shows sociodemographic and clinical data for 83,859 NHW and 4,607 Hispanic Californians with incident melanomas reported between 1988-2007. Median age at diagnosis was significantly higher in NHWs (male: 61 years; females: 54 years) than in Hispanics (55 years and 47 years respectively; P <.0001). Hispanics had significantly lower neighborhood-level SES: greater than 40% of Hispanic melanoma patients were in quintile 1 (the lowest) or 2 of neighborhood SES versus 20% of NHWs, while only 16% of Hispanics were in quintile 5 (the highest) of neighborhood SES, compared to 33-35% of NHWs (P <.0001 for all).
Melanoma Incidence in Hispanics and NHW in California by age, socioeconomic status and melanoma tumor characteristics; 1988-2007 (N=88,466)
Among males, average annual age-adjusted incidence rates were 286.1 per 1,000,000 for NHWs and 41.3 for Hispanics (P <.001). Among NHWs and Hispanic females, these rates were 183.7 and 41.8 (P <.001). Gender-specific rates varied by race/ethnicity: males accounted for 58% of melanomas in NHWs, but only 42% in Hispanics (P <.0001).
Clinical Melanoma Characteristics
Tumor thickness data was missing for 31% of NHW patients and 35% of Hispanic patients, consistent with other data from population-based cancer registries. There was a significant association between missing/unknown depth and SES in both Hispanics and NHWs (p<0.0001; data not shown). However, this did not vary substantially by race/ethnicity: NHWs had 30% missing depth in quintile 1 (lowest SES quintile) and 19% in quintile 5 (highest SES quintile), while Hispanics had 33% and 21% missing in quintiles 1 and 5 respectively.
Missing tumor thickness was strongly associated with stage: for regional/distant (vs. localized) stage, NHW had a steadily increasing socioeconomic gradient of missing data (9% in quintile 5 increasing to 15% in quintile 1; data not shown). For Hispanics these rates of missing data similarly increased, from 12.5% in quintile 5 up to 25% in quintile 1.
Among those with known thickness, distributions differed significantly by race/ethnicity and gender. Mean age-adjusted tumor thickness was greater in Hispanic (1.80mm) versus NHW (1.22mm, P <.0001) males and Hispanic (1.47mm) versus NHW (1.07mm, P <.0001) females. In addition, a significantly higher percentage of Hispanic versus NHW males had tumors >2mm thick at diagnosis (21% versus 14%, respectively, P <.0001). This difference was also observed for the thickest (>4mm) tumors; approximately twice as many Hispanic males (10%) as NHW males (5%) had tumors >4mm thick. An excess of thicker tumors was also observed among Hispanic females (15% had tumors >2mm thick) compared to NHW females (10%).
ALM and NM subtypes comprised a higher percentage of melanomas in Hispanic males than in NHW males (: P <.001), while the SSM subtype comprised a smaller percentage (P <.0001). Aside from ALM, the distribution of histologic subtypes of melanoma was similar in Hispanic and NHW females. In both racial/ethnic groups, frequency of MM/NOS histology increased with decreasing SES: MM/NOS frequency increased from 46% in quintile 5 (highest SES quintile) to 51% in quintile 1 in NHWs, and from 46% in quintile 5 to 53% in quintile 1 in Hispanics (data not shown).
Hispanic males had significantly higher incidence of tumors on the lower limbs/hips than NHW males (25% versus 9%; P <.001) and lower incidence of tumors on the trunk (33% versus 41%; P <.0001).
Socioeconomic Status and Percentage of Thicker (>2mm) Melanomas at Diagnosis
Lower-SES patients were more likely to have thicker tumors at diagnosis, irrespective of race/ethnicity or sex (P for trend <.0001 for all: ). The association between lower SES and thicker tumors was considerably stronger among Hispanic than NHW men. When compared to High-SES NHW men, the relative risk (RR) for having tumors >2mm among Middle-SES and Low-SES NHW men was 1.26 (95% CI: 1.20, 1.32) and 1.48 (95% CI: 1.37, 1.61), respectively. When compared to High-SES Hispanic men, the relative risk for thicker tumors was 1.77 (95% CI: 1.42, 2.20) for Middle-SES Hispanics men and 2.18 (95% CI:1.73, 2.74) for Low-SES Hispanic men. These findings held among women as well: Low-SES NHW women had a RR of 1.63 (95% CI 1.46, 1.83) for thicker tumors compared to High-SES NHW women; the RR increased to 1.98 (95% CI: 1.55, 2.51) for Low-SES versus High-SES Hispanic women.
Melanoma Occurrence by Tumor Thickness at Diagnosis and Relative Risk (RR) of Thicker (>2mm) versus Thinner (≤2mm) Melanoma by Socioeconomic Status (SES), Stratified by Race/Ethnicity and Gender; California 1988-2007(N=88,466)
Over 60% of NHWs with melanoma were of High SES. Among Hispanics, however, High-SES individuals comprised only one-third of those with melanoma (P <.0001). Conversely, Low-SES NHWs made up only 6% of all NHW melanoma patients; but more than 20% of Hispanic patients (P <.0001)
This racial/ethnic difference in tumor burden by SES was stronger among thicker (>2mm) tumors: among NHWs, over 50% of these tumors occurred among High-SES individuals, while among Hispanic men and women only 19% and 24% of thicker tumors occurred in those of High SES (P <.0001 for both sexes). Conversely, only 8% of thicker tumors occurred in Low-SES NHWs, while 30% and 26% of thicker tumors occurred in Low-SES Hispanic men and women, respectively (P <.0001 for both sexes).
Socioeconomic Status and Melanoma Histologic Subtype
Among males, lower-SES patients had a lower percentage of SSM subtype (P for trend <.0001 within both race/ethnicities: ). Again, this association was stronger in Hispanic than in NHW males. An association between lower SES and a higher percentage of patients with NM subtype was observed in all groups; there was little difference in the strength of this association by race/ethnicity or gender (). Among NHW and Hispanic males and females, P for trend was <.0001, .0004, <.0001, and .039 respectively.
Melanoma Histologic Subtype by Socioeconomic Status (SES) group in Hispanic and Non-Hispanic White (NHW) males and females; California 1988-2007 (N=88,466)
Socioeconomic Status by Anatomic Site of Melanoma
High-SES NHW males had more lower limb/hip melanomas than low SES-NHW males (10% vs. 7%, P <.0001: ). Conversely, High-SES Hispanic males had significantly lower proportions of these melanomas than Low-SES Hispanic males (19% vs. 27%, P for trend= .0002). While the percent of melanomas on the trunk was stable across SES categories for NHW males, it was significantly higher among High-SES versus Low-SES Hispanic males (34% versus 23%, P for trend=.0003). Head/neck and upper limb and shoulder melanoma rates did not vary by SES among either NHW or Hispanic males.
Melanoma Anatomic Site by Socioeconomic Status (SES) group in Hispanic and Non-Hispanic White (NHW) males and females; California 1988-2007 (N=88,466)
Associations between SES and anatomic location of melanomas did not vary as greatly by race/ethnicity among females. Among both NHW and Hispanic women, head/neck melanomas were significantly more common among lower-SES women. Unlike in men, lower limb and hip melanomas were only slightly more common among lower-SES versus High-SES Hispanic women.