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This biophysical study aimed to determine fitting parameters for the Lyman–Kutcher–Burman (LKB) dose–response model for normal tissue complication probability (NTCP) calculations of acute side effects and to investigate the impact of reduced radiation doses on the probability of their occurrence in supradiaphragmatic non-Hodgkin lymphoma (NHL) irradiation. A cohort of 114 patients with NHL in the cervicothoracic region, treated between 2015 and 2021 at the University Hospitals of Münster, Hamburg, and Essen, with involved site radiation therapy (ISRT), were included. Among them, 68 patients with aggressive NHL (a-NHL) received consolidative radiation therapy with 24–54 Gy following (R-)CHOP chemotherapy. Additionally, 46 patients with indolent NHL (i-NHL) underwent radiotherapy with 22.5–45.0 Gy. Two treatment plans were prospectively created for each patient (a-NHL: 30.0/40.0 Gy; i-NHL: 24.0/30.0 Gy). NTCP were then calculated using the optimized LKB model. The adapted dose–response models properly predicted the patient’s probability of developing acute side effects when receiving doses ≤ 50 Gy. In addition, it was shown that reduced radiation doses can influence the NTCP of acute side effects depending on the aggressiveness of NHL significantly. This study provided a foundation to prospectively assess the probability of adverse side effects among today’s reduced radiation doses in the treatment of NHL.

Background: Primary lymphoma of the central nervous system (PCNSL) encompasses a variety of lymphoma subtypes, with the majority being diffuse large B-cell lymphomas, which require aggressive systemic treatment. In contrast, low-grade lymphomas are reported infrequently and are mostly limited to dural manifestations. Very rarely, parenchymal low-grade PCNSL is diagnosed, and the cases documented in the literature show a wide variety of treatment approaches. Methods: We screened all cases of PCNSL treated at our department (a tertiary hematooncology and neurooncology center) in the last 15 years and conducted a comprehensive literature research in the PubMed database. Results: Overall, two cases of low-grade primary parenchymal PCNSL treated with irradiation were identified. The dose prescriptions ranged from 30.6 to 36 Gy for the involved site, with sparing of the hippocampal structures. Both patients had an excellent response to the treatment with a mean follow-up of 20 months. No clinical or radiological signs of treatment toxicity were detected. Conclusions: Our analysis corroborates the results from the literature and demonstrates that parenchymal low-grade PCNSL shows a good response to localized radiation treatment, enabling a favorable outcome while avoiding long-term treatment toxicity.

Radiotherapy (RT) is an established treatment modality in the management of patients with multiple myeloma (MM), aiming at analgesia and stabilization of osteolytic lesions. As a multifocal disease, the combined use of RT, systemic chemotherapy, and targeted therapy (ST) is pivotal to achieve better disease control. However, adding RT to ST may lead to increased toxicity. The aim of this study was to evaluate the tolerability of ST given concurrently with RT. Overall, 82 patients treated at our hematological center with a median follow-up of 60 months from initial diagnosis and 46.5 months from the start of RT were evaluated retrospectively. Toxicities were recorded from 30 days before RT up to 90 days after RT. 54 patients (65.9%) developed at least one non-hematological toxicity, with 50 patients (61.0%) showing low-grade (grade I or II) and 14 patients (17.1%) revealing high-grade (grade III and IV) toxicities. Hematological toxicities were documented in 50 patients (61.0%) before RT, 60 patients (73.2%) during RT, and 67 patients (81.7%) following RT. After RT, patients who had received ST during RT showed a significant increase in high-grade hematological toxicities (p = 0.018). In summary, RT can be safely implemented into modern treatment regimens for MM, but stringent monitoring of potential toxicities even after completion of RT has to be ensured.

