Publications by authors named "Kowalchuk R"

Purpose: The Prognostic Index for Spinal Metastasis (PRISM) is a scoring system derived from prospective data from a single institution that stratifies patients undergoing spine stereotactic radiosurgery (SSRS) for spinal metastases into subgroups by overall (OS). We sought to further demonstrate its generalizability by performing validation with a large dataset from a second high-volume institution, Mayo Clinic.

Methods And Materials: Eight hundred seventy-nine patients-424 from Mayo Clinic and 455 from MD Anderson Cancer Center (MDACC)-who received SSRS between 2007 and 2019 were identified.

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Purpose: To report patient outcomes and local tumor control rates in a cohort of patients with biopsy-proven HER-2 positive breast cancer treated with stereotactic radiosurgery (SRS) for brain metastases (BM).

Methods: This international, retrospective, multicenter study, included 195 female patients with 1706 SRS-treated BM. Radiologic and clinical outcomes after SRS were determined and prognostic factors identified.

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Purpose: To report clinical and dosimetric characteristics of 5-fraction stereotactic ablative radiotherapy (SABR) using intensity modulated proton therapy (IMPT) for localized prostate cancer.

Materials And Methods: All patients receiving IMPT SABR from 2017 to 2021 for localized prostate cancer at our institution were included. Five fractions were delivered every other day to the prostate +/- seminal vesicles [clinical target volume (CTV)] with 3 mm/3% robustness.

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Objective: To evaluate the completeness and reliability of recurrence data from an institutional cancer registry for patients with head and neck cancer.

Patients And Methods: Recurrence information was collected by radiation oncology and otolaryngology researchers. This was compared with the institutional cancer registry for continuous patients treated with radiation therapy for head and neck cancer at a tertiary cancer center.

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Article Synopsis
  • Metastasis-directed spine SBRT has been shown to improve local control and overall survival in selected patients, with a focus on clinical and dosimetric factors influencing local failure rates.
  • A study analyzed 522 treatments, highlighting that a minimum dose of 15.3 Gy in single-fraction deliveries significantly improves local control, with local failure rates being lower when this dose is achieved.
  • Epidural and soft tissue involvement are significant predictors of local failure, emphasizing the importance of targeting and dosing in SBRT for better treatment outcomes.
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  • Big genomic data and AI are helping doctors understand and treat rare diseases better by focusing on specific groups of patients.
  • Researchers created a tool called GAiN that uses advanced technology to find important genes in small sets of data, even when there aren't many samples available.
  • GAiN can be downloaded for free on GitHub and is especially useful for analyzing genes in cases with few samples, like rare diseases.
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  • * Researchers examined data from 100 patients treated for mobile spine metastases, finding that lower average HUs were linked to a higher risk of fractures, while VBQ did not show a significant correlation.
  • * The study concluded that using HUs could be a more reliable predictor for pathologic fractures post-radiotherapy compared to VBQ, with specific thresholds providing insight into fracture risk.
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  • PET/CT scans are used to assess non-Hodgkin lymphoma (NHL) patients before receiving CAR-T therapy at two key time points: before leukapheresis and before lymphodepletion chemotherapy.
  • Changes in metabolic tumor volume (MTV) and total lesion glycolysis (TLG) between these two scans were found to predict patient outcomes after CAR-T treatment.
  • A model was developed that identified rising MTV and TLG from the pre-leuk to pre-LD scans as significant indicators of increased death risk, also linking higher pre-LD MTV to a greater likelihood of severe neurotoxicity.
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Background: Though metastasis-directed therapy (MDT) has the potential to improve overall survival (OS), appropriate patient selection remains challenging. We aimed to develop a model predictive of OS to refine patient selection for clinical trials and MDT.

Patients And Methods: We assembled a multi-institutional cohort of patients treated with MDT (stereotactic body radiation therapy, radiosurgery, and whole brain radiation therapy).

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Pituitary adenomas are benign brain tumors that comprise 10%-20% of all central nervous system neoplasms. In recent years, stereotactic radiosurgery (SRS) has emerged as a highly effective treatment option in the management of functioning and nonfunctioning adenomas. It is associated with tumor control rates frequently ranging from 80% to 90% in published reports.

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Purpose/objective: Postoperative toxicity for esophageal cancer impacts patient quality of life and potentially overall survival (OS). We studied whether patient and toxicity parameters post-chemoradiation therapy predict for post-surgical cardiopulmonary total toxicity burden (CPTTB) and whether CPTTB was associated with short and long-term outcomes.

Materials/methods: Patients had biopsy-proven esophageal cancer treated with neoadjuvant chemoradiation and esophagectomy.

