Precision Medicine - The Future of Cancer Treatment

March 25, 2020

4 min read

If you've been following cancer treatment approaches and ideologies, you've undoubtedly come across the term precision medicine. Precision medicine, or personalized medicine, is a treatment approach where doctors treat a disease with guidance from a patient's unique genetic makeup. It is particularly popular in cancer treatment, where genes play a huge role in cancer development and growth. Most doctors and biomedical researchers believe that precision medicine will become the norm in the treatment of cancers.

Why is precision medicine the future of cancer treatment?

Part of why cancer has been one of the most terrifying diseases over the last century is due to the inability of modern medicine to treat it effectively. Even as we've significantly expanded our arsenal of therapy treatments options, with more being researched and discovered every day, the success of an individual in the treatment of cancer can still vary widely. The reason for this is based in misconceptions that we've started to recognize and address since the turn of the century. Historically, we've categorized cancers from the organ in which it originated: breast, lung, testis, stomach, colon, etc. This was and is a good first approach, as many of the underlying cellular and genetic driving factors that cause these types of cancer share some similarities, which is also why cancer appeared in those tissues in the first place. However, thinking of cancer on an organ level is too generalized to effectively treat the disease.

For instance, elevated levels of estrogen and progesterone hormones can increase risk for some types of breast cancer, depending on those same underlying molecular driving factors. That same increased risk of breast cancer for hormones could also turned against it for successful treatment, as anti-hormone chemotherapies have high success rates for those breast cancer types. However, there are also cancers classified as breast cancer that don't fit in with the hormone story, and don't respond to any of the anti-hormone treatment approaches - termed triple negative breast cancer. These cancers on average are less aggressive than other breast cancers, but have left doctors floundering for other approaches without knowing what's really driving the cancer growth. In just the last five years, researchers have uncovered that triple negative breast cancers are themselves composed of subcategories of tumors, finding that some therapy treatments respond much better than others depending on the tumor's subtype. These most recent revelations have brought about a paradigm shift for cancer treatment approaches: Don't treat the cancer organ, treat the underlying cellular and molecular cancer drivers. The goal doctors and researchers strive for is a clear understanding of the driving force(s) behind a cancer by genetic sequencing alone, follwed by treatment with a highly-tailored cocktail using the smallest number of drugs designed specifically against those unique targets.

So that's a great theory, but does it really work? When the genetic code is interpreted correctly and a corresponding treatment option is available, we've seen striking success stories. Chlidren cancer free in less than a month. Chronic cancer patients cured in a matter of months. Stage IV cancer patients surviving for years beyond their intial projections. For a treatment in its early stages of development and implementation, precision medicine is incredibly promising.

I've just been diagnosed with cancer. Why isn't precision medicine the first treatment option on the table?

The first approach for cancer treatments today still starts with a combination of therapies with a high likelihood of success rates for your cancer type, usually surgery, chemotherapy, immunotherapy and/or radiation therapy. It is also common to have your genome sequenced, obtaining a read for all the DNA that makes you - you. If your cancer is a solid tumor, it is also common to sequence the tumor and to see if insight can be gleaned from genetic material missing or mutated. You may even have the gene expression patterns of a tumor studied - a read on how much and quickly other parts of the cell are "reading" the DNA. Doctors can look at this information for major red flags, like mutations in specific genes known to drive the development of cancer, and can recommend certain treatments known to respond better to changes in that specific gene.

The issue is that most cancer instances don't have a major red flag for a doctor to focus on. A better analogy for the current state of precision medicine is thousands of little orange flags, in one tumor. Researchers around the world are working hard to make sense of this data in a meaningful way, including developing international databanks on the molecular signatures of cancer tumors like the Cancer Genome Atlas Program. So precision medicine isn't the first treatment option for cancer currently because we don't understand how all the thousands of cellular pieces work together or all the signatures for what those processes gone wrong looks like. As we move deeper into the 21st century, however, expect a substantial shift towards precision medicine as the first, and hopefully only need, line of defense.