Kristin J Redmond

Johns Hopkins Medicine, Baltimore, Maryland, United States

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Publications (21)48.78 Total impact

  • Carmen Kut, Kristin Janson Redmond
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    ABSTRACT: The purpose of this critical review is to explore the controversy regarding the relationship between radiation dose to the neural progenitor cell (NPC) niches and patient outcomes, in terms of both toxicity and tumor control. NPCs in the subventricular zone (SVZ) and hippocampus are paradoxically associated with long-term neurocognitive sequelae of brain irradiation, as well as resistance to therapy and tumor recurrence. The reconciliation of these somewhat opposing functions is challenging. Current literature suggests that radiation and other treatments against the NPC in the hippocampus and the SVZ may influence patient outcome. As a result, both the SVZ and the hippocampus could have important implications on radiation treatment planning strategies, and future laboratory and clinical evaluations will be critical in designing studies to optimize treatment outcome, effectiveness, and safety.
    Seminars in radiation oncology 10/2014; 24(4):265-272. · 4.32 Impact Factor
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    ABSTRACT: A familiar challenge for neuroradiologists and neuro-oncologists is differentiating between radiation treatment effect and disease progression in the CNS. Both entities are characterized by an increase in contrast enhancement on MRI and present with similar clinical signs and symptoms that may occur either in close temporal proximity to the treatment or later in the disease course. When radiation-related imaging changes or clinical deterioration are mistaken for disease progression, patients may be subject to unnecessary surgery and/or a change from otherwise effective therapy. Similarly, when disease progression is mistaken for treatment effect, a potentially ineffective therapy may be continued in the face of progressive disease. Here we describe the three types of radiation injury to the brain based on the time to development of signs and symptoms - acute, subacute and late - and then review specific imaging changes after intensity-modulated radiation therapy, stereotactic radiosurgery and brachytherapy. We provide an overview of these phenomena in the treatment of a wide range of malignant and benign CNS illnesses. Finally, we review the published data regarding imaging techniques under investigation to address this well-known problem.
    Future oncology (London, England). 05/2014; 10(7):1277-97.
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    ABSTRACT: Invasive pituitary adenomas and pituitary carcinomas are clinically indistinguishable until identification of metastases. Optimal management and survival outcomes for both are not clearly defined. The purpose of this study is to use the Surveillance, Epidemiology, and End Results (SEER) database to report patterns of care and compare survival outcomes in a large series of patients with invasive adenomas or pituitary carcinomas. One hundred seventeen patients diagnosed between 1973 and 2008 with pituitary adenomas/adenocarcinomas were included. Eighty-three invasive adenomas and seven pituitary carcinomas were analyzed for survival outcomes. Analyzed prognostic factors included age, sex, race, histology, tumor extent, and treatment. A significant decrease in survival was observed among carcinomas compared to invasive adenomas at 1, 2, and 5 years (p = 0.047, 0.001, and 0.009). Only non-white race, male gender, and age ≥65 were significant negative prognostic factors for invasive adenomas (p = 0.013, 0.033, and <0.001, respectively). There was no survival advantage to radiation therapy in treating adenomas at 5, 10, 20, or 30 years (p = 0.778, 0.960, 0.236, and 0.971). In conclusion, pituitary carcinoma patients exhibit worse overall survival than invasive adenoma patients. This highlights the need for improved diagnostic methods for the sellar phase to allow for potentially more aggressive treatment approaches.
    Neurosurgical Review 02/2014; · 1.97 Impact Factor
  • Kristin J Redmond, E Mark Mahone, Alena Horska
    Neuro-Oncology 11/2013; 15(11):1455. · 6.18 Impact Factor
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    ABSTRACT: PURPOSE: Neural progenitor cells in the subventricular zone (SVZ) have a controversial role in glioblastoma multiforme (GBM) as potential tumor-initiating cells. The purpose of this study was to examine the relationship between radiation dose to the SVZ and survival in GBM patients. METHODS AND MATERIALS: The study included 116 patients with primary GBM treated at the Johns Hopkins Hospital between 2006 and 2009. All patients underwent surgical resection followed by adjuvant radiation therapy with intensity modulated radiation therapy (60 Gy/30 fractions) and concomitant temozolomide. Ipsilateral, contralateral, and bilateral SVZs were contoured on treatment plans by use of coregistered magnetic resonance imaging and computed tomography. Multivariate Cox regression was used to examine the relationship between mean SVZ dose and progression-free survival (PFS), as well as overall survival (OS). Age, Karnofsky Performance Status score, and extent of resection were used as covariates. The median age was 58 years (range, 29-80 years). RESULTS: Of the patients, 12% underwent biopsy, 53% had subtotal resection (STR), and 35% had gross total resection (GTR). The Karnofsky Performance Status score was less than 90 in 54 patients and was 90 or greater in 62 patients. The median ipsilateral, contralateral, and bilateral mean SVZ doses were 48.7 Gy, 34.4 Gy, and 41.5 Gy, respectively. Among patients who underwent GTR, a mean ipsilateral SVZ dose of 40 Gy or greater was associated with a significantly improved PFS compared with patients who received less than 40 Gy (15.1 months vs 10.3 months; P=.028; hazard ratio, 0.385 [95% confidence interval, 0.165-0.901]) but not in patients undergoing STR or biopsy. The subgroup of GTR patients who received an ipsilateral dose of 40 Gy or greater also had a significantly improved OS (17.5 months vs 15.6 months; P=.027; hazard ratio, 0.385 [95% confidence interval, 0.165-0.895]). No association was found between SVZ radiation dose and PFS and OS among patients who underwent STR or biopsy. CONCLUSION: A mean radiation dose of 40 Gy or greater to the ipsilateral SVZ was associated with a significantly improved PFS and OS in patients with GBM after GTR.
