Treatment with TNF inhibitors linked to modest increased skin cancer risk in rheumatoid arthritis, study suggests
A new study from Sweden published in the BMJ online, has found that treatment with tumour necrosis factor (TNF) inhibitors showed an increase in risk of developing one type of non-melanoma skin cancer known as squamous cell carcinoma, but not the most common type of skin cancer, basal cell skin cancer (BCC).
This research is said to support the known association between rheumatoid arthritis and the elevated risk of developing non-melanoma cancer. However, treatment with TNF inhibitors adds little to the already elevated risk of non-melanoma skin cancers in patients with rheumatoid arthritis, according to the new study from the Karolinska Institutet, Stockholm.
Previous studies have shown significantly higher rates of non-melanoma skin cancer in patients with rheumatoid arthritis compared to the general population, but studies of RA patients with TNFi have provided mixed results.
Dr Pauline Raaschou and her team looked at data from the Swedish Biologics Register and the Swedish National Cancer Register to compare the relative risk of squamous cell skin cancer and basal cell cancer with rheumatoid arthritis and TNFi treatment.
Researchers identified 46,409 patients with rheumatoid arthritis who were naïve to TNF inhibitors, ie had not yet taken TNF drugs, and 12,558 who started anti-TNF therapy between 1998 and 2012. The patients who had not taken the drugs were matched by gender, year of birth and country of residence to 10 controls from the general population.
The study found that rheumatoid arthritis patients not treated with TNFi were 88% more likely than the general population to have a first squamous cell cancer and 22% more likely than the general population to have a first basal cell cancer.
It said that TNFi treatment further increased the risk of squamous cell cancer by 30% and the relative risks did not appear to increase with longer time on treatment or in patients with a history of squamous cell cancer. In contrast, the use of TNFi did not further increase the risk of basal cell cancer.
Dr Raaschou says, “Our findings imply that, whatever the mechanism, most of the increase in risk of squamous cell and basal cell cancer in rheumatoid arthritis patients treated with TNF inhibitors comes from factors other than the treatment.
“Given the small absolute risk increase of skin cancer associated with TNFi in this study and the often excellent effects of these drugs, our results do not significantly shift the risk-benefit of TNFi in RA.”
It is advised that all patients with rheumatoid arthritis, regardless of treatment, might benefit from increased surveillance for skin cancer and should protect themselves from the sun.
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