Aims: In the management of melanoma patients on immunotherapy, some had reported weight gain while receiving treatment at our institution. The relationship between weight, cancer and immune response is complex. In patients with advanced melanoma treated with immunotherapy, obesity (BMI ≥30) has been associated with improved outcomes (1). Less is known about whether immunotherapy itself has an association with weight changes. The study aims to describe the changes in weight of patients receiving adjuvant immunotherapy for resected melanoma.
Methods: A retrospective single-cohort study where eligible patients were identified from hospital databases, based upon nivolumab prescribed for the indication of adjuvant therapy for resected melanoma between June 2018 and November 2020. Data collection variables included patient demographics (age, gender), melanoma characteristics (location of primary, Breslow thickness, lymph node status, presence of BRAF and NRAS variants) and patient weight, measured during attendance in the outpatient setting.
Results: 20 patients were identified. Mean age was 63 years (range 22 to 87), primary site was upper limb 7, lower limb 6, torso 4, and face 3 patients. Mean Breslow thickness was 4.78mm (range 0.96 to 8.5). BRAF variants were seen in 50% (10 patients), with 8 of 10 BRAF variants being the V600E mutation, 15% (3 patients) had the NRAS Q61R variant. Treatment discontinuation occurred in 5 patients due to toxicity or disease progression. The mean change in weight compared to baseline was +1.64kg, 95% CI [-0.11, 3.39]. Weight gain compared to baseline was noted in 11 patients.
Conclusions: The small number of patients in this single-cohort experience limits the ability to provide a signal on whether there is an association between adjuvant immunotherapy and weight. Including repeat assessments of weight in future prospective trials, ideally complimented with patient-reported measures on diet and exercise, may help identify potential associations.