Near-maximum rib dose is the most relevant risk factor for ipsilateral spontaneous rib fracture: a dosimetric analysis of breast cancer patients after radiotherapy.

PURPOSE: Spontaneous rib fracture (SRF) is a common late complication in treated breast cancer patients. This study evaluated the incidence and risk factors of ipsilateral SRF after radiotherapy (RT) in breast cancer patients. In addition, we identified dosimetric parameters that were significantly associated with ipsilateral SRF. METHODS: We retrospectively reviewed 2204 patients with breast cancer who underwent RT between 2014 and 2016, and were followed up with bone scans. We evaluated clinical risk factors for ipsilateral SRF. Dose-volume histogram analysis was also performed for patients (n = 538) whose dosimetric data were available. All ipsilateral ribs were manually delineated, and dosimetric parameters of the ribs were converted into the equivalent dose in 2 Gy fractions (EQD2). RESULTS: Most of the patients with SRF (87.3%) were asymptomatic, and the remaining symptomatic patients complained of mild tenderness or chest wall discomfort; these symptoms all resolved within 6 months without any treatment. Ipsilateral SRF occurred in 14.5% of patients 3 years after RT. The median time to develop ipsilateral SRF was 15 months. In dosimetric analysis, near-maximum rib dose (D2cc) best predicted ipsilateral SRF. The cut-off value of D2cc was EQD2 52 Gy, as determined by receiver operating characteristic analysis. In multivariate analysis including dosimetric variables, D2cc EQD2 ≥ 52 Gy was the only significant risk factor for ipsilateral SRF. CONCLUSION: Our data demonstrated that near-maximum rib dose was the best dosimetric parameter to predict ipsilateral SRF in RT-treated breast cancer patients. In addition, our results suggest that patients who received RT with exceeding rib dose cut-off value and had ipsilateral SRF on bone scan be recommended routine follow-up without additional imaging tests.

Dose-response relationship in patients with newly diagnosed atypical meningioma treated with adjuvant radiotherapy.

PURPOSE: This study aimed to identify the radiation dose-response relationship in patients with newly diagnosed atypical meningioma (AM) treated with adjuvant radiotherapy (ART) using conventional fractionation. METHODS: In total, 158 patients who underwent surgery and ART between 1998 and 2018 were reviewed. Among these patients, 135 with complete information on radiotherapy (RT) dose/fractionation and pathological reports were analyzed. We entered RT dose as a continuous variable into the Cox regression model using penalized spline to allow for a nonlinear relationship between RT dose and events. Local control (LC), progression-free survival (PFS), and overall survival (OS) were evaluated. The corresponding biological equivalent dose in 2 Gy fractions (EQD2) was calculated using an α/ß ratio of 4 Gy. RESULTS: The median follow-up duration was 56.0 months. The median ART dose delivered was 61.2 Gy in 24-34 daily fractions, corresponding to a median EQD2 of 59.16 Gy. In multivariate analysis, larger size and higher mitotic count were associated with significantly reduced LC (P < 0.001 and P = 0.002, respectively), PFS (P < 0.001 and P = 0.006, respectively), and OS (P = 0.006 and P = 0.001, respectively). Meanwhile, a higher RT dose was significantly associated with improved LC, PFS, and OS. Moreover, RT showed a dose-dependent effect on LC, PFS, and OS; local failure, tumor progression, and death were reduced by 12%, 12%, and 16%, respectively, per 1 Gy increase in the dose (EQD2). CONCLUSION: The dose of ART in AM has a dose-response relationship with LC and survival outcomes.

Biotechnological Plastic Degradation and Valorization Using Systems Metabolic Engineering.

Various kinds of plastics have been developed over the past century, vastly improving the quality of life. However, the indiscriminate production and irresponsible management of plastics have led to the accumulation of plastic waste, emerging as a pressing environmental concern. To establish a clean and sustainable plastic economy, plastic recycling becomes imperative to mitigate resource depletion and replace non-eco-friendly processes, such as incineration. Although chemical and mechanical recycling technologies exist, the prevalence of composite plastics in product manufacturing complicates recycling efforts. In recent years, the biodegradation of plastics using enzymes and microorganisms has been reported, opening a new possibility for biotechnological plastic degradation and bio-upcycling. This review provides an overview of microbial strains capable of degrading various plastics, highlighting key enzymes and their role. In addition, recent advances in plastic waste valorization technology based on systems metabolic engineering are explored in detail. Finally, future perspectives on systems metabolic engineering strategies to develop a circular plastic bioeconomy are discussed.

A Versatile Strategy for Screening Custom-Designed Warhead-Armed Cyclic Peptide Inhibitors.

