Immune checkpoint inhibitors for any cancer reduce actinic keratoses lesions

Key takeaways:

• Current therapies do not prevent the onset of new lesions within a field of cancerization.
• Immune checkpoint inhibitors reduced the mean number of actinic keratoses from 47.2 to 14.3 after 1 year.

Immune checkpoint inhibitor therapy for any cancer was associated with a significant reduction of actinic keratoses, according to a study.

An area of skin that is chronically exposed to ultraviolet radiation may develop subclinical mutations, which characterize most cutaneous squamous cell carcinomas, the study explained. That can lead to the presence of multiple actinic keratoses (AKs) and keratinocyte carcinomas (KCs) over time — a process known as field cancerization.

“Current therapies for individual KCs are suboptimal at reducing their significant burden, as they do not prevent the onset of new KCs within an area of field cancerization,” Charlotte Cox, MD, MPhil, MPHTM, BMSt, a member of the experimental dermatology group, dermatology research center at the Frazer Institute at the University of Queensland in Australia, and colleagues wrote. “Therefore, field-based therapy rather than lesion-based therapy is required to manage the disease burden.”

According to Cox and colleagues, immune checkpoint inhibitor (ICI) therapy is indicated for the treatment of many types of cancers including KCs and may be effective for preventing field cancerization.

In this prospective cohort study, 23 patients (mean age, 69.7 years; 73.9% men) who had started at least a 6-month treatment regimen with an ICI, either programmed cell death 1 or programmed cell death ligand 1, for any active cancer and presented clinical AKs on their forearms were enrolled in the study. No patients discontinued, but four patients died because of disease progression during the study.

Results showed that the mean number of AKs significantly decreased from baseline to 12 months after starting ICI therapy (47.2 vs. 14.3; P < .001). Eight of the 12 patients aged younger than 65 years (66.7%, P = .007) and all 12 of those with a history of blistering sunburn (100%, P = .005) experienced a reduction of their AK numbers by 65% or more, meaning these patient groups were more likely to see a decrease in AK lesions with ICI therapy.

The researchers also observed a reduction in KC total numbers from 12 months before starting ICI therapy to 12 months after (42 vs. 17). They also saw a reduction in total cutaneous squamous cell carcinomas in the same time period (16 vs. 5). However, this finding was not statistically significant.

“The findings underscore ICIs’ potential as a novel approach to mitigating field cancerization in high-risk populations,” the authors concluded. “Given the potentially life-threatening adverse events associated with ICI therapy, this pilot study could pave the way for future prospective clinical trials to explore immunopreventive strategies in individuals at extreme risk of KCs when alternative strategies are not viable.”