O08 Lentigo maligna survival: balancing treatment decisions in those with limited life expectancy

Abstract Lentigo maligna (LM) is a type of melanoma in situ that commonly occurs in sun-damaged skin of the head and neck of older individuals. LM evolves slowly, with an estimated 5% progressing to invasive LM melanoma if left untreated. Current National Institute for Health and Care Excellence guidelines recommend surgical excision as the first line of treatment, with no reference to avoiding active treatment. The incidence and survival of LM are reported in England from the National Disease Registration Service Get Data Out (GDO) website. Survival is only reported for the first melanoma in situ tumour, while subsequent tumours are registered and included in incidence analyses. Data for patients ≥ 80 years old are reported by separate body sites in GDO, therefore head and neck LM was chosen to represent survival outcomes by age, given that this is the most common site of occurrence. Between 2013 and 2020 there were a mean of 2517 cases of LM diagnosed annually (crude incidence rate 4.6 per 100 000). A mean of 1944 cases of LM annually were at head and neck sites, of which 12.3% were in patients aged 0–59 years, 21.9% age 60–69 years, 34.8% age 70–79 years and 30.9% age ≥ 80 years. In 2014 (the latest year with 5 years of follow-up survival data available), the 5-year net survival of LM in people of all ages was reported as 104% [95% confidence interval (CI) 101–106], and Kaplan–Meier overall survival was 83.5% (95% CI 82–84.9). In the category for age ≥ 80 years and head and neck site, the 5-year Kaplan–Meier survival was 60.4% (95% CI 56.3–64.2). The reported survival with LM is excellent, including some years with net survival exceeding 100%, which means that those diagnosed with LM are surviving longer than individuals not diagnosed with LM, based on life tables that are adjusted for sex, age, geographical location and Index of Multiple Deprivation. The majority of cases of LM are registered after histological confirmation, and cases without histology are likely missing from statistical reporting, which is a limitation of this analysis. This also includes those diagnosed but treated with noninvasive options such as topical treatments. The overall survival (i.e. death from any cause) shows that 40% of patients aged ≥ 80 years die within 5 years of diagnosis, so possible benefits from invasive treatment may be limited. Validated frailty scoring tools can help identify patients with limited life expectancy who would benefit from a more informed discussion about the risks, including morbidity vs. benefits of invasive treatment. National guidelines currently do not adequately address the option of observation rather than invasive treatments for such groups.