Ex Vivo CD34+-Selected T Cell-Depleted Peripheral Blood Stem Cell Grafts for Allogeneic Hematopoietic Stem Cell Transplantation in Acute Leukemia and Myelodysplastic Syndrome Is Associated with Low Incidence of Acute and Chronic Graft-versus-Host Disease and High Treatment Response.

Ex vivo CD34+-selected T cell depletion (TCD) has been developed as a strategy to reduce the incidence of graft-versus-host disease (GVHD) after allogeneic (allo) hematopoietic stem cell transplantation (HSCT). Clinical characteristics, treatment responses, and outcomes of patients developing acute (aGVHD) and chronic GVHD (cGVHD) after TCD allo-HSCT have not been well established. We evaluated 241 consecutive patients (median age, 57 years) with acute leukemia (n = 191, 79%) or myelodysplastic syndrome (MDS) (n = 50, 21%) undergoing CD34+-selected TCD allo-HSCT without post-HCST immunosuppression in a single institution. Cumulative incidences of grades II-IV and III-IV aGVHD at 180 days were 16% (95% confidence interval [CI], 12 to 21) and 5% (95% CI, 3 to 9), respectively. The skin was the most frequent organ involved, followed by the gastrointestinal tract. Patients were treated with topical corticosteroids, poorly absorbed corticosteroids (budesonide), and/or systemic corticosteroids. The overall day 28 treatment response was high at 82%. The cumulative incidence of any cGVHD at 3 years was 5% (95% CI, 3 to 9), with a median time of onset of 256 days (range, 95 to 1645). The 3-year transplant-related mortality, relapse, overall survival, and disease-free survival were 24% (95% CI, 18 to 30), 22% (95% CI, 17 to 27), 57% (95% CI, 50 to 64), and 54% (95% CI, 47 to 61), respectively. The 1-year and 3-year probabilities of cGVHD-free/relapse-free survival were 65% (95% CI, 59 to 71) and 52% (95% CI, 45 to 59), respectively. Our findings support the use of ex vivo CD34+-selected TCD allograft as a calcineurin inhibitor-free intervention for the prevention of GVHD in patients with acute leukemia and MDS.

Adaptive Radiation Therapy: A Review of CT-based Techniques.

Adaptive radiation therapy is a feedback process by which imaging information acquired over the course of treatment, such as changes in patient anatomy, can be used to reoptimize the treatment plan, with the end goal of improving target coverage and reducing treatment toxicity. This review describes different types of adaptive radiation therapy and their clinical implementation with a focus on CT-guided online adaptive radiation therapy. Depending on local anatomic changes and clinical context, different anatomic sites and/or disease stages and presentations benefit from different adaptation strategies. Online adaptive radiation therapy, where images acquired in-room before each fraction are used to adjust the treatment plan while the patient remains on the treatment table, has emerged to address unpredictable anatomic changes between treatment fractions. Online treatment adaptation places unique pressures on the radiation therapy workflow, requiring high-quality daily imaging and rapid recontouring, replanning, plan review, and quality assurance. Generating a new plan with every fraction is resource intensive and time sensitive, emphasizing the need for workflow efficiency and clinical resource allocation. Cone-beam CT is widely used for image-guided radiation therapy, so implementing cone-beam CT-guided online adaptive radiation therapy can be easily integrated into the radiation therapy workflow and potentially allow for rapid imaging and replanning. The major challenge of this approach is the reduced image quality due to poor resolution, scatter, and artifacts. Keywords: Adaptive Radiation Therapy, Cone-Beam CT, Organs at Risk, Oncology © RSNA, 2023.

Impact of Adapted Radiotherapy Schedules on Bowel Sparing in Node-Positive Cervical Cancer.

