How does alcohol compare to tobacco as a risk factor for cancer?

Comparison of Alcohol and Tobacco as Risk Factors for Cancer

Tobacco is a significantly stronger overall cancer risk factor than alcohol, with tobacco causing more types of cancers and at higher relative risks, though both substances are established carcinogens that can act synergistically, particularly for upper aerodigestive tract cancers. 1, 2

Cancer Risk from Tobacco

• Tobacco use is a major established cause of multiple cancers:

  • Oral cavity
  • Pharynx
  • Larynx
  • Esophagus
  • Lung (extremely high risk, with 11-23 times increased risk for current smokers) 3
  • Liver

• Smoking cessation can significantly reduce cancer risk, with benefits observed as early as 5 years after quitting 4

Cancer Risk from Alcohol

• Alcohol is an established cause of at least 7 types of cancer 1:

  • Oral cavity
  • Pharynx
  • Larynx
  • Esophagus (squamous cell carcinoma)
  • Liver
  • Colorectum (1.4-fold higher risk with >3 drinks/day) 1
  • Female breast (10-12% increased risk per daily drink) 1
  • Possibly stomach cancer 1

• The American Cancer Society clearly states that "it is best not to drink alcohol" for cancer prevention 1

• Risk increases with amount consumed:

  • For breast cancer, risk increases by 7.1% for each additional 10g (1 drink) of alcohol per day 5
  • For upper aerodigestive tract cancers, risk can be up to 5 times higher in drinkers compared to non-drinkers 6

Synergistic Effects

• The combined use of alcohol and tobacco creates a multiplicative (greater than additive) effect on cancer risk, particularly for:

  • Oral cavity cancers
  • Pharyngeal cancers
  • Esophageal cancers (squamous cell carcinoma)
  • Laryngeal cancers 2, 6

• In Latin American studies, 65% of all upper aerodigestive tract cancers were attributable to the combined effect of alcohol and tobacco 6

Relative Impact on Cancer Burden

• Tobacco has a greater overall impact on cancer mortality and morbidity than alcohol:

  • Tobacco is the leading preventable cause of cancer
  • Smoking shows stronger associations with most shared cancer sites (especially lung cancer)

• Alcohol consumption was estimated to cause 5.6% of all incident cancer cases and 4% of all cancer deaths in the US (2014) 1

• For specific cancers, alcohol's contribution is substantial:

  • 40.9% of oral cavity/pharynx cancers
  • 23.2% of larynx cancers
  • 21.6% of liver cancers
  • 21% of esophageal cancers
  • 12.8% of colorectal cancers
  • 16.4% (39,060 cases) of female breast cancers 1

Key Differences

• Tobacco shows no safe level of use for cancer risk

• For alcohol, low levels of consumption (≤1 drink/day for women, ≤2 drinks/day for men) may have cardiovascular benefits in middle-aged adults that could outweigh cancer risks in certain populations 1

• Tobacco appears to have minimal independent effect on breast cancer risk when controlling for alcohol consumption 5

• Alcohol has a clear dose-dependent relationship with breast cancer risk even at low consumption levels 5

Clinical Recommendations

• Complete avoidance of tobacco is strongly recommended for cancer prevention
• For alcohol, the American Cancer Society recommends:
  • Ideally, not drinking alcohol at all 1
  • If choosing to drink, limit to no more than 1 drink/day for women and 2 drinks/day for men 1
  • Women at high risk for breast cancer might reasonably consider abstaining completely 1