Disparities in Outcomes of Cutaneous T-Cell Lymphoma in US Patients Aged < 40 Years Compared to Older Population

Background

A rapid increase in the incidence of cutaneous T-cell lymphoma in young patients (< 40 years) was recently reported.¹ However, there is a lack of data on the disease outcomes in this age group. We examined the characteristics and outcomes of CTCL patients aged <40 years compared to an older population to improve our understanding of the disease in the different age groups.

Methods

Cases of CTCL were obtained from the Surveillance, Epidemiology, and End Results (SEER) Program from 2000 to 2020. Statistical analyses were conducted with SPSS® version 25. Patients’ characteristics were reported in frequencies and compared with the Chi-squared test between patients <40 years and an older population (40+ years). The Kaplan-Meier method was used to estimate median overall survival (OS). Cox Regression was done to determine predictors of survival.

Results

16,923 cases of CTCL were identified during the study period. As shown in Table 1, gender distribution was similar among both age groups. Younger patients were more likely to be non-Whites. Mycosis fungoides was the most common subtype seen in both populations, with a higher frequency in the younger. The disease was localized in more than half of younger people but more advanced in older patients. 5- and 10-year overall survival (OS) were higher in the younger age group. There was no significant difference in sex, rates of chemotherapy use, and surgery between older and younger patients.

Table 2 shows the predictors of survival of CTCL. Being male conferred a poor prognosis in older but not younger patients. Hispanics had a worse prognosis in the younger age group, while Asians and American Indians, compared to Whites, had poorer survival in older patients. Survival was worse in both age groups in Blacks. The most aggressive CTCL sub-type in the younger age group was extranodal NK-/T-cell lymphoma, nasal type but adult T-cell leukemia/lymphoma in older patients. Beam radiation was the only form of radiotherapy associated with improved survival in only younger patients, unlike in older patients who received survival benefits from all forms of radiotherapy. Chemotherapy was associated with poorer survival in both age groups. The diagnosis period was a predictor of improved survival in both age groups.

Conclusion

The racial distribution of CTCL between the age groups is consistent with a previous US study, though the ages were higher than the cut-off used in our research.² The poorer survival outcome in older patients is likely related to a more advanced stage of the disease, as shown in our study. Key findings in our study include the age-related poor prognosis of the disease in some races: outcomes were poor for Hispanics in younger patients but not in older patients. At the same time, in Asians and American Indians, the reverse was the case. The reason for this is unclear to us. Chemotherapy seems to worsen outcomes in both age groups, consistent with a recent study.³ Also, beam radiation treatment (less used in younger patients compared to older people in our study) appears to offer some improvement in survival in younger people; probably, this should be used more in carefully selected young patients while balancing the risks with the benefits. The prognosis of CTCL has improved in recent years. Advances in treatment or earlier diagnosis may explain this. Prospective studies are needed to examine the reasons for the racial disparities in outcomes.

References

1. Cai ZR, Chen ML, Weinstock MA, Kim YH, Novoa RA, Linos E. Incidence Trends of Primary Cutaneous T-Cell Lymphoma in the US From 2000 to 2018: A SEER Population Data Analysis. JAMA Oncol. 2022 Nov 1;8(11):1690-1692. doi: 1001/jamaoncol.2022.3236. PMID: 36048455; PMCID: PMC9437821.
2. Su C, Nguyen KA, Bai HX, Cao Y, Tao Y, Xiao R, Karakousis G, Zhang PJ, Zhang G. Racial disparity in mycosis fungoides An analysis of 4495 cases from the US National Cancer J Am Acad Dermatol. 2017 Sep;77(3):497-502.e2. doi: 10.1016/j.jaad.2017.04.1137. Epub 2017 Jun 20. PMID: 28645647.
3. Dai J, Duvic Cutaneous T-Cell Lymphoma: Current and Emerging Therapies. Oncology (Williston Park). 2023 Feb 24;37(2):55-62. doi 10.46883/2023.25920984. PMID: 36862846.