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2,887 result(s) for "Lim, Do Hoon"
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Role of 23.4 Gy upfront whole-brain radiation therapy following high-dose methotrexate for primary central nervous system lymphoma: a comparative analysis of whole-brain radiation therapy versus no radiation therapy
IntroductionWe aimed to investigate the role of upfront whole-brain radiation therapy (RT), with a reduced dose of 23.4 Gy, following high-dose methotrexate (HD-MTX) in patients with primary central nervous system lymphoma (PCNSL).MethodsWe retrospectively reviewed 185 patients with PCNSL treated with HD-MTX between January 2013 and January 2020; 145 patients underwent no RT and 40 patients underwent upfront RT. Using propensity score matching (PSM) to adjust for clinical factors, 40 patients were selected from each treatment group. Event-free survival (EFS) and overall survival (OS) were compared between treatment groups.ResultsAt baseline, patients in the upfront RT group were younger, had higher LDH levels, received less frequent rituximab and stem cell transplantation than those in the no-RT group. Patients in the upfront RT group also showed a lower response rate after initial HD-MTX than those in the no-RT group (73% vs. 88%, p = 0.038). The median follow-up was 25.1 (interquartile range 13.7–43.0) months. Comparable 2-year EFS and OS rates were observed between the upfront RT and no-RT groups (56.6% vs. 53.8%, p = 0.170; and 81.7% vs. 75.3%, p = 0.097, respectively). Upfront RT was related to improved EFS and OS in patients with stable disease or progressive disease after HD-MTX, but not in patients with complete or partial response after HD-MTX. Upfront RT was also an independent predictor of EFS and OS in the PSM cohort. The cumulative incidences of treatment-related neurotoxicity at 3 years were 20.2% and 21.2% in the upfront RT and no-RT groups, respectively (p = 0.630).ConclusionsUpfront RT with a reduced dose of 23.4 Gy, showed favorable outcomes in patients with stable disease or progressive disease after initial HD-MTX. In addition, upfront RT appears to be an effective treatment for PCNSL when rituximab or stem cell transplantation is not feasible.
Chemoradiation in elderly patients with glioblastoma from the multi-institutional GBM-molRPA cohort: is short-course radiotherapy enough or is it a matter of selection?
BackgroundThe optimal radiotherapy regimen in elderly patients with glioblastoma treated by chemoradiation needs to be addressed. We provide the results of a comparison between conventionally fractionated standard radiotherapy (CRT) and short-course radiotherapy (SRT) in those patients treated by temozolomide-based chemoradiation.MethodsPatients aged 65 years or older from the GBM-molRPA cohort were included. Patients who were planned for a ≥ 6-week or ≤ 4-week radiotherapy were regarded as being treated by CRT or SRT, respectively. The median RT dose in the CRT and SRT group was 60 Gy in 30 fractions and 45 Gy in 15 fractions, respectively.ResultsA total of 260 and 134 patients aged older than 65 and 70 years were identified, respectively. CRT- and SRT-based chemoradiation was applied for 192 (73.8%) and 68 (26.2%) patients, respectively. Compared to SRT, CRT significantly improved MS from 13.2 to 17.6 months and 13.3 to 16.4 months in patients older than 65 years (P < 0.001) and 70 years (P = 0.002), respectively. Statistical significance remained after adjusting for age, performance status, surgical extent, and MGMT promoter methylation in both age groups. The benefit was clear in all subgroup analyses for patients with Karnofsky performance score 70–100, Karnofsky performance score ≤ 60, gross total resection, biopsy, methylated MGMT promoter, and unmethylated MGMT promoter (all P < 0.05).ConclusionCRT significantly improved survival compared to SRT in elderly glioblastoma patients treated with chemoradiation in selected patients amenable for chemoradiation. This study is hypothesis-generating and a prospective randomized trial is urgently warranted.