Demand for peptide-based pharmaceuticals has been steadily increasing, but only limited success has been achieved to date. To expedite peptide-based drug discovery, we developed a general scheme for cell-based screening of cyclic peptide inhibitors armed with a user-designed warhead. We combined unnatural amino acid incorporation and split intein-mediated peptide cyclization techniques and integrated a yeast-based colorimetric screening assay to generate a new scheme that we call the custom-designed warhead-armed cyclic peptide screening platform (CWCPS). This strategy successfully discovered a potent inhibitor, CY5-6Q, that targets human histone deacetylase 8 (HDAC8) with a KD value of 15 nM. This approach can be a versatile and general platform for discovering cyclic peptide inhibitors.

Current perspectives on radiotherapy in hepatocellular carcinoma management: a comprehensive review.

This review examines the transformative role of external beam radiotherapy (EBRT) in managing hepatocellular carcinoma (HCC), spotlighting the progression from traditional EBRT techniques to advanced modalities like intensity-modulated radiotherapy (RT), stereotactic body RT (SBRT), and innovative particle therapy, including proton beam therapy and carbon ion RT. These advancements have significantly improved the precision and efficacy of RT, marking a paradigm shift in the multimodal management of HCC, particularly in addressing complex cases and enhancing local tumor control. The review underscores the synergistic potential of integrating RT with other treatments like transarterial chemoembolization, systemic therapies such as sorafenib, and emerging immunotherapies, illustrating enhanced survival and disease control outcomes. The efficacy of RT is addressed for challenging conditions, including advanced HCC with macrovascular invasion, and RT modalities, like SBRT, are compared against traditional treatments like radiofrequency ablation for early-stage HCC. Additionally, the review accentuates the encouraging outcomes of particle therapy in enhancing local control and survival rates, minimizing treatment-related toxicity, and advocating for continued research and clinical trials. In conclusion, the integration of RT into multimodal HCC treatment strategies, coupled with the emergence of particle therapy, is crucial for advancing oncologic management, emphasizing the need for relentless innovation and personalized treatment approaches.

Intrathoracic Progression Is Still the Most Dominant Failure Pattern after First-Line Chemo-immunotherapy in Extensive-Stage Small-Cell Lung Cancer: Implications for Thoracic Radiotherapy.

PURPOSE: This study aimed to compare the failure patterns before and after the introduction of immunotherapy and to determine the role of thoracic radiotherapy (TRT) in extensive-stage small-cell lung cancer (ES-SCLC) treatment. MATERIALS AND METHODS: We retrospectively reviewed 294 patients with ES-SCLC, of which 62.2% underwent chemotherapy alone, 13.3% underwent chemotherapy followed by consolidative TRT (TRT group), and 24.5% underwent chemotherapy with immune checkpoint inhibitor (ICI group). We performed propensity-score matching (PSM) to compare each treatment group. RESULTS: The median follow-up duration was 10.4 months. At the first relapse, in the cohort showing objective response, the proportion of cases showing intrathoracic progression was significantly lower in the TRT group (37.8%) than in the chemotherapy-alone (77.2%, p < 0.001) and the ICI (60.3%, p=0.03) groups. Furthermore, in the subgroup analysis, TRT showed benefits related to intrathoracic progression-free survival (PFS) in comparison with ICI in patients with less than two involved extrathoracic sites (p=0.008) or without liver metastasis (p=0.02) or pleural metastasis (p=0.005) at diagnosis. After PSM, the TRT group showed significantly better intrathoracic PFS than both chemotherapy-alone and ICI groups (p < 0.001 and p=0.04, respectively), but showed no significant benefit in terms of PFS and overall survival in comparison with the ICI group (p=0.17 and p=0.31, respectively). CONCLUSION: In ES-SCLC, intrathoracic progression was the most dominant failure pattern after immunotherapy. In the era of chemoimmunotherapy, consolidative TRT can still be considered a useful treatment strategy for locoregional control.

Optimizing Recurrent Glioblastoma Salvage Treatment: A Multicenter Study Integrating Genetic Biomarkers From the Korean Radiation Oncology Group (21-02).

