Will curcumin be a valid therapy for colorectal cancer? Getting to the facts
Turmeric is a popular spice these days, appearing everywhere from the more traditional vegetable recipes to teas and latte coffees. It has been used for centuries in Ayurveda medicine and many claims are made for it being good for people with inflammation and several diseases including colon cancer. However, for any substance to be used as a therapy proper clinical trials must be carried out to find out if it is safe and also if it will negatively affect other therapies already in use. It is also difficult for the body to take up curcumin, the active ingredient in turmeric, simply from eating turmeric or curcumin extract, so finding the best way to administer it is also important.
"Previous findings from our group have shown that curcumin could enhance the therapeutic action of some important chemotherapy drugs that are currently given to colorectal cancer patients, so we decided to take a look at all the studies that have been done recently on curcumin as a treatment for this disease" says Vicenç Ruiz de Porras of the Germans Trias i Pujol Research Institute (IGTP) and the Badalona Applied Research Group in Oncology of the Catalan Institute of Oncology (B·ARGO, ICO). The work was carried out with Eva Martinez-Balibrea, of the IGTP and the Programme Against Therapeutic Resistance (ProCURE) of the ICO and Laura Layos also of B·ARGO, ICO and IGTP and has been published in Seminars in Cancer Biology.
Although colorectal cancer (CRC) is the second leading cause of cancer deaths it has been left behind by current advances in immunotherapy for cancer and only 5% of cases are susceptible to the new treatments. Screening and earlier diagnosis have improved survival rates, but 25% of newly diagnosed patients already have metastatic disease. The typical treatments for these patients are chemotherapies, with patients often being given three or more consecutive treatments as they become resistant to each one, unfortunately many are finally left without new therapeutic options.
On its own, curcumin has been shown to have anti-cancer effects on cells and living animals. It interacts with many different processes in cells that affect proliferation, cell death, the ability of cells to travel and form metastases or for larger tumours to grow blood vessels.
"Most chemotherapies work on these same pathways, so it is vital to understand the interaction between them and curcumin," explains Martinez-Balibrea. "In fact there is some evidence that curcumin will slow resistance to certain therapies."
The review covers a wide range of standard therapies in most of them their performance was improved by curcumin and toxicity was reduced. Some studies also explored the application of curcumin together with other anti-inflammatory compounds to protect the colon or the use of more bioavailable forms of the compound including nano-capsules and synthetic forms.
"The news is promising for curcumin in CRC treatment," says Ruiz de Porras, "But we are not ready to use it within standard treatment programmes yet. Many of these studies are very preliminary or are in early stages".
"Large trials are needed in order to demonstrate that curcumin improves current treatments, specially by using new promising bioavailable formulations" adds Martinez-Balibrea, "although we do have many hints that it could, also that it might help stop patients becoming resistant to treatments, which would be a big advance for CRC treatment."
Curcumin: a therapeutic strategy for colorectal cancer?
Vicenç Ruiz de Porras a,b, Laura Layos a,b,c, Eva Martínez-Balibrea b,c,d,*
Semin Cancer Biol. 2020 Sep 14:S1044-579X(20)30192-9. doi: 10.1016/j.semcancer.2020.09.004. Online ahead of print. PMID: 32942023
The authors would like to state that this article refers to medically controlled curcumin and they absolutely do not recommend ingesting large quantities of turmeric. Patients must discuss any alternative or complementary treatments with their oncologist.