Chemotherapy Drugs Can Flatten Keloid Scars

Since keloids are a type of unregulated cell growth that is similar in some ways to cancer, researchers are exploring the use of chemotherapy and immunotherapy drugs typically used to inhibit tumor growth to treat keloids.³²

How Do Chemotherapy Drugs Work?

Chemotherapy drugs such as 5-fluorouracil and doxorubicin are cell-cycle specific that interferes with cell division, which makes cells die. Doxorubicin and bleomycin are anti-tumor antibiotics produced from a soil fungus, while 5-flurouracil is an antimetabolite—an organic compound that is very similar to normal cellular substances.^34-35 Tamoxifen, commonly used to treat breast cancer, is a nonsteroidal anti-estrogen.³

These drugs work in different ways to prevent and/or treat keloid formation:³

• 5-fluorouracil inhibits fibroblast proliferation, which in turn lowers collagen production.
• Bleomycin induces skin cell death.
• Doxorubicin inactivates the enzymes needed by fibroblasts to produce or resynthesize collagen.
• Tamoxifen inhibits fibroid proliferation, lowers collagen production, and reduces inflammatory proteins.

Evidence of Benefit

Clinical studies have been conducted using 5-fluorouracil and bleomycin injections into keloids and hypertrophic scars. Bleomycin was injected superficially around the outer edge of the keloid (almost like tattoo ink) or via multiple punctures into the keloid and dripped in. Study results indicate that bleomycin has an 88-92% response rate, with most patients experiencing significant flattening of the scar tissue and symptom relief. Reported recurrence rates are minimal, and the tattoo method minimizes adverse systemic effects while still obtaining positive results. Intralesional injection of 5-fluorouracil at 50 mg/mL up to three times a week significantly reduced keloid size in the majority of patients in clinical studies. When combined with other treatment therapies (e.g., steroid injections and PDL), 5-fluorouracil helped increase the rates of positive outcomes.^3,7

Only preliminary lab experiments have been done thus far on doxorubicin and tamoxifen. Results identified anti-keloid mechanisms for both drugs that suggest the possibility of treatment and preventive benefit.³