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1.
Article in English | MEDLINE | ID: mdl-38986915

ABSTRACT

PURPOSE: The Radiation Oncology Case Rate (ROCR) aims to shift radiation reimbursement from fee-for-service (FFS) to bundled payments, which would decouple fractionation from reimbursement in the United States. This study compares historical reimbursement rates from three large centers and a national Medicare sample with proposed base rates from ROCR. It also tests the impact of methodological inclusion of treatment and disease characteristics to determine if any variables are associated with greater rate differences that may lead to inequitable reimbursement. METHODS: Using XXXX electronic medical record data from 2017-2020 and Part B claims from the Medicare 5% research identifiable files (RIF), episodic 90-day historical reimbursement rates for 15 cancer types were calculated per the ROCR payment methodology. XXXX reimbursement rates were stratified by disease and treatment characteristics and multiple linear regression was performed to assess the association of these variables on historical episode reimbursement rates. RESULTS: From XXXX, 3,498 patient episodes were included and 480,526 from the RIF. From both datasets, 25% of brain metastases and 13% of bone metastases episodes included ≥2 treatment courses with an average of 51 days between courses. Accounting for all 15 cancer types, ROCR base rates resulted in an average -2.4% and -2.9% reduction in rates for XXXX and the RIF respectively compared to historical reimbursement. On multivariate analysis of XXXX data, treatment intent (curative vs. palliative) was associated with higher historical reimbursement (+$477 to +$7,417; p ≤ 0.05) for 12 out of 12 applicable cancer types. Stage (3-4 vs. 1-2) was associated with higher historical reimbursement (+$1,169 to +$3,917; p ≤ 0.05) for 8 out of 12 applicable cancer types. CONCLUSION: Our data suggest ROCR base rates introduce an average ≤3% reimbursement rate decrease compared to historical FFS reimbursement per cancer type, which could produce the Medicare savings required for congressional approval of ROCR. Estimating comparisons with future FFS reimbursement would require consideration of additional factors such as the increased utilization of hypofractionation, proposed FFS rate cuts, and inflationary updates. A distinct rate and shortened episode duration (≤ 30 days) should be considered for palliative episodes. Applying a base rate modifier per cancer stage may mitigate disproportionate reductions in reimbursement for facilities with a higher volume of curative advanced stage patients such as freestanding centers in rural settings.

2.
Cancer Diagn Progn ; 4(4): 408-415, 2024.
Article in English | MEDLINE | ID: mdl-38962535

ABSTRACT

Background/Aim: Previous studies suggested pre-operative platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) to be predictive factors in patients with glioblastoma multiforme (GBM). This study investigated the prognostic role of PLR and NLR prior to or at the beginning of radiotherapy. Patients and Methods: In 80 patients with GBM receiving conventionally fractionated radiotherapy plus concurrent temozolomide following resection or biopsy, 12 factors including PLR and NLR were retrospectively evaluated regarding progression-free survival (PFS) and overall survival (OS). Results: On multivariable analyses, PLR ≤150, Karnofsky performance score (KPS) 90-100, and O6-methylguanine-DNA methyltransferase promoter methylation were significantly associated with improved PFS. Single lesion, KPS 90-100, and adjuvant chemotherapy were significantly associated with OS; PLR ≤150 showed a trend. NLR ≤3 showed a trend for associations with PFS and OS on univariable analyses. Conclusion: PLR prior to or at the beginning of radiotherapy was associated with treatment outcomes in patients irradiated for GBM and should be considered in future clinical trials.

