A "New" Twist on Personalized Medicine: Genetically Targeted Therapy

The overarching definition for personalized medicine has always been the following: the right drug for the right patient at the right time (see: Further Consideration of the Definition for Personalized Medicine; Term "Personalized Medicine" More About Business than Healthcare Delivery). Implicit in this definition has been the idea that the "right drug" will exploit the biologic weaknesses of a patient's tumor. The classic example has been the use of the monoclonal antibody trastuzumab, marketed as Herceptin, for breast tumors that overexpress the HER2/neu protein. A recent article discusses a subtle but interesting paradigm shift relating to personalised medicine and the workflow of cancer care (see: Personalized Medicine Redefines How Docs Treat Cancer). Below is an excerpt from it:

Imagine a world in which cancer isn't diagnosed according to where it is found on the body but according to genes found in the tumor itself. Patients with skin cancer, colon cancer and parathyroid cancer, for example, might be reclassified as "B-Raf mutation" patients and be treated with the same mutation-specific drugs. Instead of receiving breast cancer-specific chemotherapy, a breast cancer patient might join those with ovarian, uterine and cervical cancer to receive drugs targeted at inhibiting the PIK3CA mutation found in their tumors. This paradigm shift may seem revolutionary, but more than a thousand patients have already been treated this way by researchers at MD Anderson Cancer Center in Houston. In the largest study of its kind, researchers enrolled more than 1,150 cancer patients in phase I clinical trials to test the effectiveness of genetically targeted drug therapies -- an approach known broadly as personalized medicine....The trial patients have bladder, breast, cervical, colorectal, gastric, liver, lymphoma, lung, melanoma, ovarian or any number of other cancers, but cancer location didn't necessarily determine their treatment. Patients were treated according to which of 12 known genetic mutations researchers found in their tumors. For instance, a patient in a trial for the PIK3CA mutation might include those with ovarian, cervical, uterine or breast cancer. In a world used to dividing up cancers by body part and assigning colored ribbons accordingly, the gene approach to treatment marks a fundamental change in the way we even think about cancer....Genetically targeted therapy, on the other hand, isolates the abnormal proteins within the cell that only occur in the cancerous tumor itself.

So we now see emerging a more precise definition for personalized medicine -- genetically targeted cancer therapy. This idea has always been implicit in the term but this article is quite specific. In academic cancer centers and also other settings, physicians tend to be trained, and care organized, by the organ in which a cancer arises. With this new approach, patients are grouped and treated not by organ but on the basis of which genetic mutations are identified in the various tumors. For example, a patient with a cancer in the colon will be referred to the "B-Raf mutation" cancer specialist.

 All of this will result in an additional step in the referral pattern of all cancer patients, and one that is increasingly common even today. In order for a patient to be referred to an oncologist by, say, an internist, it will be insufficient to only identify the presence of a large mass in the lung or ovary of a patient with all of the characteristics of a malignant lesion. Genetically targeted therapy, and the oncology referral, will require that the lesion be biopsied and not only assigned a malignant diagnosis by a pathologist but also be genetically analyzed. This will be a necessary step in order to subsequently select the appropriate drug to treat it by the oncologist.

Comments

[Oncology Doylestown]

I agree with the previous comment. This means more personal medical information will be available which may be a good or bad thing depending on your viewpoint on the matter.

[Richard Levenson]

This is true--except for the cases in which the tumor is identified and extirpated in the patient via some kind of mechanical, thermal or toxic agent that does not rely on details of up- or down-regulated pathways... And this process may bypass the pathologist entirely.

[Joan Lowenstein]

Yes, and in many cases more people than the treating physician have access to that genetic information (for research), so "personalized" is a misnomer. Patients will think it means medicine is more personal but the reality is that it means their personal medical information is more available. It should be called pinpoint medicine or something like that.