Impact of Chromosomal Abnormalities in Acute and Lymphoma Types Adult T-Cell Leukemia-Lymphoma

Background:

Adult T-cell leukemia-lymphoma (ATL), which is a hematological malignancy related to human T-lymphotropic virus type I (HTLV-1), is known as a malignant lymphoid disease with poor prognosis. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered a treatment modality to contribute prolonging the survival in some population of patients (Katsuya H et al. 2015 Blood). A small study indicated that ATL cells frequently have chromosomal abnormalities including various numerical aberrations and complex structural abnormalities (Kamada N et al. Cancer Res. 1992). However, there has been no large study to examine the relationship between chromosomal abnormalities and survival. Here we report the impact of chromosomal abnormalities on survival in ATL patients with conventional chemotherapy.

Patients and Methods:

In this study, we extracted a population of patients from the database of ATL-PI project, which is a nation-wide survey of ATL patients newly diagnosed between January 2000 and May 2009, and the overall results were reported elsewhere (Katsuya H et al. JCO 2012, Blood 2015). Fifteen hundred and twelve patients were registered in this project, and we excluded the patients who received allo-HSCT, and who were diagnosed with smoldering and chronic type ATL. Moreover, patients whose chromosomal analysis with G-banding stain showed normal, multiploid or no mitosis, or no information on chromosomal analysis and on the factors to determine the ATL-PI were also excluded. As a consequence, 210 patients with acute (n=157) and lymphoma (n=53) types were selected for this analysis. Abnormal karyotypes were analyzed from the aspect of numerical and structural break points. To identify the specific abnormalities and to avoid the secondary changes, the stem-line karyotype, which meant the simplest abnormal clone, was used as the representative karyotype for this study. A statistical analysis was performed with 'EZR' (Kanda T. BMT 2013). We examined an overall survival (OS) in relation to chromosomal abnormalities using cox proportional hazard regression model, and p-value of less than 0.05 was considered as statistically significant.

Results:

Among the 210 patients, 119 and 91 patients were male and female, respectively. The median age of patients was 66 years (40-89). With respect to other factors of ATL-PI, the median level of soluble interleukin-2 receptor (sIL-2R), serum albumin, were 30800 U/mL (620-1,219,000), 3.6 g/dL (1.6-5.3), respectively. Almost all patients were diagnosed with stage II-IV of clinical stage (n=200), and almost half of patients certified 2-4 of ECOG-PS (n=113). Sixty-nine, 106, and 35 patients were classified as high, intermediate and low risk by ATL-PI, respectively. Specimens used for chromosomal analysis were taken from lymph nodes (n=77), bone marrow (n=72), peripheral blood (n=50), pleural fluids (n=4), ascites (n=4) and 1 each of stomach, sinusoidal tumor, and tonsillar lesions. The median number of numerical abnormalities and marker chromosomes were 2 (0-20) and 1 (0-20), and the median number of structural break points was 6 (0-21). The numerical abnormalities were loss of sex chromosomes (31%) followed in decreasing order by -14 (24%), -13 (19%), -9 (12%) and -17 (12%) while the structural break points were located at 1p (30%), 3q (30%), 14q (30%), 6q (26%) and 1q (22%). The median OS was 286 days (1-2565). ECOG-PS, serum albumin level, sIL-2R, and structural break points at 9q or 19p, and the number of structural break points over 4 or 5 points were shown to be the significant factors affecting the survival by univariate analysis. Then, the multivariate analysis indicated that 2-4 of ECOG-PS (HR: 2.021, 95%CI: 1.436-2.791, p<0.001), serum albumin level < 3.5 g/dl (HR: 1.631, 95%CI: 1.282-2.074, P<0.001), and chromosomally structural break points at 9q (HR: 1.584, 95%CI: 1.096-2.289, p<0.001) and 19p (HR: 1.765, 95%CI: 1.038-2.999, p<0.001) were factors that negatively contributed to OS.

Discussions and Conclusion:

This is the first large study showing the impact of chromosomal abnormality in acute and lymphoma types ATL on OS. It demonstrated that structural break points at 9q and 19p were the independent risk factors for OS in addition to those of ATL-PI.