By Otis W. Brawley, MD, FACP
From time to time, I encounter advocates for research in certain diseases. These are people who want better answers for a specific cancer. Oftentimes these folks or a relative has had that particular cancer. They often ask, why is so little money spent on pancreatic cancer, ovarian cancer, or even lung cancer? Why can't we spend more? These are reasonable questions, and I want to try to address them in this piece.
First I caution against what I call "disease Olympics." This is when advocates for one disease try to increase funding for their disease by decreasing funding for another disease. I have often seen this in my 25 years as an oncologist, researcher, and scientific administrator. I would point out that 90% of the grants that are submitted and judged worthy of funding to the National Cancer Institute, American Cancer Society, and other research-funding organizations are not funded due only to a lack of money. I believe the wise advocate tries to get more money for all cancer research and does not try to undermine another disease in favor of the disease that he or she is interested in.
The second reason to support the best scientific ideas as judged by the rigors of scientific peer review is that we can often benefit multiple diseases by funding the best science. Indeed, one can argue that funding the best ideas in, say, lung cancer and not the better scientific idea in another cancer could possibly hold back the advancement of lung cancer research. But let me give some examples.
Drugs with Unexpected Benefits
In the late 1960s the first targeted therapy developed for breast cancer was a drug called estramustine that was supposed to bind to breast cancer cells and kill them. Estramustine was a failure as a breast cancer drug, but from 1972 to 1999, it was the only chemotherapy drug that was approved by the Food and Drug Administration (FDA) for the treatment of prostate cancer.
You've probably heard of the chemotherapy drug Herceptin, which is used to treat about 25% of breast cancer patients. It was developed to treat neuroblastomas and gliomas, both cancers of the nervous system, but it didn't work for those cancers.
Another example, cisplatin, was first developed as a treatment for testicular cancer. It is now the most commonly used chemotherapy in the treatment of lung cancer and ovarian cancer. It is also used in some breast cancer treatments. The drug oxalaplatin used in colon cancer therapy was developed from cisplatin. So testicular cancer research benefited a number of other cancers.
Similarly, the drug leuprolide was developed in the mid-1980s as a hormonal treatment for metastatic prostate cancer. This drug has since been FDA-approved for not only treatment of metastatic prostate cancer, but also premenopausal breast cancer, endometriosis, and precocious puberty.
The number of drugs that were developed for one disease but ended up being useful in others is legendary and goes beyond cancer. Aspirin is not just a pain and fever reliever. Today we know it prevents heart disease and is the model for a class of drugs that prevents colon polyps and may prevent colon cancer. Here we have heart disease research benefiting colon cancer. Zidovudine (better known as AZT) was initially developed as a colon cancer treatment. It was a failure in colon cancer therapy, but became the first drug FDA approved to treat HIV.
So, when we look at the research money spent to create these treatments, it's hard to determine how much should be categorized to the cancer it was originally developed for, and how much should be categorized to other cancers or diseases it helps.
Genetic Discoveries Widely Applicable
Examples of good basic science with initially unforeseen spinoffs go even further. Work on the genetic mutation p53 has touched leukemia, lung cancer, breast cancer, colon cancer, and prostate cancer, among others. The retinoblastoma gene is so-named because it was found to be important in a rare eye cancer, but is now also known to be important in lung cancers.
Good basic science led to an understanding of the gene known as c-kit. This led to the development of Gleevec for chronic myelogenous leukemia and acute lymphocytic leukemia. Eventually c-kit was shown to be important in some sarcomas, especially gastrointestinal stromal tumors. And understanding how c-kit functions has led to the development of a number of other drugs for other diseases, including the chemotherapy drug Tarceva for some lung and pancreatic cancers.
The study of cell growth and division has given us many answers as to why some cells become cancerous without the presence of a cancer-causing chemical, or carcinogen. This type of research may someday help us prevent a number of cancers.
The list of unexpected discoveries made because of good scientific understanding goes on and on.
The wisest advocacy for cancer science is support for more money for cancer research in general and support for funding the best science and encouraging scientific investigators to maintain an open mind. Scientists must look for additional applications of findings beyond just their cancer of interest.
I should mention one last thing. Basic scientific research, some of it not focused on a particular cancer site, has given us so much insight into cancer that we can actually see a day in the very near future in which it doesn't even matter where the cancer started. In other words, the clinician is not going to be interested in whether it's lung cancer or breast cancer or colon cancer. The significant questions for treatment will be: Which genes are mutated? Which genes are turned on? Which genes are turned off? Which genes are amplified?
We are moving away from the definition of cancer given to us 160 years ago with the light microscope, and toward a definition of cancer explained by genes and how they work. So too, this will make "disease Olympics" irrelevant.
Dr. Brawley is the chief medical officer of the American Cancer Society.