Abstract
Introduction: Adult T-cell leukemia/lymphoma (ATLL) is a rare blood disorder associated with human T-cell leukemia virus type 1 (HTLV-1) infection. It is generally categorized into four subtypes: smoldering, chronic, lymphoma, and acute. Given the heterogeneity of these subtypes, there is a significant difference in outcomes. Robust and contemporary epidemiological data are lacking for this rare disorder. We present a retrospective cohort study of patients with ATLL, utilizing the National Cancer Database (NCDB) to better characterize the epidemiology and survival trends in the United States.
Methods: This is a retrospective cohort study using the NCDB to identify ATLL cases diagnosed from 2004-2020. Descriptive statistics summarized baseline characteristics, while chi-square tests assessed group differences. Overall survival (OS) was estimated using Kaplan-Meier analysis and compared using log-rank tests. Multivariable Cox proportional hazards models identified independent prognostic factors (p < 0.05 considered significant).
Results: A total of 635 patients were identified with ATLL, including 344 (54%) males and 291 (46%) females, with a median age at diagnosis of 59 years (range: 19-90). Most patients came from the Middle Atlantic (NY, NJ, PA) region (33%), followed by the South Atlantic (DC, DE, FL, GA, MD, NC, SC, VA, WV) region (20%) and the East North Central (IL, IN, MI, OH, WI) region (8%). Of the 635 patients, 335 (52%) were Black, 247 (39%) White, and 26 (4%) Asian. Sixty-five (10%) patients were of Hispanic origin. Over half of patients with ATLL (54%) had a median income below $46,000. International Prognostic Index (IPI) score was only available for 16 patients: three (19%) patients were in the high-risk group, 7 (43%) in the high-intermediate group, and 6 (37.5%) in the low-intermediate group. Treatment groups included 357 (56%) patients treated with chemotherapy and 29 (4.5%) who received radiation therapy. Thirty-three (5%) patients underwent hematopoietic stem cell transplant (HSCT), including 27 autologous and 16 allogeneic transplants.
The median survival time in the cohort was 9 months (95% CI 7.3-10.7). One-year OS rate in the cohort was 43%, while 2-year and 5-year OS rates were 31% and 23.5%, respectively. Patients over the age of 65 had a significantly shorter median OS than those under 65 (4 vs. 11 months, p=0.001) and were significantly less likely to undergo HSCT (p< 0.001). Black patients had significantly shorter median OS compared to White patients (7.8 months vs 13.3 months, p=0.014), despite similar treatment rates with chemotherapy and HSCT. Median OS appeared to improve over time, from 8 months in patients diagnosed between 2004-2009 to 10 months for those diagnosed between 2016-2020, although this was not statistically significant (p=0.145). Treatment with allogeneic HSCT was associated with significantly prolonged median survival, compared to those who did not receive transplant (50 months vs. 7 months, p<0.05). Additionally, receiving chemotherapy and/or radiation compared to not receiving treatment was also associated with significantly prolonged median survival (p<0.05).
Patients treated in the Middle Atlantic region had a median survival of 8.8 months, compared to 23.2 months in the West South Central (AR, LA, OK, TX) region (p< 0.001). Increased education and income levels were not significantly associated with improved survival. There were no significant differences in survival between males and females.
Conclusions: We provide contemporary estimates on the epidemiology of ATLL. Factors associated with improved prognosis included undergoing HSCT, radiation, or chemotherapy. We report that increased age and Black race are negative prognostic factors. Regional differences in incidence and survival persist in the US. Our study findings underscore the need for increasing access to treatment, including HSCT for those who are good candidates. Additionally, there remains work to be done to address racial disparities in the care of patients with ATLL.