3.
In Vivo ; 38(4): 1806-1813, 2024.
Article in English | MEDLINE | ID: mdl-38936935

ABSTRACT

BACKGROUND/AIM: Prognostic factors can facilitate treatment personalization in patients with glioblastoma multiforme (GBM). This study investigated different Glasgow prognostic scores (GPS) and the LabBM score in patients with GBM receiving chemoradiation following resection or biopsy. PATIENTS AND METHODS: Four GPS versions, LabBM score, and 10 other factors were retrospectively investigated for progression-free survival (PFS) and overall survival (OS) in 86 patients. GPS versions included original GPS (oGPS), modified GPS (mGPS), high-sensitivity mGPS (HS-mGPS), and high-sensitivity oGPS (HS-oGPS). RESULTS: On multivariate analysis, higher oGPS was significantly associated with worse OS (p=0.006). On univariate analyses, trends were found for associations between higher mGPS and worse OS (p=0.098) and between higher LabBM scores and worse PFS (p=0.059). CONCLUSION: The oGPS was an independent predictor of OS in patients receiving chemoradiation for GBM and can help personalizing the treatment for these patients. The LabBM score may be useful for predicting PFS.


Subject(s)
Chemoradiotherapy , Glioblastoma , Humans , Glioblastoma/therapy , Glioblastoma/mortality , Glioblastoma/pathology , Female , Male , Prognosis , Middle Aged , Chemoradiotherapy/methods , Aged , Adult , Brain Neoplasms/therapy , Brain Neoplasms/mortality , Brain Neoplasms/pathology , Retrospective Studies , Aged, 80 and over , Treatment Outcome
4.
Anticancer Res ; 44(7): 3059-3066, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38925836

ABSTRACT

BACKGROUND/AIM: Many patients with glioblastoma experience an intracerebral recurrence and require a personalized treatment. This study aimed to facilitate this approach by identifying prognostic factors for progression-free survival (PFS) and overall survival (OS). PATIENTS AND METHODS: In 102 patients with recurrent glioblastoma following primary treatment with resection or biopsy plus adjuvant chemoradiation, 11 characteristics were retrospectively investigated regarding PFS and OS. RESULTS: In the multivariate analyses, Karnofsky performance score (KPS) 90-100 at the time of recurrence (p=0.032), maximum cumulative diameter of recurrent lesions ≤40 mm (p=0.002), resection of recurrent glioblastoma (p=0.025), and systemic therapy for recurrent glioblastoma (p=0.025) were significantly associated with improved PFS. In addition, KPS 90-100 (p=0.024), maximum cumulative diameter ≤40 mm (p=0.033), and systemic therapy (p=0.006) were significantly associated with better OS. CONCLUSION: Our study identified high Karnofsky Performance Status (KPS 90-100), maximum cumulative diameter of recurrent glioblastoma lesions ≤40 mm, and systemic therapy for recurrent glioblastoma as independent predictors of overall survival (OS) and progression-free survival (PFS). These independent prognostic factors may help select the most suitable treatment for individual patients with recurrent glioblastoma, potentially improving patient outcomes.


Subject(s)
Brain Neoplasms , Glioblastoma , Neoplasm Recurrence, Local , Progression-Free Survival , Humans , Glioblastoma/mortality , Glioblastoma/pathology , Glioblastoma/therapy , Male , Female , Middle Aged , Neoplasm Recurrence, Local/pathology , Aged , Prognosis , Brain Neoplasms/mortality , Brain Neoplasms/pathology , Brain Neoplasms/therapy , Adult , Retrospective Studies , Karnofsky Performance Status , Aged, 80 and over
5.
Anticancer Res ; 44(6): 2617-2620, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38821595

ABSTRACT

BACKGROUND/AIM: We investigated grade ≥2 dermatitis in patients irradiated for breast cancer. This study evaluated associations between dermatitis and the season during which radiotherapy took place. PATIENTS AND METHODS: Associations between the season and grade ≥2 dermatitis were retrospectively evaluated in 327 breast cancer patients. Seasons were March to May (spring), June to August (summer), September to November (autumn), and December to February (winter). Subgroup analyses were performed considering fractionation, radiation technique, treatment volume, radiation boost, and deep-inspiration breath-hold technique. Furthermore, warmer and cooler months were compared. RESULTS: The season had no significant impact on the rate of grade ≥2 dermatitis in the entire cohort (p=0.63) nor in the subgroup analyses (p-values between 0.17 and 0.82). No significant difference in rate was found between warm and cool months. CONCLUSION: Grade ≥2 dermatitis was not associated with the season during which radiotherapy was performed. This factor may not be important for stratification in prospective trials.


