What Are Targeted Therapies for Cancer Treatment?

Last Updated: December 5, 2019

Targeted therapy works by using medication to target the cancer’s specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. Thoracic oncologist Dr. Jyoti Patel explains how this personalized or precision medicine works, and how it differs from other cancer treatments. 

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Cancer.Net: Doctor-Approved Patient Information from ASCO®

What Are Targeted Therapies for Cancer Treatment?

Voiceover: Targeted therapy is a cancer treatment that uses drugs to target a cancer’s specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. These genes and proteins are found in cancer cells or in cells related to cancer growth, like blood vessel cells. Researchers are learning that specific changes take place in certain cancers. So they are developing drugs that target those  changes to fight the cancer.

Jyoti Patel, MD; Thoracic Oncologist; Member, American Society of Clinical Oncology: We often just describe targeted therapies as precision medicine or molecularly targeted drugs. Essentially, they’re drugs that hit particular proteins that are important in cancer cell growth.

Targeted therapies hone to particular cancer cells because they hone to these proteins that are expressed either in the cell or on the outside of the cell.

As we’ve learned more about why cancer cells grow, there’s been tremendous excitement about targeted therapies.  So often, we’ll find that there are particular genetic aberrations in a cancer cell that cause it to proliferate. We’ve developed a number of drugs that hit these mutations and essentially shot these proteins down that cause cancer cells to grow, and we see some dramatic responses. 

Voiceover: Doctors can use targeted therapy along with chemotherapy and other treatments, but targeted therapies work in a completely different way than traditional chemotherapy.

Dr. Jyoti Patel: Chemotherapy was designed to kill cells that were rapidly dividing and cause lowering of blood counts or changes in hair; targeted therapies are often given chronically.  So oral drugs are taken almost every day.  There are infusional drugs that are monoclonal antibodies that are given periodically.  But, these drugs are given for often a longer duration than we think of chemotherapy by vein. 

Voiceover: Just as the treatment differs from traditional chemotherapy, the side effects of targeted therapy are different as well. If you are prescribed targeted therapy for cancer treatment, be sure to talk with your oncologist about what side effects—also called toxicities—you can expect and when.

Dr. Jyoti Patel: Generally, targeted therapies are well tolerated by patients.  They are associated with long benefits in good chronic use.  But, it needs to be personalized for each patient.  It’s about the appropriate dose, about managing these mild, but chronic toxicities and about understanding when resistance may develop.

They can be cumulative.  Patients can develop sort of low-grade toxicity over months.  And that’s very different than the chemotherapy-associated fatigue that many patients have either experienced or have seen friends and family experience, meaning significant fatigue because of low blood counts for a few days before they rebound. Our hope with targeted therapies is that these are chronic medications and patients can be on them for months or even years.  And so, side effects can be subtle, but build up.  And so, even low-grade toxicities need to be reported to your healthcare team to assess whether or not the dosing is appropriate or whether or not you need treatment breaks or other supportive medications.

Voiceover: Targeted therapy is very personalized according to the specifics of the type of  disease.  And, targeted therapy is not yet an option for every type of cancer. It is important that you have a conversation with your oncologist about whether targeted therapy is an available treatment option for you.

Dr. Jyoti Patel: Often, we’ll have information just based on the initial diagnosis and protein staining of the cancer whether or not a targeted therapy makes sense.  But often it takes another layer of testing, and that’s the genetic testing to see whether or not a particular cancer harbors those mutations that would make targeted therapy very appropriate.

If you are told that targeted therapy is appropriate, then the questions that may come to mind are what do the side effects look like?  How often will I be monitored for these side effects, and what other options do I have? 

Voiceover: Targeted therapies have shown success in a number of different types of cancers, and researchers are continuing to develop more targeted drugs as they learn more about specific changes in different types of cancer cells.

Dr. Jyoti Patel: One good example is lung cancers.  So patients with non-squamous, non-small cell lung cancer, the most predominate kind of lung cancer, who have advanced disease undergo genetic profiling to see if they have particular mutations.  Other tumor types in which we’ve seen success with targeted therapies include things like breast cancer.  We’ve seen success with gastrointestinal stromal tumors, with some leukemia.  So, certainly a broad range of cancers have molecularly targeted therapies. 

Voiceover: With so much cancer information available online, be sure the source you are using is credible and trustworthy.

Dr. Jyoti Patel: Targeted therapies are certainly a mainstay of cancer treatment in this modern era of precision medicine.  You can find out more about targeted therapies, potential side effects, and what researchers are focusing on in the future at ASCO’s Cancer.Net. 

On-screen: To learn more about targeted therapies, please visit: Cancer.Net/TargetedTherapy

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Cancer.Net: Doctor-Approved Patient Information from ASCO®

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