What do systematic reviews say?

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

Systemic beta carotene or carotenoids (incl. lycopene) may leads to lower improvement of histological features (not improved) compared with placebo or no treatment (low certainty).

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

  5 months (treatment lasted 3 months)
  RR 0.24 [0.12, 0.46]
  1 study · 58 participants
  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

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

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

  5 to 12 months
  SoF 2, Safety of the intervention at 5 to 12 months: 'Systemic beta carotene did not cause any adverse effects in 1 study supplementing 10 mg/d (Nagao), and caused adverse effects of varying severity in 9% of…
  3 studies
  GRADE not reported

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

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

  5 to 12 months
  SoF 2, Clinical resolution (not completely resolved) at 5 to 12 months: 'The 3 studies could not be combined in meta-analysis. 2 found benefit for systemic beta carotene, and 1 did not.' No GRADE rating. Effects text…
  3 studies
  GRADE not reported