Epidermal Growth Factor Receptor (EGFR) inhibitors are a class of targeted cancer therapies designed to block the activity of EGFR, a protein that can contribute to cancer cell growth. While these medications offer a focused approach to treatment, they can also lead to a range of side effects. Understanding these potential effects helps patients manage their treatment.
Common Skin-Related Changes
One of the most frequent side effects of EGFR inhibitors involves the skin, as EGFR plays a role in the normal function of skin and hair follicles. A common manifestation is an acne-like rash (papulopustular rash or acneiform eruption), affecting 50% to 100% of patients. This rash typically appears within the first one to two weeks of treatment, presenting as red, inflamed bumps and pustules, often on the face, chest, and back, though it can appear elsewhere on the body. Unlike typical acne, these eruptions usually lack blackheads or whiteheads.
Dry skin (xerosis) is another common skin effect, impacting most patients. This dryness can lead to scaly, itchy skin and may progress to asteatotic eczema (dry, cracked skin). Itching (pruritus) often accompanies dryness and rash.
Nail changes, such as paronychia, are common (10% to 15% of patients), typically appearing around two months into treatment. Paronychia involves painful inflammation and swelling around the nail folds, often starting with the great toenails, and can sometimes lead to the formation of pus-filled lesions or granulation tissue. Hair changes include thinning (alopecia), usually partial, and changes in texture, such as increased brittleness. Eyelashes may also grow longer, thicker, and more curled (trichomegaly), potentially irritating the eyes.
Digestive and Other Widespread Effects
Beyond skin issues, EGFR inhibitors can cause systemic side effects, with gastrointestinal disturbances being common. Diarrhea is a frequent adverse event, with incidence rates varying by specific EGFR inhibitor (e.g., 26% to 57% on erlotinib, 83% to 95% on afatinib). It can begin as early as 2-3 days after starting treatment, and its severity can be dose-dependent.
Fatigue is another common effect, impacting daily life for many individuals on EGFR inhibitors. Mouth sores (mucositis or stomatitis) can also develop, leading to inflammation of oral tissues, including gums and the inner lining of the mouth. The incidence of mucositis varies, ranging from 6% to 17% with gefitinib and 52% to 72% with afatinib.
Eye irritation and dryness are reported in about a third of patients receiving EGFR inhibitor therapy. This can manifest as blepharitis, an inflammation of the eyelid margins, or conjunctivitis, which causes redness and sometimes discharge. Liver enzyme elevations, typically mild to moderate and transient, may also be observed, indicating a temporary impact on liver function.
Strategies for Managing Side Effects
Managing side effects often involves a combination of at-home care and communication with the healthcare team. For skin-related issues, applying a thick, emollient cream or moisturizer (ideally without dyes or fragrances) to the face and body once or twice daily from the start of medication can help prevent or lessen dryness and rash. Limiting direct sun exposure and using sunscreen with an SPF of 30 or higher is also advisable, as photosensitivity can occur. Gentle skin care, including bathing with warm or cool water and using mild soaps, can further support skin health.
For diarrhea, dietary adjustments can be beneficial, such as avoiding fatty or spicy foods and ensuring adequate fluid intake. Over-the-counter anti-diarrheal medications, like loperamide, can be used as directed by a healthcare provider. Staying well-hydrated is important to counteract fluid loss from diarrhea and can help with fatigue.
Addressing hair and nail changes involves specific care. For brittle hair or thinning, therapeutic shampoos might offer some relief. Eyelashes that grow long and curl inward should be trimmed, and an ophthalmologist can assist if corneal irritation occurs. For nail discomfort, protecting affected areas and considering antiseptic cleansers for nails daily can be helpful. It is important to inform the oncology team about any side effects, as they can provide tailored advice and adjust treatment if necessary.
When to Seek Professional Medical Care
Recognizing when to contact a healthcare provider for EGFR inhibitor side effects is important. Prompt communication is needed for severe or widespread skin rash, especially if accompanied by blistering, peeling, or signs of infection (increased redness, warmth, swelling, or pus). A dermatologist referral may be needed for severe skin toxicities.
Persistent or severe diarrhea, defined as more than six episodes per day, or diarrhea that does not improve with over-the-counter remedies, warrants immediate medical attention. This helps prevent dehydration and electrolyte imbalances. Any new or worsening symptoms, including significant fatigue that interferes with daily activities, severe pain, or difficulty breathing, should be reported to the healthcare team without delay.