The association between hypertension and melanoma is unclear, and previous analyses of data from the ASPirin in Reducing Events in the Elderly (ASPREE) study demonstrated a reduced number of invasive melanoma events amongst aspirin-exposed hypertensive individuals.
Data from the ASPREE study which included (1) the intervention period with a median follow-up of 4.7 years, and (2) the observational period with an additional 2 years follow-up, were combined for this analysis. Logistic regression analyses examined the association between baseline hypertension and treatment status and past melanoma history. Survival analyses examined the association between hypertension and melanoma risk, and the effect of aspirin across hypertension groups. Cox proportional hazards models were used to compare incidence across groups.
19,114 participants (median age of 74 years) were randomised to daily 100 mg aspirin or placebo. At baseline, hypertension and past melanoma history were recorded in 14,195 and 685 individuals, respectively. After adjustment for confounders, hypertension was significantly associated with past melanoma history (OR=1.34, 95%CI: 1.11–1.62). In a prospective analysis, baseline hypertension was not associated with melanoma risk. However, aspirin was associated with a reduced risk of incident melanoma amongst individuals with uncontrolled hypertension (blood pressure ≥140/90 mmHg; HR=0.63, 95%CI 0.44–0.89), but not in those with controlled hypertension (HR=1.04, 95%CI 0.74–1.46).
Our results support a reduced melanoma incidence amongst individuals with uncontrolled hypertension exposed to aspirin. Additional studies are required to confirm these findings.
- • Aspirin may reduce incident melanoma risk in uncontrolled hypertensives.
- • High-risk groups who may benefit from aspirin chemoprevention need exploration.
- • The association between hypertension and melanoma warrant further investigation.
Cutaneous melanoma is an aggressive form of skin cancer, with a relatively high mortality due to its tendency to metastasise . Global incidence rates have steadily increased over the past decades, and melanoma is amongst the 5 most common cancer types in Australia and the United States (US) . Primary preventive strategies have largely focused on ultra-violet (UV) radiation protection, given its established role in melanomagenesis, but more recently, alternative approaches such as chemoprevention, have been explored. Mounting evidence suggest that aspirin may have anti-cancer properties against various malignancies, including melanoma .
In a previous analysis exploring the effect of aspirin on cutaneous melanoma risk in older individuals of a large randomised controlled trial (RCT) of daily aspirin (ASPirin in Reducing Events in the Elderly – ASPREE), we did not find strong evidence to support a chemopreventive effect of aspirin . However, a reduced number of melanoma events with aspirin was observed amongst hypertensive individuals. By contrast, some suggest that hypertension is linked with an increased risk of cancer – including renal, colon and breast cancer . A possible association between hypertension and melanoma has also been reported, but few studies have explored this association and the evidence base is inconclusive . Additionally, some studies suggest that hypertension may be a risk factor for aspirin resistance, and thus aspirin’s effect might vary by hypertension status .
In this analysis, we use data from the ASPREE trial and its extension observational study to explore the association between hypertension and melanoma, and further investigate whether the effect of aspirin on incident melanoma risk varies across different hypertension groups.