Metastatic volume: an old oncologic concept and a new prognostic factor for stage IV melanoma patients

BACKGROUND: The last melanoma staging system of the 2009 American Joint Committee on Cancer takes into account, for stage IV disease, the serum levels of lactate dehydrogenase (LDH) and the site of distant metastases. OBJECTIVE: Our aim was to compare the significance of metastatic volume, as evaluated at the time of stage IV melanoma diagnosis, with other clinical predictors of prognosis. METHODS: We conducted a retrospective multicentric study. To establish which variables were statistically correlated both with death and survival time, contingency tables were evaluated. The overall survival curves were compared using the Kaplan-Meier method. RESULTS: Metastatic volume and number of affected organs were statistically related to death. In detail, patients with a metastatic volume >15 cm(3) had a worse prognosis than those with a volume lower than this value (survival probability at 60 months: 6.8 vs. 40.9%, respectively). The Kaplan-Meier method confirmed that survival time was significantly related to the site(s) of metastases, to elevated LDH serum levels and to melanoma stage according to the latest system. CONCLUSION: Our results suggest that metastatic volume may be considered as a useful prognostic factor for survival among melanoma patients