Subject(s)
Breast Neoplasms , Radiodermatitis , Seasons , Humans , Female , Breast Neoplasms/radiotherapy , Breast Neoplasms/complications , Breast Neoplasms/pathology , Middle Aged , Aged , Retrospective Studies , Adult , Radiodermatitis/etiology , Radiodermatitis/pathology , Aged, 80 and over
6.
In Vivo ; 38(3): 1220-1228, 2024.
Article in English | MEDLINE | ID: mdl-38688652

ABSTRACT

BACKGROUND/AIM: Meningeal melanocytomas are rare tumors of the central nervous system and optimal treatment needs further clarification. This study compared subtotal resection (STR), STR plus radiation therapy (RT), gross total resection (GTR), and GTR+RT to better define the role of postoperative RT. PATIENTS AND METHODS: All cases reported in the literature were reviewed. Patients (n=184) with complete data were analyzed for local control (LC) and overall survival (OS). RESULTS: On univariate analysis, GTR (vs. STR) was associated with improved LC (p=0.016). When comparing the treatment regimens, best and worst results were found after GTR+RT and STR alone, respectively (p<0.001). On univariate analysis, GTR resulted in better OS than STR (p=0.041). Moreover, the treatment regimen had a significant impact on OS (p=0.049). On multivariate analyses of LC and OS, extent of resection and treatment regimen were found to be significant factors. After STR, RT significantly improved LC but not OS. After GTR, RT did not significantly improve LC or OS. CONCLUSION: GTR was significantly superior to STR regarding LC and OS. STR+RT resulted in significantly better LC when compared to STR alone.


Subject(s)
Melanoma , Meningeal Neoplasms , Humans , Meningeal Neoplasms/radiotherapy , Meningeal Neoplasms/pathology , Meningeal Neoplasms/mortality , Female , Male , Melanoma/radiotherapy , Melanoma/pathology , Melanoma/mortality , Middle Aged , Adult , Aged , Combined Modality Therapy , Treatment Outcome , Adolescent
7.
ACS Cent Sci ; 10(4): 803-812, 2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38680565

ABSTRACT

The post-transcriptional reduction of uridine to dihydrouridine (D) by dihydrouridine synthase (DUS) enzymes is among the most ubiquitous transformations in RNA biology. D is found at multiple sites in tRNAs, and studies in yeast have proposed that each of the four eukaryotic DUS enzymes modifies a different site; however, the molecular basis for this exquisite selectivity is unknown, and human DUS enzymes have remained largely uncharacterized. Here we investigate the substrate specificity of human dihydrouridine synthase 2 (hDUS2) using mechanism-based cross-linking with 5-bromouridine (5-BrUrd)-modified oligonucleotide probes and in vitro dihydrouridylation assays. We find that hDUS2 exclusively modifies U20 across diverse tRNA substrates and identify a minimal GU sequence within the tRNA D loop that underlies selective substrate modification. Further, we use our mechanism-based platform to screen small molecule inhibitors of hDUS2, a potential anticancer target. Our work elucidates the principles of substrate modification by a conserved DUS and provides a general platform for studying RNA modifying enzymes with sequence-defined activity-based probes.

