82015Oct
Immunotherapy vs. Chemotherapy

Immunotherapy vs. Chemotherapy

Written By: Dr. Adam McLeod, ND, BSc

Recently, there has been a surge of interest in immunotherapies and cancer care. These therapies are a major paradigm shift from conventional chemotherapy. In the past, cytotoxic chemotherapy was the only option available to many patients. This involves the use of compounds that are toxic to both cancerous cells and normal cells. In these cases it becomes a delicate balance between killing cancer and maintaining a functioning immune system. Immunotherapy focuses on stimulating the immune system and helping your own defences to fight cancer rather than injecting a toxin that directly damages cancer cells.

There are several different types of immunotherapy but the underlying mechanism is very similar. When an immune cell interacts with a cancer cell there are several processes that must occur in order for your immune system to effectively destroy the cancer. Some molecular pathways stimulate the immune system while others inhibit immune function. One immunotherapy drug known as Ipilimumab (Yervoy) blocks CTLA-4 which normally down regulates the immune system. When this pathway is blocked then your immune system is more likely to become activated in the presence of cancer because your immune cells are no longer being inactivated by this CTLA-4 pathway.

Cancer cells are always looking for ways to grow and evade detection by the immune system. Many cancer cells will actually increase their concentration of a protein called PD-L1 as this will inactivate immune cells when they come in contact with it. By doing this it essentially creates a field around the tumour which inactivates the immune system as it gets close to the tumour.  There is a drug called Nivolumab which blocks the PD-1 receptors on T-cells so that the cancer can no longer hide from your immune system. What is exciting about this pathway is that a wide range of cancers are dependent on this mechanism to survive. These immunotherapies have elicited durable clinical responses and, in a fraction of patients, long term remissions where patients exhibit no clinical signs of cancer for many years1.

Many people have the assumption that if a drug is only stimulating your immune system then it should not have side effects. This is not true, these immunotherapies can have significant side effects. Your immune system has inhibitory pathways for a reason. These pathways prevent your immune system from indiscriminately attacking healthy cells in the body. When you remove this inhibition they are much more likely to attack the wrong cells and this can cause substantial damage in some patients. There are often gastrointestinal toxicities and use of these drugs significantly increases the incidence of autoimmune diseases2. Although these drugs show great promise, we are still in the early phases of understanding how to use them more effectively to treat cancer.

More patients need to recognize that there are also natural options that can be used to support your immune system while on conventional cancer therapies. These natural approaches are safe when used properly but you need professional guidance from a licensed Naturopathic Doctor to know what is appropriate for you. Integrative oncology excels at supporting the immune system during chemotherapy and radiation. These supports should be used during chemotherapy and radiation, not just after the therapy is complete.

There are many effective natural immune supports that are well supported in the scientific literature. One of these supports is a herb known as Astragalus membranaceus. Astragalus is an herb that is commonly given to help fight respiratory infections. It is well established in the scientific literature as an immune-boosting supplement that has applications with cancer3,4. The mechanism of this immune-boosting effect is poorly defined but the results are undeniable5. I have personally witnessed patients who have had an increase in their neutrophil and white blood cell count during chemotherapy. Their medical oncologists were shocked to see the numbers improve during such an intense chemotherapy regimen. Because of its safety and effectiveness, astragalus is regularly used with chemotherapy. It is usually a great way to support the immune system during chemotherapy, but as with any natural supplement, there are exceptions to its use.

You must have professional guidance when developing a cancer treatment plan. A Naturopathic Doctor can help you to develop a safe and effective treatment plan. Dr. Adam McLeod is a Naturopathic Doctor (ND), BSc. (Hon) Molecular biology, Motivational Speaker and International Best Selling Author. He currently practices at his clinic in Vancouver, British Columbia where he focuses on integrative oncology. http://www.yaletownnaturopathic.com

References:

1) Sharma, Padmanee, and James P. Allison. “The future of immune checkpoint therapy.” Science 348.6230 (2015): 56-61.

2) Scarpati, Giuseppina Della Vittoria, et al. “Ipilimumab in the treatment of metastatic melanoma: management of adverse events.” OncoTargets and therapy 7 (2014): 203.

3) Block, Keith I., and Mark N. Mead. “Immune system effects of echinacea, ginseng, and astragalus: a review.” Integrative cancer therapies 2.3 (2003): 247-267.

4) Chu, Da-Tong, et al. “Fractionated extract of Astragalus membranaceus, a Chinese medicinal herb, potentiates LAK cell cytotoxicity generated by a low dose of recombinant interleukin-2.” Journal of clinical & laboratory immunology 26.4 (1988): 183-187.

5) Ríos, José-Luis. “Effects of triterpenes on the immune system.” Journal of ethnopharmacology 128.1 (2010): 1-14.




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