Curcumin has been garnering increased attention as a potential anticancer treatment. It is the major active compound in turmeric, a popular Indian spice made from the rhizomes, or underground stalks, of a plant in the ginger family.

In multiple myeloma and the precursor condition monoclonal gammopathy of undetermined significance (MGUS), cell culture studies and one animal study have shown that curcumin can kill cancer cells and prevent them from multiplying. The Beacon also found two early-stage clinical trials studying curcumin’s effects in people with multiple myeloma and MGUS.  Their results were promising, but not definitive.

All of the studies discussed here suggest that curcumin is relatively safe.

In India, where turmeric is used extensively in cooking, the average person consumes 60 to 200 mg of curcumin through his daily diet, according to the National Institutes of Health’s Medline Plus.

Studies in myeloma cells and in mice

Several recent lab studies have demonstrated that curcumin kills myeloma cells and increases the effects of conventional drug therapy:

• At Zhongnan Hospital of Wuhan University in Wuhan, China, scientists found that the addition of curcumin to melphalan (Alkeran) reduced myeloma cell proliferation, increased myeloma cell death, and increased the concentration of melphalan in cells. They found that curcumin reduces the production of a protein that helps tumor cells repair damaged DNA. The journal Annals of Hematology (abstract) published their research in September.
• M. D. Anderson Cancer Center scientists in Houston found that curcumin slowed down the growth of multiple myeloma cells that are resistant to dexamethasone (Decadron), doxorubicin (Adriamycin), and melphalan. It also enhanced the effects of thalidomide (Thalomid) and Velcade (bortezomib). By performing experiments on mice, the researchers confirmed curcumin’s ability to augment the effect of Velcade. They published their findings in the journal Molecular Cancer Therapeutics (abstract) in April.
• Two older studies by the same M. D. Anderson researchers also found evidence of curcumin’s ability to kill myeloma cells, reduce or prevent myeloma cell proliferation, and enhance the effectiveness of conventional drugs. These studies appeared in the journals Blood and The Journal of Immunology (PDF) in 2003.

Clinical trials

Clinical trials on curcumin’s effects on people with multiple myeloma or MGUS have also been promising, but thus far the evidence is limited to small, preliminary studies. The Myeloma Beacon found two such studies.

• In Sydney, Australia, one trial examined 26 people with MGUS who either took 4 g of curcumin by mouth every day for three months, then switched to a placebo, or took the placebo first for three months, then switched to the curcumin treatment. The researchers found that during the placebo phase, study participants’ abnormal protein levels either stayed steady or increased, while during the curcumin phase, participants’ protein levels either stayed steady or decreased. The curcumin treatment tended to work better for participants who had higher starting levels of abnormal protein in their serum (20 g/L or more). Two participants had to drop out of the study early because of abdominal cramping and diarrhea. The research was published in the journal Clinical Cancer Research (abstract) in September.
• In the same issue of the Clinical Cancer Research journal, Dr. S. Vincent Rajkumar of the Mayo Clinic published a commentary (abstract) on the study. Rajkumar wrote that the study uses “nonstandard response criteria” to evaluate the participants’ responses to the curcumin therapy, and the results therefore will not affect how doctors treat people with MGUS. He added that curcumin needs further research.
• In a Phase 1/2 clinical trial, M. D. Anderson researchers examined curcumin’s effects on two molecular pathways known to cause tumor cells to grow and spread. Twenty-nine people with multiple myeloma were divided into two groups – one group taking curcumin alone in increasing doses and the other group taking curcumin plus Bioperine, a compound from black pepper, also in increasing doses. The researchers found that curcumin reduced the growth and spread of myeloma cells, but participants did not show any statistically significant responses. Researchers reported that their study participants did not feel any significant side effects. They presented their findings at the American Society of Hematology’s (abstract) 2007 Annual Meeting.

Due to the insufficient number of clinical trials, Medline Plus gives the use of curcumin for cancer a “C” grade, which means there is “unclear scientific evidence for this use.”

Taking curcumin

Nevertheless, some myeloma experts are enthusiastic about using curcumin to treat multiple myeloma and MGUS. Because it works against many steps in cancer, curcumin is “ideal” to use against multiple myeloma, said Bharat Aggarwal, University of Texas biochemistry professor and principal investigator for many of the M. D. Anderson curcumin studies, in an International Myeloma Foundation webcast. He widely promotes the therapeutic use of curcumin through interviews, a Web site, and a book.

Margaret Graziano, diagnosed with MGUS in 1999 and smoldering myeloma in 2005, has been taking curcumin for four years. She decided to try curcumin when her myeloma markers were worsening and her hematologist suggested she start chemotherapy.

She told her doctor she wanted to try taking curcumin for eight weeks before starting any chemotherapy. Her doctor agreed to delay treatment. After the eight weeks were up, her myeloma markers had improved to the point that her diagnosis returned to smoldering, with no need for chemotherapy. She has been considered a smoldering myelma patient ever since.

“I am almost one hundred percent positive that, had I not taken this yellow powder, I would have progressed to active myeloma by now. Just a gut feeling, though,” wrote Graziano, who takes curcumin supplements daily, in an email to The Myeloma Beacon. Her hematologist knows about the supplements she takes and supports her, she added.

Those who decide to try curcumin should keep in mind that at this time, it is regulated by the Food and Drug Administration as a dietary supplement. Companies who make it are responsible for ensuring its safety, but do not need to register with the FDA.

After a supplement is on the market, the FDA monitors its safety but not its effectiveness. There is not yet any medical standard for how much curcumin patients should take, or how often. Trials in multiple myeloma and in other cancers have tested varying doses.

Patients can read tips on how to choose supplements on the FDA’s Web site. They can also find information on potential side effects and drug interactions on Medline.

Multiple myeloma patients may have to wait a while before the efficacy of curcumin is studied according to modern medicine’s standards. Meanwhile, patients have numerous preclinical and early clinical trials and other resources to consider before choosing whether to take curcumin supplements. Patients should always consult their physicians before taking any supplements.