We identified a total of 4496 patients diagnosed with cutaneous lymphoma between 2004–2008. There were 1713 patients with MF, 1518 with non-MF CTCL, and 1265 patients with cutaneous B-cell lymphoma (). For mycosis fungoides, non-MF cutaneous T-cell lymphomas, and the cutaneous B-cell lymphomas, the incidence rates were 4.5, 4.0, and 3.3 respectively (per 1 million persons). For MF by race, the incidence was 4.0 for whites, 6.1 for African Americans, 3.0 for Asian/Pacific Islanders, and 0.9 for Native Americans/other/unknown. The incidence rates for the non-white groups were all significantly different than for whites. Fornon-MF cutaneous T-cell lymphomas, the incidence rates were 4.0 for whites, 4.3 for African Americans, 2.0 for Asian/Pacific Islanders, and 1.9 for Native Americans/other/unknown. For the B-cell lymphomas, the incidence rates were 3.6 for whites, 1.8 for African Americans, 1.9 for Asian/Pacific Islanders and 0.8 for Native Americans/other/unknown and the non-white incidence rates were significantly different compared with the white population as a baseline.
Incidence and Gender
Incidence rates for mycosis fungoides by gender revealed a rate of 5.6 per million persons for males and 3.6 for females. For the non-MF CTCL patients, the rates were 5.2 for males and 3.1 for females. The incidence rates for the B-cell lymphomas were 4.3 for males and 2.5 for females ().
Incidence Rates by low stage-high stage and gender
Incidence of Advanced T Stage by Race for Mycosis Fungoides
With regard to T-stage, incidence was only evaluated for the histology of mycosis fungoides given that the TNM staging system is particular for MF. For non-MF cutaneous lymphomas, incidence per overall stage (i.e higher stage-III–IV versus lower I–II) was evaluated. For patients with MF, non-white populations had significantly different incidence rates for T0–T2 levels of disease compared to whites as a reference group. The incidence of T0–T2 disease for whites was 3.0 per million compared with 4.0 for African Americans (p=0.0015), 2.4 for Asian/Pacific Islanders (p=0.048), and 0.4 for Native Americans/other/unknown (p=0.0023). For those presenting with MF and T3/ T4 disease, the incidence was 0.5 for whites, 0.9 for African Americans, 0.3 for Asian/Pacific Islanders and 0.6 for Native Americans/other/unknown. For those groups, only African Americans had a significant increase compared to whites in incidence by higher T-stage (p=0.0039),
Incidence of Advanced Stage by Race for Non-MF CTCL and CBCL patients
With regard to non-MF cutaneous T-cell lymphomas, the incidence rate for stage I–II was 2.8 per million for whites, 2.3 for African Americans, 1.0 for Asian/Pacific Islanders and 0.9 for Native Americans/other/unknown. The incidence rates for Native Americans/other/unknown and Asian/Pacific Islanders were significantly different than the white reference group but not for African Americans. With regard to incidence for stage III–IV disease for non-MF cutaneous T-cell lymphomas, whites had an incidence of 0.6 per million, blacks 1.2, Asian/Pacific Islanders 0.7, and Native Americans/other/unknown 0.4. Within this group, only the incidence rate for African Americans was significantly different (p=0.0006) compared to the white reference group.
Disease Severity at Diagnosis-Multivariate Analysis
With regard to gender, there was a trend for females to be less likely to present with a higher T-stage (T3–T4) than males with an odds ratio of 0.74 on univariate, and 0.73 on multivariate analysis (p=0.06), adjusted for registry, age, race and marital status. With respect to race, African Americans had a significantly increased risk of presenting with higher T-stage (T3–T4) disease than other groups with an odds ratio of 1.34 on univariate and 1.72 on multivariate (p=0.02) compared with the white reference group. The odds ratios for Asian/Pacific Islanders and Native Americans/other/unknown were 0.64 and 0.60 and not significantly different than the white reference group. Those with unknown marital status had a decreased risk of presenting with higher stage disease. For the non-MF cutaneous T-cell lymphoma group, females had a lower risk of presenting with higher stage (overall stage III–IV vs. stage I–II) disease than males with an odds ratio of 0.83 univariate and 0.73 in multivariate (p=0.04) analysis. Regarding race and likelihood of presentation of higher stage (III–IV) for the non-MF cutaneous T-cell patients, African Americans and Asian/Pacific Islanders had increased odds ratios at 2.48 and 2.21 respectively on multivariate analysis (p=0.01) (, ).
Logistic regression (univariate and multivariate) for odds of being high T-stage (T3–T4) for MF
Logistic regression (univariate and multivariate) for odds of being high overall stage for non-MF CTCL
Age at Diagnosis
For patients with MF, the mean age at diagnosis was higher for males vs. females (58.6 years for males vs. 55.4 for females (p=0.0005). For whites, African Americans, Asian/Pacific Islanders and Native Americans/other/unknown, the mean age at diagnosis was 59.2, 51.5, 51.3, and 53.8. African Americans, Asian/Pacific Islanders, and Native Americans/other/unknown patients presented at a significantly different age than the white group. For African Americans, Asian/Pacific Islanders, Native American/other/unknown, the p values in reference to differences in age at diagnosis compared to whites are 0.0001, 0.0001, and 0.0006. The differences between Asian/Pacific Islanders and African Americans, and native American/other/unknown and African Americans, were not significantly different.
For patients with non-MF T-cell lymphoma, the mean age at diagnosis was 60.2 for males and 60 for females (p=.82). The mean age at diagnosis was 61.2 for whites, 54.5 for African Americans, 57.1 for Asian/Pacific Islanders, and 56.2 for Native American/other/unknown. The difference between whites and African Americans was significant (p=0.0001) as was the difference between whites and Native Americans/other/unknown (p=0.01). There were no significant differences between Asian/Pacific Islanders and African Americans, Asians and whites, and African Americans compared to Native Americans/other/unknown.
For those with cutaneous B-cell lymphoma, the mean age at diagnosis for males was 61.3 and for females was 65.6 (p=0.0001). The mean age at diagnosis for whites, African Americans, Asian/Pacific Islanders and Native Americans/other/unknown were 63.7, 56.7, 60.4, and 61.5. The difference between whites and African Americans was significant (p=0.0006). Differences between Asian/Pacific Islanders and African Americans, Asians and whites, whites and Native Americans/other/unknown, and African Amricans compared to native American/other/unknown are not significantly different ().
Comparison of age at diagnosis