The Ken Burns film, “Cancer: The Emperor of All Maladies,” based on the book by Siddhartha Mukherjee, is a compelling story of the progress that’s been made against cancer over the last several decades.
And we have indeed come a long way in 30 or 40 years. Yet, as the move makes clear, we are far from a “cure” and continued investment in research is going to be critical to building on what has been learned and accomplished so far.
The movie portrays how unrealistic the thinking was in the 1970s, when the “War on Cancer” was declared. At that time, no one even understood what causes carcinogenesis, the process by which ordinary cells are transformed into cancer cells. Without this understanding, the idea that a cure could be found was far-fetched at best.
Progress in the understanding of cancer since the 1970s has included learning about the role of oncogenes and tumor suppressor genes in the initiation and progression of cancer as well as understanding how external exposures, viruses, inherited genetic mutations and randomly occurring genetic mutations all contribute to the onset of cancer.
Much progress has been made too in the way we think about trying to cure cancer. In presenting the work of Sidney Farber and others in the 1940s and 1950s, the movie shows that in those days people truly believed that cancer was one disease. They thought that, if you could find a cure for one type of cancer such as childhood leukemia, you would have found your “magic bullet” which would lead to a cure for all types of cancer.
As recently as the 1990s, the idea that the most radical treatment possible, just short of killing the patient, was the way to cure cancer still prevailed. Thankfully, it was eventually shown through clinical trials that these approaches, including the radical mastectomy and high-dose chemotherapy with autologous bone marrow transplant to treat breast cancer, were no more effective than standard treatments.
The movie shows how we have entered the era of targeted therapies. A small number, including Herceptin for a type of breast cancer, and Gleevec for a type of leukemia, have been very successful. But expectations that targeted therapies would be the answer have not panned out.
The problem with drugs that target mutations is that cancer eventually mutates again. Treatment for advanced cancer becomes a never-ending process, with a patient receiving a sequence of drugs, each of which may work for perhaps six months. But eventually, as was the case with a man shown in the movie, there is nothing that works and the patient dies.
And all of these new drugs are extremely expensive, typically costing $100,000 a year or more, a huge problem in itself. The solution offered in the film is “understanding even more about the mechanisms of cancer so that so much money is not wasted on pursuing the wrong targets.” Perhaps. But this is an issue that demands attention and action in the near term as increasing numbers of patients can’t afford their medications.
Continuing the story of where we are right now, the movie points out that most cancers are still treated with chemotherapy and/or radiation, both of which can have severe adverse side effects. Also, certain treatments for cancer can themselves be cancer-causing.
The film certainly makes clear that searching for a so-called “magic bullet” is not the solution, but offers hope that there is a way forward. There are promising leads we are told, but we need to follow them through. One is the insight that some of the many mutations that are present in cancer are critical driver mutations which are common to many types of cancer. If a way can be found to target a small number of these mutations simultaneously, that approach might be much more effective than targeting them individually or sequentially.
Another completely different approach, which offers many possible strategies, involves finding ways to boost the body’s immune system so it can fight cancer. Some experimental immune system therapies have been successful in individual patients for long periods of time.
I thought that a strength of the film was how vividly it portrayed the critical role of patients in research. It’s sometimes forgotten that the progress that has been made would never have been possible without the willingness of patients to participate in clinical trials of new therapies.
The film does an excellent job of showing that, yes, we have made an enormous amount of progress against cancer over the last several decades, but also that there is still a long road ahead and we need to continue to invest in research and participate in clinical trials to build on the progress that has been made.
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Photo credit: kenburns.com