Journal of Dermatology for Physician Assistants

The official journal of the Society of Dermatology Physician Assistants

Racial Disparity in Melanoma Survival Among Non-Hispanic Black Patients

By Kathleen R. Kane, PA-S; and Alicia Elam, PharmD

Kathleen R. Kane, PA-S, and Alicia Elam, PharmD, are from Augusta University College of Allied Health Sciences in Augusta, Georgia.

Disclosures: The authors have disclosed no potential conflicts of interest, financial or otherwise, relating to the content of this article.

ADDRESSING PRACTICE GAPS
This manuscript addresses practice gaps in early diagnosis of melanoma, specifically acral lentiginous melanoma (ALM), in non-Hispanic Black patients and discusses the barriers which result in the disproportionately low melanoma-specific survival rate (MSS) in this population. This review of the most up-to-date studies on ALM and the worsening racial disparity of MSS provides a clinical guide to the dermoscopic and histologic diagnosis of ALM and serves as a strong call-to-action for improvement in targeted patient education to improve the melanoma survival rates in the Black population.

ABSTRACT
Melanoma is widely considered as a malignancy of people with fairer skin. While the incidence of this aggressive form of skin cancer is significantly higher in non-Hispanic White populations than non-Hispanic Black populations, the melanoma survival rate among the Black population is astoundingly lower in comparison. Black patients have been found to be diagnosed with melanoma at later stages; however, survival rates are lower in the Black population at every stage of diagnosis compared to the White population. Several factors at play have been identified through the literature that could be influencing this disparity, including the differences in most common histological subtype, stages at diagnosis, socioeconomic status, health insurance, education level, and perception of risk among patients. A strong need exists for greater melanoma awareness and education among non-Hispanic Black patients as well as more frequent, thorough skin examinations by primary care physicians and dermatologists including acral regions.

KEYWORDS
Racial disparity, melanoma survival, non-Hispanic Black population, acral lentiginous melanoma

INTRODUCTION

Cutaneous melanoma is regarded as one of the most aggressive forms of skin cancer due to its metastatic potential and rank as the leading cause of skin cancer-related mortality. According to the Centers for Disease Control and Prevention (CDC) and National Cancer Institute (NCI), for every 100,000 people in the United States in the year of 2017, 23 new melanoma cases among all races and ethnicities were reported.1 When analyzing the melanoma data provided by the US Cancer Statistics, a significant disparity is apparent between non-Hispanic White people and non-Hispanic Black people with comparison of the melanoma-specific incidence and survival rates. The incidence rate for melanoma in White people from 2013 to 2017 was 25.6 per 100,000 while the incidence in Black people was 1 per 100,000.

Even though non-Hispanic Black people are affected less commonly by melanoma than non-Hispanic White people, the survival rates are significantly lower in the Black population compared to the White population as reported by the 2017 US cancer statistics. The five-year relative melanoma-specific survival (MSS) was 89.5 percent in White people versus 67.4 percent in Black people.1 The great extent of this disparity has warranted further investigation regarding the potential exacerbating causes and risk factors. An analysis of the association between MSS and race using the Surveillance, Epidemiology, and End Results (SEER) database from 1975 to 2016 identified that this racial disparity in melanoma survival has worsened since 1975. This study additionally reports improvements in five-year MSS rates in most races since 2010; however, the extent of improvement in survival rates among ethnic minority groups is significantly less than that of non-Hispanic White people.2 This discouraging trend warrants further investigation of the factors at play within the Black community that influence this disproportionately poor prognosis of melanoma. The literature has recognized a slew of these determinants and has offered recommendations regarding how to address these issues.

FACTORS AT PLAY
Histological subtype of melanoma
The four main histological subtypes of melanoma are the superficial spreading melanoma (SSM), lentigo maligna, nodular melanoma, and acral lentiginous melanoma (ALM).3 Numerous studies analyzing the racial disparity of melanoma using the SEER database have identified that of these subtypes, Black patients make up the largest proportion of ALMs, whereas White patients represent the majority of SSMs, the least invasive subtype.4-8 Black patients were found to be affected to the least degree by the superficial spreading subtype.4,5 Independent of race, the survival rate of patients with ALM is poorer than that of SSM, which has been deemed partially responsible for the decreased survival rates in the non-Hispanic Black population with melanoma as this population is more commonly afflicted with ALM.4,7