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The pituitary gland is a potential site for a range of pathologies, for which treatment can involve resection and/or ionizing radiation. Modern stereotactic radiosurgery (SRS) involves highly conformal radiation, allowing for the delivery of high doses to the tumor while simultaneously sparing nearby healthy structures. SRS has become a standard treatment option for residual or recurrent pituitary adenomas.

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Background: Stereotactic body radiotherapy (SBRT) is commonly used to provide targeted treatment to metastatic lung disease. Investigation is needed to understand the influence of histology on treatment outcomes. We report how tumor histology affects local control (LC) in a cohort of patients with non-small cell lung cancer (NSCLC) receiving SBRT for oligometastatic and recurrent pulmonary lesions.

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Purpose: Stereotactic radiosurgery (SRS) and immune checkpoint inhibitors (ICI) are highly effective treatments for brain metastases, particularly when these therapies are administered concurrently. However, there are limited data reporting the risk of radiation necrosis (RN) in this setting.

Methods And Materials: Patients with brain metastases from primary non-small cell lung cancer, renal cell carcinoma, or melanoma treated with SRS and ICI were considered.

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Background: This study was aimed at developing and validating a decision-making tool predictive of overall survival (OS) for patients receiving stereotactic body radiation therapy (SBRT) for spinal metastases.

Methods: Three hundred sixty-one patients at one institution were used for the training set, and 182 at a second institution were used for external validation. Treatments most commonly involved one or three fractions of spine SBRT.

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Objective: Stereotactic radiosurgery (SRS) is an effective treatment for intracranial metastatic disease, but its role in triple-negative breast cancer requires further study. Herein, the authors report overall survival (OS) and local tumor control in a multiinstitutional cohort with triple-negative breast cancer metastases treated with SRS.

Methods: Patients treated from 2010 to 2019 at 9 institutions were included in this retrospective study if they had biopsy-proven triple-negative breast cancer with intracranial metastatic lesions treated with SRS.

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Stereotactic radiosurgery (SRS) is the delivery of a high dose ionizing radiation in a highly conformal manner, which allows for significant sparing of nearby healthy tissues. It is typically delivered in 1-5 sessions and has demonstrated safety and efficacy across multiple intracranial neoplasms and functional disorders. In the setting of brain metastases, postoperative and definitive SRS has demonstrated favorable rates of tumor control and improved cognitive preservation compared to conventional whole brain radiation therapy.

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Article Synopsis
  • Lung cancer, particularly non-small cell lung cancer (NSCLC), is the top cause of cancer-related deaths globally, and advancements in radiotherapy and new therapies are enhancing treatment options beyond just palliative care.
  • A group of international radiotherapy experts worked together to develop evidence-based recommendations for the use of radiotherapy in patients with metastatic NSCLC, focusing on personalized patient management.
  • Radiotherapy can provide quick symptom relief and improve survival rates when used correctly, especially for patients with fewer metastases or brain metastases; however, further research is needed to determine the best treatment combinations and strategies.
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Purpose: This study reports on the risk of radiation-induced myelitis (RM) of the spinal cord from a large single-institutional experience with 1 to 5 fraction stereotactic body radiation therapy (SBRT) to the spine.

Methods And Materials: A retrospective review of patients who received spine SBRT to a radiation naïve level at or above the conus medullaris between 2007 and 2019 was performed. Local failure determination was based on SPIne response assessment in Neuro-Oncology criteria.

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Background: Patients with high-risk prostate cancer (HRPC) have multiple accepted treatment options. Because there is no overall survival benefit of one option over another, appropriate treatment must consider patient life expectancy, quality of life, and cost.

Methods: The authors compared quality-adjusted life years (QALYs) and cost effectiveness among treatment options for HRPC using a Markov model with three treatment arms: (1) external-beam radiotherapy (EBRT) delivered with 20 fractions, (2) EBRT with 23 fractions followed by low-dose-rate (LDR) brachytherapy boost, or (3) radical prostatectomy alone.

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Introduction: Glioblastomas (GBMs) are highly aggressive tumors. A common clinical challenge after standard of care treatment is differentiating tumor progression from treatment-related changes, also known as pseudoprogression (PsP). Usually, PsP resolves or stabilizes without further treatment or a course of steroids, whereas true progression (TP) requires more aggressive management.

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  • HPV-associated oropharyngeal squamous cell carcinoma (HPV[+]OPSCC) needs refined clinical staging to enhance treatment decisions, specifically by analyzing the number of radiographically positive lymph nodes in patients classified as clinical N1 (cN1).
  • A study involving 260 patients who underwent surgical treatment and various radiation therapies found that the count of positive lymph nodes significantly influenced progression-free survival (PFS), with higher counts correlating to worse outcomes.
  • The findings suggest using the number of positive lymph nodes as a meaningful categorization tool for cN1 patients with HPV(+)OPSCC, warranting further research to validate these results.
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