8.
Anticancer Res ; 44(5): 2073-2079, 2024 May.
Article in English | MEDLINE | ID: mdl-38677766

ABSTRACT

BACKGROUND/AIM: Pneumonitis is a serious radiotherapy complication. This study, which is a prerequisite for a prospective trial, aimed to identify the prevalence of pneumonitis and risk factors in elderly patients with lung cancer. PATIENTS AND METHODS: Ninety-eight lung cancer patients aged ≥65 years were included. Seventeen factors were investigated regarding grade ≥2 pneumonitis at 24 weeks following radiotherapy. RESULTS: The prevalence of grade ≥2 pneumonitis at 24 weeks was 27.3%. On univariate analysis, a significant association was observed for mean (ipsilateral) lung dose (MLD; ≤13.0 vs. 13.1-20.0 vs. >20.0 Gy; 0% vs. 24.9% vs. 48.7%). Results were significant also for ≤13.0 vs. >13.0 Gy (0% vs. 37.1%) or ≤20.0 vs. >20.0 Gy (13.4% vs. 48.7%). MLD achieved significance on multivariate analysis. CONCLUSION: Elderly patients receiving MLDs >13.0 Gy, particularly >20.0 Gy, have a high risk of grade ≥2 pneumonitis. These results are important for designing a prospective trial.


Subject(s)
Lung Neoplasms , Radiation Pneumonitis , Humans , Aged , Radiation Pneumonitis/epidemiology , Radiation Pneumonitis/etiology , Lung Neoplasms/radiotherapy , Female , Male , Aged, 80 and over , Prevalence , Risk Factors , Radiotherapy Dosage , Lung/radiation effects , Prospective Studies
10.
Anticancer Res ; 44(4): 1525-1531, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38537981

ABSTRACT

BACKGROUND/AIM: Patients with breast cancer receiving adjuvant radiotherapy may experience grade ≥2 dermatitis. In the Interreg-project HeAT, a mobile application (app) reminding patients to perform skin care will be prospectively tested with the goal of decreasing clinically significant radiation dermatitis. This study aimed to identify the prevalence of grade ≥2 dermatitis and risk factors, required for designing the prospective trial. PATIENTS AND METHODS: In a retrospective study of 327 patients with breast cancer irradiated during 2022-2023, the prevalence of grade ≥2 dermatitis and 23 potential risk factors were investigated. RESULTS: The prevalence of grade ≥2 dermatitis was 31.2%. On multivariate analysis, it was significantly associated with chronic inflammatory disease (p=0.001), significant cardiovascular disease (p<0.001), smoking history >10 pack years (p<0.001), advanced T-stage (p=0.017), normo-fractionation (p<0.001), and radiation boost (p<0.001). CONCLUSION: The prevalence of grade ≥2 dermatitis and independent risk factors during adjuvant radiotherapy for invasive breast cancer were identified that contribute to improved patient care and the design of a prospective trial.


Subject(s)
Breast Neoplasms , Radiodermatitis , Humans , Female , Breast Neoplasms/complications , Radiotherapy, Adjuvant/adverse effects , Prospective Studies , Retrospective Studies , Radiodermatitis/epidemiology , Radiodermatitis/etiology
11.
Int J Radiat Oncol Biol Phys ; 119(4): 1208-1221, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-38395086

ABSTRACT

Stereotactic body radiation therapy (SBRT) and hypofractionation using pencil-beam scanning (PBS) proton therapy (PBSPT) is an attractive option for thoracic malignancies. Combining the advantages of target coverage conformity and critical organ sparing from both PBSPT and SBRT, this new delivery technique has great potential to improve the therapeutic ratio, particularly for tumors near critical organs. Safe and effective implementation of PBSPT SBRT/hypofractionation to treat thoracic malignancies is more challenging than the conventionally fractionated PBSPT because of concerns of amplified uncertainties at the larger dose per fraction. The NRG Oncology and Particle Therapy Cooperative Group Thoracic Subcommittee surveyed proton centers in the United States to identify practice patterns of thoracic PBSPT SBRT/hypofractionation. From these patterns, we present recommendations for future technical development of proton SBRT/hypofractionation for thoracic treatment. Among other points, the recommendations highlight the need for volumetric image guidance and multiple computed tomography-based robust optimization and robustness tools to minimize further the effect of uncertainties associated with respiratory motion. Advances in direct motion analysis techniques are urgently needed to supplement current motion management techniques.


