Higher severity grade of erlotinib-induced rash is associated with lower skin phototype

Epidermal growth factor receptor inhibitors (EGFRIs) are associated with a characteristic papulopustular rash, an adverse event considered to be a class effect of these agents. Erlotinib, a small-molecule EGFRI, causes a papulopustular rash in 68-75% of patients. The limited reported data suggest that deleterious effects of ultraviolet radiation (UVR) may enhance the development of EGFRI-induced rash. Because the level of the biological pigment melanin correlates with increased protection against UVR, we hypothesized that lighter levels of skin pigmentation are associated with greater severity of rash.

To characterize the relationship between skin phototype (SPT) and rash severity.

A retrospective chart review was conducted of 40 patients on erlotinib. Skin sensitivity to UVR was categorized using the Fitzpatrick SPT classification scheme. Grading of rash was performed using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE), version 3.

There was an inverse relationship between SPT and rash severity. Grade 0 was seen in the majority of patients with SPT V/VI, grade 1/2 in the majority of patients with SPT III/IV, and grade 3/4 rash in the majority of patients with SPT I/II (grade 0: 7% SPT I/II, 32% SPT III/IV and 50% SPT IV/V; grade 1/2: 33%, 63% and 50%, respectively; grade 3/4: 60%, 5% and 0%, respectively) (P < 0.01, Fisher exact test).

Prevention and management of cutaneous side-effects from EGFR inhibitors is important to achieve maximum patient compliance and therapeutic benefit. The results of this study suggest that SPT may be an independent predictive factor for EGFRI-induced papulopustular rash, thus pre-therapy counselling and early intervention are important.