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MEDIA
STATEMENT
11th October 2005
Sudbø J et al. Non-steroidal anti-inflammatory drugs and
the risk of oral cancer: a nested case-control study.
Lancet online. Published online October 7, 2005. DOI:10.1016/SO140-6736(05)67488-0
Summary
This observational study from Norway found that regular long-term use
of NSAIDs, including ibuprofen, is associated with a reduced risk of oral
cancer in heavy smokers. However, overall mortality was not reduced because
regular long-term NSAID use was also associated with an increased risk
of death from cardiovascular disease.
Neither of these findings is directly relevant to the intermittent use
of low doses of ibuprofen typical of over-the-counter-use.
Why was the study carried out?
Observational studies have suggested that regular use of NSAIDs is associated
with a reduced risk of certain cancers (in the case of colorectal cancer,
interventional studies suggest that NSAIDs actually do reduce this risk).
However, data on their effects on the risk of oral cancer are based on
the use only of aspirin and are inconclusive. This study sought to provide
more conclusive information.
How was the study carried out?
The study was an analysis of data from the Norwegian Health Survey, a
database of 123,234 people who participate in 5-yearly physical examinations
and interviews about their health and medication.
The study identified 9,241 participants who were heavy smokers; of these,
454 who had oral cancer (cases) were matched with 454 heavy smokers who
had no cancer of any kind (controls). The use of prescribed NSAIDs or
paracetamol was then compared in the two groups.
Heavy smokers were defined as those with a history of at least 15 pack-years
(a pack-year is calculated by multiplying the number of packs of 20 cigarettes
smoked per day by the number of years of smoking). Controls were matched
for age and sex. Over two-thirds of smokers used hand-rolled unfiltered
cigarettes; these are associated with a particularly high risk of oral
cancer.
In Norway, all NSAIDs are available only on prescription. In this study,
long-term use was defined as taking an NSAID at least once a day for 6
months and this could be confirmed by prescribing records. This definition
is stricter than has been used in other observational studies, which have
defined NSAID use by a person's recollection of having taken as little
as one or more tablets up to several times per week.
Information about the prevalence of cardiovascular disease was not recorded
and it is therefore unknown what proportion of NSAID users were at increased
risk of cardiovascular events as a result.
Principal findings
Regular use of an NSAID, but not paracetamol, was significantly associated
with a reduced risk of oral cancer among heavy smokers. Overall, the risk
was nearly halved in those taking an NSAID for up to 5 years and reduced
by 70 percent in those who had taken an NSAID for at least 15 years. The
risk was reduced by about 60 percent among people who had stopped smoking.
There were no significant differences in risk associated with individual
NSAIDs and all (except ketoprofen, for which analysis was complicated
by low numbers) were associated with a statistically significant risk
reduction (e.g ibuprofen, 63 percent; aspirin, 62 percent; naproxen, 50
percent).
NSAIDs were not, however, associated with an increase in overall survival.
Deaths due to cardiovascular disease occurred in 16 percent of NSAID users
and 7 percent of non-users. NSAID use was associated with a doubling of
the risk of death due to cardiovascular disease after adjustment for smoking
status. This was statistically significant for indomethacin and ibuprofen
but comparisons of individual drugs should be interpreted cautiously because
of the small numbers of people taking each agent.
Interpretation
This observational study does not prove that regular use of an NSAID caused
the positive or negative effects identified but its findings are consistent
with what is known about these medicines. The lower risk of oral cancer
associated with NSAID use was comparable with that of smoking cessation
and suggests that, subject to the findings of suitably designed clinical
trials, regular NSAID use may be a viable preventative treatment for oral
cancer in heavy smokers.
The data are relevant only to regular consumption of prescribed NSAIDs
and their significance for the occasional use of low doses of ibuprofen
is unknown. There is no information about the rate of oral cancer among
smokers who take ibuprofen occasionally. By contrast, OTC ibuprofen is
unlikely to increase the risk of cardiovascular events: the Medicines
and Healthcare Products Regulatory Agency recently concluded: '….short-term
use [of ibuprofen] at the doses that can be bought over the counter is
unlikely to be associated with any measurable increased risk.'1
Ends
1. Medicines and Healthcare Products regulatory Agency. Cardiovascular
safety of NSAIDs. Review of evidence. (www.mhra.gov.uk/home/groups/plp/documents/drugsafetymessage/con1004303.pd;
accessed 10.10.2005)
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