Trans-Differentiation of Neural Stem Cells: A Therapeutic Mechanism Against the Radiation Induced Brain Damage
Radiation therapy is an indispensable therapeutic modality for various brain diseases. Though endogenous neural stem cells (NSCs) would provide regenerative potential, many patients nevertheless suffer from radiation-induced brain damage. Accordingly, we tested beneficial effects of exogenous NSC supplementation using in vivo mouse models that received whole brain irradiation. Systemic supplementation of primarily cultured mouse fetal NSCs inhibited radiation-induced brain atrophy and thereby preserved brain functions such as short-term memory. Transplanted NSCs migrated to the irradiated brain and differentiated into neurons, astrocytes, or oligodendrocytes. In addition, neurotrophic factors such as NGF were significantly increased in the brain by NSCs, indicating that both paracrine and replacement effects could be the therapeutic mechanisms of NSCs. Interestingly, NSCs also differentiated into brain endothelial cells, which was accompanied by the restoration the cerebral blood flow that was reduced from the irradiation. Inhibition of the VEGF signaling reduced the migration and trans-differentiation of NSCs. Therefore, trans-differentiation of NSCs into brain endothelial cells by the VEGF signaling and the consequential restoration of the cerebral blood flow would also be one of the therapeutic mechanisms of NSCs. In summary, our data demonstrate that exogenous NSC supplementation could prevent radiation-induced functional loss of the brain. Therefore, successful combination of brain radiation therapy and NSC supplementation would provide a highly promising therapeutic option for patients with various brain diseases.
Treatment outcome of relapsed/refractory primary central nervous system diffuse large B-cell lymphoma: a single-center experience of autologous stem cell transplantation
No salvage treatment strategy has been established for relapsed or refractory primary central nervous system lymphoma (PCNSL). We compared treatment outcomes of patients who underwent salvage chemotherapy with or without autologous stem cell transplantation (ASCT). We retrospectively analyzed PCNSL patients who were histologically diagnosed with diffuse large B-cell lymphoma. All patients relapsed after high-dose methotrexate (MTX)-based chemotherapy, or were refractory to high-dose MTX. Patients were treated with salvage chemotherapy, such as ICE/D (ifosfamide, carboplatin, etoposide, and dexamethasone) or high-dose MTX. High-dose chemotherapy containing thiotepa and busulfan followed by ASCT was performed if patients were eligible for ASCT after salvage treatment. Forty-five patients (35 relapsed and 10 refractory) received ICE/D or high-dose MTX. Despite the important difference that ICE/D was used predominantly for early relapsed or refractory patients, the two salvage treatments produced similar overall response rates [84.4 % (38/45) for ICE/D and 81.3 % (13/16) for high-dose MTX re-treatment]. Eighteen patients underwent ASCT, whereas 27 patients received salvage chemotherapy alone. The median progression-free survival of patients who underwent ASCT (19.5 months) was significantly better than that of patients who did not receive ASCT (6.7 months, P  = 0.023). Multivariate analysis showed that refractoriness to initial treatment and no ASCT were significantly associated with poor survival outcome. Our study suggested that the combination of ifosfamide, carboplatin, etoposide, and dexamethasone may represent a feasible salvage treatment option for relapsed or refractory PCNSL, and that high-dose chemotherapy containing thiotepa and busulfan followed by ASCT may be effective for patients with a favorable toxicity profile.