ALM is a distinct subtype that varies significantly in its presentation and disease course from the classic cutaneous melanoma (Table 1).3 Unlike SSM, risk factors for ALM do not include ultraviolet (UV) radiation exposure, personal history of melanoma, pre-existing melanocytic nevi, and fair skin type (Table 2). Instead, genetic factors and long-term trauma are considered variables at play in the development of acral melanomas. With regard to clinical presentation, ALMs present on the palms, soles, and nail beds, whereas SSMs present characteristically on sun-exposed areas.3 Several studies have identified the most common anatomical site of melanomas in non-Hispanic Black patients as being the lower extremities, which differs significantly from the trunk and upper extremities in non-Hispanic White patients.4,5,7 The lower extremities are often overlooked in self-skin examinations and even in physician-assisted exams as this area is not considered one with significant sun exposure risk. For this reason, among several others, delays in diagnosis are not uncommon among Black patients with melanoma.5

Stage at Diagnosis/Tumor Thickness
Advanced stage at diagnosis and greater tumor thickness are some of the most important prognostic factors in melanoma.6,7 For this reason, delays in diagnosis can be detrimental to the survival of an individual with this disease. Differences between histological subtypes of melanoma and racial groups have been found to be significant in determining an individual’s prognosis with regard to stage and tumor thickness.

In an analysis of the SEER data from 2006 to 2015 conducted by Huang et al,6 cutaneous malignant melanomas (CMM) were found to be diagnosed with thinner tumors compared to ALMs. This study specifically reported that 67 percent of CMMs were diagnosed at 0.01–1.00 mm of thickness and 17 percent were diagnosed at >2.00 mm. Meanwhile, 35.7 percent of ALMs were diagnosed at 0.01–1.00 mm and 44.3 percent were diagnosed at >2.00 mm. With respect to racial differences in this study, non-Hispanic Black patients displayed the highest rate of thick ALMs (>4.00 mm), whereas non-Hispanic White patients had the highest rate of thin ALMs (0.01–1.00 mm). The five-year melanoma survival rates (MSS) for ALMs at 0.01–1.00 mm and 1.01–2.00 mm were significantly lower than those same degrees of thickness of CMM.6

Diagnosis of localized melanoma, or early stage disease, confers a significantly higher survival rate than a later stage diagnosis with regional spread or distant metastasis.4 Black patients have been found to present with more sentinel lymph node positive disease and distant metastases than White patients.4,6 In fact, Black patients represent the smallest proportion of stage I diagnoses and the highest proportion of later stage diagnoses (II-IV), whereas their White patient counterparts are most commonly diagnosed with stage I disease.5

Interestingly, regardless of the stage at diagnosis, non-Hispanic Black patients have lower survival rates than non-Hispanic White patients. As described by Culp and Lunsford4 in their analysis of the US Cancer Statistics between 2011 and 2015, survival for localized stage for non-Hispanic Black populations was 85.8 percent versus 97.5 percent for non-Hispanic White people; for regional stage, survival was 52.8 percent for non-Hispanic Black people versus 63.8 percent for non-Hispanic White people and for distant stage, 19.0 percent for non-Hispanic Black people versus 19.8 percent for non-Hispanic White people. From these results and others, it is evident that Black patients experience poorer melanoma outcomes compared to White patients, even with early stage diagnoses.2

Socioeconomic Status
Evidence shows that socioeconomic status is a crucial determinant of melanoma incidence and outcome. An extensive review conducted by Harvey et al analyzing these associations, identified that higher socioeconomic status (SES) is associated with greater incidence of cutaneous malignant melanoma; however, it also reported that their lower SES counterparts with lower incidence rates of CMM experience greater delays in diagnosis resulting in thicker, more advanced disease and worsened mortality rates.2,9 One of the studies analyzed in this review found that older non-White individuals with annual income less than $30,000 had the highest percentages of advanced melanoma and thicker tumors.10 This study also found that patients living in low-income areas had lower five-year melanoma-specific survival rates compared to those residing in high-income areas. A possible explanation of this disparity was identified by the same author who determined that these patients with advanced disease living in low-income areas were less likely to receive chemotherapy compared to their counterparts living in high-income areas.9,11

