves deep or 

intense pressure. Any direct pressure over a tumor usually is discouraged.

NIH Research on Complementary Health Practices for Cancer 

NCCAM funds numerous laboratory studies and clinical trials related to cancer. Recent 

NCCAM-supported clinical trials have been investigating:

• Massage for swelling of the arms and legs (lymphedema) related to breast cancer treatment

• Tai chi for physical fitness and stress in cancer survivors

• Yoga and qi gong for fatigue in breast cancer survivors.

In addition to NCCAM-funded research on cancer, the National Cancer Institute conducts 

many studies through its Office of Cancer Complementary and Alternative Medicine (OCCAM), 

some of which are cofunded with NCCAM. Additional information on OCCAM is available at 

www.cancer.gov/cam. 
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If You Have Been Diagnosed With Cancer and Are Considering a 

Complementary Health Practice 

• Cancer patients need to make informed decisions about using complementary health 

practices. NCCAM and the National Cancer Institute have written a brochure that can help: 

Thinking About Complementary and Alternative Medicine: A Guide for People with Cancer

(www.cancer.gov/cancertopics/thinking-about-CAM).

• Gather information about the complementary health product or therapy that interests you, 

and then discuss it with your health care providers. If you have been diagnosed with cancer, it 

is especially important to talk with your health care providers before you use any 

complementary health practice. Some practices may interfere with standard treatment or may 

be harmful when used along with standard treatment. Examples of questions to ask include:

o What is known about the benefits and risks of this complementary health product or 

therapy? Do the benefits outweigh the risks?

o What are the potential side effects?

o Will this complementary health practice interfere with conventional treatment?

o Can you refer me to a practitioner who provides the complementary health product 

or therapy?

• Do not use any health product or therapy that has not been proven safe and effective as a 

replacement for conventional cancer care or as a reason to postpone seeing your health 

care provider about any medical problem.

• Tell all your health care providers about any complementary health practices you use. Give 

them a full picture of what you do to manage your health. This will help ensure 

coordinated and safe care. For tips about talking with your health care providers about 

complementary and alternative medicine, see NCCAM’s Time to Talk campaign at 

nccam.nih.gov/timetotalk. 

Selected References 

Barnes PM, Bloom B, Nahin RL. Complementary and alternative medicine use among adults and children: United 

States, 2007. CDC National Health Statistics Report #12. 2008.

Bjelakovic G, Nikolova D, Simonetti RG, et al. Antioxidant supplements for preventing gastrointestinal cancers. Cochrane 

Database of Systematic Reviews. 2008;(3):CD004183. Accessed at http://www.thecochranelibrary.com on April 7, 2010.

Boehm K, Borrelli F, Ernst E, et al. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database of 

Systematic Reviews. 2009;(3):CD005004. Accessed at http://www.thecochranelibrary.com on April 10, 2010.

Cohen AJ, Menter A, Hale L. Acupuncture: role in comprehensive cancer care—a primer for the oncologist and review 

of the literature. Integrative Cancer Therapies. 2005;4(2):131-143.

Coulter I, Hardy M, Shekelle P, et al. Effect of the Supplemental Use of Antioxidants Vitamin C, Vitamin E, and Coenzyme Q10 

for the Prevention and Treatment of Cancer. Evidence Report/Technology Assessment No. 75. Rockville, MD: Agency 

for Healthcare Research and Quality; 2003. AHRQ Publication No. 04-E003.

Deng GE, Frenkel M, Cohen L, et al. Evidence-based clinical practice guidelines for integrative oncology: 

complementary therapies and botanicals. Journal of the Society for Integrative Oncology. 2009;7(3):85-120.
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Dy G, Bekele L, Hanson L, et al. Complementary and alternative medicine use by patients enrolled onto phase I clinical 

trials. Journal of Clinical Oncology. 2004;22(23):4810-4815.

Ernst E. Massage therapy for cancer palliation and supportive care: a systematic review of randomised clinical trials. 

Supportive Care in Cancer. 2009;17(4):333-337.

Ezzo J, Richardson MA, Vickers A, et al. Acupuncture-point stimulation for chemotherapy-induced nausea or vomiting. Cochrane 

Database of Systematic Reviews. 2006;(2):CD002285. Accessed at http://www.thecochranelibrary.com on April 7, 2010.

Frenkel M, Ben-Ayre B, Baldwin C, et al. Approach to communicating with patients about the use of nutritional 

supplements in cancer care. Southern Medical Journal. 2005;98(3):289-294.

Gansler T, Chiewkwei K, Crammer C, et al. A population-based study of prevalence of complementary methods use by 

cancer survivors: a report from the American Cancer Society’s studies of cancer survivors. Cancer.

2008;113(5):1048-1057.

Greenwald P, Anderson D, Nelson SA, et al. Clinical trials of vitamin and mineral supplements for cancer prevention. 

American Journal of Clinical Nutrition. 2007;85(1):314S-317S.

Kutner J, Smith M, Corbin S, et al. Massage therapy versus simple touch to improve pain and mood in patients with 

advanced cancer: a randomized trial. Annals of Internal Medicine. 2008;149(6):369-379.

Lawenda BD, Kelly KM, Ladas EJ, et al. Should supplemental antioxidant administration be avoided during 

chemotherapy and radiation therapy? Journal of the National Cancer Institute. 2008;100(11):773-783.

