Melanoma
Clare Peterson, MRes
Medical Student
Norwich Medical School
Richmond, England, United Kingdom
Disclosure: Disclosure information not submitted.
Treatment options available for melanoma in transit metastases (ITMs) are diverse, from local to regional therapies, and more recently systemic therapy. The current AJCC melanoma classification system is relatively non-discriminatory for ITMs, which adds to the difficulty of treatment planning.
Aim: to devise a prognostic classification system based on burden and extent of disease.
Methods: Retrospective cohort study from a supra-regional referral service based in an academic cancer center. Primary endpoints: disease-specific survival (DSS) and distant metastasis-free survival (DMFS).
Results: 142 patients (M:F 44:56%) with median age 70 (IQR 59-75). Median Breslow thickness was 3.1 millimetres (IQR 2.1-5.4) and ulceration was present in 47%. Median follow up was 39 months (IQR 17-70). Number of deaths from any cause was 78 (55%) with 69 (49%) from melanoma. Distant disease or death was noted in 111 patients (78%). Disease progression or death occurred in 134 (94%) patients. Median ITMs-free interval was 17 months (IQR 7-32). At initial presentation of ITMs, the median number of lesions was 1 (IQR 1-2). At time of diagnosis of ITMs, 46% presented with isolated ITMs; 35% had regional lymph node involvement and 19% had distant disease.
Multivariate analysis found that worse DSS was associated with distant disease at ITMs diagnosis (HR: 2.07, [1.11-3.88]; p=0.022) and increasing number of ITMs at diagnosis (HR: 1.04 [1.01-1.08]; p=0.016). An ITMs-free interval >18 months was associated with a favorable DSS (HR: 0.99 [0.98-1.00]; p=0.015). Maximum threshold analysis using the clinical endpoint DSS determined the optimal cut-point for ITMs-free interval was ≥18 months (p < 0.0001); the number of ITMs at first diagnosis ≤2 (p < 0.0001) and Breslow thickness < 2.0mm (p=0.0037) (fig 1).
Conclusions:
Patients presenting with more than 2 ITMs at initial presentation, < 18 months from diagnosis of the primary or with concomitant nodal or distant disease, have a high risk of systemic relapse and/or death and may preferentially benefit from primary systemic therapy. Primary locoregional treatment strategies may be considered for low-risk, isolated ITM disease, as identified by this analysis.