Danielle M. Bello, MD
Assistant Attending, Gastric Mixed Tumor Service
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Disclosure: Philogen (Individual(s) Involved: Self): Advisor or Review Panel member
Clinical trials have demonstrated the efficacy of modern systemic therapies in metastatic melanoma; however patients with in-transit melanoma (ITM) are understudied, representing < 10% of patients in these trials. This study combines two large databases to define characteristics of ITM and describe outcomes in the context of effective therapies.
Methods:
Patients with ITM who received treatment from 1990-2021 were identified from two prospectively maintained institutional databases. Primary tumor characteristics, sentinel node (SN) status, recurrence patterns, and survival were analyzed. To determine the association of systemic therapies with overall survival (OS), the cohort was analyzed in two time periods: 1990-2010, the pre-systemic therapy era, and 2010-2021 the era of FDA approval of modern systemic agents.
Results: In total, 964 patients with ITM were identified with a median follow-up of 65.4 months. Median age at diagnosis was 62; 58% were male. The major histologic subtypes of primary tumors were superficial spreading (n=235, 24%), acral lentiginous (n=122, 12.5%), and nodular (n=96, 10%). In primary tumors, median thickness was 2.6 mm (IQR 1.6, 4.5) with ulceration in 35%. Most originated on the lower extremity (n=473, 49%). Satellite or ITM was present at initial diagnosis in 15%. SN biopsy was positive in 44% (n=261/591). Median time to first ITM recurrence was 16.9 months (IQR 7.8, 39.7). Most patients presented with ITM alone (87%), 9% had concomitant lymph node disease, and 4% had distant metastases. Median follow-up from ITM diagnosis was 36.4 months (IQR 17.6, 80.0). Patients treated in a modern era of immune and targeted therapy had significantly improved OS compared to those who were treated prior (Figure), with a median OS of 75.8 and 48.0 months, respectively (p=0.001).
Conclusions:
Conclusions: Patients with ITM have a high SN positivity rate, and many develop ITM within 2 years of initial treatment. Most patients who develop an ITM recurrence present with ITM alone, without metastasis, supporting the use of local/regional therapies. However, OS in the modern era of systemic therapy has greatly improved. Further analysis will define the association of systemic treatment with outcomes.