    International journal of radiation oncology, biology, physics 03/2013; · 4.59 Impact Factor
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    ABSTRACT: Background Neurocognitive toxicity from radiation therapy (RT) for brain tumors may be related to damage to neural progenitor cells that reside in the subventricular zone and hippocampus. This prospective study examines the relationship between RT dose to neural progenitor cell niches, temporal lobes, and cerebrum and neurocognitive dysfunction following cranial irradiation.Methods Standardized assessments of motor speed/dexterity, verbal memory, visual perception, vocabulary, and visuospatial working memory were conducted in 19 pediatric patients receiving cranial RT and 55 controls at baseline and 6, 15, and 27 months following completion of RT. Prescription doses ranged from 12 Gy to 59.4 Gy. Linear mixed effects regression model analyses were used to examine the relationships among neuropsychological performance, age, and radiation dose to the subventricular zone, hippocampus, temporal lobes, and cerebrum.ResultsPerformance on all neuropsychological tests, except vocabulary, was significantly reduced in patients relative to controls, particularly among younger children. Performance on motor speed/dexterity decreased with increasing dose to hippocampus (P < .05) and temporal lobes (P < .035). There was also a significant relationship between (i) reduced performance on verbal learning and increasing dose to the cerebrum (P = .022) and (ii) reduced performance on visual perception and increasing dose to the left temporal lobe (P = .038). There was no association between radiation dose to evaluated structures and performance on vocabulary or visuospatial working memory.Conclusions These prospective data demonstrate a significant association between increasing RT dose to hippocampus and temporal lobes and decline in neurocognitive skills following cranial irradiation. These findings have important implications for trials, including RTOG 0933 (hippocampal-sparing whole brain radiation therapy for brain metastases).
    Neuro-Oncology 01/2013; · 6.18 Impact Factor
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    ABSTRACT: Cancers, such as melanoma, that are associated with immune deficiencies are a major cause of morbidity and mortality in HIV-infected patients. Once patients develop melanoma metastases to the brain, treatment is often limited to palliative surgery and/or radiation. Ipilimumab, a CTLA-4 antagonist, has been shown to improve the median survival of patients with metastatic melanoma. However, available data regarding the safety and efficacy of ipilimumab in HIV-infected patients who develop intracranial melanoma metastases is limited. Here we report our experience administering ipilimumab to a patient with HIV-AIDS who developed multiple intracranial melanoma metastases. Following treatment, our patient showed improvement in systemic tumor control without any apparent interference with antiretroviral treatment.
    Case reports in oncological medicine. 01/2013; 2013:946392.
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    ABSTRACT: PURPOSE/AIM 1.To review imaging changes following radiation therapy for primary and secondary CNS malignancies. 2. Discuss limitations of standard MRI in distinguishing between treatment effect and disease progression. 3. Discuss how functional imaging can help understand therapeutic response. CONTENT ORGANIZATION Review imaging changes, including pseudoprogression and radionecrosis, following radiation therapy for CNS malignancies. Review imaging changes following radiosurgery. Compare radiation induced changes with imaging findings in true disease progression. Include case examples with pathology. Discuss emerging data regarding alternative MRI sequences and their potential future role in helping to distinguish radiation induced changes and disease progression. Diffusion MRI MRI spectroscopy Perfusion MRI Quiz: Three cases will be presented. The corresponding images will be displayed and discussed in regards to appropriate next steps in management. SUMMARY Differentiating radiation induced changes from disease progression is an ongoing challenge in neuro-oncology. Methods to non-invasively differentiate the two are critical to providing appropriate management and and are an important area of ongoing investigation.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
  • Fuel and Energy Abstracts 10/2011; 81(2).
