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Observational epidemiological surveys (WG 3) page 15
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Table: 7 Level of evidence of protection provided by studies on vitamin E
and cancers
cancer sites CNERNA
World Cancer Res COMA Food and Nutrition
(France, 1996) Fund (USA, 1997) Policy (UK, 1998)
mouth and pharynx insufficient insufficient no data reported
larynx no data reported no data reported no data reported
oesophagus insufficient insufficient moderately consistent
lung and respiratory
tract
moderately consistent possible insufficient
stomach insufficient no relationship inconsistent
colon-rectum insufficient insufficient inconsistent
pancreas insufficient insufficient insufficient
liver no data reported no data reported ND
breast inconsistent no relationship insufficient
ovary no data reported no data reported no data reported
endometrium no data reported no data reported no data reported
cervix insufficient possible moderately consistent but
limited
prostate no data reported insufficient inconsistent
kidney ND no data reported ND
bladder ND insufficient insufficient
thyroid
ND: Not Done
ND no data reported ND
Comments on table 7
None of the reference books had data on larynx, liver, ovary, endometrium, kidney and
thyroid cancers. They agreed that data are insufficient for mouth and pharynx, oesophagus,
colon, rectum, pancreas and prostate cancers. For stomach and breast cancers, the
prevalent opinion is that there is no relationship. The only possible reduction of risk provided
by vitamin E could be for lung and respiratory tract cancers (COMA said it was insufficient
because they took into account intervention trials), and for cervix cancers, although data were
limited.
Comparison between tables 2 and 7
There was little overlapping between Table 2 and Table 7, the only exception being the
possible effect of vitamin E on lung and respiratory tract cancers. This discrepancy is largely
explained by the food source of vitamin E which was mainly seed oils and not fruit and
vegetables.
1.1.7 Concluding Statements
• Tomatoes:
⇒ convincing for oesophagus, stomach and lung cancers; possible for mouth
and pharynx cancers. For most of the other cancers, the results were