Subject(s)
Consensus , Proton Therapy , Radiation Dose Hypofractionation , Radiosurgery , Thoracic Neoplasms , Proton Therapy/methods , Humans , Radiosurgery/methods , Thoracic Neoplasms/radiotherapy , Organs at Risk/radiation effects , Radiation Oncology/standards , Practice Patterns, Physicians' , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Image-Guided/methods , United States , Tomography, X-Ray Computed , Lung Neoplasms/radiotherapy , Lung Neoplasms/diagnostic imaging
12.
ArXiv ; 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38351927

ABSTRACT

Stereotactic body radiation therapy (SBRT) and hypofractionation using pencil-beam scanning (PBS) proton therapy (PBSPT) is an attractive option for thoracic malignancies. Combining the advantages of target coverage conformity and critical organ sparing from both PBSPT and SBRT, this new delivery technique has great potential to improve the therapeutic ratio, particularly for tumors near critical organs. Safe and effective implementation of PBSPT SBRT/hypofractionation to treat thoracic malignancies is more challenging than the conventionally-fractionated PBSPT due to concerns of amplified uncertainties at the larger dose per fraction. NRG Oncology and Particle Therapy Cooperative Group (PTCOG) Thoracic Subcommittee surveyed US proton centers to identify practice patterns of thoracic PBSPT SBRT/hypofractionation. From these patterns, we present recommendations for future technical development of proton SBRT/hypofractionation for thoracic treatment. Amongst other points, the recommendations highlight the need for volumetric image guidance and multiple CT-based robust optimization and robustness tools to minimize further the impact of uncertainties associated with respiratory motion. Advances in direct motion analysis techniques are urgently needed to supplement current motion management techniques.

13.
Int J Radiat Oncol Biol Phys ; 119(1): 66-77, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38000701

ABSTRACT

PURPOSE: This study aimed to predict the probability of grade ≥2 pneumonitis or dyspnea within 12 months of receiving conventionally fractionated or mildly hypofractionated proton beam therapy for locally advanced lung cancer using machine learning. METHODS AND MATERIALS: Demographic and treatment characteristics were analyzed for 965 consecutive patients treated for lung cancer with conventionally fractionated or mildly hypofractionated (2.2-3 Gy/fraction) proton beam therapy across 12 institutions. Three machine learning models (gradient boosting, additive tree, and logistic regression with lasso regularization) were implemented to predict Common Terminology Criteria for Adverse Events version 4 grade ≥2 pulmonary toxicities using double 10-fold cross-validation for parameter hyper-tuning without leak of information. Balanced accuracy and area under the curve were calculated, and 95% confidence intervals were obtained using bootstrap sampling. RESULTS: The median age of the patients was 70 years (range, 20-97), and they had predominantly stage IIIA or IIIB disease. They received a median dose of 60 Gy in 2 Gy/fraction, and 46.4% received concurrent chemotherapy. In total, 250 (25.9%) had grade ≥2 pulmonary toxicity. The probability of pulmonary toxicity was 0.08 for patients treated with pencil beam scanning and 0.34 for those treated with other techniques (P = 8.97e-13). Use of abdominal compression and breath hold were highly significant predictors of less toxicity (P = 2.88e-08). Higher total radiation delivered dose (P = .0182) and higher average dose to the ipsilateral lung (P = .0035) increased the likelihood of pulmonary toxicities. The gradient boosting model performed the best of the models tested, and when demographic and dosimetric features were combined, the area under the curve and balanced accuracy were 0.75 ± 0.02 and 0.67 ± 0.02, respectively. After analyzing performance versus the number of data points used for training, we observed that accuracy was limited by the number of observations. CONCLUSIONS: In the largest analysis of prospectively enrolled patients with lung cancer assessing pulmonary toxicities from proton therapy to date, advanced machine learning methods revealed that pencil beam scanning, abdominal compression, and lower normal lung doses can lead to significantly lower probability of developing grade ≥2 pneumonitis or dyspnea.