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    ABSTRACT: During the past two decades, radiosurgery has arisen as a promising approach to the management of glomus jugulare. In the present study, we report on a systematic review and meta-analysis of the available published data on the radiosurgical management of glomus jugulare tumors. To identify eligible studies, systematic searches of all glomus jugulare tumors treated with radiosurgery were conducted in major scientific publication databases. The data search yielded 19 studies, which were included in the meta-analysis. The data from 335 glomus jugulare patients were extracted. The fixed effects pooled proportions were calculated from the data when Cochrane's statistic was statistically insignificant and the inconsistency among studies was <25%. Bias was assessed using the Egger funnel plot test. Across all studies, 97% of patients achieved tumor control, and 95% of patients achieved clinical control. Eight studies reported a mean or median follow-up time of >36 months. In these studies, 95% of patients achieved clinical control and 96% achieved tumor control. The gamma knife, linear accelerator, and CyberKnife technologies all exhibited high rates of tumor and clinical control. The present study reports the results of a meta-analysis for the radiosurgical management of glomus jugulare. Because of its high effectiveness, we suggest considering radiosurgery for the primary management of glomus jugulare tumors.
    International journal of radiation oncology, biology, physics 06/2011; 81(4):e497-502. · 4.59 Impact Factor
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    ABSTRACT: Radiation therapy (RT) for brain tumors is associated with neurocognitive toxicity which may be a result of damage to neural progenitor cells (NPCs). We present a novel technique to limit the radiation dose to NPC without compromising tumor coverage. A study was performed in mice to examine the rationale and another was conducted in humans to determine its feasibility. C57BL/6 mice received localized radiation using a dedicated animal irradiation system with on-board CT imaging with either: (1) Radiation which spared NPC containing regions; (2) Radiation which did not spare these niches; or (3) Sham irradiation. Mice were sacrificed 24 h later and the brains were processed for immunohistochemical Ki-67 staining. For the human component of the study, 33 patients with primary brain tumors were evaluated. Two intensity modulated radiotherapy (IMRT) plans were retrospectively compared: a standard clinical plan and a plan which spares NPC regions while maintaining the same dose coverage of the tumor. The change in radiation dose to the contralateral NPC-containing regions was recorded. In the mouse model, non-NPC-sparing radiation treatment resulted in a significant decrease in the number of Ki67(+) cells in dentate gyrus (DG) (P = 0.008) and subventricular zone (SVZ) (P = 0.005) compared to NPC-sparing radiation treatment. In NPC-sparing clinical plans, NPC regions received significantly lower radiation dose with no clinically relevant changes in tumor coverage. This novel radiation technique should significantly reduce radiation doses to NPC containing regions of the brain which may reduce neurocognitive deficits following RT for brain tumors.
    Journal of Neuro-Oncology 02/2011; 104(2):579-87. · 3.12 Impact Factor
  • Fuel and Energy Abstracts 01/2011; 81(2).
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    ABSTRACT: This study was designed to examine the effect of adjuvant 5-FU-based chemoradiation therapy (CRT) after distal pancreatectomy for adenocarcinoma of the distal pancreas. All patients underwent curative resection for adenocarcinoma of the distal pancreas between December 1985 and June 2006. Patients who received adjuvant CRT were compared with those who underwent surgery alone. A Kaplan-Meier estimate of the survival curve was used to determine estimates of the median survival and proportion alive at 1 and 2 years; log-rank tests were used to make comparisons between groups. A total of 123 patients underwent distal pancreatectomy; 29 patients were excluded for distant metastases at the time of surgery (n = 12, 10%) or before adjuvant therapy (n = 11, 9%), death within 2 months of surgery (n = 2, 2%), or if CRT treatment status was unknown (n = 4, 3%). Of the remaining 94 patients, 72% received adjuvant 5-FU-based CRT and 28% underwent surgery alone. Overall median survival was 16.2 (95% confidence interval (CI), 13.1-18.9) months. The groups were similar with respect to tumor size, nodal status, and margin status. There was no significant difference in overall survival between patients treated with adjuvant CRT versus surgery alone (p = 0.23). An exploratory subgroup analysis suggested a potential survival benefit of adjuvant CRT in patients with lymph node metastases (16.7 vs. 12.1 months, p < 0.01). Adjuvant CRT did not increase survival compared with surgery alone; however, patients with node-positive disease appear to benefit from adjuvant CRT.
    Annals of Surgical Oncology 12/2010; 17(12):3112-9. · 4.12 Impact Factor
  • Fuel and Energy Abstracts 11/2010; 78(3).
  • Fuel and Energy Abstracts 01/2010; 78(3).
