Tens of millions of Americans develop sun-linked skin lesions called actinic keratoses, which are tied to later cancer risk.
Many will get a combo of treatments to help clear the blemishes.
Now, research shows that the same two-ointment combo -- one used to ward off skin cancer and the other a psoriasis drug -- also greatly reduce the odds for squamous cell carcinomas (SCCs), the second most common form of skin cancer.
In the new trial, use of the psoriasis treatment calcipotriol, plus 5-fluorouracil (5-FU) cream, cut the odds for these cancers on the face and scalp by nearly 75 percent, researchers said. Both drugs are already approved by the U.S. Food and Drug Administration.
"This is groundbreaking and will change many lives," said one dermatologist, Dr. Michele Green, who wasn't involved in the new research.
"According to the Skin Cancer Foundation, more than 58 million Americans are affected by actinic keratosis and more than a million are affected by squamous cell carcinoma," noted Green, who practices at Lenox Hill Hospital in New York City.
She believes the combo therapy will prove "very effective" against both conditions.
The new study was led by Dr. Shawn Demehri of the Center for Cancer Immunology at Massachusetts General Hospital in Boston.
In prior research, his team found that twice-daily treatment for four days with a combination of calcipotriol and 5-FU creams significantly reduced the number and size of actinic keratosis lesions.
The new study followed up on 72 of the 130 participants from the first study, to see if the same approach might cut the risk of squamous cell carcinomas.
Three years after treatment, 28 percent of those treated with only 5-FU cream had developed SCC on the face and scalp. But that number was only 7 percent for those who got both medicines, Demehri's group reported.
The combo treatment did not reduce the risk of SCC on the arms, however. The researchers theorized that a longer treatment period may be needed to cut the odds of SCC on the arms and other parts of the body besides the face and scalp.
The study was published online March 20 in the journal JCI Insight.
Dr. Scott Flugman, a dermatologist at Northwell Health's Huntington Hospital in Huntington, N.Y., was also impressed by the new findings.
"Treatment of actinic keratoses has long been established to be medically necessary," he explained.
"Although the risk of any individual lesion transforming into squamous cell carcinoma is only 1 to 2 percent, that risk increases dramatically in patients who have areas of the skin that are literally covered with actinic keratoses," Flugman said. "A 1 percent risk sounds small, but when a patient has dozens or hundreds of these lesions, the risk of developing a skin cancer becomes very high."
He said there are multiple ways to treat actinic keratoses, but some are either expensive, time-consuming or both.
So, "the new study accomplishes two novel objectives," said Flugman, who did not take part in the research. "It reduces treatment time to four days, which is much more manageable for patients. And it does this by combining two well-established, generic medications [5-FU and calcipotriol] that are typically covered on most insurance plans."
Given all that, the combo therapy "has the potential to become a widely adopted treatment method," Flugman said.
Study author Demehri agreed.
"The primary reason for treating actinic keratosis is to prevent [cancer] development, and our findings suggest this immunotherapy may be an effective way of achieving that goal," he said in an MGH news release.
Demehri also believes the finding that immunotherapy for precancerous lesions could prevent cancer "may be applicable to other organs than the skin, something we hope to investigate for malignancies such as breast cancer, for which immunoprevention is an urgent, unmet need."
The U.S. National Cancer Institute has more on skin cancer prevention.
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