Introduction: In patients with mantle cell lymphoma (MCL), long-term remissions can be achieved by stem cell transplantation (SCT). Different conditioning treatment protocols exist with or without total body irradiation (TBI). There are few data published on the role of TBI before autologous stem cell transplantation (autoSCT) or allogenic stem cell transplantation (alloSCT). We report on the long-term survival data of patients treated by TBI prior to autologous or allogenic SCT at our center. Patients: In a retrospective analysis, the data of patients treated at the University Hospital of Muenster from May 2004 to February 2015 were collected and evaluated. For the analysis, all data of patients who were histopathologically diagnosed with MCL and underwent TBI prior to stem cell transplantation (SCT) were evaluated. Results: A total of 22 patients (19 men and 3 women) were treated with a TBI-based conditioning prior to SCT. The median age at initial diagnosis was 57.5 years (38–65 years). Seventeen patients had Ann Arbor stage IV, two patients had Ann Arbor stage III, and three patients Ann Arbor stage II disease. AutoSCT was performed in 19 patients and alloSCT was performed in 3 patients. In 18 patients, autoSCT was applied as part of first-line therapy, and in one patient after relapse. Two patients received alloSCT after relapse of MCL, and one patient received alloSCT during first-line therapy after an inadequate treatment response. TBI was performed in 12 patients with 10 Gy and in 6 patients with 12 Gy, these patients subsequently received autoSCT. In the group of four patients who received TBI with four Gy, four patients subsequently received alloSCT and one patient received autoSCT. Median overall survival after autoSCT and previous TBI was 11.4 years (142 months). In total, 11 out of 19 patients treated with autoSCT lived longer than 6.8 years (82–202 months). After alloSCT and previous TBI, the median overall survival was 3.25 years (14–59 months). Conclusions: A large proportion of patients with advanced MCL survived remarkably longer than 11.4 years after high-dose chemotherapy, TBI, and SCT. The present results of multimodal treatment support the published reports that TBI-based high-dose therapy followed by autoSCT is highly effective in this prognostically unfavorable disease situation.

The aim of this retrospective study is to compare the two boost subgroups, IORT or IMRT, in terms of overall survival (OS), progression-free survival (PFS), cosmesis, and acute and late toxicity. It shall be shown whether and which of the boost techniques offers better results with respect to the facial points, since there are already many studies on applying boost to the tumor bed after/during breast conserving surgery, and there are few which compare the different techniques. For this comparison, two subgroups of 76 patients each (n = 152), treated between 2002 and 2015, were enrolled in the study. In one subgroup, the 9 Gy boost was intraoperatively administered after complete removal of the primary tumor, while the other subgroup received the boost of 8.4 Gy percutaneously and simultaneously integrated into the tumor bed after breast conserving surgery. Both subgroups have subsequently undergone whole breast irradiation (WBI) of 50.4/50 Gy in 1.8–2 Gy per fraction. OS and the incidence of late toxicity did not differ between the two subgroups and no risk factor was found regarding PFS. Acute toxicities initially occurred significantly less (p < 0.001) in the IORT subgroup; however, after WBI took place, this difference vanished. Therefore, boost application by means of IORT or IMRT can be considered equivalent.

Gastric marginal zone lymphoma (gMZL) of mucosa-associated lymphoid tissue (MALT) may persist even after H. pylori eradication, or it can be primarily Helicobacter pylori (H. pylori) independent. For patients without the successful eradication of lymphoma, or with progressive disease, treatment options have historically included partial or total gastrectomy. Presently, in these instances, curative radiation therapy (RT) is the current standard of care. This review emphasizes the historically changing role of radiation therapy in gMZL, progressing from large-volume RT without surgery, to localized RT, on its own, as a curative organ-preserving treatment. This overview shows the substantial progress in radiation therapy during the recent two to three decades, from high-dose, large-field techniques to low-dose, localized target volumes based on advanced imaging, three-dimensional treatment planning, and advanced treatment delivery techniques. RT has evolved from very large extended field techniques (EF) with prophylactic treatment of the whole abdomen and the supradiaphragmatic lymph nodes, applying doses between 30 and 50 Gy, to involved-field RT (IF), to the current internationally recommended involved site radiation therapy (ISRT) with a radiation dose of 24–30 Gy in gMZL. Stage-adapted RT is a highly effective and safe treatment with excellent overall survival rates and very rare acute or late treatment-related toxicities, as shown not only in retrospective studies, but also in large prospective multicenter studies, such as those conducted by the German Study Group on Gastrointestinal Lymphoma (DSGL). Further de-escalation of the radiation treatments with low-dose 20 Gy, as well as ultra-low-dose 4 Gy radiation therapy, is under investigation within ongoing prospective clinical trials of the International Lymphoma Radiation Oncology Group (ILROG) and of the German Lymphoma Alliance (GLA).

