Skin Reactions to Targeted Therapies
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4/07 Targeted therapies represent a new type of cancer treatment, in which specific molecules in cancer cells are blocked to slow or stop the growth of cancer. Compared with conventional chemotherapy, these drugs are more specific and cause fewer side effects commonly associated with chemotherapy, such as infections, weakness, and changes to blood counts. However, most patients receiving a targeted therapy develop skin, hair, nail, and/or eye problems. Causes The causes of these skin reactions are drugs that block specific molecules in cancer cells. If the drug blocks one molecule, it is called a single-targeted therapy. If the drug blocks more than one molecule, it is called a multitargeted therapy. Specific side effects to the skin, hair, and nails depend on the drug that the patient receives. One of the largest groups of targeted therapies are those directed against a molecule known as epidermal growth factor receptor (EGFR), such as cetuximab (Erbitux), erlotinib (Tarceva), and panitumumab (Vectibix). Although EGFR fuels the growth of cancer cells, it also plays a role in the normal growth of the skin, hair, and nails. Consequently, rashes and changes to the hair and nails may occur after treatment with these drugs. Drugs with multiple targets include sorafenib (Nexavar) and sunitinib (Sutent). Overall, these side effects can be managed in most patients so that appearance of the skin, hair, and nails is unaffected or minimally affected, and treatment can continue. It is important to note that the skin side effects associated with these drugs are not an allergic or infectious reaction. Signs and symptoms of EGFR inhibitors A rash affecting the face and upper body develops in 45% to 100% of patients taking drugs that target EGFR and usually occurs within the first few weeks of taking these medications. The rash is usually preceded by redness or a warm sensation of the skin on the face that may feel like sunburn. After several days, tender pimples and pus bumps appear, and the surrounding skin feels slightly tender. Rashes tend to be mild to moderate; however, in some cases they are severe and cause significant physical and cosmetic discomfort. Other symptoms may include the following:
In addition to the cosmetic appearance of the rash, the skin can become very tender and itchy, interfering with daily activities and sleep. Vigorous scratching can result in breaks that may make the skin more prone to infections. The inflammation around the nails can make grooming, dressing, and other activities painful or difficult. Signs and symptoms of multitargeted inhibitors (sorafenib, sunitinib) The hands and feet can be affected by thickened areas in the skin in 20% to 40% of patients receiving multitargeted inhibitors; these skin areas can be very painful and develop blisters. These areas may also become tender, interfering with daily activities, such as walking or holding objects. However, most skin reactions are mild and manageable. Other symptoms include a rash that occurs in 20% to 40% of patients taking this type of medication. Along with redness, the rash is characterized by a sensation of warmth or burning on the face. Hair loss occurs in up to 25% of patients on sorafenib, but tends to be mild. Dry skin is also common and should be treated early to prevent the development of itching. Management Although rashes, dry skin, and nail and hair reactions are rarely severe, they can cause significant discomfort, and in some cases, may lead a patient to decide to stop cancer treatment. It is important to inform your doctor as soon as you start feeling or seeing the appearance of side effects. Early and effective treatments for these reactions are available and may be obtained from an oncologist, oncology nurse, dermatologist, or ophthalmologist familiar with these drugs and their side effects. The following suggestions may help with the management of these reactions:
Summary of Targeted Therapies and Common Side Effects
More Information Cancer.Net: Managing Side Effects Cancer.Net Feature: Understanding Targeted Treatments Last Updated: April 16, 2007 |