Cancer is one of the most dreaded diseases in the world today. It is caused by genetic mutations that instruct normal cells to grow and divide nonstop. Usually, cells divide to produce more cells so that we can grow and develop. These new cells also replace old and damaged ones.
But cells only divide up to a certain limit, after which they die. This organized process is impaired by genetic mutations, where cells continue to divide uncontrollably. These rapidly dividing cells can form a benign or malignant mass. Malignant tumours can spread and destroy tissues and organs.
Cancer causing genetic mutations can either be inherited or occur after you are born. In fact, most genetic mutations are not inherited and are rather caused by external factors such as smoking, chronic stress, viruses, certain infections, unhealthy sleep patterns, chemicals in foods, obesity, excessive consumption of alcohol, lack of exercise and exposure to ionizing radiation and environmental pollutants.
Most of these factors cause oxidative damage to cells which results in chronic inflammation, the main driving force behind all age-related degenerative health conditions known to us in the modern world.
There are approximately 150 anti-cancer drugs used to treat different types of cancers, but their efficacy is marred by the serious side effects. Aggressive conventional cancer treatments like radiation and chemotherapy are associated with severe side effects. For example, chemotherapy causes damage to bone marrow, the gastrointestinal tract, liver and kidneys. It leads to weight loss, poor appetite, weakened immunity, lack of energy and hair loss. In addition, prolonged use of anti-cancerous drugs can even cause cancer cells to develop resistance. These drugs are also known to induce secondary tumours in healthy cells.
No wonder both patients and health practitioners are searching for better and safer anti-cancer treatments, that don’t adversely impact the quality of life in patients. In this regard, natural chemical compounds have been extensively studied for their role in reducing inflammation, toxicity against cancer cells and their safety profile.
Curcumin, a polyphenol derived from the spice turmeric, is fast emerging as a natural agent with strong antioxidant, anti-inflammatory, and anti-cancer properties.
Curcumin as an alternative cancer treatment?
Although we need more research, small scale clinical studies suggest that curcumin can be effective in fighting various types of cancers. It has also been found to enhance the effects of conventional cancer treatments such as chemotherapy and radiation therapy while reducing the associated side effects.
Its potential as an alternative cancer treatment is credited to its ability to curb inflammation and improve your body’s internal anti-oxidant capacity. These actions also make curcumin a powerful natural substance to manage many other chronic conditions such as heart disease, arthritis, depression, diabetes, metabolic syndrome, dementia and Alzheimer’s.
This review notes that, “to date, over 100 different clinical trials have been completed with curcumin, which clearly show its safety, tolerability and its effectiveness against various chronic diseases in humans.” 
There are many processes that initiate the growth of cancer cells. These processes involve expressions of various genes and activation of signalling pathways and inflammatory molecules. That’s why a substance that can target these multiple targets can be successfully used to prevent or treat cancer.
Studies show that curcumin may work through multiple mechanisms to fight cancer and stop cancer cells from growing and dividing. Most importantly, curcumin reduces inflammatory burden in the body.
- Inhibits the initiation, progression, invasion and spreading of cancer cells.
- Activates apoptotic signalling pathways that induce programmed death in cancer cells so these cells die naturally.
- Reduces inflammation by downregulating a wide range of transcription factors (NF-κB), growth factors, inflammatory cytokines and enzymes. One of the most important mechanisms through which it controls inflammation is by blocking the nuclear factor-kappa B, group of proteins that control genes responsible for regulating inflammation, immune responses and cell growth. Abnormal activation of the NF-κB signalling pathway has been implicated in many inflammatory diseases including cancer.
- Reduces the side effects of chemotherapy and radiation therapy
- Supports your immune system in seeking and killing cancer cells on its own
- Improves the body’s antioxidant status. Curcumin increases the levels of antioxidant enzyme systems such as superoxide dismutase (SOD), glutathione peroxidase (GSH), glutathione and catalase.