BACKGROUND AND OBJECTIVES: Few studies have used real-world patient data to compare overall treatment patterns and survival outcomes for recurrent glioblastoma (rGBM). This study aimed to evaluate postprogression survival (PPS) according to the treatment strategy for rGBM by incorporating biomarker analysis. METHODS: We assessed 468 adult patients with rGBM who underwent standard temozolomide-based chemoradiation. The impact of predictors on PPS was evaluated in patients with isocitrate dehydrogenase wild-type rGBM (n = 439) using survival probability analysis. We identified patients who would benefit from reirradiation (re-RT) during the first progression. RESULTS: Median PPS was 3.4, 13.8, 6.6, and 10.0 months in the best supportive care (n = 82), surgery (with/without adjuvant therapy, n = 112), chemotherapy alone (n = 170), and re-RT (with/without chemotherapy, n = 75) groups, respectively. After propensity score matching analysis of the cohort, both the surgery and re-RT groups had a significantly better PPS than the chemotherapy-only group; however, no significant difference was observed in PPS between the surgery and re-RT groups. In the surgery subgroup, surgery with chemotherapy ( P = .024) and surgery with radio(chemo)therapy ( P = .039) showed significantly improved PPS compared with surgery alone. In the no-surgery subgroup, radio(chemo)therapy showed significantly improved PPS compared with chemotherapy alone ( P = .047). Homozygous deletion of cyclin-dependent kinase inhibitor 2A/B, along with other clinical factors (performance score and progression-free interval), was significantly associated with the re-RT survival benefit. CONCLUSION: Surgery combined with radio(chemo)therapy resulted in the best survival outcomes for rGBM. re-RT should also be considered for patients with rGBM at first recurrence. Furthermore, this study identified a specific genetic biomarker and clinical factors that may enhance the survival benefit of re-RT.

Biodegradation of oxidized low density polyethylene by Pelosinus fermentans lipase.

Polyethylene (PE) exhibits high resistance to degradation, contributing to plastic pollution. PE discarded into the environment is photo-oxidized by sunlight and oxygen. In this study, a key enzyme capable of degrading oxidized PE is reported for the first time. Twenty different enzymes from various lipase families were evaluated for hydrolytic activity using substrates mimicking oxidized PE. Among them, Pelosinus fermentans lipase 1 (PFL1) specifically cleaved the ester bonds within the oxidized carbon-carbon backbone. Moreover, PFL1 (6 µM) degraded oxidized PE film, reducing the weight average and number average molecular weights by 44.6 and 11.3 %, respectively, within five days. Finally, structural analysis and molecular docking simulations were performed to elucidate the degradation mechanism of PFL1. The oxidized PE-degrading enzyme reported here will provide the groundwork for advancing PE waste treatment technology and for engineering microbes to repurpose PE waste into valuable chemicals.

Impact of Postmastectomy Radiation Therapy on Breast Cancer Patients According to Pathologic Nodal Status after Modern Neoadjuvant Chemotherapy.

PURPOSE: The utility of postmastectomy radiation therapy (PMRT) for breast cancer patients after neoadjuvant chemotherapy (NAC) is highly controversial. This study evaluated the impact of PMRT according to pathologic nodal status after modern NAC. Materials and Methods: We retrospectively reviewed 682 patients with clinical stage II-III breast cancer who underwent NAC and mastectomy from 2013 to 2017. In total, 596 patients (87.4%) received PMRT, and 86 (12.6%) did not. We investigated the relationships among locoregional recurrence-free survival (LRRFS), disease-free survival (DFS), overall survival (OS), and various prognostic factors. Subgroup analyses were also performed to identify patients who may benefit from PMRT. RESULTS: The median follow-up duration was 67 months. In ypN+ patients (n=368, 51.2%), PMRT showed significant benefits in terms of LRRFS, DFS, and OS (all p < 0.001). In multivariate analyses, histologic grade (HG) III (p=0.002), lymphovascular invasion (LVI) (p=0.045), and ypN2-3 (p=0.02) were significant risk factors for poor LRRFS. In ypN1 patients with more than two prognostic factors among luminal/human epidermal growth factor receptor-2-negative subtype, HG I-II, and absence of LVI, PMRT had no significant effect on LRRFS (p=0.18). In ypN0 patients (n=351, 48.8%), PMRT was not significantly associated with LRRFS, DFS, or OS. However, PMRT showed better LRRFS in triple-negative breast cancer (TNBC) patients (p=0.03). CONCLUSION: PMRT had a major impact on treatment outcomes in patients with residual lymph nodes following NAC and mastectomy. Among ypN0 patients, PMRT may be beneficial only for those with TNBC.

Feasibility and safety of neck level IB-sparing radiotherapy in nasopharyngeal cancer: a long-term single institution analysis.

PURPOSE: Nasopharyngeal cancer (NPC) has a higher prevalence of regional nodal metastasis than other head and neck cancers; however, level IB lymph node involvement is rare. We evaluated the safety and feasibility of level IB-sparing radiotherapy (RT) for NPC patients. MATERIALS AND METHODS: We retrospectively reviewed 236 patients with NPC who underwent definitive intensity-modulated RT with or without chemotherapy between 2004 and 2018. Of them, 212 received IB-sparing RT, and 24 received non-IB-sparing RT. We conducted a propensity score matching analysis to compare treatment outcomes according to IB-sparing status. In addition, dosimetric analysis of the salivary glands was performed to identify the relationship between xerostomia and the IB-sparing RT. RESULTS: The median follow-up duration was 78 months (range, 7 to 194 months). Local, regional, and distant recurrences were observed in 11.9%, 6.8%, and 16.1% of patients, respectively. Of the 16 patients with regional recurrence, 14 underwent IB-sparing RT. The most common site categorization of regional recurrence was level II (75%), followed by retropharyngeal lymph nodes (43.8%); however, there was no recurrence at level IB. In the matched cohorts, IB-sparing RT was not significantly related to treatment outcomes. However, IB-sparing RT patients received a significantly lower mean ipsilateral and contralateral submandibular glands doses (all, p < 0.001) and had a lower incidence of chronic xerostomia compared with non-IB-sparing RT patients (p = 0.006). CONCLUSION: Our results demonstrated that IB-sparing RT is sufficiently safe and feasible for treating NPC. To reduce the occurrence of xerostomia, IB-sparing RT should be considered without compromising target coverage.

