Topical 5-fluorouracil for skin cancer prevention
Topical 5-fluorouracil 5% (single 2-4 week course) vs. Vehicle cream · for Keratinocyte carcinoma (high-risk) · real-time analysis of 1 studies · updated 2026-05-29
A single field course of topical 5-fluorouracil to the face and ears sharply reduced squamous-cell carcinoma requiring surgery in the first year, with no significant effect on basal-cell carcinoma.
Efficacy (RCT): Efficacy evidence on clinical outcomes. Effects are risk ratios with number-needed-to-treat where a baseline risk is available. Glossary →
Large but time-limited: squamous-cell carcinomas needing surgery fell ~75% in the first year, then the difference faded—field therapy clears existing damage rather than giving lasting protection. Basal-cell was not significantly reduced.
Forest plot—Squamous-cell carcinoma (needing surgery)
Study results—Squamous-cell carcinoma (needing surgery)
| Study | Design | Dose / regimen | Treatment | Control | RR [95% CI] | Improvement | NNT | Weight |
|---|---|---|---|---|---|---|---|---|
| VAKCC (Weinstock) 2018 note | DB-RCT | 5-FU 5% single course | 5/468 | 20/464 | 0.25 [0.09–0.65] | 75% | 31 | 100% |
RR < 1 favors treatment for outcomes where lower is better. Rows in gray have a confidence interval crossing 1 (individually inconclusive). “~” marks effects reported as OR/HR and treated as RR-approximations. “excl” = excluded from pooling (e.g. reviews).
Notes & interpretation
- VAKCC (Weinstock) 2018—Squamous-cell carcinoma requiring surgery, first year (~75% reduction). Effect faded after year 1.
Forest plot—Basal-cell carcinoma
Study results—Basal-cell carcinoma
| Study | Design | Dose / regimen | Treatment | Control | RR [95% CI] | Improvement | NNT | Weight |
|---|---|---|---|---|---|---|---|---|
| VAKCC (Weinstock) 2018 note | DB-RCT | 5-FU 5% single course | 45/468 | 50/464 | 0.89 [0.61–1.31] | 11% | 87 | 100% |
RR < 1 favors treatment for outcomes where lower is better. Rows in gray have a confidence interval crossing 1 (individually inconclusive). “~” marks effects reported as OR/HR and treated as RR-approximations. “excl” = excluded from pooling (e.g. reviews).
Notes & interpretation
- VAKCC (Weinstock) 2018—Basal-cell carcinoma, first year; not significant.
Background
The VAKCC trial randomized 932 veterans at high risk of keratinocyte carcinoma to a single 2-4 week course of 5-fluorouracil 5% cream versus vehicle, with a median 2.8 years of follow-up.
Topic methodology & caveats
Studies
- 2018 · DB-RCT Weinstock MA, Thwin SS, Siegel JA, et al. Chemoprevention of basal and squamous cell carcinoma with a single course of fluorouracil, 5%, cream (VAKCC). JAMA Dermatol. 2018;154:167-174.
- 2018 · DB-RCT Weinstock MA, Thwin SS, Siegel JA, et al. Chemoprevention of basal and squamous cell carcinoma with a single course of fluorouracil, 5%, cream (VAKCC). JAMA Dermatol. 2018;154:167-174.