I am presently sitting in a lecture hall at the American Society of Clinical Oncology annual meeting listening to a presentation by one of the world’s experts on the sequencing of the human genome.
The expert, Dr. Francis Collins, is discussing how much we have learned over the past several years about our genes and how they relate to cancer, and how much we will continue to learn about this topic over the next several years.
The progress we have made in this arena has been truly astounding. And it is exciting to anticipate how much more we are going to learn in the near future.
The practical implication is that we will be able learn more about an individual’s cancer, and how to best treat that cancer with drugs specifically targeted to that cancer. We may also learn which cancers have a good prognosis and which ones don’t, and then be able to determine whether or not an individual needs intensive therapy or will do well with observation alone.
Another highly regarded expert, Dr. Dennis Slamon, yesterday afternoon presented a review of his research that led up to the development and clinical applications of the targeted therapy drug trastuzumab.
He made a comment that summarized very nicely where we were in the past and where we are today in our understanding of cancer and its treatment.
When I started in my oncology training, we treated different types of cancers. There were lung cancers, colon cancers, breast cancers, lymphomas, and many others. But, as Dr. Slamon pointed out, we basically had to rely on a “one size fits all” approach to our treatment of the particular cancer in question.
In other words, we didn’t have the knowledge to distinguish one colon cancer from another, other than through our crude ability to stage a cancer to reflect whether it was localized or had spread.
Our chemotherapy approaches were similarly “shotgun” in approach.
When I started in training, our main tools were surgery, radiation therapy and chemotherapy. It was also a time when immunotherapy and vaccine therapy were in their relative infancy.
We really believed that it was going to take one more drug, or a higher dose level, or a more toxic combination of drugs that would result in a dramatic advance or even cure of some cancers.
We were successful in certain instances. Childhood leukemia responded to our research efforts, as did Hodgkin’s disease and testicular cancer.
But I think it is fair to say that we did not achieve the goals that many of us thought were near at hand, especially since at that time we had access to such exciting new drugs as adriamycin, VP-16, and cis-platinum.
While we were working on new drug trials in the clinic, our laboratory colleagues were busy working on basic cancer cellular mechanisms.
Now we are finding out that our chemotherapy efforts, which although well-intentioned and certainly invaluable in the treatment of many patients with cancer, have probably reached a point where we won’t be seeing many broad based significant advances in the treatment of most of the common cancers we see today.
That doesn’t mean that progress with chemotherapy has stopped. But it does mean that most oncologists aren’t looking to chemotherapy with standard drugs for the next “big thing.”
But now, instead of a “one size fits all” approach to cancers and their treatment, we are developing a more “targeted” concept.
That means we realized that even though one cancer may look similar to another under the microscope, in fact their genetic makeup may be different, and their behaviors may similarly be much different.
So we no longer look at each type of cancer being the same within each “family” of cancers, and we no longer think that each cancer in the family is going to respond to the same treatments.
Last year at ASCO, we reached what I called a watershed moment where it was clear that targeted therapies were valuable, were having a significant impact on patient care, and were basically here to stay.
In contrast, immunotherapy hasn’t achieved its promise, and success in cancer treatment with vaccines hasn’t produced consistent positive results in many cancers where they have been tried.
So where do we stand this year?
First, there are new targeted therapy drugs that are demonstrating promising results as reported at this meeting. Second, we are seeing reports on new drugs that are targeting entirely different processes in cancer cells, and producing intriguing results. Third, we are seeing new trials produce positive results with drugs previously discussed at ASCO either in the same cancers but at earlier points in the disease process, or in other diseases altogether. And, last but not least, we are seeing some of the drugs that have been in clinical use based on prior trials enter a “maturation” phase where researchers are concentrating on answering some basic questions on the best way to use the drug in the treatment of patients.
The genetics talk I mentioned at the beginning of this entry augurs well for the future. As we learn more about the human genome, we will be able to learn more about the specific changes in a patient’s cancer and the cells that make up that cancer.
We will able to determine the prognosis and the treatment options for patients based on an analysis of their tumor, and provide a specific prescription for their cancer.
Looking into the future, we will also be identifying many more targets that will in turn produce more targeted drugs to be used in the treatment of various cancers.
The end result is that last year’s watershed moment continues unabated, with much excitement and enthusiasm.
From my vantage point, although I tended in the past to be a skeptic about the “next big thing,” I have never been more excited about what the future holds.
In my follow-up blogs I hope to highlight some of the papers presented at this meeting, and put them in context regarding their implications for patient care.