Precision Medicine in Cancer: Identifying Effective Targeted Therapies

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• Precision Medicine in Cancer: Separating Hype from Reality
• Where Targeted Cancer Therapy is Applied Successfully
• Chemotherapy as the Backbone of Modern Cancer Treatment
• The Critical Role of Molecular Tumor Testing
• The 20-Year History of Personalized Oncology
• The Enduring Importance of Standard Cancer Treatments
• Full Transcript

Precision Medicine in Cancer: Separating Hype from Reality

Dr. Bruce Chabner, MD, a leading oncologist, addresses the central question of how to separate the tangible benefits of precision medicine from the surrounding hype. He confirms that while the field has revolutionized our understanding of cancer biology, its clinical application is not universal. The core value lies in identifying the specific genetic mutations that drive a tumor's growth, which then allows for the use of a targeted medication to block that process.

This approach, however, is not a magic bullet for all patients. Dr. Chabner clarifies that a majority of cancer patients will still require treatment with traditional chemotherapy, which has been refined over the last four decades.

Where Targeted Cancer Therapy is Applied Successfully

Dr. Bruce Chabner, MD, identifies several major cancer types where targeted therapy has become a standard and effective component of treatment. These include a significant number of lung cancers, skin cancers like melanoma, and certain breast and colon cancers. The success in these areas is a direct result of precision medicine research that defined the oncogenic drivers.

For these specific tumor subsets, targeted cancer medications offer a more precise attack on the cancer cells, often with a different side effect profile compared to traditional chemotherapy. Dr. Bruce Chabner, MD, emphasizes that this represents a major advancement, but it is crucial to remember that these are subsets of patients, not the entire population with those cancer types.

Chemotherapy as the Backbone of Modern Cancer Treatment

Despite the exciting advances in targeted therapy, Dr. Bruce Chabner, MD, states that traditional chemotherapy remains the backbone of treatment for many cancers. These are the cytotoxic agents developed and tested over the last 40 years, which Dr. Chabner has witnessed become invaluable tools in oncology.

He explains that for the majority of cancer patients, these standard chemotherapies, often combined with other modalities, are the most appropriate and effective first-line treatment. The development of targeted agents has not replaced these foundational treatments but has instead added a powerful new layer of options for specific situations.

The Critical Role of Molecular Tumor Testing

The key to unlocking the potential of precision medicine, according to Dr. Chabner, is comprehensive molecular tumor testing. This diagnostic process involves analyzing a patient's tumor tissue to see if any of the known, clinically relevant mutations or genetic changes are present.

Dr. Bruce Chabner, MD, stresses that this testing is the essential step that separates a generalized treatment plan from a truly personalized one. A positive test result for a specific mutation can indicate that a targeted cancer medication should be used instead of, or in sequence with, long-standing chemotherapy protocols. This makes molecular profiling a non-negotiable part of modern cancer diagnosis and treatment planning for many solid tumors and hematologic malignancies.

The 20-Year History of Personalized Oncology

Dr. Bruce Chabner, MD, places the current state of precision medicine in its historical context, noting that this revolution began in earnest 15 to 20 years ago. Seminal discoveries were made in cancers like chronic myeloid leukemia (CML) and breast cancer, where the identification of specific genetic targets led to the development of groundbreaking medications.

Drugs like imatinib for CML and trastuzumab for HER2-positive breast cancer became the prototypes for targeted therapy. These successes established the model that is used today: discover a driver mutation, develop a drug to inhibit it, and test patients for its presence. Dr. Bruce Chabner, MD, notes that what started as research has now become standard-of-care treatment for identifiable subsets of cancer patients.

The Enduring Importance of Standard Cancer Treatments

In his discussion with Dr. Anton Titov, MD, Dr. Bruce Chabner, MD, concludes by reaffirming the critical role of standard cancer treatments. He reminds patients and clinicians that precision medicine is an addition to the oncologist's toolkit, not a replacement for proven modalities.

Surgery to remove tumors, radiation therapy to treat localized disease, and traditional chemotherapy remain the most appropriate and effective treatments for a vast number of patients. The goal of modern oncology is to intelligently integrate new targeted agents and immunotherapies with these established treatments to achieve the best possible outcome for each individual patient.

Full Transcript

Dr. Anton Titov, MD: Cancer treatment continues to rely on chemotherapy. Targeted cancer drugs are selectively available for some tumors. Precision medicine, personalized medicine, targeted cancer medications—all these words are everywhere in cancer treatment.

Where can precision medicine help patients? Where can precision medicine not help patients? How do we separate hype from reality?

Dr. Bruce Chabner, MD: Correct. That's a big question! Precision medicine has helped us understand the biology of cancer. It has helped us define what changes are driving cancers. We know what mutations are making cancers grow.

We now have cancer medications that actually block that cancer process. They're called "targeted medicines." That applies to a significant number of cancers that arise in the lung, targeted therapy for skin cancers called melanoma, and targeted cancer medications for breast cancers and colon cancers.

But it is still the minority of tumors. A majority of cancer patients will need treatment with oncology cancer medications. They will receive the standard kinds of chemotherapy that have been developed over the last 40 years.

Dr. Bruce Chabner, MD: My own presence in oncology—I’ve watched many cancer medications undergo testing and become valuable. They are still the backbone of treatment for many cancers.

There are subsets of cancers that can be treated effectively with these targeted cancer medications. The way one finds out about that is by testing the tumor. You have to see if any of the relevant important mutations or changes are present.

That would indicate you should use a targeted cancer medication here. Do not use simply the long-standing chemotherapy that's been used in the past.

Sometimes patients think about personalized medicine. Of course, cancer treatment has been personalized for patients by astute and sophisticated doctors for a long time. But it is probably the appearance of the molecular diagnostics.

It is adjusting the cancer treatment to the genetics of the tumor and to the patient that has developed over the last few years. So patients should understand this.

Dr. Bruce Chabner, MD: That's correct! This all started really about 15 to 20 years ago. There were discoveries in breast cancer and in chronic leukemia.

Some important new cancer medications came forth from this research. Now it is our standard treatment for subsets of cancer patients. It is not for all leukemia patients, but subsets.

It requires testing the tumor to find out if these mutations are present. Then we identify the appropriate cancer medication. So there are a number of instances where this strategy is actually useful.

But it isn't in all patients.

Dr. Bruce Chabner, MD: As I mentioned, there are standard treatments using chemotherapy and radiation therapy.

Dr. Anton Titov, MD: Of course, there is cancer surgery to remove tumors. These are still the most appropriate treatments for many patients with cancer.