Subject(s)
Lung Neoplasms , Pneumonia , Proton Therapy , Humans , Young Adult , Adult , Middle Aged , Aged , Aged, 80 and over , Lung Neoplasms/drug therapy , Proton Therapy/adverse effects , Protons , Prospective Studies , Pneumonia/etiology , Dyspnea/etiology , Radiotherapy Dosage
14.
Med Phys ; 51(2): 1484-1498, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37748037

ABSTRACT

BACKGROUND: Accurate and efficient dose calculation is essential for on-line adaptive planning in proton therapy. Deep learning (DL) has shown promising dose prediction results in photon therapy. However, there is a scarcity of DL-based dose prediction methods specifically designed for proton therapy. Successful dose prediction method for proton therapy should account for more challenging dose prediction problems in pencil beam scanning proton therapy (PBSPT) due to its sensitivity to heterogeneities. PURPOSE: To develop a DL-based PBSPT dose prediction workflow with high accuracy and balanced complexity to support on-line adaptive proton therapy clinical decision and subsequent replanning. METHODS: PBSPT plans of 103 prostate cancer patients (93 for training and the other 10 for independent testing) and 83 lung cancer patients (73 for training and the other 10 for independent testing) previously treated at our institution were included in the study, each with computed tomography scans (CTs), structure sets, and plan doses calculated by the in-house developed Monte-Carlo dose engine (considered as the ground truth in the model training and testing). For the ablation study, we designed three experiments corresponding to the following three methods: (1) Experiment 1, the conventional region of interest (ROI) (composed of targets and organs-at-risk [OARs]) method. (2) Experiment 2, the beam mask (generated by raytracing of proton beams) method to improve proton dose prediction. (3) Experiment 3, the sliding window method for the model to focus on local details to further improve proton dose prediction. A fully connected 3D-Unet was adopted as the backbone. Dose volume histogram (DVH) indices, 3D Gamma passing rates with a criterion of 3%/3 mm/10%, and dice coefficients for the structures enclosed by the iso-dose lines between the predicted and the ground truth doses were used as the evaluation metrics. The calculation time for each proton dose prediction was recorded to evaluate the method's efficiency. RESULTS: Compared to the conventional ROI method, the beam mask method improved the agreement of DVH indices for both targets and OARs and the sliding window method further improved the agreement of the DVH indices (for lung cancer, CTV D98 absolute deviation: 0.74 ± 0.18 vs. 0.57 ± 0.21 vs. 0.54 ± 0.15 Gy[RBE], ROI vs. beam mask vs. sliding window methods, respectively). For the 3D Gamma passing rates in the target, OARs, and BODY (outside target and OARs), the beam mask method improved the passing rates in these regions and the sliding window method further improved them (for prostate cancer, targets: 96.93% ± 0.53% vs. 98.88% ± 0.49% vs. 99.97% ± 0.07%, BODY: 86.88% ± 0.74% vs. 93.21% ± 0.56% vs. 95.17% ± 0.59%). A similar trend was also observed for the dice coefficients. This trend was especially remarkable for relatively low prescription isodose lines (for lung cancer, 10% isodose line dice: 0.871 ± 0.027 vs. 0.911 ± 0.023 vs. 0.927 ± 0.017). The dose predictions for all the testing cases were completed within 0.25 s. CONCLUSIONS: An accurate and efficient deep learning-augmented proton dose prediction framework has been developed for PBSPT, which can predict accurate dose distributions not only inside but also outside ROI efficiently. The framework can potentially further reduce the initial planning and adaptive replanning workload in PBSPT.


Subject(s)
Deep Learning , Lung Neoplasms , Prostatic Neoplasms , Proton Therapy , Radiotherapy, Intensity-Modulated , Male , Humans , Radiotherapy Dosage , Protons , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Intensity-Modulated/methods , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/radiotherapy , Lung Neoplasms/surgery , Prostatic Neoplasms/radiotherapy
15.
In Vivo ; 38(1): 313-320, 2024.
Article in English | MEDLINE | ID: mdl-38148066

