Intralesional Use of 5-FU in Subcutaneous Fibrosis

5-fluorouracil (5-FU) is an antimetabolic cytostatic drug that inhibits DNA formation. It is potentially toxic for the dysplasic epithelium, and it has therefore been used successfully as an antineoplastic for the treatment of various types of cancer. It has been successfully applied topically to treat pre-malignant and malignant skin and mucous membrane lesions.

5-FU was first used as an antifibrotic in the 1960s in the field of ophthalmology to prevent scarring after glaucoma surgery, and to prevent recurrence after pterygia surgery^1,2,3,4. In February of 1999 it was suggested as a potential way to prevent the formation of fibrotic adhesion after tendon surgery⁵. In March of 1999, Fitzpatrick published his paper on the use of 5-FU for the treatment of scar hypertrophy and keloids, presenting his results in some 1000 patients over 7 years⁶. Reading that paper inspired us immediately to use that drug ourselves in those difficult types of lesions⁷. Moved and excited by the results obtained, we decided to use the drug in other type of lesions in the subcutaneous tissue, due to the fact that in our practice we frequently see other pathologies linked to the excessive production of fibrous tissue.

It has been proved that in laboratory cultures the 5-FU barely reduces collagen reduction in normal fibroblasts, but produces a drastic reduction in the altered fibroblasts, as happens in Dupuytren's disease, acting on the gene controlling the amount of protein or the messenger⁸. It also seems to counteract the capacity of growth factor TGF-1 to stimulate collagen production⁸.