Jan 20, 2012

Cancer therapy: from one-size-fits all to custom designed

     Most cancer treatment today can be described as “one size (hopefully) fits all.”  We try a “standard” drug in all patients with the same cancer.  Some patients get a lot of benefit from treatment, others very little or no benefit at all.  Some patients have severe side effects, others very few.  We find this out by trying medications and hoping for the best.  It often takes a couple of months of treatment before a cancer patient can know if the right treatment was chosen. 

         It is likely that, in the near future, a sample of an individual’s cancer will be carefully and extensively analyzed in the laboratory before any therapy is started. The results of this analysis will allow us to select a treatment that will likely work the first time.  By matching drugs to the specific defects in an individual human being’s cancer, we should be able to avoid the “trial and error” approaches of today.

         In 2011, two new cancer treatments were approved that illustrate this new paradigm. Crizotinib (Xalkori®) was approved for the treatment of lung cancer that harbors a specific mutation in the ALK gene. Vemurafenib (Zelboraf®) was approved for the treatment of melanoma, the deadliest form of skin cancer. This drug targets BRAF—a protein that is mutated in nearly half of melanomas and drives the cancer’s growth. Both of these drugs will only be helpful to people whose cancer carries the target mutation and that is why the drugs were approved together with a test to determine if an individual person's cancer is likely to be susceptible.  

     We will see many more such drug–test combinations, and they promise to bring much better results to cancer patients. The approval of these two drugs shows that the era of personalized medicine has begun to arrive. 


  1. These targeted therapies are encouraging developments and undoubtedly will help many people! Thank you for offering such a valuable resource here to those of us out here looking for guideposts in what is at times a confusing and dark night. I look forward to your book and understanding more about the world of clinical trials in cancer treatment.
    I have a question about clinical trials specifically for maintenance therapies. I was specifically interested in pancreatic cancer and have recently seen a quote by a well-regarded oncologist at the Mayo Clinic who specializes in gastrointestinal saying that he used maintenance therapies in cases of inoperable stage iv colon cancer patients who had achieved successful results after an initial chemo regimen. He goes on to say the evidence is just circumstantial but that giving the patient a complete break from of therapy is probably not a good idea (when they are tolerating it well and risk/benefit is clearer). Do you see any general trends or new developments in the study of maintenance chemotherapies?

  2. Thanks for the comment. The use of maintenance chemotherapy is another area where there is no "one size fits all" answer, but there is quite a bit of history on this topic. In fact 20 to 30 years ago, it was common practice to treat patients with many cancers with extended chemotherapy. Studies then began to show that similar benefits were achievable with shorter duration of therapy in many cases. That is how, for many cancers, maintenance therapy became uncommon. This did not happen for all cancers, however. In some leukemias, for example, chemotherapy for 1 or even 2 years remains the standard of care. With newer agents, the idea of long term maintenance has had a bit of renaissance. For example, in some cancers, the anti-angiogenic drug bevacizumab can be prescribed as maintenance even when chemotherapy is completed. The immunotherapy drug ipilimumab, recently approved for melanoma, is also being studied in this way. These are just a couple of examples. So, in some situations, there is clearly a role for extended therapy, but to be sure, we need clinical trials to quantify the benefits and the side effects and make sure the balance favors maintenance therapy. All the best.

  3. Thanks for posting this informative article, which is an excellent example of superior writing. I really appreciate it and I think people will like you.