Radiotherapy vs imiquimod: Which is a better nonsurgical option for lentigo maligna?

Radiotherapy and imiquimod are both efficacious and well-tolerated in patients with complex lentigo maligna who are not suitable for surgery, with no negative effects on health-related quality of life (HRQoL) at 24 months, reports a study.

A team of investigators carried out a multicentre phase III randomized trial between August 2015 and November 2021. They randomly allocated 126 patients to receive either imiquimod or radiotherapy. Treatment failure at 24 months was the primary endpoint, while response at 6 months, development of invasive disease, toxicity, and HRQoL were secondary endpoints.

At 6 months, the response rate was 95 percent in both radiotherapy and imiquimod groups. The rates of treatment failure were low, with 12 in the radiotherapy arm and six in the imiquimod arm at 24 months (odds ratio, 2.35, 95 percent confidence interval, 0.82‒6.75; p=0.11).

Both treatment approaches demonstrated good tolerability, with mainly grade 1 and 2 acute skin toxicity. No significant between-group differences were noted in skin symptoms or HRQoL in the long term. Furthermore, patients in both groups had significantly better emotional scores after treatment than at baseline.

However, the study was underpowered due to early cessation of recruitment, according to the investigators.

“For patients with lentigo maligna who are not suitable for surgery, radiotherapy [and] topical imiquimod are alternative nonsurgical treatments,” the investigators said.