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    ABSTRACT: To determine whether lung tumor respiratory excursion at simulation is predictive of excursion during radiation and whether phase offsets between tumor and surrogate markers are constant throughout treatment. Respiration-correlated CT scans and two rescans (using a Brilliance Big Bore spiral CT simulator; Philips, Inc.) were obtained from 20 patients at simulation. Gross tumor volume (GTV) was contoured on 10 phases of the respiratory cycle, and excursions were calculated. Diaphragm and xyphoid motion were quantified. Phase offsets, DeltaPhi, were calculated for patients with a GTV motion of >3 mm. Interfraction differences in excursions between simulation and rescans and magnitudes of variation in phase offset between fractions were evaluated. Mean GTV excursions at simulation in superior-inferior, anterior-posterior, and medial-lateral directions were 0.67, 0.29, and 0.21 cm, respectively. The magnitude of superior-inferior GTV excursion correlated with tumor location (upper vs. lower lobe, p = 0.011). GTV excursions between simulation and rescan 1 (p = 0.115) and between simulation and rescan 2 (p = 0.071) were stable. Fourteen patients were analyzed for variations in phase offsets. GTV-xyphoid phase offset changed significantly between simulation and rescan 1 (p = 0.007) and simulation and rescan 2 (p = 0.008), with mean DeltaPhi values of 13.2% (rescan 1) and 14.3% (rescan 2). Xyphoid-diaphragm offset changed between simulation and rescan 1 (p = 0.004) and between simulation and rescan 2 (p = 0.012), with mean DeltaPhi values of 14.5% (rescan 1) and 7.6% (rescan 2). Interfraction consistency in tumor excursion suggests tumor excursion at simulation may direct therapy. Significant variations in phase lag between GTV and other anatomic structures throughout treatment have important implications for techniques that rely on surrogate structures to predict tumor motion.
    International journal of radiation oncology, biology, physics 12/2009; 75(5):1605-12. · 4.59 Impact Factor
  • Kristin J Redmond, Danny Y Song
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    ABSTRACT: This article has reviewed radiation treatment of thoracic malignancies in elderly patients. In general the literature suggests that thoracic irradiation is equally efficacious in elderly patients as in younger patients and is associated with increased but acceptable toxicity. Technical advances are allowing a further reduction in morbidity with preliminary results suggestive of stable outcomes. Prospective data from elderly specific trials are needed to determine the optimal treatment of lung cancer and to compare innovative radiation technology with standard therapies.
    Thoracic Surgery Clinics 08/2009; 19(3):391-400.
  • Fuel and Energy Abstracts 01/2009; 75(3).
  • Fuel and Energy Abstracts 01/2009; 75(3).
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    ABSTRACT: Dose escalation for lung cancer is limited by normal tissue toxicity. We evaluated sequential computed tomography (CT) scans to assess the possibility of adaptively reducing treatment volumes by quantifying the tumor volume reduction occurring during a course of radiotherapy (RT). A total of 22 patients underwent RT for Stage I-III non-small-cell lung cancer with conventional fractionation; 15 received concurrent chemotherapy. Two repeat CT scans were performed at a nominal dose of 30 Gy and 50 Gy. Respiration-correlated four-dimensional CT scans were used for evaluation of respiratory effects in 17 patients. The gross tumor volume (GTV) was delineated on simulation and all individual phases of the repeat CT scans. Parenchymal tumor was evaluated unless the nodal volume was larger or was the primary. Subsequent image sets were spatially co-registered with the simulation data for evaluation. The median GTV reduction was 24.7% (range, -0.3% to 61.7%; p < 0.001, two-tailed t test) at the first repeat scan and 44.3% (range, 0.2-81.6%, p < 0.001) at the second repeat scan. The volume reduction was not significantly different between patients receiving chemoradiotherapy vs. RT alone, a GTV >100 cm(3) vs. <100 cm(3), and hilar and/or mediastinal involvement vs. purely parenchymal or pleural lesions. A tendency toward a greater volume reduction with increasing dose was seen, although this did not reach statistical significance. The results of this study have demonstrated significant alterations in the GTV seen on repeat CT scans during RT. These observations raise the possibility of using an adaptive approach toward RT of non-small-cell lung cancer to minimize the dose to normal structures and more safely increase the dose directed at the target tissues.
    International journal of radiation oncology, biology, physics 12/2008; 74(2):341-8. · 4.59 Impact Factor

Publication Stats

96 Citations
48.78 Total Impact Points


  • 2014
    • Johns Hopkins Medicine
      • Department of Neurosurgery
      Baltimore, Maryland, United States
  • 2009–2013
    • Johns Hopkins University
      • • Department of Neurosurgery
      • • Department of Radiation Oncology and Molecular Radiation Sciences
      Baltimore, MD, United States