Abstract:
Malignant melanoma is one of the more aggressive cancers in the skin, with an increasing
incidence every year. Melanoma has a better prognosis if diagnosed early and survival tends to
decrease once the disease has metastasized. Positron emission tomography (PET) with 2-[18F]fluoro2-deoxy-D-glucose (18F-FDG) has been used extensively over the past two decades in staging and
assessing responses to therapy in patients with melanoma. Metabolic PET parameters have been
demonstrated to be independent prognostic factors for progression-free survival (PFS) and overall
survival (OS) in different malignancies, melanoma included. In our study, we evaluated the metabolic
parameters of 18F-FDG PET/CT (flourodeoxyglucose positron emission tomography/computed
tomography) in predicting the overall survival in patients with malignant melanoma who presented
for restaging. Metabolic PET parameters (maximum standardized uptake value (SUVmax), metabolic
tumor volume (MTV) and total lesion glycolysis (TLG)) of the primary tumor, as well as whole-body
MTV and TLG of the metastatic disease, were measured. Survival curves for OS were constructed and
mortality rates were determined using the different PET variables. Forty-nine patients who presented
for a PET/CT restaging in melanoma were included in this study. We found that non-survivors
had significantly higher median MTV (11.86 cm3 vs. 5.68 cm3
; p-value = 0.022), TLG (3125 vs. 14;
p-value = 0.0357), whole-body MTV (53.9 cm3 vs. 14.4 cm3
; p-value = 0.0076) and whole-body TLG
(963.4 vs. 114.6; p-value = 0.0056). This demonstrated that high MTV and TLG values of the primary
tumor and whole-body TLG as quantified by 18F-FDG PET/CT were prognostic factors for overall
survival. The findings may potentially guide clinicians in decision making and identifying patients
with a poorer prognosis.