Nanostring-Based Multigene Assay to Predict Recurrence for Gastric Cancer Patients after Surgery
Despite the benefits from adjuvant chemotherapy or chemoradiotherapy, approximately one-third of stage II gastric cancer (GC) patients developed recurrences. The aim of this study was to develop and validate a prognostic algorithm for gastric cancer (GCPS) that can robustly identify high-risk group for recurrence among stage II patients. A multi-step gene expression profiling study was conducted. First, a microarray gene expression profiling of archived paraffin-embedded tumor blocks was used to identify candidate prognostic genes (N=432). Second, a focused gene expression assay including prognostic genes was used to develop a robust clinical assay (GCPS) in stage II patients from the same cohort (N=186). Third, a predefined cut off for the GCPS was validated using an independent stage II cohort (N=216). The GCPS was validated in another set with stage II GC who underwent surgery without adjuvant treatment (N=300). GCPS was developed by summing the product of Cox regression coefficients and normalized expression levels of 8 genes (LAMP5, CDC25B, CDK1, CLIP4, LTB4R2, MATN3, NOX4, TFDP1). A prospectively defined cut-point for GCPS classified 22.7% of validation cohort treated with chemoradiotherapy (N=216) as high-risk group with 5-year recurrence rate of 58.6% compared to 85.4% in the low risk group (hazard ratio for recurrence=3.16, p=0.00004). GCPS also identified high-risk group among stage II patients treated with surgery only (hazard ratio=1.77, p=0.0053).
Selective salvage radiotherapy could provide favorable outcomes in patients with refractory or relapsed primary central nervous system lymphoma
Introduction To date, there is no relevant data supporting the role of salvage radiotherapy (sRT) in patients with refractory or relapsed primary central nervous system lymphoma (PCNSL). Herein, we aimed to investigate the impact of sRT in patients with refractory or relapsed PCNSL following upfront HD-MTX. Methods We retrospectively reviewed 89 patients who had refractory (n = 16) or recurrent disease after an initial favorable response (n = 73); among them, 41 were treated with sRT and 48 were treated without sRT (nRT). Event-free survival (rEFS) and overall survival (rOS) after first recurrence were considered from the date of recurrence to date of each event. Results Overall, the first failure was diagnosed at a median of 11.0 months [interquartile range (IQR), 5.6–26.4] after first treatment. More than half of the patients had recurrent disease involving initial tumor bed (n = 47), deep structure (n = 67), and multiple lesions (n = 58). Among 19 patients who were initially treated with 23.4 Gy of whole brain RT, 10 patients received sRT as a re-irradiation; other 31 patients in sRT group were RT naïve patients. There was no significant difference in tumor characteristics between sRT and nRT group. Overall and complete response after salvage treatment were 80% and 48%, respectively; sRT provided higher overall response rate than nRT (93% vs. 69%, p = 0.011). With a median follow-up of 14.3 months (IQR, 7.9–31.4), 2-year rEFS and rOS rates were 27% and 57%, respectively. There were no differences in rEFS and rOS according to sRT (sRT vs. nRT, 26% vs. 28%, p = 0.730; 63% vs. 50%, p = 0.690). Poor performance, recurrence interval < 8 months, and unfavorable response following salvage treatment were associated with inferior rEFS and rOS. Additionally, sRT and stem cell transplantation improved response rate independently after multivariate analysis for complete/partial response. Conclusions We found favorable response rate and comparable survival outcomes following sRT compared with non-local treatments for patients with refractory/relapsed PCNSL. Further studies of patient selection could stratify patients who can benefit from sRT.
Long-term effects of local radiotherapy on growth and vertebral features in children with high-risk neuroblastoma
Background To evaluate the effects of local radiotherapy (RT) on growth, we evaluated the chronological growth profiles and vertebral features of children with high-risk neuroblastoma. Methods Thirty-eight children who received local photon or proton beam therapy to the abdomen or retroperitoneum between January 2014 and September 2019 were included. Simple radiography of the thoracolumbar spine was performed before and every year after RT. The height and vertical length of the irradiated vertebral bodies (VBs) compared with the unirradiated VBs (vertebral body ratio, VBR) were analyzed using the linear mixed model. Shape feature analysis was performed to compare the irradiated and unirradiated vertebrae. Results The follow-up was a median of 53.5 months (range, 21–81 months) after RT. A decline in height z-scores was mainly found in the early phase after treatment. In the linear mixed model with height, the initial height (fixed, p  < 0.001), sex (time interaction, p  = 0.008), endocrine dysfunction (time interaction, 0.019), and age at diagnosis (fixed and time interaction, both p  = 0 . 002) were significant. Unlike the trend in height, the change in VBR (ΔVBR) decreased gradually ( p  < 0.001). The ΔVBR in the group that received more than 30 Gy decreased more than in the group that received smaller doses. In the shape feature analysis, the irradiated VBs changed to a more irregular surface that were neither round nor rectangular. Conclusion The irradiated VBs in children were gradually restricted compared to the unirradiated VBs in long-term follow-up, and higher RT doses were significantly affected. Radiation-induced irregular features of VBs were observed.