PURPOSE: Definitive radiation therapy (RT) for locally advanced node-positive cervical cancer confers significant toxicity to pelvic organs including the small bowel. Gross nodal disease exhibits significant shrinkage during RT, and yet conventional RT does not account for this change. We evaluated the reduction in absorbed bowel dose using various adaptive RT schedules. METHODS AND MATERIALS: We obtained 130 evaluable scans (computed tomography simulation and 25 cone beam computed tomography scans per patient) of 5 patients who had received definitive external beam RT for lymph node positive cervical cancer daily over 5 weeks. Using a single universal volumetric modulated arc therapy plan with predefined optimization priorities, we created adapted RT plans in 4 schedules: Daily, Weekly, Twice, and NoAdapt (mimicking conventional nonadapted RT). The in silico (computer modeled) patients were treated to 45 Gy to primary cervical disease with a simultaneous integrated boost to 55 Gy to involved lymph nodes. We evaluated dose metrics including D2cc, D15cc, and V45 to determine the impact of adapted RT schedules on bowel sparing. Statistical tests included the Student t test, analysis of variance, and the Spearman rank correlation. RESULTS: The quantity of reduced bowel dose was significantly associated with the chosen planning schedule in all evaluated metrics and was proportional to the frequency of adaptive RT with significant moderate-to-strong monotonicity. Both D2cc and D15cc were reduced an average of 2.7 Gy using daily replanning compared with a nonadapted approach. A minimally adapted strategy of only 2 replans also confers a significant dosimetric benefit over a nonadapted approach. Reduced standard deviations of D2cc and V45 bowel doses over the treatment courses were significantly associated with the choice of planning schedule with strong monotonicity. CONCLUSIONS: All adaptive RT schedules evaluated confer significant dosimetric advantages in bowel sparing over a conventional nonadapted technique, with greater sparing seen with more frequent replanning schedules. These findings warrant future trials of adaptive RT for pelvic malignancies.

Frameless Stereotactic Radiosurgery on the Gamma Knife Icon: Early Experience From 100 Patients.

BACKGROUND: The Gamma Knife (GK) Icon (Elekta AB) uses a cone-beam computed tomography (CBCT) scanner and an infrared camera system to support the delivery of frameless stereotactic radiosurgery (SRS). There are limited data on patients treated with frameless GK radiosurgery (GKRS). OBJECTIVE: To describe the early experience, process, technical details, and short-term outcomes with frameless GKRS at our institution. METHODS: We reviewed our patient selection and described the workflow in detail, including image acquisition, treatment planning, mask-based immobilization, stereotactic CBCT localization, registration, treatment, and intrafraction monitoring. Because of the short interval of follow-up, we provide crude rates of local control. RESULTS: Data from 100 patients are reported. Median age is 67 yr old. 56 patients were treated definitively, 21 postoperatively, and 23 had salvage GKRS for recurrence after surgery. Forty-two patients had brain metastases, 26 meningiomas, 16 vestibular schwannomas, 9 high-grade gliomas, and 7 other histologies. Median doses to metastases were 20 Gy in 1 fraction (range: 14-21), 24 Gy in 3 fractions (range: 19.5-27), and 25 Gy in 5 fractions (range: 25-30 Gy). Thirteen patients underwent repeat SRS to the same area. Median treatment time was 17.7 min (range: 5.8-61.7). We found an improvement in our workflow and a greater number of patients eligible for GKRS because of the ability to fractionate treatments. CONCLUSION: We report a large cohort of consecutive patients treated with frameless GKRS. We look forward to studies with longer follow-up to provide valuable data on clinical outcomes and to further our understanding of the radiobiology of hypofractionation in the brain.

Monitoring Radiation Treatment Effects in Glioblastoma: FLAIR Volume as Significant Predictor of Survival.

Glioblastoma is the most common adult central nervous system malignancy and carries a poor prognosis. Disease progression and recurrence after chemoradiotherapy are assessed via serial magnetic resonance imaging sequences. T2-weighted fluid-attenuated inversion recovery (FLAIR) signal is presumed to represent edema containing microscopic cancer infiltration. Here we assessed the prognostic impact of computerized volumetry of FLAIR signal in the peri-treatment setting for glioblastoma. We analyzed pre- and posttreatment FLAIR sequences of 40 patients treated at the Columbia University Medical Center between 2011 and 2014, excluding those without high-quality FLAIR imaging within 2 weeks before treatment and 60 to 180 days afterward. We manually contoured regions of FLAIR hyperintensity as per Radiation Therapy Oncology Group guidelines and calculated the volumes of nonenhancing tumor burden. At the time of this study, all but 1 patient had died. Pre- and posttreatment FLAIR volumes were assessed for correlation to overall and progression-free survival. Larger post-treatment FLAIR volumes from sequences taken between 60 and 180 days after conclusion of chemoradiotherapy were negatively correlated with overall survival (P = .048 on Pearson's correlation and P = .017 and P = .043 on univariable and multivariable Cox regression analyses, respectively) and progression-free survival (P = .002 on Pearson's correlation and P = < .001 and P = < .001 on univariable and multivariable Cox regression analyses). This study suggests that higher FLAIR volumes in the 2- to 6-month posttreatment window are associated with worsened survival.

Radiation Therapy for the Management of Brain Metastases.

