Consolidative Radiotherapy to Residual Masses After Chemotherapy Is Associated With Improved Outcome in Diffuse Large B-Cell Lymphoma. A Retrospective, Population-Based Study

Primary Splenic Diffuse Large B-Cell Lymphoma: A Case Report and Literature Review of a Rare Condition

Introduction

Primary splenic lymphoma is a rare lymphoproliferative disorder that involves the spleen, exhibits diverse clinical presentations, and lacks a clear consensus in terms of management strategies.

Case Presentation

We present the case of a 52-year-old patient with a complex medical history marked by multiple chronic medical conditions. The patient was diagnosed with primary splenic lymphoma, specifically the diffuse large B-cell subtype. Treatment for our patient involved a shortened course of chemotherapy (4 cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone [R-CHOP] followed by two doses of rituximab) due to issues related to compliance and treatment-related complications. This was followed by consolidative radiotherapy without resorting to splenectomy.

Conclusion

Remarkably, despite using a shortened course of R-CHOP, the patient achieved complete resolution, and a positron emission tomography scan conducted at the end of the 6-month posttreatment period confirmed sustained complete remission.

Long-term results of PET-guided radiation in patients with advanced-stage diffuse large B-cell lymphoma treated with R-CHOP

Consolidative radiation therapy (RT) for advanced-stage diffuse large B-cell lymphoma (DLBCL) remains controversial, with routine practice continuing to include RT in patients with initial bulky disease or residual masses. Positron emission tomography (PET)-computed tomography is a sensitive modality for detecting the presence of residual disease at the end of treatment (EOT). A PET-guided approach to selectively administering RT has been the policy in British Columbia since 2005. Patients with advanced-stage DLBCL diagnosed from 1 January 2005 to 1 March 2017 and treated with at least 6 cycles of R-CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone plus rituximab), who underwent EOT PET, were included in this analysis. Those with complete metabolic response (PET-negative [PET-NEG]) were observed; those with PET-positive (PET-POS) scans were offered consolidative RT, when feasible. Of the patient records reviewed, 723 were identified, with median follow-up of 4.3 years: 517 (72%) were PET-NEG; 206 (28%) were PET-POS. Time to progression (TTP) and overall survival (OS) at 3 years were 83% vs 56% and 87% vs 64%, in patients with PET-NEG and PET-POS scans, respectively. PET-POS patients with nonprogressing disease treated with consolidative RT (109 and 206; 53%) had outcomes approaching those of PET-NEG patients, with 3-year estimates of 76% and 80% for TTP and OS. PET-NEG patients who had bulky disease (≥10 cm) at diagnosis had outcomes indistinguishable from those without bulk, despite the omission of RT. These data suggest that patients with advanced-stage DLBCL who are PET-NEG at EOT and receive no RT have excellent outcomes. 18F-fluorodeoxyglucose-PET can reliably guide selective administration of consolidative RT, even in patients with initially bulky disease.

Significance of bulky mass and residual tumor-Treated with or without consolidative radiotherapy-To the risk of relapse in DLBCL patients

Bulky and residual tumor are considered to increase the risk of relapse in diffuse large B‐cell lymphoma (DLBCL) patients. Radiotherapy is conventionally used to reduce the risk, but the evidence is controversial. We performed a retrospective analysis to evaluate the significance of bulky and residual tumor treated with or without radiotherapy in DLBCL patients. We analyzed 312 DLBCL patients treated from 2010‐2017 in Oulu University Hospital. A bulky tumor was detected in 123 patients and 55 of these patients (44.3%) received consolidative radiation therapy (RT) to the bulky tumor. Residual tumor meeting the required criteria was found in 138 (39.3%) patients, and 65 (45.5%) of these patients received consolidative RT to the site of residual tumor. iPET‐CT scans were performed in 102 patients. In multivariate analyses, bulky was an independent risk factor in limited stage patients in progression free survival (HR 6.43 [95%CI 1.609‐25.710]; P = .008) not related to International prognostic index (HR 1.35 [95% CI 0.256‐7.124]; P = .724) or age (HR 1.62 [95% CI 0.468‐5.638]; P = .445). This was not seen in advanced stage patients or in patients with residual tumor. Radiotherapy to the bulky or residual tumor was not able to improve the long‐term PFS of patients. In this study, it appears that performing iPET is the most convincing method in improving evaluation and in finding patients with increased risk of relapse. Evidently, patients with negative iPET will not benefit from including RT in the treatment after metabolic complete response (CR), and patients with primary refractory disease are most likely in the group of positive iPET.