Frontiers of Oncology: Precision Medicine and Immunotherapy
While cancer continues to strike many Americans – this year, there will be an estimated 1,735,350 new cases diagnosed1 – death rates are declining, down 26% since 1991 as of 2015.2 That’s in part due to a decline in smoking, cancer detection, and treatment advances.1
“Cancer treatment has become individualized,” says Dr. Swati Sikaria, a medical oncologist with Torrance Memorial Medical Center. Today, depending on a patient’s mutation, “they may receive a completely different first treatment, including targeted therapies and immunotherapy. Before these targets were discovered, all patients would have received chemotherapy.”
Physicians like Dr. Sikaria have The Cancer Genome Atlas to thank for these advances. Funded with a $375 million investment from 2006 to 2015,3 it produced data that enable them to better understand tumor types and come up with more targeted treatments as a result. Researchers discovered 10 million mutations, resulting in the identification of 15 different pathways that lead otherwise healthy cells to become cancerous.4
“There are a number of ways on a genetic level that a cell can become cancerous,” says Dr. Sikaria. “Sometimes it is caused by a gene mutation in a cell growth pathway that allows cells to continue dividing. Other times, the gene is not mutated, but its expression is changed. There can be mutations in DNA repair proteins and tumor suppressor proteins that also lead to cancer development.”
One way in which oncologists are attacking these pathways is through immunotherapy. Normally, one’s immune system attacks so-called foreign substances found in the body, thereby protecting it from harm. Germs, like that of the common cold for example, cause the immune system to attack in warding off illness.5
Cancer cells, however, can evade one’s immune system. That’s because, in some cases, the body doesn’t recognize them as different enough from healthy cells. In other cases, the immune system might not have the muscle to fight off virulent cancer cells.5
With this in mind, oncologists are turning to immunology. Their methods include:
- Monoclonal antibodies, which are synthetic immune system proteins that can target a specific area of a cancer cell
- Immune checkpoint inhibitors, which release the brakes on one’s immune system so it can better identify and attach cancer cells
- Vaccines, which propel the immune system to prevent or treat a certain cancer
- Other, nonspecific immunotherapies, which boost the immune system in a general way but can still help the immune system attack cancer cells5
While many oncologists and researchers are optimistic about the landscape for novel cancer therapies, Dr. Sikaria stresses that even more traditional treatments are tailored to the individual.
“I’d like to think that all cancer treatment is precise,” she says. “It is based on an individual patient’s functional status, stage of cancer, preferences, and comorbidities. Molecularly targeted therapies are incorporated where there is a proven benefit for the drug. We are not yet at a point where decisions should be made exclusively based on a person’s tumor genomic profile, but finding these mutations is very helpful for enrollment in clinical trials and when standard therapies have failed.”
1. Cancer facts & figures 2018. American Cancer Society. https://www.cancer.org/research/cancer-facts-statistics/all-cancer-facts-figures/cancer-facts-figures-2018.html. Accessed February 21, 2018.
2. Facts & figures 2018: rate of deaths from cancer continues decline. American Cancer Society. https://www.cancer.org/latest-news/facts-and-figures-2018-rate-of-deaths-from-cancer-continues-decline.html. Accessed February 21, 2018.
3. The future of cancer genomics. Nat Med. https://www.nature.com/articles/nm.3801. Accessed February 21, 2018.
4. Genomics and the future of cancer treatment. Cancer Treatment Centers of America®. https://www.cancercenter.com/community/newsletter/article/genomics-and-the-future-of-cancer-treatment/. Accessed February 21, 2018.
5. What is cancer immunotherapy? American Cancer Society. https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/immunotherapy/what-is-immunotherapy.html. Accessed February 21, 2018.
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