This 2018 report concludes “The anticancer-promoting effects of CUR have largely been attributed to its ability to suppress cell growth, angiogenesis, and metastasis as well as to induce apoptosis in a variety of cancer types. Furthermore, the positive effects of the combined treatment of CUR with conventional chemotherapy drugs or radiotherapy should be considered as a subject of subsequent research, opening up new opportunities for effective intervention in cancer treatment.” 
Curcumin improves the effects of chemotherapy
One of the ways curcumin fights cancer is through its strong anti-inflammatory effects and its ability to modulate various signalling pathways and enzymes that are involved in cancer initiation and development.
Another important way curcumin works is by enhancing the effects of chemotherapy drugs. Studies show that curcumin can make cancer cells sensitive to anti-cancer drugs, while minimizing their side effects.
In clinical practice, curcumin has been widely used in combination with anti-cancer drugs like cisplatin, carboplatin, 5-fluorouracil (5-FU) and gemcitabine. The effect of this combination has been observed in various cancer types, including lung, breast, colon, pancreas, gastric, liver and prostate cancers. 
How does curcumin work as a chemosensitizer? While it targets many pathways, enzymes and inflammatory molecules, the ability of curcumin to inhibit transcription factor NF-κB appears to be one of most important mechanisms here.
The combination of docetaxel (a chemotherapy drug) and curcumin was used in advanced and metastatic breast cancer patients. Though it was a very small study, most patients showed improvement and the researchers were able to define the recommended dose of curcumin to be “6000 mg/d for 7 consecutive days every 3 weeks in combination with a standard dose of docetaxel. “
The combination of docetaxel and curcumin also shows potential in castration-resistant prostate cancer. 
It has been found that curcumin improves the effectiveness of Mitomycin C, a strong drug used to fight different types of cancers. Curcumin makes cancer cells more sensitive to Mitomycin C. It also reduces the side effects of this anti-cancerous drug, as prolonged use of Mitomycin C is known to cause permanent damage to kidneys as well as bone marrow damage. Long-term use also causes secondary tumours in normal cells. 
This 2010 study found that, “The treatment of curcumin with MMC results in a significant dose-dependent increase in cell viability and decrease in lipid peroxidation and DNA damage, suggesting a protective role of curcumin against the anti-cancerous drug mitomycin C.” 
Curcumin, when used along with conventional cancer treatment, also improved the results in chronic myeloid leukemia (CML). 
Radio sensitizing and radioprotective properties
Curcumin also provides protection against radiation therapy while improving the effect of radiation on cancer cells.
Approximately 95% of breast cancer patients who receive radiotherapy get radiation dermatitis. In a randomized, double-blind, placebo-controlled clinical trial, researchers found that curcumin reduces the skin damage caused by radiation therapy. The study concluded that, “oral curcumin, 6.0 g daily during radiotherapy, reduced the severity of radiation dermatitis in breast cancer patients.” 
Another pilot study found that curcumin can protect patients with prostate cancer from the side effects caused by radiation therapy. Radiation therapy can cause a range of side effects including acute urinary dysfunction. This is because of inflammation and loss of mucosa at the neck of the bladder and also within the prostate and other structures.
As we know, curcumin is a strong anti-inflammatory and anti-oxidant compound. In this study, curcumin supplementation at 3 gram per day reduces the severity of urinary symptoms caused by radiation therapy, improving the quality of life in patients with prostate cancer.  It must be noted, however, that curcumin was not able to reduce the severity of other radiation-induced side effects like bowel symptoms.
Curcumin’s anti-cancer potential marred by low bioavailability
Curcumin has been widely studied as a natural compound to fight cancer. And from all the small-scale and pilot studies, it is clear that curcumin has many properties that not only help prevent cancer cells to grow further but also improve the efficacy of conventional cancer treatments such as chemotherapy and radiotherapy.
Studies show that curcumin can be effective in many types of cancer, especially lung, breast, prostate, cervical and liver cancers. In spite of all the evidence, researchers have not been able to replicate the expected results in most human studies. It is believed that curcumin’s anti-cancer effects are marred by its poor bio-availability and poor solubility, the main reason why curcumin has failed to produce desired results in-vivo studies.
