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M W McDermott

Publications and source records attributed to M W McDermott.

At least 19 recordsLinked to original sources
PubMed2006

Perfusion MR imaging of an intracranial collision tumor confirmed by image-guided biopsy.

We present a patient with a new intracranial mass lesion that was initially interpreted as a metastasis on conventional anatomic MR imaging. On dynamic, contrast-enhanced, susceptibility-weighted perfusion MR imaging, however, there were regional hemodynamic differences within the lesion. Image-guided open biopsy targeting these regions uncovered a collision tumor between a typical meningioma and a metastatic breast carcinoma. In cases where conventional anatomic MR imaging is ambiguous, physiology-based neuroimaging methods provide complementary physiologic information useful for discriminating between histologically unique tissue types.

Biopsy↗
PubMed2001

Dose conformity of gamma knife radiosurgery and risk factors for complications.

PURPOSE: To quantitatively evaluate dose conformity achieved using Gamma Knife radiosurgery, compare results with those reported in the literature, and evaluate risk factors for complications. METHODS AND MATERIALS: All lesions treated at our institution with Gamma Knife radiosurgery from May 1993 (when volume criteria were routinely recorded) through December 1998 were reviewed. Lesions were excluded from analysis for reasons listed below. Conformity index (the ratio of prescription volume to target volume) was calculated for all evaluable lesions and for lesions comparable to those reported in the literature on conformity of linac radiosurgery. Univariate Cox regression models were used to test for associations between treatment parameters and toxicity. RESULTS: Of 1612 targets treated in 874 patients, 274 were excluded, most commonly for unavailability of individual prescription volume data because two or more lesions were included within the same dose matrix (176 lesions), intentional partial coverage for staged treatment of large arteriovenous malformations (AVMs) (33 lesions), and missing target volume data (26 lesions). The median conformity indices were 1.67 for all 1338 evaluable lesions and 1.40-1.43 for lesions comparable to two linac radiosurgery series that reported conformity indices of 1.8 and 2.7, respectively. Among all 651 patients evaluable for complications, there were one Grade 5, eight Grade 4, and 27 Grade 3 complications. Increased risk of toxicity was associated with larger target volume, maximum lesion diameter, prescription volume, or volume of nontarget tissue within the prescription volume. CONCLUSIONS: Gamma Knife radiosurgery achieves much more conformal dose distributions than those reported for conventional linac radiosurgery and somewhat more conformal dose distributions than sophisticated linac radiosurgery techniques. Larger target, nontarget, or prescription volumes are associated with increased risk of toxicity.

Brain Neoplasms↗
PubMed2001

Relationship between pattern of enhancement and local control of brain metastases after radiosurgery.

PURPOSE: A desired goal in the radiosurgery (RS) of brain metastases is improved local control. Our earlier retrospective review identified pattern of enhancement on day-of-treatment imaging as a prognostic indicator for freedom from progression (FFP) after RS in 219 brain metastases. The current study was performed to corroborate this preliminary finding. METHODS AND MATERIALS: Records and imaging studies of patients treated with RS from 1991 to 1997 were reviewed. Each metastasis was categorized as homogeneously-, heterogeneously-, or ring-enhancing. Kaplan-Meier FFP was calculated from the date of RS to the first imaging showing tumor progression. Univariate and multivariate analyses were performed using Cox proportional hazard models stratified by primary site and type of RS (alone, as a boost, or for recurrence). RESULTS: Of 682 lesions in 258 patients, 518 lesions in 193 patients were evaluable. Pattern of enhancement was homogeneous in 59%, heterogeneous in 32%, and ring-like in 8% of lesions. One-year FFP probabilities for homogeneously-, heterogeneously-, and ring-enhancing lesions were 90% (95% confidence interval, 84-93%), 76% (64-84%), and 57% (35-74%), respectively. The p-value for pattern of enhancement from the stratified multivariate analysis was 0.019 adjusting for RS dose and treatment period (1991-1994 vs. 1995-1997). Similar results were achieved adjusting for tumor volume instead of RS dose. CONCLUSION: Pattern of enhancement is confirmed as a significant prognostic factor for FFP of brain metastases treated with RS, independent of dose and volume. A possible explanation is radioresistance of hypoxic tumor cells associated with necrotic regions, suggesting future investigations with radiosensitizers, hypoxic cell sensitizers, or strategies to improve tumor oxygenation.

