Study withdrawn due to volunteer disinterest in participating.

This research is being done to study whether using of topical tretinoin can help prevent the common rash that patients often get while taking epidermal growth factor inhibitor (EGFR-I) medications such ascetuximab or erlotinib.

Patients taking EGFR-I medications often develop skin irritation and acne-like bumps on their face, chest, and other areas. This rash from EGFR-I's is often treated with moisturizers and topical or oral antibiotics. However, there has not yet been a study looking at a way to prevent this common side effect from occurring, and topical tretinoin may be useful in reducing the rash.

Tretinoin 0.025% cream is approved by the Food and Drug Administration (FDA) for the treatment of acne, acne scarring, and photodamage. It is not approved for use in preventing rashes associated with EGFR-I's.

Inclusion Criteria:

• Age 18 years or over
• Scheduled to begin treatment with an EGFR inhibitor drug

Exclusion Criteria:

• Pregnant or nursing
• History of bleeding disorder
• History of keloids or large, thick, puffy-looking scars in the last 10 years
• Used topical retinoids in the last year (e.g. tretinoin/Retin-A, adapalene/Differin, tazarotene/Tazorac)