Radiotherapy or Imiquimod in Complex Lentigo Maligna (RADICAL)

A Randomised Controlled Multicentre Trial of Imiquimod Versus Radiotherapy for Lentigo Maligna (LM) When Staged Surgical Excision With 5mm Margins is Not Possible, is Refused, or Fails

The purpose of this study is to investigate the effectiveness of using either radiotherapy (RT) or Imiquimod (ImiQ) to treat the Lentigo Maligna (LM), when surgery is not possible, is refused, or fails.

Surgery is the standard treatment for people diagnosed with LM. However for some people, it may not be possible due to the location of their LM lesion(s). Currently, the Australian and New Zealand Melanoma Treatment Guidelines recommend radiotherapy for the treatment of LM however there is no clinical trial evidence for this and a trial is needed to prove which treatment is safer and more effective. Some clinicians may also recommend the use of a cream called Imiquimod. It is approved and widely used in Australia to treat solar keratosis, superficial basal cell carcinoma, external genital warts, and perianal warts. Although not currently licensed for treatment use in LM, there is some evidence to suggest that it is both safe and effective in treating LM. This trial will scientifically evaluate and compare these two treatments in a controlled clinical setting. The primary objective of this trial is to compare the rate of LM treatment failure and recurrence rate measured at 24 months (primary endpoint), and measured at 6, 12 months (secondary endpoints) following treatment with ImiQ or RT. For this study, treatment failure includes both the recurrence and persistence of LM, and is defined as the presence of LM cells within the original field of treatment confirmed by histopathology.

Topical imiquimod 5% cream application to treatment area for 5 days/week for a total of 12 weeks dispensed at baseline visit along with patient diary

Radiotherapy treatment regimen determined by treating radiation oncologist and as per standard practice at local institution treatment to commence within 8 weeks of randomisation

Proportion of patients experiencing LM treatment failure (as determined by systematic biopsy) 6 months following completion of treatment.

Incidence of invasive melanoma within treatment fields; a sub-study to evaluate the utility of reflectance confocal microscopy (RCM) compared with standard biopsy in diagnosing recurrence

Inclusion Criteria: Aged 18 years or older. A biopsy-proven LM. This includes previous treatment failures (not with imiquimod or RT) of LM that are diagnosed as biopsy-proven LM. LM that is in a location amenable to treatment with imiquimod and radiotherapy. Willing and able to comply with study requirements. Written informed consent. Exclusion Criteria: Invasive melanoma. Medical or psychiatric condition that compromises the ability of the patient to complete protocol treatment or follow-up assessments. Patients who are pregnant or lactating. Women of child bearing potential must have a confirmed negative urine pregnancy test at study entry. Life expectancy of less than 2 years. Radiotherapy sensitivity syndrome