Adolescent↗
PubMed2001

Intraoperative fiber-optic endoscopy for ventricular catheter insertion.

OBJECTIVE: Ventricular catheter placement is a common neurosurgical procedure often resulting in inaccurate intraventricular positioning. We conducted a comparison of the accuracy of endoscopic and conventional ventricular catheter placement in adults. METHODS: A retrospective analysis of data was performed on 37 consecutive patients undergoing ventriculo-peritoneal shunt (VPS) insertion with endoscopy and 40 randomly selected, unmatched patients undergoing VPS insertion without endoscopy, for the treatment of hydrocephalus of varied etiology. A grading system for catheter tip position was developed consisting of five intraventricular zones, V1 -V5, and three intraparenchymal zones, A, B, C. Zones V1 for the frontal approaches and V1 or V2 for the occipital approaches were the optimal catheter tip locations. Postoperative scans of each patient were used to grade the accuracy of ventricular catheter placement. RESULTS: Seventy-six percent of all endoscopic ventricular catheters were in zone V1 and 100% were within zones V1-V3. No endoscopically inserted catheters were observed in zones V4, V5 or intraparenchymally. Thirty-eight percent of the conventionally placed catheters were in zone V1, 53% in zones V1-3 and 15% intraparenchymally. There was a statistically significant difference in the percentage of catheters in optimal location versus in any other location, favoring endoscopic guidance (p<0.001). CONCLUSION: We conclude that endoscopic ventricular catheter placement provides improved positioning accuracy than conventional techniques.

Catheterization↗
PubMed2001

Radiosurgery and radiotherapy for non-small-cell lung cancer metastatic to brain.

Non-small-cell lung cancer metastatic to brain represents a common problem in oncology. Treatment modalities include stereotactic radiosurgery (SRS), whole-brain radiotherapy (WBRT), surgical resection, supportive care, or a combination of these options. This review outlines therapeutic strategies for treatment with particular attention to the use of SRS. Radiosurgical technique, radiobiology, dose prescription, patient selection, and results of therapy are discussed. The term SRS describes a radiation procedure that utilizes a three-dimensional stereotactic localization system to precisely treat small intracranial targets with a single, large, highly focal radiation dose. Stereotactic radiosurgery is appealing for several reasons; it is minimally invasive, easily tolerated, and highly effective, and patients return to normal baseline function within 24 hours. Stereotactic radiosurgery provides much higher control rates of treated lesions than does WBRT. Randomized trials are underway to ascertain the optimal role and timing of SRS in relation to WBRT in order to maximize control, survival, quality of life, and neuropsychological outcome.

Journal Article↗
PubMed2001

Preoperative proton MR spectroscopic imaging of brain tumors: correlation with histopathologic analysis of resection specimens.

