Intralesional 5‐Fluorouracil in Nodular Basal Cell Carcinoma: An Exploratory Prospective Pilot Study With 1‐Year Follow‐Up
Shatila Torabi, Ahmad Reza Taheri, Monavvar Afzalaghaee, Mahdi El HusseiniBackground
Surgical excision is the standard for basal cell carcinoma (BCC), but it is frequently unfeasible due to patient comorbidities or sensitive lesion sites. This study evaluates the 1‐year efficacy of intralesional 5‐fluorouracil (IL 5‐FU) for nodular BCC, addressing a critical gap in 1‐year follow‐up literature. This exploratory pilot study was designed to generate hypotheses regarding the 1‐year durability of IL 5‐FU and its potential as a neoadjuvant agent.
Methods
This prospective, single‐arm pilot trial evaluated 12 patients with 23 biopsy‐proven nodular BCC lesions. Patients received weekly intralesional injections of 50 mg/mL 5‐FU (with lidocaine/epinephrine) for 6–10 weeks. Primary outcomes included relative reduction in two‐dimensional surface area and complete clinical response (CCR) at 6 months and 1 year.
Results
IL 5‐FU demonstrated a profound debulking effect, reducing mean two‐dimensional lesion surface area by 84.22%. The CCR rate was 65.2% (15/23 lesions) at 6 months but declined to 52.17% (12/23 lesions) at 1 year due to three delayed clinical recurrences; notably, because post‐treatment biopsies were limited to clinically suspicious lesions, this rate may overestimate the true histopathologic cure by missing occult microscopic disease. At the patient level ( n = 12), only 33.3% (4 of 12) achieved a sustained CCR across all treated lesions at the 1‐year mark. The treatment was well‐tolerated with zero reported pain in the immediate postprocedure period and only transient local reactions.
Conclusion
A 1‐year CCR rate of 52.17% is insufficient to universally replace surgical excision. However, the true value of IL 5‐FU appears to lie in its remarkable 84.22% debulking capability. This observed debulking effect supports prospective evaluation of a potential neoadjuvant role to downstage large or anatomically complex tumors before tissue‐sparing surgery.
Trial Registration: IRCT20240822062839N1.