Targeted therapy for thyroid cancer
Vandetanib (Caprelsa®) is the first targeted drug to demonstrate a significant benefit in thyroid cancer, and it has been approved specifically for patients with symptomatic medullary cancers that have progressed on other therapies. A large clinical trial showed that in patients with this specific type of cancer, vandetanib stopped the cancer cells from growing for on average six months longer than compared to a placebo.
The most common side effects associated with this type of targeted drug therapy are diarrhea, rash, nausea, high blood pressure, headache, fatigue, decreased appetite and abdominal pain. However, vandetanib has also been associated with rare but serious side effects, such as an irregular heartbeat, heart failure or infection, in some cases resulting in death.
If your doctors at CTCA think you are a candidate for targeted drug therapy using this agent, they will thoroughly discuss the risks and benefits of this treatment, and your care team will work with you and watch you closely for any potential side effects.
In addition, some targeted drugs that affect the growth of new blood vessels in tumors, and which are used to treat other types of cancers, have also demonstrated activity in several subtypes of thyroid cancer. In some cases, your doctor may also suggest these as options.
What is targeted therapy?
Targeted therapies are drugs or other substances designed to block the growth and spread of cancer by preventing cancer cells from dividing or by destroying them directly. While standard chemotherapy affects all cells in the body, targeted therapy directs drugs or other specially created substances (e.g., immune system proteins developed in the lab) to attack cancer cells. The goal of targeted therapy is to interfere with genes or proteins involved in tumor growth to block the spread of the disease.
By targeting specific molecules that are responsible for the growth, progression and spread of cancer, targeted therapy differs from standard chemotherapy, which attacks the disease systemically and, therefore, also damages healthy cells. Because targeted therapy specifically seeks out cancer cells, it is designed to reduce the harm to healthy cells, which may lead to fewer side effects than standard chemotherapy.
Targeted therapies serve as the foundation of precision medicine, which uses information about a person’s genes or a tumor’s DNA profile to identify additional treatment options. Tailored treatments target abnormalities that may be found in each tumor’s DNA profile. This innovation marks a shift from traditional treatments designed for the average patient, toward more precise therapies.
Targeted therapy is an evolving science, and not all cancer types may be treated with targeted drugs. Several targeted therapies have been approved by the U.S. Food and Drug Administration for use in cancer treatment, including hormone therapies, immunotherapies, signal transduction inhibitors, apoptosis inducers, gene expression modulators, angiogenesis inhibitors and toxin delivery molecules.
To help identify an appropriate targeted therapy for your cancer, your doctor may order tests to learn more about the genetic disposition, protein composition and other factors the tumor exhibits. Patients may be a candidate for targeted therapy if the cancer did not respond to other therapies, has spread, is inoperable or meets other criteria. Targeted therapy may also be combined with surgery, chemotherapy, radiation therapy or hormone therapy.
Targeted therapy may be prescribed as oral pills, administered intravenously or delivered in other ways. Targeted therapy drugs may be administered in the hospital, or prescribed in pill form and taken at home. The treatment schedule is specific to each person and his or her cancer.