BACKGROUND AND PURPOSE: Tumor progression is often difficult to distinguish from nonneoplastic treatment response on the basis of MR images alone. This study correlates metabolite levels measured by preoperative MR spectroscopic (MRS) imaging with histologic findings of biopsies, obtained during image-guided resections of brain mass lesions, to clarify the potential role of MRS in making this distinction. METHODS: Twenty-nine patients with brain tumors underwent high-resolution (0.2-1 cc) 3D proton MRS imaging and MR imaging before undergoing surgery; 11 had a newly diagnosed neoplasm, and 18 had recurrent disease. Surgical biopsies were obtained from locations referenced on MR images by guidance with a surgical navigation system. MR spectral voxels were retrospectively centered on each of 79 biopsy locations, and metabolite levels were correlated with histologic examination of each specimen. RESULTS: All mass lesions studied, whether attributable to tumor or noncancerous effects of previous therapy, showed abnormal MR spectra compared with normal parenchyma. When the pattern of MRS metabolites consisted of abnormally increased choline and decreased N-acetyl aspartate (NAA) resonances, histologic findings of the biopsy specimen invariably was positive for tumor. When choline and NAA resonances were below the normal range, histologic findings were variable, ranging from radiation necrosis, astrogliosis, and macrophage infiltration to mixed tissues that contained some low-, intermediate-, and high-grade tumor. CONCLUSION: This study demonstrated that 3D MRS imaging can identify regions of viable cancer, which may be valuable for guiding surgical biopsies and focal therapy. Regions manifesting abnormal MR spectra had a mixture of histologic findings, including astrogliosis, necrosis, and neoplasm.

Adolescent↗
PubMed2001

Neurosurgical suite of the future. I.

Although the past 10 years have seen a huge influx of technology into the operating room, the environment within which this technology is used has not been greatly modified. The result is a poorly integrated collection of machines and an overcrowded situation in the floor space around the operating room table. Clearly, many areas are open for improvement in the process of surgery, from booking a case to carrying out the operation. Newer operating room designs need to incorporate the flexibility to handle the ever-increasing digital information load that is being generated and that is necessary for the surgical environment to be efficient in time and cost. Room for expansion without major reconstruction should also be incorporated in these designs. In addition, because one operating room design cannot be all things to all specialties, specialized room designs for surgical services would be practical and necessary. The next 10 years will offer the opportunity to make some of these changes, and many groups are working toward making them a reality.

Humans↗
PubMed2000

Endovascular and surgical treatment of unruptured cerebral aneurysms: comparison of risks.

Unruptured cerebral aneurysms are commonly treated by surgical clipping, but endovascular coil embolization is increasingly employed as an alternative. In a blinded review of unruptured aneurysms treated at our institution since 1990, we identified patients whose aneurysms were judged to be treatable by both neurosurgeons and neurointerventional radiologists. A change in Rankin Scale score of 2 or more from hospital admission to discharge, indicating a new moderate disability or worse, was predefined as the primary outcome measure. Long-term follow-up was obtained by mailed questionnaire and telephone interview. Length of stay and hospital charges were totaled for all hospitalizations, including follow-up. Sixty-eight patients treated surgically and 62 patients treated with endovascular coil embolization were considered candidates for either procedure on blinded review, and overall anticipated procedure risk was rated as identical. A larger proportion of patients in the surgical group developed a change in Rankin Scale score of 2 or more (25% of surgical patients vs 8% of endovascular patients). Total length of stay was longer (mean days: 7.7 for surgical patients vs 5.0 for endovascular patients) and hospital charges were greater (mean, $38,000 for surgical patients vs $33,400 for endovascular patients) for the surgical patients. At follow-up, an average of 3.9 years after the procedure, surgical patients were more likely to report persistent new symptoms or disability since treatment (34% of surgical patients vs 8% of endovascular patients) and a longer period for recovery to normal (50% returning to normal in 1 year for surgery and in 27 days for coil embolization). Coil embolization of unruptured cerebral aneurysms seems to be associated with significantly fewer complications than surgical clipping. More long-term data on aneurysm rupture rates are required to confirm efficacy.

Adult↗
PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗
PubMed1999

A multi-institutional analysis of complication outcomes after arteriovenous malformation radiosurgery.

