Study Reveals Poor Prognostic Factors Associated With DLBCL of the Urinary Tract

Patients with primary diffuse large B-cell lymphoma of the urinary tract (UT-DLBCL) may face a poorer prognosis if they are older, are male, have not undergone surgical resection or chemotherapy, or have stage 4 disease, according to a study published in Frontiers in Oncology.

The population-based study is the largest study investigating factors indicating a poor prognosis in patients with UT-DLBCL, which is a rare lymphoma subtype that may have different etiology, clinical characteristics, and survival outcomes than lymphomas originating at other sites.

Approximately 30% of non-Hodgkin lymphoma diagnoses are for DLBCL. The use of rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone has significantly improved survival outcomes in patients with DLBCL. However, questions remain about treatment-related adverse effects and long-term complications.

Previous studies have found that extranodal sites may possess distinct clinical characteristics, result in different survival outcomes, and require specific treatment, but studies on clinical features and survival outcomes of UT-DLBCL are limited.

The investigators used the Surveillance, Epidemiology, and End Results (SEER) database to enroll patients diagnosed with lymphoma from 18 state registries in the United States from 1975 to 2016. The patients were split into 3 groups based on age (0-60 years, 60-75 years, and older than 75 years). They were also divided into 2 groups based on the site of origin:

• Upper UT (UUT) group, with sites that include the kidneys, renal pelvis, and ureter
• Lower UT (LUT) group, with sites that include urinary bladder and urethra

In total, 489 eligible patients were enrolled in the analysis. The mean age at diagnosis was 69 years, and when split into groups based on age at diagnosis, 143 (29.24%) fell in the group younger than 60, 166 (33.95%) were in the group aged 60 to 75, and 180 (36.81) were in the over group older than 75. The most common primary sites were kidney (72.39%) and urinary bladder (24.95%).

Cancer-directed surgery was conducted in 56.44% of patients. Additionally, 7.77% (n = 41) had undergone radiation therapy and 72.80% (n = 356) had undergone chemotherapy. 167 (34.15%) patients had stage 1 disease and 168 (34.35%) had stage 4 disease.

Patients older than 75 years had the worst survival outcomes, having an overall survival (OS) of only 8 months and a disease-specific survival (DSS) of 12 months (P < .001). Patients younger than 60 and those in the 60 to 75 age range had a 5-year OS of 64.29% and 43.51%, respectively, which was considerably higher than that of the over-75 group (27.10%). The 5-year DSS of the age groups was 69.06%, 51.36%, and 39.23%, respectively.

There were no differences in OS or DSS between genders, races, or sites of origin. However, patients who had cancer-directed surgery had an OS of 63 months, which was much higher than the 16 months for patients who had not (HR, 1.310; 95% CI, 1.051-1.633, P = .016). A similar outcome was observed for DSS in these 2 groups (HR, 1.624; 95% CI, 1.241-2.127; P < .001).

Radiotherapy did not provide a survival benefit for patients with UT-DLCBL. However, patients who had not undergone chemotherapy had approximately twice the risk of death as those who had (P < .001).

After accounting for potential confounding factors, the multivariate survival analysis revealed that older patients still had worse OS and DSS than younger patients. Patients who were men also had worse OS (HR, 1.336; 95% CI, 1.061-1.681; P = .014) and DSS (HR, 1.340; 95% CI, 1.020-1.759; P = .036). Patients who received surgical resection had better OS and DSS than those who did not (P < .05).

Chemotherapy continued to have a positive effect on survival in patients (P < .001). Additionally, patients with stage 4 disease had worse OS (HR, 1.606; 95% CI, 1.202-2.146; P = .001) and DSS (HR, 1.835; 95% CI, 1.298-2.594; P = .001) than patients with stage 1 disease.

Lack of data on specific treatments, such as chemotherapy and combination therapy, was listed as a main limitation of the study. The investigators indicated that future research needs to involve a larger population to confirm their findings.

Reference

Liu ZH, Yang LC, Song P, et al. Primary diffuse large B-cell lymphoma of the urinary tract: a population-based analysis. Front Oncol. 2021;11:609882. doi:10.3389/fonc.2021.609882