What is the treatment approach for primary non-Hodgkin's lymphoma (NHL) of the spleen?

Treatment of Primary Non-Hodgkin's Lymphoma of the Spleen

For primary splenic non-Hodgkin's lymphoma confined to the spleen or spleen plus splenic hilum (true Stage I-II disease), splenectomy followed by systemic chemotherapy provides the best outcomes, with potential for cure and 5-year survival rates exceeding 60%. 1, 2

Diagnostic Confirmation and Staging

Before initiating treatment, you must establish the diagnosis and extent of disease:

• Splenectomy serves as both diagnostic and therapeutic intervention for primary splenic lymphoma, as fine-needle aspiration and core needle biopsy of the spleen are not routinely performed and provide inadequate tissue for complete characterization 3
• Perform comprehensive staging with contrast-enhanced CT of chest, abdomen, and pelvis, or preferably PET-CT for accurate disease assessment 4
• Obtain bone marrow biopsy if PET-CT is not available to exclude marrow involvement 4
• Check complete blood count, LDH, and screen for hepatitis B, hepatitis C, and HIV prior to treatment 4

Treatment Algorithm Based on Disease Extent

True Primary Splenic Lymphoma (Spleen Only or Spleen + Splenic Hilum)

Splenectomy followed by chemotherapy is the optimal approach:

• Early splenectomy combined with chemotherapy achieves complete remission rates of 31.6-40% and 5-year overall survival of 64.7-67.2%, significantly superior to chemotherapy alone (37.1% 5-year survival) 1
• Splenectomy prevents continuous dissemination from the primary tumor site, eliminates the possibility of local splenic relapse (which occurs in 72.7-90% of patients treated with chemotherapy alone), and corrects cytopenias to optimize conditions for subsequent chemotherapy 1
• The median remission duration is longest (74.5 months) when splenectomy is followed by combination chemotherapy 1

Post-splenectomy systemic therapy:

• For low-grade histology: Consider observation if truly localized (Stage I), or single-agent rituximab or rituximab-based regimens for Stage II disease 5, 1
• For intermediate or high-grade histology: Administer 6-8 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) every 21 days 4
• Histologic subtype does not reliably predict prognosis in primary splenic lymphoma when properly staged 2

Advanced Disease (Liver, Bone Marrow, or Distant Nodes Involved)

If staging reveals involvement beyond the spleen and splenic hilum, this is NOT primary splenic lymphoma but rather disseminated disease:

• Treat according to standard NHL protocols with rituximab-based chemoimmunotherapy 5
• R-CHOP remains the standard for diffuse large B-cell lymphoma variants 4
• Splenectomy may still provide symptomatic relief and improve cytopenias but is not curative in this setting 1, 6

Critical Pitfalls to Avoid

Do not treat with chemotherapy alone without splenectomy for truly localized disease:

• Chemotherapy-only approaches result in local splenic relapse rates of 72.7-90% and inferior 5-year survival (37.1-39.4%) compared to splenectomy-based strategies (64.7-67.2%) 1

Do not assume favorable prognosis without pathologic staging:

• Many historical series reporting poor outcomes included patients with hepatic or nodal disease misclassified as "primary splenic lymphoma" 7, 2
• True primary splenic lymphoma (spleen ± splenic hilum only) has prognosis approximating other limited-stage NHL, with median survival of 7.48 years and potential for cure 7, 2

Do not rely on needle biopsy for diagnosis:

• Splenic needle biopsy is not routinely offered and provides inadequate tissue for complete lymphoma characterization 3
• Splenectomy provides definitive diagnosis and immediate therapeutic benefit 1, 3

Post-Treatment Surveillance

• Perform interim response evaluation during chemotherapy to exclude disease progression 4
• Use PET-CT for response assessment in FDG-avid lymphomas 4
• Follow-up schedule: every 3 months for 6 months, then every 6 months until year 4, then annually 4
• CT scans should confirm remission status, then only as clinically indicated 4

Prognosis

Patients with truly localized primary splenic lymphoma (spleen ± splenic hilum only) treated with splenectomy and chemotherapy have outcomes similar to other limited-stage NHL, with 5-year survival rates of 64.7-67.2% and potential for cure 1, 7, 2. In contrast, patients with advanced disease involving liver, bone marrow, or distant nodes have significantly worse outcomes and should be managed as disseminated NHL 6.