Curcumin in oral potentially malignant disorders and oral squamous cell carcinoma: Clinical and biological evidence from a systematic review.

BACKGROUND

Oral squamous cell carcinoma is associated with poor survival and frequently develops from oral potentially malignant disorders, particularly oral leukoplakia and oral lichen planus. Conventional management is mainly based on the removal of clinically altered areas; however, the risk of progression may persist. In this context, curcumin, a natural compound derived from turmeric with antioxidant, anti-inflammatory, and antineoplastic properties, has been investigated as a potential therapeutic alternative.

MATERIALS AND

METHODS

A qualitative systematic review was conducted following the Cochrane Handbook and PRISMA guidelines. Literature was searched in MEDLINE (PubMed), Web of Science, Scopus, and SciELO (September-December 2025), including human studies from the last 15 years in English, Spanish, or Portuguese. Studies on adult patients with oral leukoplakia, oral lichen planus, or oral squamous cell carcinoma treated with curcumin or Curcuma longa derivatives (oral or topical) were included. Outcomes assessed included clinical efficacy (lesion size and symptoms), anti-inflammatory effects, and molecular biomarkers.

RESULTS

A total of 1,527 articles were identified, of which 18 met the inclusion criteria, comprising 1,189 participants. Most studies were clinical trials. In oral leukoplakia, all studies reported clinical improvement, mainly reflected by lesion size reduction, although without consistent histopathological changes. In oral lichen planus, eight of ten studies showed reductions in pain and lesion size, with decreases in VAS scores and statistically significant differences (p<0.05). Relevant reductions in lesion size were also observed (p<0.05). In oral squamous cell carcinoma, a significant decrease in inflammatory cytokines (IL-1β, IL-8, TNF-α) was reported. Comparable efficacy to corticosteroids was observed in most comparative studies.

CONCLUSIONS

The use of curcumin appears to provide favorable clinical effects and relevant anti-inflammatory benefits in oral leukoplakia, oral lichen planus, and oral squamous cell carcinoma, mainly reflected by reductions in pain and lesion size. However, further well-designed clinical trials are required to confirm its efficacy and to better define its role in clinical practice.