Certain types of scars are particularly problematic, not only because of the way they look, but due to their tendency to become raised, thickened, and painful. Keloids and hypertrophic scars represent an abnormal scar healing process. Many different treatments have been tried for these difficult scars including surgical scar revision, steroid injections, and radiation therapy, often in combination. Any new scar therapies are welcome.
Anectodal reports exist for numerous new pharmacological treatments, one of which is 5-fluorouracil. (5-FU) 5-FU is a well-known drug used as a chemotherapy agent against cancer for several decades. It works by inhibiting DNA replication which is important in stopping cancer cells which usually multiply faster than normal cells. In dermatology, 5-FU is most commonly used topically (as a cream) for treating actinic (solar) keratoses and some types of basal cell cancers of the skin. (e.g., Efudex or Carac) It is thought that it might work in scar problems because it appears to block collagen synthesis which might help to control excessive scar formation.
In the January 2009 issue of the journal Plastic and Reconstructive Surgery, 5-FU treatment of problematic scars was reported. Keloids were treated by excision and 5-FU injections after in 32 patients and hypertrophic scars were treated by 5-FU injections only in 21 patients. The dose of 5-FU injections was 50mg mixed with lidocaine given one month apart for 10 injections until the maximum dose of 500mg was reached. For keloids, the recurrence rate was 19% at one year. For hypertrophic scars, the response rate was 86% with a 50% reduction in scar volume at one year.
While no scar study will ever be perfect and no two scars are ever the same, it is hard to know from this study if 5-FU offers a real improvement over steroid injections. You could argue that a prospective study using steroids and 5-FU would be helpful in addressing this question. But given the relatively poor response to treatment of most keloids with steroids, I will consider 5-FU injections for future cases. For hypertrophic scars, I am not so sure but the apparent lack of any side effects (steroids are well known to cause tissue thinning and atrophy) gives it some appeal. 5-FU is not a ‘magic bullet’ but it does offer another option for difficult scar problems.
Dr. Barry Eppley
Indianapolis, Indiana