Prognostic Impact of Sarcopenia and Radiotherapy in Patients With Advanced Gastric Cancer Treated With Anti-PD-1 Antibody
We explored the combined effects of sarcopenia (SAR) and radiotherapy (RT) on outcomes in patients with advanced gastric cancer (AGC) treated with immune-checkpoint blockade (ICB). Among 185 patients with AGC treated with ICB, we defined SAR as skeletal muscle index <49 cm2/m2 for men and <31 cm2/m2 for women; 93 patients met criteria. We defined high neutrophil-to-lymphocyte ratio (hNLR) as NLR≥3. Palliative RT was performed in 37 patients (20%) before ICB. We frequently observed hNLR in patients with SAR (53% 35%, p = 0.02). The median overall survival (OS) for the entire cohort was 5 months. Stratification by risk factors of SAR or hNLR revealed a significant difference in median OS (0 [N = 60] 1 [N = 76] 2 [N = 49]: 7.6 6.4 2.2 months, p < 0.001). Patients with microsatellite instability-high (MSI-H, N = 19) or Epstein-Barr virus (EBV)-positive tumors (N = 13) showed favorable outcomes compared to those with microsatellite stable (MSS, N = 142) tumors (median OS, not reached 16.8 3.8 months, respectively). The benefit of RT was evident in patients with both SAR and hNLR (median OS, 3.1 1.3 months, p = 0.02) and MSS/EBV-negative tumor (median OS, 6.5 3.5 months, p = 0.03), but outcomes after RT in MSI-H tumor were not significantly different. In multivariable analysis, SAR/hNLR, molecular subtypes, and a history of RT were associated with OS (all p < 0.05). We demonstrated the negative predictive value of SAR/hNLR on outcomes after ICB for AGC, and the history of RT could overcome the negative impact of SAR/hNLR and the MSS/EBV-negative subtype.
Search for practical scaling factors of Bragg peak arrangement for line-scanning proton beam therapy in RayStation
To enhance the efficiency of treatment planning and beam delivery in line-scanning proton beam therapy, we conducted a comparative analysis of various strategies for arranging the Bragg peak within the optimization of treatment plans. In RayStation, we had the flexibility to manipulate optimization parameters, specifically energy layer and line spacing, to control the Bragg peak’s location. To assess the impact of these parameters, we created a virtual spherical target and generated treatment plans employing both single and dual beams with diverse arrangement strategies. We then evaluated the target volume coverage using the homogeneity index. Furthermore, we selected 15 line-scanning plans. For each line-scanning plan, we generated nine comparative plans, employing distinct Bragg peak arrangement strategies. These strategies involved variations in energy layer and line spacing settings. We optimized these plans and compared their quality to the default setting. In addition, treatment planning and beam delivery efficiency were estimated. Our analysis indicated that smaller energy layer and line spacing generally resulted in improved homogeneity indices. Notably, reducing line spacing proved to be more efficient than decreasing energy layer spacing, a trend that remained consistent in the line-scanning plans. For line-scanning plans, adjustments in line spacing produced more efficient improvements in the conformity index and D 1cc . Based on our findings, adjusting line spacing is a more effective strategy for optimizing Bragg peak placement in RayStation. This adjustment not only enhances treatment planning but also improves beam delivery efficiency by reducing the time required for energy layer switching.