PURPOSE: To better understand radiation complications of arteriovenous malformation (AVM) radiosurgery and factors affecting their resolution. METHODS AND MATERIALS: AVM patients (102/1255) who developed neurological sequelae after radiosurgery were studied. The median AVM marginal dose (Dmin) was 19 Gy (range: 10-35). The median volume was 5.7 cc (range: 0.26-143). Median follow-up was 34 months (range: 9-140). RESULTS: Complications consisted of 80/102 patients with evidence of radiation injury to the brain parenchyma (7 also with cranial nerve deficits, 12 also with seizures, 5 with cyst formation), 12/102 patients with isolated cranial neuropathies, and 10/102 patients with only new or worsened seizures. Severity was classified as minimal in 39 patients, mild in 40, disabling in 21, and fatal in 2 patients. Symptoms resolved completely in 42 patients for an actuarial resolution rate of 54% +/- 7% at 3 years post-onset. Multivariate analysis identified significantly greater symptom resolution in patients with no prior history of hemorrhage (p = 0.01, 66% vs. 41%), and in patients with symptoms of minimal severity: headache or seizure as the only sequelae of radiosurgery (p < 0.0001, 88% vs. 34%). CONCLUSION: Late sequelae of radiosurgery manifest in varied ways. Further long-term studies of these problems are needed that take into account symptom severity and prior hemorrhage history.

Adrenal Cortex Hormones↗
PubMed1999

Radiosurgery for brain metastases: is whole brain radiotherapy necessary?

PURPOSE: Because whole brain radiotherapy (WBRT) may cause dementia in long-term survivors, selected patients with brain metastases may benefit from initial treatment with radiosurgery (RS) alone reserving WBRT for salvage as needed. We reviewed results of RS +/- WBRT in patients with newly diagnosed brain metastasis to provide background for a prospective trial. METHODS AND MATERIALS: Patients with single or multiple brain metastases managed initially with RS alone vs. RS + WBRT (62 vs. 43 patients) from 1991 through February 1997 were retrospectively reviewed. The use of upfront WBRT depended on physician preference and referral patterns. Survival, freedom from progression (FFP) endpoints, and brain control allowing for successful salvage therapy were measured from the date of diagnosis of brain metastases. Actuarial curves were estimated using the Kaplan-Meier method. Analyses to adjust for known prognostic factors were performed using the Cox proportional hazards model (CPHM) stratified by primary site. RESULTS: Survival and local FFP were the same for RS alone vs. RS + WBRT (median survival 11.3 vs. 11.1 months and 1-year local FFP by patient 71% vs. 79%, respectively). Brain FFP (scoring new metastases and/or local failure) was significantly worse for RS alone vs. RS + WBRT (28% vs. 69% at 1 year; CPHM adjustedp = 0.03 and hazard ratio = 0.476). However, brain control allowing for successful salvage of a first failure was not significantly different for RS alone vs. RS + WBRT (62% vs. 73% at 1 year; CPHM adjusted p = 0.56). CONCLUSIONS: The omission of WBRT in the initial management of patients treated with RS for up to 4 brain metastases does not appear to compromise survival or intracranial control allowing for salvage therapy as indicated. A randomized trial of RS vs. RS + WBRT is needed to assess survival, quality of life, and cost in good-prognosis patients with newly diagnosed brain metastases.

Adult↗
PubMed1999

Mucocele involving the anterior clinoid process: MR and CT findings.

We report two patients with surgically proved mucoceles involving the anterior clinoid process. One patient had a mucocele of an Onodi cell and the other had a mucocele isolated to the anterior clinoid process. The MR signal was increased on both T1- and T2-weighted images in the first patient but was isointense on both sequences in the second patient, a finding that resulted in misdiagnosis. The developmental and anatomic features, as well as the diagnostic pitfalls, are discussed.

Adult↗
PubMed1998

Survival benefit of hyperthermia in a prospective randomized trial of brachytherapy boost +/- hyperthermia for glioblastoma multiforme.

