Could there be a skin-protecting effect from such common painkillers as ibuprofen or ASA, often sold as aspirin?
A new study from Denmark finds that people who took painkillers regularly over many years -- especially at high doses -- were less likely to develop skin cancer compared to those who rarely used those medications.
While the findings add to growing evidence that long-term use of non-steroidal anti-inflammatory drugs, or NSAIDs, may help protect people against skin cancers, this study had a number of weaknesses. Most notably, it failed to look at what effect sun exposure had on the findings.
The study, published online in Cancer, the journal of the American Cancer Society, looked at more than 18,000 people from Denmark who had been diagnosed with different forms of skin cancer between 1991 and 2009. Of them, around 13,000 had been diagnosed with the most common form, basal cell carcinoma; 3,000 with the most dangerous form, malignant melanoma; and 2,000 or so with another form, called squamous cell carcinoma.
The researchers, from Aarhus University Hospital in Denmark, looked at the prescription records of those patients and compared it with information from 178,000 Danes without skin cancer.
They found that those people who had filled more than two prescriptions for NSAIDs had a 15 per cent decreased risk of developing squamous cell carcinoma compared to those who filled fewer prescriptions for the medications. They also had a 13 per cent decreased risk for developing malignant melanoma.
Interestingly, those taking NSAIDs did not seem to have a reduced risk of developing basal cell carcinoma, although they did have a 15 per cent and 21 per cent reduced risk of developing this type of cancer on less-exposed sites (body areas other than the head and neck) when they took them long term or at high intensity, respectively.
When the researchers looked at people who had taken the drugs over the long term -- at least seven years -- and used them twice a week or more, they found an even stronger link between NSAID use and the reduced risk of the three forms of skin cancer.
While the link found was significant, the researchers point out they were only able to monitor the number of prescriptions the patients received, not how much of the medications they took. Nor were they able to account for any NSAID use that came from over-the-counter medications.
And, they did not look at sun exposure - the most important factor in the development of skin cancer.
Still, the lead author on the study, Dr. Sigrun Alba Johannesdottir, says there is good reason to suspect NSAIDs might play a role in preventing skin cancer formation. In comments to Reuters Health, she says that the drugs are known to inhibit specific enzymes involved in inflammation.
Previous studies show that elevated levels of these enzymes are found in skin cancer and are involved in important steps of cancer development, such as suppression of the immune system.
Johannesdottir says she hopes her study will lead to more research on the potential cancer-protective effect of NSAIDs against skin cancer.
"This potential cancer-protective effect should be taken into account when discussing benefits and harms of NSAID use," she added.
It's important for patients considering NSAIDs to discuss their risks with their doctor. The medications have known bleeding risks and have been linked to an increased risk of kidney cancer.
