Reasons for Patient Call-backs while being Treated with Topical 5-fluorouracil: A Retrospective Chart Review

To assess the frequency and character of adverse events (AE) associated with 5-FU and compare rate of these events to topical tacrolimus, another irritating topical treatment, as a control.

Patients prescribed 5-FU for Actinic keratosis (AK) between 1/2015 to 10/2021 were contacted via phone to assess frequency of AE and why they did or did not contact their dermatologist via retrospective chart review. A similar retrospective chart review was done for patients prescribed topical tacrolimus between 1/2015 to 10/2021.

Participants frequently reported AE with 5-FU treatment (58%), which most commonly included redness or inflammation (38%) and burning, stinging, or pain (27%). There were 33 call backs for 5-FU (37 distinct questions) and the most common reasons included issues obtaining the medication (n=12) and inquiries about severe LSR (n=11). There were two call backs for topical tacrolimus related to issues obtaining the medication.

Topical tacrolimus as a control helps address the lack of objective assessment of AE severity and potential recall bias limitations of the study methodology.

Participants in our cohort frequently reported AE, and those who reported AE often contacted their dermatologist. The irritation induced by 5-FU is of greater severity compared to topical tacrolimus, as evidenced by much greater call-back rate. Addressing the risks and benefits of 5-FU, severity of LSR, and use of alternative treatments may improve AK treatment outcomes.