Melanoma patients still at higher risk for new malignancy after successful systemic immunotherapy

Reuters Health - 24/09/2020 - Patients successfully treated for metastatic melanoma with immune-checkpoint inhibitors remain at increased risk for developing new primary cutaneous melanoma, according to a new study.

"The 5-year risk was nearly 5%," Dr. Michael A. Marchetti of Memorial Sloan Kettering Cancer Center, in New York City, told Reuters Health by email. "This implies that patients who respond to systemic treatments may benefit from continued primary and secondary prevention strategies."

He and his colleagues examined data on more than 2,200 patients who were treated at their institution between 2003 and 2019. Patients received ipilimumab, nivolumab and/or pembrolizumab. Their mean age at the start of therapy was 62.5 years, and nearly two-thirds were men.

The median duration of time from the first dose of immune-checkpoint inhibitor to the first new cutaneous melanoma, last follow-up, or death was 12.1 months, the researchers report in JAMA Dermatology.

At a median of a little more than a year after the start of treatment a total of 48 new cutaneous melanomas were seen in 42 patients. Although there were no differences in age, sex, race and ethnicity in these patients compared with the others, they were significantly more likely to have a family history of melanoma (23.8% vs. 16.3%).

Altogether, 62.5% of the new melanomas were diagnosed after immunotherapy was completed and 40.5% were identified through a screening examination. Most were found by physicians, but the patient or family were first to spot them in ten cases. Overall, 27 were in situ and the remaining 21 were invasive.

The incidence rate of new melanoma was 1,103 cases per 100,000 person-years and the incidence proportion 1.9%. After five years, the cumulative cause-specific risk of new primary cutaneous melanoma was 4.9%.

The researchers caution that more than a third of patients received ipilimumab alone, which is no longer a first-line treatment for metastatic melanoma. In addition six patients also received vemurafenib monotherapy, which may have predisposed them to new cutaneous melanoma development.

Dr. Joseph J. Skitzki of Roswell Park Cancer Institute, in Buffalo, New York, who was not involved in the study, told Reuters Health by email, "Although a theoretical decrease in new melanoma would be anticipated from immune-checkpoint inhibitors, the data from this large series of patients suggests that this is not the case."

"The study is helpful in acknowledging that melanoma patients treated with immune-checkpoint inhibitors still remain at risk for the development of new cutaneous melanomas and require close dermatologic surveillance," he said.

By David Douglas

SOURCE: https://bit.ly/3coyKpA JAMA Dermatology, online September 16, 2020.

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Posted on 24 September, 202029 September, 2020