- Fast metabolism and low bioavailability: Your body is not able to absorb much curcumin either from foods or supplements. It is broken down rapidly and is also quickly eliminated from the body. You can take oral curcumin supplements with piperine to improve its absorption and bio-availability. However, prolonged use of piperine can cause side effects.
- Curcumin is fat-soluble.
To overcome bioavailability challenges, researchers have explored all kinds of drug delivery systems – including solid dispersion, micelles, microemulsion and liposomes.
A 2017 review sheds light on liposomal curcumin and its application in cancer. It notes that liposomal formulation of curcumin provides quite an effective mode of delivery for curcumin and exerts superior anti-cancer effects. In other words, liposomal delivery enhances anti-tumour effects and reduces the dose required to destroy cancerous cells. This means you don’t need to take curcumin in extremely high doses to get the desired health outcomes, which could be reduced pain and swelling or reduced risk of heart disease and diabetes.
The review noted that “Liposomal CUR formulation has greater growth inhibitory and pro-apoptotic effects on cancer cells.” and concluded the “combination of CUR and liposomes should enhance the stability, bioavailability, targeting property and anticancer efficacy of CUR.” 
Liposomes are unique, double-layered spherical structures that can be used to carry both fat-soluble and water-soluble drugs and nutrients, which are delivered directly to the target cells. Liposomal formulation not only improves the bioavailability and absorption but also protects the stability of encapsulated agents.
So far, preliminary studies in this area show that curcumin can be an effective natural compound to fight cancer. In fact, with its powerful antioxidant and anti-inflammatory properties, curcumin has been found to be useful in many other health conditions:
- Reduces inflammation, an important risk factor in heart disease
- Improves endothelial function
- Reduces pain and joint function in arthritis; and may work even better than anti-inflammatory drugs to bring relief in this condition.
- Improves insulin resistance and may cut down the risk of diabetes in people who are already at a high risk
- Reduces cellular and DNA damage caused by radiation exposure
- Reduces the risk of dementia and depression in the elderly
- Reduces damage caused by smoking and protects lung health
- May be helpful against Alzheimer’s as it lowers inflammation in the brain; prevents the build-up of amyloid-β plaques (hallmark Alzheimer’s disease).
- Kunnumakkara et al. Curcumin, the golden nutraceutical: multitargeting for multiple chronic diseases. Br J Pharmacol. 2017
- Wojcik et al. Molecular Mechanisms Underlying Curcumin-Mediated Therapeutic Effects in Type 2 Diabetes and Cancer. Oxidative Medicine and Cellular Longevity. 2018.
- Kumar et al. Molecular mechanisms underlying chemopreventive potential of curcumin: current challenges and future perspectives. Life Sciences. 2016.
- Bayet-Robert et al. Phase I dose escalation trial of docetaxel plus curcumin in patients with advanced and metastatic breast cancer. Cancer Biology & Therapy. 2010.
- Mahammedi et al. The new combination docetaxel, prednisone and curcumin in patients with castration-resistant prostate cancer: a pilot phase II study. Oncology. 2016.
- Zhou et al. Curcumin improves MMC-based chemotherapy by simultaneously sensitising cancer cells to MMC and reducing MMC-associated side-effects. Eur J Cancer. 2011
- Siddique YH et al. Assessment of cell viability, lipid peroxidation and quantification of DNA fragmentation after the treatment of anticancerous drug mitomycin C and curcumin in cultured human blood lymphocytes. Exp Toxicol Pathol. 2010
- Ghalaut et al. Effect of imatinib therapy with and without turmeric powder on nitric oxide levels in chronic myeloid leukemia. J Oncol Pharm Pract. 2012
- Ryan et al. Curcumin for radiation dermatitis: a randomized, double-blind, placebo-controlled clinical trial of thirty breast cancer patients. Radiation Research. 2013.
- Hejazi et al. A pilot clinical trial of radioprotective effects of curcumin supplementation in patients with prostate cancer. Journal of Cancer Science & Therapy. 2013
- Feng et al. Liposomal curcumin and its application in cancer. Int J Nanomedicine. 2017