E134: Unveiling Melanoma: A Deep Dive into Disparities at a Latin-American Cancer Institute

Worldwide incidence of melanoma has increased in the last 40 years. Literature usually shows data from fair-skin cases and mentions that the non-Caucasic population has worse morbidity and mortality rates. Our aim was to describe the clinic pathological characteristics and outcomes of three cohorts of patients diagnosed with melanoma in a Latin-American cancer institute during the last 20 years.

Methods:

We evaluated three retrospective patient cohorts diagnosed with melanoma at Instituto Nacional de Enfermedades Neoplásicas (INEN) a public hospital in Lima, Peru, for the years 2005-2006, 2010-2011, and 2017-2018. We analyzed demographics, tumor characteristics, time to diagnosis and staging, and assessed survival rate differences using the Log-rank test.

Results:

584 patients were included in the analysis (only trunk & extremities), 51% male. The mean age was 61 (3-97) years, and 98% of them were of Hispanic ethnicity. Approximately 48% of the patients resided in rural areas. About half of them had biopsy and then referred to INEN for management. The mean time to diagnosis was 22.6 months, and the mean Breslow thickness was 7.4 mm (T3). One-third (30%) of the patients presented with Acral lentiginous subtype, with the lower extremity being the most common location (72%). A majority of the patients (55%) had metastases at the time of presentation, with 36% in Stage III and 19% in Stage IV, followed by 23% in Stage II and 8.0% in Stage I. Cohorts were distributed as follows: A) 2005-2006 (n=171), B) 2010-2011 (n=223), and C) 2017-2018 (n=190). Surgical management included wide local excision (30.6%, 50.3%, and 53.8%) and sentinel node biopsy (44.1%, 49.2%, and 53.1%). No immunotherapy was used. When comparing outcomes by location, worse overall survival (OS) rates at 3-years were observed in both the upper (91%, 92%, 58%, p< 0.01) and lower extremities (84%, 86%, 48%, p< 0.01) for Cohorts B and C. Cohort C exhibited the most significant increase in Stage IV diagnoses (12.3%, 15.7%, 28.4%, p< 0.01). The median OS rates at the 3-year follow-up demonstrated a decline over the years for stages II (97%, 98%, 57%, p< 0.05) and III (66%, 77%, 37%, p< 0.01). The median follow-up periods for the cohorts were 24.8, 23.8, and 19.3 months, respectively.

Conclusions:

There has been a worsening in the incidence of late-stage metastatic melanoma in Peru throughout the years, coupled with a significant decline in overall survival rates. This is underscored by the fact that half of the population lives in regions devoid of oncological access. Comprehensive public health interventions aimed at early diagnosis and treatment are urgently needed.