What do systematic reviews say?

NSAIDs (ketorolac oral rinse; systemic celecoxib) vs placebo or no treatment

• Interventions for treating oral leukoplakia to prevent oral cancer 2016 · Cochrane All outcomes
  SoF 3 (NSAIDs vs placebo), Cancer development: SoF cell 'Not measured'. Effects text: cancer development was among outcomes in Papadimitrakopoulou 2008 (celecoxib) but did not occur in either arm, probably because of…
  1 study
  GRADE not reported

Vitamin A or retinoids (systemic or topical; incl. 13-cis-retinoic acid, acitretin) vs placebo or no treatment

It is very uncertain whether vitamin A or retinoids (systemic or topical; incl. 13-cis-retinoic… changes oral cancer development compared with placebo or no treatment (very low certainty).

• Interventions for treating oral leukoplakia to prevent oral cancer 2016 · Cochrane All outcomes

  24 months (treatment lasted 12 months)
  RR 0.11 [0.01, 2.05]
  1 study · 85 participants
  Very low

Topical bleomycin vs placebo or no treatment

It is very uncertain whether topical bleomycin changes oral cancer development compared with placebo or no treatment (very low certainty).

• Interventions for treating oral leukoplakia to prevent oral cancer 2016 · Cochrane All outcomes

  up to 7 years
  RR 3.00 [0.32, 27.83]
  1 study · 20 participants
  Very low

Systemic beta carotene or carotenoids (incl. lycopene) vs placebo or no treatment

It is very uncertain whether systemic beta carotene or carotenoids (incl. lycopene) changes oral cancer development compared with placebo or no treatment (very low certainty).

• Interventions for treating oral leukoplakia to prevent oral cancer 2016 · Cochrane All outcomes

  24 months
  RR 0.71 [0.24, 2.09]
  2 studies · 132 participants
  Very low

Herbal extracts (tea components; Chinese herbal mixture; freeze-dried black raspberry gel) vs placebo or no treatment

• Interventions for treating oral leukoplakia to prevent oral cancer 2016 · Cochrane All outcomes
  SoF 4 (Herbal extracts vs placebo), Cancer development: SoF cell 'Not measured'. Effects text: cancer development was among the outcomes in Tsao 2009 (green tea extract) but it was not possible to analyse the data…
  1 study
  GRADE not reported

Bowman-Birk inhibitor vs placebo or no treatment

The review found no eligible studies for this question.

• Interventions for treating oral leukoplakia to prevent oral cancer 2016 · Cochrane All outcomes
  SoF 6 (Bowman-Birk inhibitor vs placebo), Cancer development: 'Not measured'. Effects text: 'Cancer development was not among the outcomes of the study testing the Bowman-Birk inhibitor (Armstrong 2013).'
  0 studies
  No studies found