Topical Fluorouracil Therapy for Residual Superficial Basal Cell Carcinoma Following Mohs Micrographic Surgery

May 2020 | Volume 19 | Issue 5 | Original Article | 485 | Copyright © May 2020


Published online April 10, 2020

Hannah Pederson , Cecil Jordan Staples , Chad Housewright

aDepartment of Dermatology, Baylor Scott & White Health, Texas A&M Health Science Center College of Medicine, Temple, TX bTexas A&M Health Science Center College of Medicine, Temple, TX

Abstract
When treating invasive basal cell carcinoma (BCC) with Mohs micrographic surgery (MMS), including infiltrative and nodular subtypes, the goal is complete surgical removal of the tumor. In some cases, after several stages of MMS, residual foci of superficial BCC are noted with no dermal invasive components apparent. Some patients and surgeons have opted for halting surgery and treating residual superficial BCC with adjuvant topical fluorouracil. In this retrospective study, this treatment method is shown to be effective with a recurrence rate of BCC of 3.7% over a mean follow up of 28 months. This treatment method reduces the number of stages of MMS as the surgery is stopped was invasive BCC is removed. This can be beneficial when considering the morbidity of prolonged surgical procedures in frail, elderly patients experiencing surgical fatigue, the cost of additional stages, and the cost of advanced repairs due to enlarging defect size.

J Drugs Dermatol. 2020;19(5): doi:10.36849/JDD.2020.4811

INTRODUCTION

Mohs micrographic surgery (MMS) is characterized by its histopathologic margin control and ability to spare tissue, particularly in cosmetically sensitive areas.1 According to National Comprehensive Cancer Network, MMS has the highest cure rate of any modality and is a first line treatment for non-melanoma skin cancers.2 For superficial basal cell carcinoma (BCC), topical fluorouracil has been used prior to MMS to decrease tumor size and subsequently decrease the number of stages.3 When treating invasive BCC, including infiltrative and nodular subtypes, some Mohs surgeons also utilize topical fluorouracil post-operatively once invasive BCC is removed by MMS to treat remaining superficial BCC. This is performed in an effort to reduce the size of a defect in a cosmetically sensitive area. To our knowledge, outcome data for this practice has not been reported.

METHODS

A retrospective chart review from January 1, 2014 to September 1, 2018 was performed of patients who had residual superficial BCC on the final stage of MMS and elected to halt surgical removal of BCC and be treated with topical fluorouracil. Patients were excluded from the study if they had less than six months of follow up or if they did not use fluorouracil as prescribed. Each recurrence was confirmed with photographs.

RESULTS

A total of 109 patients were included in this study with an average age of 73. Of these, 94% were Caucasian and 56% were male. Out of the 109 patients, 106 had invasive tumors with histologic subtypes of either nodular or infiltrative BCC. Three of the patients had superficial BCC. Over a mean follow-up of 28 months and a median of 27 months, the recurrence rate of BCC was 3.7% (4 patients). The recurrences occurred an average of 13 months after surgery, with a range from 3-17 months.

DISCUSSION

While surgical methods remain the gold standard in BCC treatment, several alternative treatment options exist, including topical fluorouracil.4 Topical fluorouracil has been shown to be a safe and effective modality of treatment of superficial BCC in non-surgical candidates, and is regarded as a cost-effective, convenient, non-invasive, and non-disfiguring topical chemotherapy.5

In some cases after several stages of MMS, residual foci of superficial BCC are noted with no dermal invasive components apparent. While complete tumor clearance with MMS of both the invasive and superficial components of BCC is optimal for the highest cure rate, there are other significant factors to consider with ongoing tumor extirpation, including functional and cosmetic outcomes, cost, and surgical morbidity. Some patients and surgeons have opted for halting surgery and treating residual superficial BCC with adjuvant topical fluorouracil. This is analogous to the use of topical 5% imiquimod for the treatment of residual melanoma in situ after surgical resection of the primary lesion.6

Our study shows topical fluorouracil is an effective treatment for