Brain metastases are the most common malignant intracranial tumors and carry a poor prognosis. The management of brain metastases may include a variety of treatment modalities including surgical resection, radiation therapy, and/or systemic therapy. The traditional treatment for brain metastasis involved whole brain irradiation. However, improved systemic control of primary cancers has led to longer survival for some groups of patients and there is increasing need to consider the late effects of radiation to the entire brain. With advances in imaging and radiation treatment planning and delivery stereotactic radiosurgery has become more frequently utilized and may be delivered through Gamma Knife Stereotactic Radiosurgery or linear accelerator-based systems. Furthermore, experience in treating thousands of patients on clinical trials has led to diagnosis-specific prognostic assessment systems that help guide our approach to the management of this common clinical scenario. This review provides an overview of the literature supporting radiotherapy for brain metastasis and an update on current radiotherapeutic options that is tailored for the nonradiation oncologist.

Hypofractionated radiation therapy versus standard fractionated radiation therapy with concurrent temozolomide in elderly patients with newly diagnosed glioblastoma.

PURPOSE: Adjuvant hypofractionated radiation therapy (HRT) for elderly patients with newly diagnosed glioblastoma (GBM) is a reasonable option compared with standard fractionation radiation therapy (SFRT). Outcomes in patients receiving HRT in the presence of temozolomide (TMZ) compared with SFRT with TMZ are unclear. We examined HRT for GBM with TMZ in comparison to SFRT with TMZ. METHODS AND MATERIALS: We conducted a retrospective analysis of patients ≥60 years of age with newly diagnosed GBM who received SFRT or HRT from 1994 to 2014 in the postoperative setting. Inclusion criteria included SFRT (60 Gy/30 fractions or 59.4 Gy/33 fractions) versus HRT (40 Gy/15 fractions). RESULTS: In this cohort, 158 patients were treated with SFRT versus 26 with HRT. Median survival in patients receiving SFRT compared with HRT was 430 and 475 days (P = .550), respectively. Ninety-five percent of the SFRT patients received TMZ versus 100% of those treated with HRT. Patients receiving HRT were older (median, 72 vs 66 years). All HRT patients were treated with the intensity modulated radiation therapy (IMRT) technique versus SFRT, in which 57% had IMRT. Multivariate Cox regression showed decreased overall survival (OS) associated with patient age >70 (hazard ratio [HR], 1.84), lower Karnofsky performance status (HR, 5.25), biopsy versus surgical resection (HR, 4.18), radiation therapy planning technique 3- or 2-dimensional planning versus IMRT (HR, 1.91; HR, 3.40, respectively). Analysis restricted to patients receiving IMRT-based planning showed no difference in OS between HRT and SFRT. For patients receiving TMZ, there was no survival difference between those treated with HRT and those treated with SFRT. CONCLUSIONS: Elderly GBM patients receiving HRT and those receiving SFRT had similar OS. Subset analysis patients receiving concurrent TMZ showed no difference in OS between the HRT and SFRT groups.

A Modern Radiotherapy Series of Survival in Hispanic Patients with Glioblastoma.

BACKGROUND: Studies have shown racial differences in cancer outcomes. We investigate whether survival differences existed in Hispanic patients with glioblastoma (GBM) compared with other ethnicities from our modern radiotherapy series, because no study to date has focused on outcomes in this group after radiation therapy. METHODS: We retrospectively evaluated 428 patients diagnosed with GBM from 1996 to 2014 at our institution, divided into 4 groups based on self-report: white, black, Hispanic, and Asian/Indian. The primary outcome was overall survival. We analyzed differences in prognostic factors among the whole cohort compared with the Hispanic cohort alone. RESULTS: Baseline characteristics of the 4 racial groups were comparable. With a median follow-up of 387 days, no survival differences were seen by Kaplan-Meier analysis. Median overall survival for Hispanic patients was 355 days versus 450 days for the entire cohort. Factors significant for patient outcomes in the entire cohort differed slightly from those specific to Hispanic patients. Low Karnofsky Performance Status was significant on multivariate analysis in the whole population, but not in Hispanic patients. Extent of resection, recursive partitioning analysis class, and radiation therapy total dose were significant on multivariate analysis in both the whole population and Hispanic patients. CONCLUSIONS: We found that Hispanic patients with GBM had no difference in survival compared with other ethnicities in our cohort. Differences exist in factors associated with outcomes on single and multivariate analysis for Hispanic patients with GBM compared with the entire cohort. Additional studies focusing on Hispanic patients will aid in more personalized treatment approaches in this group.