Clinical Features and Therapeutic Outcomes Comparing Primary Mediastinal Large B-cell Lymphoma to Mediastinal Hodgkin Disease.

Currently, there is limited data available comparing Primary Mediastinal Large B-cell Lymphoma (PMBL) and mediastinal Hodgkin disease, nodular sclerosis type (HDNS). This is a retrospective cohort study that compares the clinical features, histology through immunohistochemistry (IHC) and treatment outcomes of 19 cases of PMBL and 39 cases of HDNS diagnosed over 13 years at a single institution in San Juan, PR. Superior Vena Cava syndrome (SVCS) and elevated Lactate Dehydrogenase (LDH) levels were more frequently seen in the PMBL cohort. At the median follow-up visit, of 74 months, no significant difference was seen in overall survival or progression free survival between PMBL and HDNS. Almost all of the relapses in the PMBL group occurred within 12 months of diagnosis. Our data suggests that PMBL and HDNS differ in their clinical presentation and have a favorable prognosis.

Structure-specific rigid dose accumulation dosimetric analysis of ablative stereotactic MRI-guided adaptive radiation therapy in ultracentral lung lesions.

BACKGROUND: Definitive local therapy with stereotactic ablative radiation therapy (SABR) for ultracentral lung lesions is associated with a high risk of toxicity, including treatment related death. Stereotactic MR-guided adaptive radiation therapy (SMART) can overcome many of the challenges associated with SABR treatment of ultracentral lesions. METHODS: We retrospectively identified 14 consecutive patients who received SMART to ultracentral lung lesions from 10/2019 to 01/2021. Patients had a median distance from the proximal bronchial tree (PBT) of 0.38 cm. Tumors were most often lung primary (64.3%) and HILUS group A (85.7%). A structure-specific rigid registration approach was used for cumulative dose analysis. Kaplan-Meier log-rank analysis was used for clinical outcome data and the Wilcoxon Signed Rank test was used for dosimetric data. RESULTS: Here we show that SMART dosimetric improvements in favor of delivered plans over predicted non-adapted plans for PBT, with improvements in proximal bronchial tree DMax of 5.7 Gy (p = 0.002) and gross tumor 100% prescription coverage of 7.3% (p = 0.002). The mean estimated follow-up is 17.2 months and 2-year local control and local failure free survival rates are 92.9% and 85.7%, respectively. There are no grade ≥ 3 toxicities. CONCLUSIONS: SMART has dosimetric advantages and excellent clinical outcomes for ultracentral lung tumors. Daily plan adaptation reliably improves target coverage while simultaneously reducing doses to the proximal airways. These results further characterize the therapeutic window improvements for SMART. Structure-specific rigid dose accumulation dosimetric analysis provides insights that elucidate the dosimetric advantages of SMART more so than per fractional analysis alone.

Stereotactic MR-guided Adaptive Radiation Therapy (SMART) is a type of radiation therapy for cancer. With SMART, treatment can be adapted based on daily changes in the body seen via imaging. SMART can safely deliver radiation to lung tumors near the center of the body which are risky to treat, due to potential damage to nearby organs. We looked at 14 patients who received SMART to determine how much changing the radiation plan each day improved our ability to safely deliver high doses. We found that SMART not only improved our ability to cover the entirety of the tumor with the dose originally intended, but also reduced dose to nearby organs. Treatment resulted in excellent control of the tumor with few side effects. SMART shows promise for safer and more effective treatment for lung tumors in this part of the body.

Outcomes After Reduced-Dose Intensity Modulated Radiation Therapy for Gastric Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma.

PURPOSE: In patients with gastric extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma, the standard radiation therapy (RT) dose is ≥30 Gy. We report the outcome of patients treated with reduced dose 24 Gy compared with those treated with ≥30 Gy. METHODS AND MATERIALS: We reviewed results from 32 patients who received a diagnosis of gastric MALT lymphoma between 2007 and 2017 who were treated with involved site RT using intensity modulated radiation therapy (IMRT). Response to therapy was based on post-RT endoscopic biopsy. Freedom from local treatment failure (FFLTF), freedom from treatment failure (FFTF), and overall survival (OS) outcomes were determined. RESULTS: The median age of patients at diagnosis was 58 years. Therapy for MALT was given prior to RT in 14 patients with residual biopsy proven disease documented in all cases (anti-microbial, n=11; rituximab, n=2; rituximab, cyclophosphamide, doxorubicin, vincristine, n=1). One patient received RT (36 Gy) and concurrent rituximab. The median RT dose was 30 Gy; it was 30 to 36 Gy in 66% of patients (n = 21) and 24 Gy in 34% of patients (n = 11). Post-RT biopsy documented a complete response in all patients. Failures occurred in the stomach and duodenum, respectively, at 3.6 and 4.5 years, after 30 Gy. At a median follow-up of 55.2 months (73.8 for ≥30 Gy compared with 28.7 for 24 Gy; P < .001), the 2-year FFLTF, FFTF, and OS were 100%, 100%, and 97%, respectively. No association was found between the lower (24-Gy) dose and FFLTF (P = .819), FFTF (P = .819), or OS (P = .469). CONCLUSIONS: Contemporary RT with involved site targeting using IMRT is associated with high complete response rates for patients with gastric MALT lymphoma, even using reduced doses of 24 Gy. Additional follow-up and increased patient numbers are required to confirm equivalent disease control.