This retrospective study examined the role of 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) in stage-related therapy of follicular lymphomas (FL). Twelve patients each in stages I and II, 13 in stage III and 11 in stage IV were treated in the Department of Radiation Oncology, University Hospital of Muenster, Germany from 2004 to 2016. Radiotherapy (RT), as well as additional chemoimmunotherapy were analyzed with a median follow-up of 87.6 months. Ultrasound (US), CT and 18F-FDG-PET/CT were used to determine progression-free survival (PFS), overall survival (OS) and lymphoma-specific survival (LSS) over 5- and 10- years. 23 of 24 patients with stage I/II (95.8%) had complete remissions (CR) and 17 of 24 patients with stages III/IV FL showed CR (70.8%). 5- and 10-year PFS in stages I/II was 90.0%/78.1% vs. 44.3%/28.5% in stages III/IV. 5- and 10-year OS rates in stages I/II was 100%/93.3% vs. 53.7%/48.4% in stages III/IV. 5- and 10-year LSS of stages I/II was 100%/93.8% vs. 69.2%/62.3% in stages III/IV. FL of stages I/II, staged by 18F-FDG-PET/CT, revealed better survival rates and lower risk of recurrence compared to studies without PET/CT-staging. Especially, patients with PET/CT proven stage I disease showed significantly better survival and lower relapses rates after RT.

Abstract. The MabThera and Involved field Radiotherapy study investigated efficacy and safety of involved field (IF) radiotherapy in combination with the anti-CD20 antibody Rituximab for early-stage follicular lymphoma (FL) in a prospective, single-arm multicenter phase 2 design. Eighty-five stage I–II FL patients received 8 cycles of Rituximab (375 mg/m2) and IF irradiation (30/40 Gy). The primary endpoint was progression-free survival (PFS) 2 years from treatment start. Secondary endpoints were overall survival (OS), complete response rates, toxicity, quality of life, and minimal residual disease (MRD) response with protocol defined visits up to month 30. For the primary endpoint, PFS at 2 years was 85% for the intention-to-treat set. Long-term data were captured in selected sites and evaluated as post hoc analysis in the per protocol (PP) set: PFS and OS were 78% and 96% at 5 years with a median follow-up of 66 or 78 months, respectively. There were 17/76 recurrences in the PP set, of which 14 were outside the radiation volume only. MRD analyses revealed a clonal marker in 36% of patients at diagnosis. All but 1 marker positive patients experienced a molecular treatment response. There were 13 serious adverse events (4 related to the therapy) during the first 30 months. IF radiotherapy combined with Rituximab is well tolerated and highly efficient with low rates of recurrence in the first years in early-stage FL. The efficacy is comparable with more aggressive therapy approaches without compromising the quality of life and maintains for an extended follow-up of more than 5 years.

Successful studies on radiation therapy for gastric lymphoma led to a decrease in planning target volume (PTV) and radiation dose with low toxicities, maintaining excellent survival rates. It remains unclear as to which effects are to be expected concerning dose burden on organs at risk (OAR) by decrease in PTV vs. dose and whether a direct impact on toxicity might be expected. We evaluated 72 radiation plans, generated prospectively for a cohort of 18 patients who were treated for indolent gastric lymphoma in our department. As a prospective work, four radiation plans with different radiation doses and target volumes (40 Gy-involved field, 40 Gy-involved site, 30 Gy-involved field, 30 Gy-involved site) were generated for each patient. Mean dose burden on adjacent organs was compared between the planning groups. Cohort toxicity data served to estimate parameters for the Lyman–Kutcher–Burman (LKB) model for normal tissue complication probability (NTCP). These were used to anticipate adverse events for OAR. Literature parameters were used to estimate high-grade toxicities of OAR. Decrease of dose and/or PTV led to median dose reductions between 0.13 and 5.2 Gy, with a significant dose reduction on neighboring organs. Estimated model parameters for liver, spleen, and bowel toxicity were feasible to predict cohort toxicities. NTCP for the endpoints elevated liver enzymes, low platelet count, and diarrhea ranged between 15.9 and 22.8%, 27.6 and 32.4%, and 21.8 and 26.4% for the respective four plan variations. Field and dose reduction highly impact dose burden and NTCP for OAR during stomach radiation. Our estimated LKB model parameters offer a good approximation for low-grade toxicities in abdominal organs with modern radiation techniques.