Health Insurance
An individual’s health insurance plays a crucial role in access and timeliness of health care and treatment of illness, which are major determinants of melanoma survival outcomes. An example of health insurance acting as a mediator rather than a barrier is the Health Maintenance Organization or “HMO effect.” Patients with HMOs more frequently and regularly see their primary care physicians than those with fee-for-service. More frequent contact with a physician provides more opportunities for preventive skin examinations and earlier melanoma diagnoses.9 According to a review conducted by Qian et al,2 several studies have identified that ethinic minority groups experience longer waiting periods between diagnosis and surgery, which can help explain the disparity of survival rates regardless of stage at diagnosis. This prolonged time until treatment in ethnic minority groups is associated with health insurance status. Privately insured patients have been found to be less likely to experience delays in surgery, followed by Medicare then Medicaid.2

Education and Perception of Risk
A heightened perception of risk is a positive predictor of preventive behaviors in melanoma. Several studies have identified that non-Hispanic Black patients consider themselves to be at low risk of developing melanoma.4,9,12 The general level of knowledge regarding melanoma is lower in Black people compared to White people, which translates to a lower likelihood that Black patients will perform self-skin examinations. Numerous studies have identified significantly lower rates of self-skin examinations and physician-assisted skin exams in non-Hispanic Black patients compared to non-Hispanic White Patients.9 Black patients are also less likely to seek medical care if they have a suspicious skin lesion. This lower level of knowledge of melanoma and minimal perception of risk result in diagnoses with greater tumor thickness and lower survival rates.9 Decreased risk perceptions have been associated with lower levels of education.13

Numerous studies have employed video-based interventions, focus groups, or educational class-based interventions that have aimed to increase knowledge of melanoma and promote skin-safe practices among non-Hispanic Black people and other people of color with promising outcomes.12,14 Several interventions have incorporated photographs to encourage recognition of the ABCDEs of melanoma and increase perception of risk in darker skin types. Knowledge that melanoma is a type of skin cancer, sunburns do occur in skin of color, and people of color are at risk for melanoma increased across the board after the implementation of these interventions.

One study in particular conducted by Chao et al12 compared the efficacy of a general educational intervention informing participants of melanoma versus a targeted intervention focusing on skin of color. The comparison group received a pamphlet about the ABCDEs of melanoma and the targeted group received a modified version of this pamphlet that included a “skin of color” section, the nomenclature “melanoma skin cancer” and “for all races and skin colors”, as well as a photo of an individual performing a self-skin examination, specifically of the foot to bring awareness to the risk of acral lentiginous melanoma.12 The “Skin of Color” section reiterated that melanoma affects all races and ethnicities and informed participants of the increased risk of a melanoma presenting in acral, subungual, and mucosal surfaces in people of color. This section was accompanied by images of ALMs on ethnic skin located on the lips, bottoms of feet, and nail beds. Results of the study showed significant increase in skin self-examinations using the ABCDE criteria post-intervention and at the two-month follow up in the targeted intervention group. Between 40 and 57 percent of melanomas are commonly first detected by patients themselves, so this improvement in skin self-exams from targeted education is significant in improving early diagnoses. However, while perception of melanoma risk increased immediately post-intervention, the increase was no longer significant at the two-month follow up. This indicates that repeated melanoma education may be necessary to maintain a heightened perception of risk in patients with skin of color.12

DISCUSSION
Though we are unable to change the fact that non-Hispanic Black people are most commonly afflicted by an aggressive subtype of melanoma, ALM, essentially every other factor at play leading to delays in diagnosis and strikingly disproportionate survival rates is modifiable. Of great importance, if not greatest importance, is targeted patient education that changes the Black population’s perception of their melanoma risk. Providing this population with the knowledge of their risk, how and where melanoma presents on their skin, and the importance of skin-examinations has been shown to be effective in earlier diagnoses of this disease. Because many patients have limited access to specialty care, primary care physicians should be trained to not only provide thorough skin examinations involving the feet, palms, and nails, but also to educate non-Hispanic Black patients about their melanoma risk. This patient education should be offered repeatedly as melanoma knowledge decreases over time.12,14 Additionally, more investigation is needed in identifying barriers to postdiagnosis care and mitigating these barriers as much as possible.15 Adequate representation of minorities in melanoma clinical trials should be a goal of improvement, as it could greatly ameliorate the limited access to immunotherapy in non-Hispanic Black patients and ultimately improve melanoma outcomes.2

CONCLUSION
The significant racial disparity of MSS among non-Hispanic Black patients warrants increased clinical suspicion and ongoing, targeted patient education from all medical providers, especially in the fields of primary care and dermatology. Awareness of the clinical features and common presentation of ALM in non-Hispanic Black patients will improve early diagnosis and in turn aid in the improvement of the worsening disparity overall.

References

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