Demographic and Clinical Characteristics of Melanoma in Hispanic Patients
Among Hispanics, white Hispanics comprise the majority of melanoma cases.5 Median age at diagnosis is younger in Hispanics compared to whites.5,6 Hispanic men typically are older (median age, 61 years) than Hispanic women (median age, 52 years) at diagnosis.5 Similar to what is seen in NHWs, young Hispanic women experience a higher melanoma incidence than young Hispanic men.5 Among older Hispanics, melanoma is more common in men.5,8
Melanomas located on the lower extremities and hips are more prevalent in Hispanics than in NHWs.5,8,18 Among Hispanics, there are age- and sex-based variations in the anatomic location of primary tumors: in Hispanic men, truncal tumors predominate, and in Hispanic women, tumors of the lower extremities are most common across all age groups.5 The incidence of melanomas located in the head and neck region increases with age for both Hispanic men and women.
For melanomas in which the histologic type is known, superficial spreading melanoma is the most common subtype among Hispanics.5,17,19 Acral lentiginous melanomas and nodular melanomas are more common among Hispanics than among NHWs.5,17,19
The observation that Hispanics with melanoma are more prone to lower-extremity tumors and nodular and acral lentiginous melanoma subtypes than NHWs suggests that UV exposure history may be of less importance in this population. Although numerous studies have explored melanoma risk factors in NHWs, there is a striking paucity of such studies in Hispanics. For example, there are conflicting data regarding the role of UV exposure in melanoma risk among Hispanics. Hu et al20 found that UV index and latitude correlated with melanoma risk in this population, whereas Eide et al21 found no association between UV exposure and melanoma incidence in Hispanics. A prospective study involving a multiethnic cohort (of whom 40 of the 107 participants were Hispanic) found no clear association between a history of sunburn and melanoma risk in Hispanics.18
Strategies for Reducing Disparities in Outcomes
Our knowledge of melanoma epidemiology in Hispanics derives mainly from secondary analyses of state-level and national cancer registry data sets.5-8,13-15,17,19,20 These administrative data sources often are limited by missing data (eg, tumor thickness, histologic subtype) or lack important patient-level information (eg, self-identified race and ethnicity, health insurance status). Additionally, the manner in which data are collected and integrated into research varies; for example, socioeconomic measures often are reported as either area-based or composite measures. Thus, there is a need to improve the consistency of reporting on demographic and socioeconomic measures across studies. Polite et al22 recommended standardization of reporting criteria and that a standard set of demographic and socioeconomic status measures be included in clinical registries and research protocols.22 Researchers should strive to collect self-reported information on race and ethnicity, as well as the most granular level of detail on health insurance status, ancestry, and immigration status.
The host phenotypic characteristics of melanoma in NHWs are well understood, but the biological and environmental determinants of melanoma risk in Hispanics and other minorities are unknown. For example, fair complexion, red hair, blue eyes, increased freckling density, and the presence of numerous dysplastic and common melanocytic nevi indicate a propensity toward cutaneous melanoma.23,24 However, the relevance of such risk factors in Hispanics is unknown and has not been widely investigated in this patient population. Park et al18 found that a person’s sunburn susceptibility phenotype (defined as hair and eye color, ability to tan, and skin reaction to sunlight) was associated with an increased risk of melanoma among nonwhite, multiracial individuals. However, this study was limited by a small number of minority cases, which included only 40 Hispanic participants with melanoma.18 There is a need for rigorous observational studies to clearly define the phenotypic characteristics, sun-exposure behavior patterns, and genetic contributors to melanoma genesis in Hispanics.
The biologic determinants of postdiagnosis survival in Hispanics with melanoma are not well understood. It is unknown if genetic predisposition modifies melanoma risk in Hispanics. For example, the frequency of BRAF gene mutation or other driver mutations in US Hispanics has been understudied. It is important to know if mutation frequency patterns differ in Hispanics patients compared to NHWs because this knowledge could have considerable implications for treatment. Several recommendations should be considered to address these knowledge gaps. First, there is a need for development or enhancement of melanoma biorepositories, which should include tumor and nontumor specimens from a diverse sample of melanoma patients. Additionally, multi-institutional and multidisciplinary consortiums need to be created in order to amass a number of Hispanic melanoma patients to identify genetic, biologic, and behavioral risk factors specific to this subgroup of patients. The AMBER Consortium, which focuses on breast cancer epidemiology and risk in black women, is a model for the type of consortium needed for the study of melanoma in Hispanics.25 Lastly, community engagement will be central to developing sustainable recruitment and data-collection efforts.26 Involvement of key stakeholders will provide an in-depth assessment of community needs as well as real-time feedback on the process and practicality of research questions. Buy-in from affected communities also may facilitate dissemination of research findings to affected communities.
Conclusion
Hispanics are more likely to present with an advanced stages of disease and have higher melanoma-specific mortality rates than NHWs. Regrettably, a huge knowledge gap exists regarding contributors and solutions to melanoma disparities among this fast-growing, understudied segment of the US population. Accordingly, critical research is needed to address the most pressing questions regarding melanoma risk and poor outcomes among Hispanics to foster implementation of interventional efforts in prevention, early detection, and treatment. A multi-institutional and multidisciplinary approach across multiple levels is needed to eliminate disparate outcomes. Although melanoma is relatively uncommon among Hispanics, studies of melanoma in Hispanics (given their diverse genetic ancestry and migration) provide a unique backdrop against which researchers can explicate melanoma etiology—thus benefiting Hispanics and non-Hispanics alike.