Clinical and Prognostic Features of Primary Retroperitoneal Diffuse Large B-Cell Lymphoma: A Single-Center Experience in China
Primary retroperitoneal diffuse large B-cell lymphoma (PRLBCL) is a rare and heterogeneous subtype of diffuse large B-cell lymphoma (DLBCL) that originates in the retroperitoneal space. Due to its unique anatomical location and clinical presentation, PRLBCL poses significant diagnostic and therapeutic challenges. This study retrospectively analyzed 20 cases of PRLBCL treated at Renmin Hospital of Wuhan University between January 2014 and September 2019, aiming to better understand the clinical characteristics, treatment outcomes, and prognostic factors associated with this disease.
Introduction
The retroperitoneal space, characterized by its large size and loose connective tissue, allows tumors to grow silently before clinical symptoms become apparent. This often results in bulky masses at the time of diagnosis, making it difficult to distinguish PRLBCL from other retroperitoneal tumors, such as gastrointestinal stromal tumors and neurofibromas. The Revised European-American Lymphoma (REAL) classification emphasizes the importance of identifying the primary site of lymphoma for accurate diagnosis and treatment. PRLBCL, although rarely reported, represents a distinct clinical entity with unique features and outcomes.
Patient Characteristics
The study included 20 patients with PRLBCL, with a male-to-female ratio of 1.86:1. The median age of the patients was 60 years, ranging from 26 to 77 years. At the time of diagnosis, 85% of the patients had elevated lactate dehydrogenase (LDH) levels, and 3.0% were positive for hepatitis B virus (HBV) infection. Imaging studies revealed that all patients had retroperitoneal masses larger than 7.5 cm in diameter, with the largest mass measuring 24.0 cm × 13.3 cm × 18.5 cm.
Clinical symptoms varied, with 45% of the patients presenting with acute abdomen requiring exploratory laparotomy, while the remaining 55% experienced chronic abdominal distension and underwent ultrasound-guided puncture biopsy for diagnosis. Pathological biopsy and immunohistochemistry confirmed the diagnosis of PRLBCL in all cases. Based on Han’s classification, 40% of the cases were classified as germinal center B-cell (GCB) type, and 60% were non-germinal center B-cell (n-GCB) type. Double expression (DE) of MYC and Bcl-2 was observed in 30% of the cases.
Staging and Risk Assessment
Clinical staging was performed according to the Lugano classification, with 35% of the patients classified as stage II, 45% as stage III, and 20% as stage IV. The National Comprehensive Cancer Network-International Prognostic Index (NCCN-IPI) was used to assess risk, with 65% of the patients falling into the middle- and high-risk groups (score ≥4) and 35% in the low- and middle-risk groups (score 0–3). The majority of patients (85%) had a Ki-67 proliferation index greater than 60%, indicating high tumor aggressiveness.
Treatment Approaches
Treatment strategies varied among the patients. Sixty-five percent of the patients underwent radiotherapy (RT) or surgical resection, while 35% did not. Sixty percent of the patients received rituximab (R) as part of their treatment, and 40% did not. Combination modality therapy (CMT), which included chemotherapy (CT) with or without RT or surgery, was administered to 65% of the patients, while 35% received CT alone.
After first-line treatment, one patient achieved complete remission (CR), 13 patients achieved partial remission (PR), and six patients experienced progressive disease (PD). The objective response rate (ORR) was significantly higher in patients who received first-line treatment plus RT compared to those who did not (8/8 vs. 6/12, P = 0.042). Fifty percent of the patients required second- or third-line treatments due to disease progression or relapse.
Survival Outcomes
The median follow-up time was 30.1 months. The median progression-free survival (mPFS) was 24.0 months, and the overall survival (OS) ranged from 8 to 36 months. The 3-year cumulative survival rate was 55.0%. Univariate analysis identified several prognostic factors for OS and PFS. Elevated serum LDH levels were associated with poorer OS (P = 0.038). Patients with GCB type had superior OS (P = 0.036) and PFS (P = 0.004) compared to those with n-GCB type. Patients who underwent RT or surgical resection had longer OS (P = 0.009) and PFS (P = 0.008). Additionally, patients treated with CMT had better OS compared to those treated with CT alone (P = 0.012).
Discussion
PRLBCL is a rare and heterogeneous subtype of DLBCL with unique clinical and prognostic features. The retroperitoneal location of the tumor often leads to delayed diagnosis, resulting in bulky masses and advanced disease at presentation. The study highlights the importance of early detection and accurate diagnosis to avoid life-threatening complications caused by mass compression or invasion.
The findings suggest that elevated LDH levels and Han’s classification are significant prognostic factors for PRLBCL. Patients with GCB type had better survival outcomes compared to those with n-GCB type, consistent with previous studies on DLBCL. The study also underscores the role of RT and surgical resection in improving survival outcomes, particularly in patients with bulky masses or acute abdomen.
The treatment of PRLBCL remains challenging due to the lack of standardized protocols. While the R-CHOP regimen has improved outcomes in DLBCL, its efficacy in PRLBCL, especially in high-risk patients, is less clear. The study observed that patients in the high-risk group had a higher PR rate after first-line treatment, but achieving CR was difficult. Salvage treatments, including immunotherapy and targeted therapies, showed limited efficacy, highlighting the need for novel therapeutic approaches.
Conclusion
PRLBCL is a rare and aggressive subtype of DLBCL with distinct clinical and prognostic features. Early diagnosis and prompt treatment are crucial to improving outcomes. The study highlights the prognostic significance of LDH levels, Han’s classification, and the role of RT and surgical resection in managing PRLBCL. Further research and international collaboration are needed to develop standardized treatment protocols and explore new therapeutic options for this challenging disease.
doi.org/10.1097/CM9.0000000000001473
Was this helpful?
0 / 0