ABSTRACT

BACKGROUND/AIM: When assigned to radiotherapy (RT), elderly patients may experience distress. We investigated distress during RT and potential risk factors in these patients. PATIENTS AND METHODS: Six-hundred-and-nineteen patients completed pre-RT and post-RT distress thermometers. Seven characteristics were investigated including age, sex, Karnofsky performance score (KPS), grouped KPS, tumor type, intent of RT, and previous RT. Additional analyses were performed in 358 patients with pre-RT scores ≤5. RESULTS: Mean change of distress was -0.5 (±2.7) points and associated with KPS (p=0.005) and grouped KPS (p<0.001). Male sex (p=0.035), KPS 90-100 (p=0.001), and curative intent (p=0.037) were associated with increased distress on univariable analyses, and KPS 90-100 (odds ratio=1.92, p=0.004) on multivariable analysis. In patients with baseline scores ≤5, mean change was +0.5 (±2.5) points and associated with KPS (p=0.040) and grouped KPS (p=0.025). CONCLUSION: Psychological assistance should be considered for all patients including those with baseline scores ≤5 and KPS 90-100. Patients with risk factors for increased distress would especially benefit.


Subject(s)
Brain Neoplasms , Humans , Male , Aged , Prognosis , Brain Neoplasms/radiotherapy , Survival Analysis , Retrospective Studies , Karnofsky Performance Status
16.
bioRxiv ; 2023 Nov 08.
Article in English | MEDLINE | ID: mdl-37965204

ABSTRACT

Dihydrouridine is an abundant and conserved modified nucleoside present on tRNA, but characterization and functional studies of modification sites and associated DUS writer enzymes in mammals is lacking. Here we use a chemical probing strategy, RNABPP-PS, to identify 5-chlorouridine as an activity-based probe for human DUS enzymes. We map D modifications using RNA-protein crosslinking and chemical transformation and mutational profiling to reveal D modification sites on human tRNAs. Further, we knock out individual DUS genes in two human cell lines to investigate regulation of tRNA expression levels and codon-specific translation. We show that whereas D modifications are present across most tRNA species, loss of D only perturbs the translational function of a subset of tRNAs in a cell type-specific manner. Our work provides powerful chemical strategies for investigating D and DUS enzymes in diverse biological systems and provides insight into the role of a ubiquitous tRNA modification in translational regulation.

17.
bioRxiv ; 2023 Nov 05.
Article in English | MEDLINE | ID: mdl-37961591

ABSTRACT

The post-transcriptional reduction of uridine to dihydrouridine (D) by dihydrouridine synthase (DUS) enzymes is among the most ubiquitous transformations in RNA biology. D is found at multiple sites in tRNAs and studies in yeast have proposed that each of the four eukaryotic DUS enzymes modifies a different site, however the molecular basis for this exquisite selectivity is unknown and human DUS enzymes have remained largely uncharacterized. Here we investigate the substrate specificity of human dihydrouridine synthase 2 (hDUS2) using mechanism-based crosslinking with 5-bromouridine (5-BrUrd)-modified oligonucleotide probes and in vitro dihydrouridylation assays. We find that hDUS2 modifies U20 in the D loop of diverse tRNA substrates and identify a minimal GU motif within the tRNA tertiary fold required for directing its activity. Further, we use our mechanism-based platform to screen small molecule inhibitors of hDUS2, a potential anti-cancer target. Our work elucidates the principles of substrate modification by a conserved DUS and provides a general platform to studying RNA modifying enzymes with sequence-defined activity-based probes.

18.
In Vivo ; 37(6): 2755-2759, 2023.
Article in English | MEDLINE | ID: mdl-37905616

ABSTRACT

BACKGROUND/AIM: Breast cancer patients receiving radiation therapy (RT) may experience considerable distress. We investigated the course of distress during an RT-course for breast cancer. PATIENTS AND METHODS: Three-hundred-and-thirty breast cancer patients completed Distress Thermometers before and directly after RT. Distress was evaluated in the entire cohort and different groups of age, sex, Karnofsky performance score (KPS), intent of RT, and previous RT. RESULTS: Mean change of distress scores was - 0.4 points, which was significantly associated with KPS. Decrease of distress was more pronounced in patients with KPS ≤80 or age <64 years. Deterioration (yes vs. no) was non-significantly associated with no previous RT. In patients with pre-RT distress scores ≤5 points, mean score increased by +0.5 points; no significant associations between characteristics and investigated endpoints were found. CONCLUSION: Psychological assistance should be offered to all patients irradiated for breast cancer, particularly to those with risk factors, regardless of the pre-RT distress score.