Lippman SM, Klein EA, Goodman PJ, et al. Effect of selenium and vitamin E on risk of prostate cancer and other 

cancers: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA. 2009;301(1):39-51.

Manksy PJ, Wallerstedt DB. Complementary medicine in palliative care and cancer symptom management. Cancer 

Journal. 2006;12(5):425-431.

Mao JJ, Farrar JT, Xie SX, et al. Use of complementary and alternative medicine and prayer among a national sample of 

cancer survivors compared to other populations without cancer. Complementary Therapies in Medicine. 2007;15(1):21-29.

Miller S, Stagl J, Wallerstedt DB, et al. Botanicals used in complementary and alternative medicine treatment of cancer: 

clinical science and future perspectives. Expert Opinion on Investigational Drugs. 2008;17(9):1353-1364.

Naeim A, Dy S, Lorenz K, et al. Evidence-based recommendations for cancer nausea and vomiting. Journal of Clinical 

Oncology. 2008;26(23):3903-3910.

National Cancer Institute. Calcium and Cancer Prevention: Strengths and Limits of the Evidence. National Cancer Institute 

Web site. Accessed at http://www.cancer.gov/cancertopics/factsheet/prevention/calcium#9 on April 9, 2010.

National Cancer Institute. Complementary and Alternative Medicine in Cancer Treatment (PDQ), Patient Version. National 

Cancer Institute Web site. Accessed at http://www.cancer.gov/cancertopics/pdq/cam/cam-cancertreatment/patient/allpages on April 13, 2010.

National Cancer Institute, National Center for Complementary and Alternative Medicine. Thinking About Complementary 

and Alternative Medicine: A Guide for People With Cancer. National Cancer Institute Web site. Accessed at 

http://www.cancer.gov/cancertopics/thinking-about-CAM on April 13, 2010.

Richardson M, Straus S. Complementary and alternative medicine: opportunities and challenges for cancer 

management and research. Seminars in Oncology. 2002;29(6):531-545.

Sagar SM. Acupuncture as an evidence-based option for symptom control in cancer patients. Current Treatment Options 

in Oncology. 2008;9(2-3):117-126.

Sagar SM, Lawenda BD. The role of integrative oncology in a tertiary prevention survivorship program. Preventive 

Medicine. 2009;49(2-3):93-98.
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Smith KB, Pukall CF. An evidence-based review of yoga as a complementary intervention for patients with cancer. 

Psycho-Oncology. 2009;18(5):465-475.

Sparber A, Wooton J. Surveys of complementary and alternative medicine: Part II. Use of alternative and 

complementary cancer therapies. Journal of Alternative and Complementary Medicine. 2001;7(3):281-287.

Velicer CM, Ulrich CM. Vitamin and mineral supplement use among U.S. adults after cancer diagnosis: a systematic 

review. Journal of Clinical Oncology. 2008;26(4):665-673.

Verhoef MJ, Balneaves LG, Boon HS, et al. Reasons for and characteristics associated with complementary and alternative 

medicine use among adult cancer patients: a systematic review. Integrative Cancer Therapies. 2005;4(4):274-286.

For More Information

NCCAM Clearinghouse

The NCCAM Clearinghouse provides information on NCCAM and complementary health 

practices, including publications and searches of Federal databases of scientific and medical 

literature. The Clearinghouse does not provide medical advice, treatment recommendations, 

or referrals to practitioners.

Toll-free in the U.S.: 1-888-644-6226

TTY (for deaf and hard-of-hearing callers): 1-866-464-3615

Web site: nccam.nih.gov

E-mail: info@nccam.nih.gov

National Cancer Institute

The National Cancer Institute is the Federal Government’s lead agency for cancer research. 

The agency’s Cancer Information Service provides comprehensive information about cancer.

Toll-free in the U.S.: 1-800-4-CANCER (1-800-422-6237)

Web site: www.cancer.gov

E-mail: cancergovstaff@mail.nih.gov

The National Cancer Institute’s Office of Cancer Complementary and Alternative Medicine 

coordinates and enhances the National Cancer Institute’s activities in complementary and 

alternative medicine research.

Web site: www.cancer.gov/cam

PubMed®

A service of the National Library of Medicine, PubMed contains publication information and (in 

most cases) brief summaries of articles from scientific and medical journals.

Web site: www.ncbi.nlm.nih.gov/sites/entrez
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Acknowledgments 

NCCAM thanks the following individuals for their technical expertise and review of this 

publication: Lorna Patrick, National Cancer Institute; Cornelia Ulrich, Ph.D., Fred Hutchinson 

Cancer Research Center; Jeffrey White, M.D., National Cancer Institute; Scott Miller, M.D., 

NCCAM; and Barbara Sorkin, Ph.D., NCCAM.

This publication is not copyrighted and is in the public domain.

Duplication is encouraged.

NCCAM has provided this material for your information. It is not intended to substitute for the 

medical expertise and advice of your primary health care provider. We encourage you to 

discuss any decisions about treatment or care with your health care provider. The mention of 

any product, service, or therapy is not an endorsement by NCCAM.

National Institutes of Health

♦♦♦

U.S. Department of Health and Human Services
D453

Created September 2005

Updated March 2012