Background:
Obesity is hypothesised to worsen melanoma prognosis, yet there is conflicting literature.
Objective:
To explore the association between body mass index (BMI) and melanoma prognosis (tumour stage at diagnosis and tumour recurrence) in patients with high-risk (T1b – T4a) primary cutaneous melanoma in Queensland, Australia.
Methods:
For this prospective study, 700 patients with newly diagnosed stage T1 to T4b cutaneous melanoma were recruited between 2010-2014 in Queensland, Australia. We used logistic regression and Cox survival regression to evaluate the associations between BMI, tumour stage and tumour recurrence, respectively.
Results:
Obese participants were significantly more likely to have an earlier tumour stage at diagnosis compared to healthy-weight participants (adjusted odds ratio [OR] 1.99, 95% confidence interval [CI] 1.10 – 3.61, p-value 0.05). No association was found between BMI and melanoma recurrence at 7 years post-diagnosis of the primary tumour (adjusted hazard ratio [HR] 0.94, 95% CI 0.76 – 1.16, p-value 0.55 for overweight; HR 0.93, 95% CI 0.74 – 1.18, p-value 0.55 for obese).
Limitations:
BMI is an imperfect tool to measure body composition.
Conclusion:
Our findings suggest obese patients are diagnosed at earlier tumour stages, yet BMI has no effect on melanoma recurrence.