Long-term outcomes of low-dose radiotherapy in Kasabach-Merritt syndrome.

PURPOSE: Reports on results of radiation therapy (RT) for Kasabach-Merritt syndrome (KMS) are limited. We performed a retrospective study to evaluate the response rates and late complications and to determine the adequate RT dose for patients with KMS patients. MATERIALS AND METHODS: We studied 11 patients who received RT between October 1988 and September 2008 for KMS refractory to pharmacologic therapy. All patients had external hemangiomas and received the diagnosis of KMS within 12 months of birth. All 11 patients received steroids as the first-line therapy; eight patients additionally received interferon-α therapy, and one patient underwent surgery. Nine patients underwent single-course RT with a total dose of 4.5-8 Gy (1.5-2 Gy/fraction). Two patients received multiple courses of RT, with a cumulative total dose of 12 Gy (2 Gy/fraction) and 18Gy (1.5 Gy/fraction), respectively. RESULTS: The median follow-up period was 156 months (interquartile range [IQR], 75 to 226 months). The median total dose of RT was 6 Gy, and all patients maintained complete remission until the last follow-up. An additional course of RT was performed for refractory cases or cases of local relapse after initial RT. Rapid platelet count increase after RT was seen in most patients, which returned to normalcy in a median of 20 days (IQR, 5 to 178 days). However, seven patients experienced radiation-related long-term complications. CONCLUSION: Low-dose RT is effective and yields rapid response in patients with KMS. However, given growth-related late complications, RT should be carefully considered.

Clinical outcomes of salvage treatment in lymph node-positive prostate cancer patients after radical prostatectomy.

INTRODUCTION: The optimal salvage treatment strategies for lymph node-positive (LNP) patients after radical surgery have not been clearly defined in prostate cancer with biochemical recurrence or persistence of elevated prostate-specific antigen (PSA). In this study, we compared the clinical outcomes of two different salvage treatments, androgen deprivation therapy (ADT) alone versus ADT with radiotherapy (RT). We also investigated prognostic factors that could support the use of ADT with RT in LNP prostate cancer. MATERIALS AND METHODS: We retrospectively reviewed 94 LNP prostate cancer patients who underwent radical prostatectomy (RP) followed by salvage treatment between 2004 and 2018. Salvage treatments involved either ADT alone or ADT with RT according to the clinical judgment of the physician. We analyzed clinicopathological and treatment factors related to 2nd biochemical failure (2nd BCF), clinical progression (CP), and progression-free survival (PFS). The cumulative failure after salvage treatment was defined as including both 2nd BCF and CP. RESULTS: The median duration of follow-up was 55 months (interquartile range, 35-97 months). Thirty-seven (39.4%) patients were treated with ADT alone, and 57 patients (60.6%) were treated with a combination of ADT with RT. During follow-up period, the incidence of failure after salvage treatment in the ADT alone group and the combined treatment group was 89.2% and 45.6%, respectively (HR, 22.4; 95% CI 5.43-92.1; P < 0.001). The combination of ADT with RT was associated with better 2nd BCF and PFS than ADT alone (P = 0.007 and P = 0.015, respectively). In multivariate analyses, number of positive LN ≥ 2 and PSA nadir ≥ 0.005 ng/ml after RP were associated with poor 2nd BCF, CP, and PFS after salvage treatment. Salvage by combined ADT plus RT showed better 2nd BCF and PFS than ADT alone. Specifically, patients with number of positive LN ≥ 2 or PSA nadir ≥ 0.005 ng/ml after RP showed better 2nd BCF (P = 0.004) or PFS (P = 0.011) when treated with ADT plus RT rather than ADT alone. CONCLUSIONS: In patients with LNP prostate cancer, salvage ADT plus RT improved 2nd BCF and PFS compared to ADT alone. In particular, when the patients had more than two positive lymph nodes or PSA nadir ≥ 0.005 ng/ml after RP, ADT with RT seems to be a more beneficial salvage treatment resulting in better 2nd BCF and PFS.