Abstract 4003: Acral lentiginous melanoma and infiltrating lymphocytes in a Latin American population

Abstract

Abstract Background: Acral lentiginous melanoma (ALM) is unusual in Caucasian but is the most common subtype in Hispanic populations, and has been associated to poor prognosis. Herein we compare clinicopathological features associated to ALM in a Latin-American population and prospectively evaluate its association with tumor infiltrating lymphocytes (TIL). Patients and Methods: All patients with melanoma presenting from 2005 to 2012 at Instituto Nacional de Enfermedades Neoplasicas in Lima, Peru, were retrospectively identified. Analysis of association between clinicopathological features and ALM was performed. Survival analysis compared the outcome of ALM to whole group and extremity NALM. We performed prospective evaluation of TIL following Azimi et al recently presented classification. Results: A total of 537 ALM and 287 NALM cases were identified. Older age (p= 0.02), thicker Breslow (p= 0.008), positive lymph node (p= 0.051) and ulceration (p<0.001) were found to be more frequent in ALM. Acral had worse OS compared with both whole group (p= 0.04) and extremity NALM (p <0.001). Stage I-II patients had a median OS of 5.3 (95%CI: 4.3-6.2) for ALM and 9.2 (95% CI: 5.0 - 7.0) for extremity NALM (p=0.016). TIL was prospectively evaluated in 490 cases, and Grade 0-1, II and III of TIL represented 44.7%, 33.6% and 27.1%, respectively. Higher TIL grade was associated to less Breslow thickness (p= 0.021), less mitosis index and NAM. Higher TIL grade was also associated to better OS (p< 0.001) Conclusion: ALM is highly prevalent in Latin-America and carry poor outcome. Lower TIL levels was associated to poor outcome and ALM. Citation Format: Carlos Castaneda, Carlos Torres-Cabala, Sandro Casavilca, Miluska Castillo, Valeria Villegas, Joselyn Sanchez, Claudio Flores, Henry Gomez, Tatiana Vidaurre. Acral lentiginous melanoma and infiltrating lymphocytes in a Latin American population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4003. doi:10.1158/1538-7445.AM2017-4003