Editor's Note

Are We There Yet?

When it comes to curing cancer, targeted therapies and genomic sequencing are helping, but we still have far to go.

By Jeanette McCarthy, MPH, PhD

Last March, there was a lot of buzz around the debut of Ken Burns’ documentary Cancer: The Emperor of All Maladies, based on the Pulitzer Prize-winning book by oncologist Siddhartha Mukherjee. And rightly so. This epic work provides a riveting history of cancer, from the time of the ancient Egyptians to the present. It reminded me that cancer has been around for a long time and remains the second leading cause of death in the U.S. But it also made me appreciate just how far we’ve come since the disfiguring radical mastectomies used to treat breast cancer patients from the late 19th century through the 1970s. Today, we are able to predict and prevent some inherited forms of cancer. Targeted treatments, based on the molecular profile of the tumor itself, are extending the lives of cancer patients. Novel therapeutic strategies are being developed that harness a patient’s immune system. President Obama recently pledged funds to expand efforts in cancer genomics through the Precision Medicine Initiative. There is much to be optimistic about.

In the face of all this promise, I recently watched from a distance as a friend was losing his battle with a rare cancer of his tonsil. I wondered why, given this progress, precision medicine couldn’t help him. When I first found out about his diagnosis, I immediately thought about tumor sequencing. In some cases, tumor sequencing can reveal a genetic culprit amenable to treatment with a targeted therapy. Unlike radiation and chemotherapy that affect both healthy and cancerous cells, targeted therapies act only on the tumor cells and, in some cases, make them melt away. Given the rarity of my friend’s particular cancer, some would advocate for sequencing his tumor.

As I explored this option for my friend, I realized that it was not so easy to bring this cutting- edge technology to the patient. The doctors couldn’t remove the tumor without risking damage to his artery. No tumor, no tumor sequencing. But new tests that can detect tumor DNA in the bloodstream, so-called liquid biopsies, gave me hope that tumor sequencing might still be possible.

Yet, as for any late-stage cancer patient, time is of the essence, and a one- to two-week turnaround for a test result is an eternity. The same could be said for using microbial genome sequencing to diagnose an infectious disease (“DNA Tests for Infectious Diseases,” page 26). In the current issue of Genome, you’ll also read about another application of genome sequencing — this one in the neonatal intensive care setting — where researchers in Kansas City have developed a rapid sequencing test with a turnaround of a couple of days, not weeks (page 34).

Even if my friend had more time, the price tag of tumor sequencing and the targeted treatment that he might have been prescribed is out of reach for many patients, and insurance coverage is patchy. I thought about just paying for the test, but then wondered why I wouldn’t do the same for all of my close friends, family members, and acquaintances battling cancer. The numbers started adding up, and I quickly realized that this was not a viable strategy. It was akin to trying to end world hunger by throwing a pizza party for a few people.

I know that even the best targeted treatments, while they may extend life, aren’t a cure for cancer. Although some people have incredible responses using these drugs, many do not. I still can’t help wondering if tumor sequencing could have helped my friend. Could he have been one of the lucky ones whose tumor was dissolved by a targeted treatment?

This experience reminded me why I became an educator in precision medicine. Without informed healthcare providers, how will these medical innovations get to the patients who need them? How will healthcare providers learn about sequencing to profile tumors or infectious diseases, for example, and how to adopt it into their practice?

Patients and caregivers are increasingly filling that gap. They are seeking information about all possible diagnostic and treatment options. They are educating themselves and are battling with insurance companies for coverage. They discuss their diseases in detail — and with complete strangers! But even informed patients sometimes do not know how to discuss their interest in a test or treatment with their doctor. In “When Cancer Runs in the Family” (page 30), you’ll learn just that.

I applaud the patients who arrives at their doctor’s office armed with information about their health condition, prepared to have a discussion. But when seeking health information outside of the doctor’s office, it’s important to not believe everything you read. Too often, health information is inaccurate, and even when science debunks a health myth, it can persist. Such is the case with the link between vaccines and autism. In our Deep Dive into autism in this issue (page 58), you’ll learn about the role that de novo mutations (those not found in the parents) play in autism, and why family history might not be the best gauge of genetic susceptibility in this instance.

At Genome, we will continue providing healthcare consumers with information about new precision medicine tests and treatments as well as giving them practical tips on how to navigate the maze of ethical, economic, and technical hurdles that currently prevent widespread use. Our hope is that the next time a friend of mine, or yours, is diagnosed with cancer, the path to accessing precision medicine is straightforward.