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Outcomes of Treatment With 5-Fluorouracil 5% Cream in Patients With Squamous Cell Carcinoma In Situ
TAKE-HOME MESSAGE
- This retrospective study investigated the outcomes of treatment with 5-fluorouracil 5% cream in patients with squamous cell carcinoma in situ and identified factors influencing treatment outcomes. A total of 149 cases were included in the analysis. A complete clinical response was noted in 87.9% of the cases. Tumors treated for 4 weeks or longer showed the highest clinical response rates. A shorter treatment duration was significantly associated with treatment failure (OR, 0.26; P = .007). Furthermore, larger tumor size was associated with higher treatment failure rates (OR, 2.40; P = .037).
- This study concludes that topical 5-fluorouracil is effective, particularly for smaller lesions and extended treatment durations, and highlights its potential as a non-surgical treatment option even for immunosuppressed patients.
abstract
This abstract is available on the publisher's site.
Access this abstract now Full Text Available for ClinicalKey SubscribersBACKGROUND
Complete clinical response (CCR) rates for squamous cell carcinoma in situ (SCCis) treated with 5-fluorouracil (5-FU) 5% cream range from 27-85%. Factors associated with CCR are not well-established.
METHODS
Retrospective review of biopsy-proven primary SCCis diagnosed between 5/1/2019-4/30/2020 and treated with 5-FU 5% cream. Disease status at follow-up was recorded, with treatment failure defined as persistent or recurrent disease.
RESULTS
The study included 149 SCCis cases, including 33.6% (50/149) arising in the context of immunosuppression. Eighteen cases failed treatment (10 persistent disease, 8 recurrent disease). By tumor size, CCR was noted in 128/144 (88.9%) tumors measuring <2 centimeters in diameter and 3/5 tumors ≥2 centimeters (60.0%, p=0.051). By treatment duration, CCR was observed in 4/7 (57.1%) tumors treated for <2 weeks, 72/83 (86.7%), tumors treated for 2 to <4 weeks, and 55/59 (93.2%) tumors treated for ≥4 weeks (p=0.019). On multivariate analysis, treatment failure was significantly associated with shorter treatment durations (OR 0.26; p=0.007) and increasing tumor size (OR 2.40; p=0.037).
CONCLUSIONS
Shorter treatment duration and larger lesion size were significantly associated with failure of 5-FU in SCCis. Immunosuppression and anatomic location were not significant factors, supporting 5-FU use for SCCis in the immunosuppressed population and highlighting its versatility irrespective of anatomic location.
Additional Info
5-fluorouracil 5% cream for squamous cell carcinoma in situ: Factors impacting treatment response
J Am Acad Dermatol 2024 Nov 07;[EPub Ahead of Print], CP Lin, N Kibbi, T Bandali, K Hirotsu, SZ AasiFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Squamous cell carcinoma in situ (SCCis) is a common skin malignancy that can be treated using surgical or non-surgical interventions. Topical 5-fluorouracil (5-FU) is FDA-approved for the treatment of actinic keratosis and superficial basal cell carcinoma, but it is also frequently used off-label to treat SCCis. Guidelines for the treatment of SCCis using 5-FU currently do not exist — in part owing to a lack of data defining how specific characteristics of SCCis affect treatment response.
This retrospective cohort study from Stanford assessed the tumor characteristics affecting complete clearance response rates or treatment failure in patients with SCCis treated with 5-FU. Tumor size and treatment duration were both found to be significantly associated with treatment response. Treatment failure occurred in approximately 11% of tumors less than 2 cm in diameter, but this rate increased to 40% among tumors measuring 2 cm or greater in diameter. Treatment failure occurred in approximately 13% of the tumors treated between 2 to 4 weeks and approximately 7% of those treated for 4 weeks or longer, but the rate was significantly higher (approximately 43%) among tumors treated for less than 2 weeks. This study is limited by its retrospective nature, follow-up bias, and inability to identify the exact duration of 5-FU usage. Furthermore, the inclusion of lesions with a biopsy diagnosis of "at least SCC in situ," without ruling out invasive SCC, may have affected the study results. The generalizability of the results may be affected owing to the high percentage of immunosuppressed patients in this cohort.
Topical 5-FU has traditionally been used in the treatment of SCCis owing to its ease of use and excellent cosmetic results and for patients who are not suitable candidates for surgery. When treating SCCis with topical 5-FU, dermatologists should consider longer treatment durations (at least 2–4 weeks) and smaller tumors (<2 cm) — particularly in the immunosuppressed population.