5-FU is a chemotherapy agent that kills rapidly dividing cells. Although it is traditionally used for cancer patients, it is also highly effective for reducing the size and appearance of hypertrophic scars and keloid scars. It comes in many forms, including topicals and injections, and produces results within weeks.
5-FU is a special chemotherapy drug that acts as an antimetabolite. Specifically, it acts by inhibiting DNA replication in actively dividing cells, such as fibroblasts, which are the collagen-producing cells in your skin. The resulting cell death of fibroblasts upon local 5-FU administration thus decreases the collagen density in your skin and softens the scar tissue. This leads to a noticeable reduction in the raised profile of your scars.
Due to their potent antimetabolic effects, 5-FU is especially effective against hypertrophic and keloid scars, whose fibroblastic activity is elevated compared to that of other scar types. In addition, 5-FU has shown to be equally effective for old and new scars because scars of all ages undergo constant remodeling. In addition, we’ve observed that 5-FU has been highly effective when used in combination with our other treatments, such as Kenalog injections or lasers. At our clinic, we would evaluate your scars to see what concentration, combination, and number of phases are optimal for treating your scars specifically. Since most acne scars are atrophic in nature, 5-FU is most likely not the most viable treatment. Atrophic acne scars result from a depletion in collagen, which would be exacerbated with 5-FU injections. However, in rare cases where your acne scars are hypertrophic, then 5-FU injections may certainly be the right treatment option for you.
5-FU injections are a low-risk and minimally invasive procedure. Local anesthetics are not needed with these painless injections but if the patient desires, a topical anesthetic can be applied to make the procedure more comfortable. After treatment, you may experience a burning sensation and soreness at the injection site. In highly rare circumstances, you may have an infection, which would easily be resolved with antibiotics, or ulceration if aftercare instructions are not carefully implemented.
Most patients will have to come in for several rounds of 5-FU injections in combination with other therapies to see maximal benefit, especially for those with more severe and extensive scarring. It generally takes several weeks to start seeing a noticeable difference and up to a year to see optimal results. To expedite the process, we combine 5-FU therapies with Kenalog or laser resurfacing, as we’ve found these combinations to be highly effective. In our years of experience, we have never experienced recurrence of scars after many sessions of 5-FU. Therefore, you should not expect 5-FU injections to be an indefinite treatment plan.
The cost of 5-FU injections is highly dependent on the severity and location of your scars. Deeper, faster-growing scars in complex regions on your body will require more aggressive treatment and thus translate into a higher treatment cost. We will have to thoroughly evaluate your scars to determine if 5-FU is right for you and, if so, for how long and in what concentration.