Subject(s)
Breast Neoplasms , Humans , Middle Aged , Female , Breast Neoplasms/radiotherapy , Breast Neoplasms/psychology , Karnofsky Performance Status , Risk Factors
19.
In Vivo ; 37(6): 2654-2661, 2023.
Article in English | MEDLINE | ID: mdl-37905621

ABSTRACT

BACKGROUND/AIM: Adjuvant radiotherapy (RT) for breast cancer can be associated with acute dermatitis (ARD) and pneumonitis (RP). Prevalence and risk factors were characterized. PATIENTS AND METHODS: This study included 489 breast cancer patients receiving adjuvant RT with conventional fractionation (CF) ± sequential or simultaneous integrated boost, or hypo-fractionation ± sequential boost. RT-regimen and 15 characteristics were investigated for grade ≥2 ARD and RP. RESULTS: Prevalence of grade ≥2 ARD and RP was 25.3% and 2.5%, respectively. On univariate analyses, ARD was significantly associated with CF and radiation boost (p<0.0001), age ≤60 years (p=0.008), Ki-67 ≥15% (p=0.012), and systemic treatment (p=0.002). On multivariate analysis, RT-regimen (p<0.0001) and age (p=0.009) were associated with ARD. Chronic inflammatory disease was significantly associated with RP on univariate (p=0.007) and multivariate (p=0.016) analyses. CONCLUSION: Risk factors for grade ≥2 ARD and RP were determined that may help identify patients who require closer monitoring during and after RT.


Subject(s)
Breast Neoplasms , Lung Neoplasms , Pneumonia , Radiation Pneumonitis , Radiodermatitis , Humans , Middle Aged , Female , Breast Neoplasms/radiotherapy , Breast Neoplasms/complications , Radiation Pneumonitis/diagnosis , Radiation Pneumonitis/epidemiology , Radiation Pneumonitis/etiology , Radiodermatitis/diagnosis , Radiodermatitis/epidemiology , Radiodermatitis/etiology , Dose Fractionation, Radiation , Lung Neoplasms/complications
20.
In Vivo ; 37(6): 2628-2633, 2023.
Article in English | MEDLINE | ID: mdl-37905665

ABSTRACT

BACKGROUND/AIM: Many breast cancer patients receive adjuvant radiotherapy. Tumor bed boost may reduce risk of local failure in high risk patients. We compared hypofractionated whole-breast irradiation (WBI) plus boost (HF+boost) and conventionally fractionated WBI plus boost (CF+boost). PATIENTS AND METHODS: One-hundred-and-twenty-eight patients receiving HF-WBI (40 Gy in 15 fractions) plus boost (group A) were matched to 127 patients receiving CF-WBI (50.4 Gy in 28 fractions) plus boost (group B), utilizing 10 characteristics. RESULTS: Grade ≥2 dermatitis rates were 16.4% in group A vs. 44.1% in group B (p<0.0001), and grade ≥2 pneumonitis rates were 1.6% vs. 2.4% (p=0.68). Four-year rates of local control, metastases-free survival, and overall survival were 100% vs. 99% (p=0.81), 98% vs. 100% (p=0.29), and 98% vs. 100% (p=0.17), respectively. CONCLUSION: HF+boost was associated with significantly less grade ≥2 dermatitis with similar disease control and survival.


Subject(s)
Breast Neoplasms , Dermatitis , Humans , Female , Breast Neoplasms/pathology , Mastectomy, Segmental , Neoplasm Staging , Breast/pathology , Radiotherapy, Adjuvant/adverse effects , Dermatitis/etiology
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