A study of thousands of women has found that cholesterol-lowering statins do nothing to prevent the deadly skin cancer, despite earlier evidence suggesting otherwise.
Evidence from experiments on cells and one trial in people had suggested some of the same properties of statins that protect against heart disease might also prevent melanoma, the most lethal type of skin cancer.
But researchers led by Michael Simon, at Karmanos Cancer Institute in Detroit, found no impact on melanoma in women who took the drugs, which include atorvastin and pravastatin, to lower their cholesterol.
"I don't think there's anything here that suggests statins may be protective for melanoma," says Simon.
The researchers, whose report was published in the journal Cancer, used data from the Women's Health Initiative study, which has tracked about 120,000 women for more than a decade.
They compared roughly 8800 white women who took a statin medication to 111,000 white women who did not, finding 89 cases of melanoma among the statin users and 1111 cases among the non-users doing a 12-year period.
That translated to identical rates of melanoma in each group, nine cases a year for every 10,000 women.
The results were the same no matter what type of statin the women took or how long they took it.
"For primary prevention (of melanoma) I think we're putting the nail into the coffin of that theory," says Dr Robert Dellavalle, chief of dermatology at the Denver VA Medical Center, who was not involved in the research.
Doesn't translate into humans
Simon's team write that because statins have demonstrated benefits on skin cells in laboratories, it's possible that people who take them don't achieve sufficient concentrations of the drugs to make a difference to their melanoma risk.
Further studies of people at higher risk for melanoma than the broad group of women in the current study could also "provide more conclusive results", they add.
Based on the evidence that statins can help destroy tumour cells in a Petri disk, there might be a way to use the drugs in people already diagnosed with melanoma, says Dellavalle.
But as far as prevention goes, Simon says it would be better to spend resources on things that are known to prevent skin cancer.
Risk factors for melanoma include exposure to UV radiation from sunlight or tanning beds, fair skin that tends to burn, moles or other types of pigmented birthmarks, smoking and family history of the cancer.
"I think based on (the study results) we should continue to put our resources into education about sun protection: staying out of the noonday sun, wearing protective sunscreen," says Simon.