Excellent response to very-low-dose radiation (4 Gy) for indolent B-cell lymphomas: is 4 Gy suitable for curable patients?

Radiotherapy plays an important role in managing highly radiosensitive, indolent non-Hodgkin lymphomas, such as follicular lymphoma and marginal zone lymphoma. Although the standard of care for localized indolent non-Hodgkin lymphomas remains 24 Gy, de-escalation to very-low-dose radiotherapy (VLDRT) of 4 Gy further reduces toxicities and duration of treatment. Use of VLDRT outside palliative indications remains controversial; however, we hypothesize that it may be sufficient for most lesions. We present the largest single-institution VLDRT experience of adult patients with follicular lymphoma or marginal zone lymphoma treated between 2005 and 2018 (299 lesions; 250 patients) using modern principles including positron emission tomography staging and involved site radiotherapy. Outcomes include best clinical or radiographic response between 1.5 and 6 months after VLDRT and cumulative incidence of local progression (LP) with death as the only competing risk. After VLDRT, the overall response rate was 90% for all treated sites, with 68% achieving complete response (CR). With a median follow-up of 2.4 years, the 2-year cumulative incidence of LP was 25% for the entire cohort and 9% after first-line treatment with VLDRT for potentially curable, localized disease. Lesion size >6 cm was associated with lower odds of attaining a CR and greater risk of LP. There was no suggestion of inferior outcomes for potentially curable lesions. Given the clinical versatility of VLDRT, we propose to implement a novel, incremental, adaptive involved site radiotherapy strategy in which patients will be treated initially with VLDRT, reserving full-dose treatment for those who are unable to attain a CR.

Excellent Outcomes with Surgery or Radiotherapy in the Management of Castleman Disease Including a Case of Oligocentric Disease.

BACKGROUND: Castleman disease (CD) is a rare polyclonal lymphoproliferative disorder of unclear etiology. Standard therapy for unicentric CD is surgical resection. Radiotherapy can be used; however, its efficacy is poorly characterized. PATIENTS AND METHODS: We reviewed patients with histologically confirmed CD undergoing definitive local therapy at our institution between 1990 and 2017. Overall survival was determined from the date of diagnosis. Local progression-free survival and distant failure-free survival were determined from the date of first definitive therapy. The Kaplan-Meier method was used to analyze survival. RESULTS: Forty-four patients (29 female and 15 male) were identified with a median age at diagnosis of 40 years (range, 14-70 years). Thirty-five (80%) patients received surgery alone, 3 (7%) had surgery followed by radiotherapy, and 6 (14%) had radiotherapy alone. Thirty-nine (89%) patients had a single area of involvement, and 3 (7%) patients had limited regional involvement. Two (5%) patients had multicentric CD and received consolidative radiotherapy. The 3-year overall, local progression-free, and distant failure-free survival were 92%, 100%, and 100%, respectively. No distant failures were observed. The median radiation dose was 3960 cGy (range, 3600-5940 cGy) in 22 fractions (range, 18-33 fractions). CONCLUSIONS: Unicentric CD is readily amenable to cure with local therapy. Surgical excision is preferred, but radiation appears to be an effective alternative for patients when surgery is high risk or not feasible. Patients with oligo- or multi-centric CD may experience prolonged disease-free survival with consolidative radiotherapy after partial response to systemic therapy.

Langerhans cell histiocytosis in adults is associated with a high prevalence of hematologic and solid malignancies.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disorder of histiocyte proliferation. Previous case studies suggest a higher prevalence of hematologic and solid malignancies among LCH patients, possibly due to treatment with tumorigenic agents such as etoposide. We report the first large, single-institution experience of adult LCH patients with additional malignancies to study the characteristics of these patients. METHODS: We identified 132 consecutive patients >18 years of age with histologically confirmed LCH at our center between 1990 and 2015. Demographics and detailed oncologic history were recorded to identify patients with additional malignancies. RESULTS: Of 132 adult LCH patients, 42 (32%) patients had an additional malignancy. There were 53 malignancies among the 42 patients, with 31 (58%) preceding LCH diagnosis, 11 concurrent (≤3 months; 21%) with LCH diagnosis, and 11 (21%) after. Median age was 54 years (range 28-89) with a median follow-up of 3.7 years (0.1-22.2) for this cohort. OS at 3 years was 98% in patients with LCH alone and 82% among patients with additional malignancies, with 30 (71%) alive at last follow-up. Solid tumors, lymphomas, and other hematologic malignancies were observed as follows: 39 (74%), 9 (17%), and 5 (9%). CONCLUSION: Our cohort of adult LCH patients demonstrates an unusually high number of additional malignancies. Our study includes predominantly malignancies diagnosed preceding or concurrent with LCH, suggesting a cause of malignancy independent of LCH treatment. Further exploration of the biology of this rare disease may elucidate the mechanism of frequent additional malignancies.

Cargo rigidity affects the sensitivity of dynein ensembles to individual motor pausing.

Cytoplasmic dynein is a minus-end directed microtubule-based motor protein that drives intracellular cargo transport in eukaryotic cells. Although many intracellular cargos are propelled by small groups of dynein motors, the biophysical mechanisms governing ensemble motility remain largely unknown. To investigate the emergent motility of motor ensembles, we have designed a programmable DNA origami synthetic cargo "chassis" enabling us to control the number of dynein motors in the ensemble and vary the rigidity of the cargo chassis itself. Using total internal reflection fluorescence microscopy, we have observed dynein ensembles transporting these cargo chassis along microtubules in vitro. We find that ensemble motility depends on cargo rigidity: as the number of motors increases, ensembles transporting flexible cargos move comparatively faster than a single motor, whereas ensembles transporting rigid cargos move slower than a single motor. To explain this, we show that ensembles connected through flexible cargos are less sensitive to the pauses of individual motors within the ensemble. We conclude that cargo rigidity plays an important role in communicating and coordinating the states of motors, and consequently in the subsequent mechanisms of collective motility. The insensitivity of ensemble-driven cargos to the pausing of individual motors may contribute to the robustness and versatility of intracellular cargo transport. © 2016 Wiley Periodicals, Inc.