PURPOSE: To determine if adjuvant interstitial hyperthermia (HT) significantly improves survival of patients with glioblastoma undergoing brachytherapy boost after conventional radiotherapy. METHODS AND MATERIALS: Adults with newly-diagnosed, focal, supratentorial glioblastoma < or = 5 cm in diameter were registered postoperatively on a Phase II/III randomized trial and treated with partial brain radiotherapy to 59.4 Gy with oral hydroxyurea. Those patients whose tumor was still implantable after teletherapy were randomized to brachytherapy boost (60 Gy at 0.40-0.60 Gy/h) +/- HT for 30 min immediately before and after brachytherapy. Time to progression (TTP) and survival from date of diagnosis were estimated using the Kaplan-Meier method. RESULTS: From 1990 to 1995, 112 eligible patients were entered in the trial. Patient ages ranged from 21-78 years (median, 54 years) and KPS ranged from 70-100 (median, 90). Most commonly due to tumor progression or patient refusal, 33 patients were never randomized. Of the patients, 39 were randomized to brachytherapy ("no heat") and 40 to brachytherapy + HT ("heat"). By intent to treat, TTP and survival were significantly longer for "heat" than "no heat" (p = 0.04 and p = 0.04). For the 33 "no heat" patients and 35 "heat" patients who underwent brachytherapy boost, TTP and survival were significantly longer for "heat" than "no heat" (p = 0.045 and p = 0.02, respectively; median survival 85 weeks vs. 76 weeks; 2-year survival 31% vs. 15%). A multivariate analysis for these 68 patients adjusting for age and KPS showed that improved survival was significantly associated with randomization to "heat" (p = 0.008; hazard ratio 0.51). There were no Grade 5 toxicities, 2 Grade 4 toxicities (1 on each arm), and 7 Grade 3 toxicities (1 on "no heat" and 6 on the "heat" arm). CONCLUSION: Adjuvant interstitial brain HT, given before and after brachytherapy boost, after conventional radiotherapy significantly improves survival of patients with focal glioblastoma, with acceptable toxicity.

Adult↗
PubMed1998

Radiation therapy and hydroxyurea followed by the combination of 6-thioguanine and BCNU for the treatment of primary malignant brain tumors.

PURPOSE: This study was designed to evaluate a combined modality treatment for malignant gliomas using radiation therapy with a radiosensitizer and an adjuvant chemotherapy regimen designed to modify resistance to BNCU. METHODS AND MATERIALS: Patients were eligible if they were 15 years of age or older, and had newly diagnosed glioblastoma multiforme (GBM), or anaplastic glioma (AG). Treatment consisted of external beam radiotherapy given to a dose of 60 Gy using a single daily fraction Monday to Friday. Concurrent hydroxyurea at a dose of 300 mg/m2 every 6 h every other day was given during radiation. Following radiotherapy, patients were then treated with BCNU and 6-Thioguanine (6TG). The 6-TG was given by mouth every 6 h for 12 doses prior to BCNU. Patients were initially treated with 60 mg/m2/dose of 6TG, with escalation to a maximum dose of 100 mg/m2/dose. The primary study end points were time to tumor progression and survival. RESULTS: A total of 245 eligible patients were enrolled from 1/18/88 to 12/26/91. The histologic subtypes included 135 GBM, and 110 with AG (103 with anaplastic astrocytoma, 7 with high-grade mixed oligoastrocytoma). For the GBM group, the median time to tumor progression (TTP) and median survival were 33 (95% CI 26, 39) and 56 (95% CI 49, 69) weeks, respectively. For the AG group the median TTP was 282 weeks (95% lower confidence bound = 155 weeks). Median survival for this group has not been reached (95% lower confidence bound = 284 weeks) with a median follow-up for surviving patients of 298 weeks. A proportional hazards model was used to look at potential prognostic factors for survival, including initial Karnofsky Performance Scale (KPS), age, and extent of surgery, as well as dose of 6TG. Higher KPS, and lower age, predicted for longer survival (p < 0.01, < 0.001) in GBM patients; lower age was significant (p = 0.05) for AG cases. A higher (greater than 95 mg/m2) or lower dose of 6TG was not statistically significant in this model. CONCLUSIONS: This therapy was no more effective in patients with GBM than other reported series. In patients with malignant gliomas other than GBM, prolonged progression-free and overall survival is noted, without a median survival reached at the time of this report. In this subset of AG patients, survival is comparable to recent studies using halogenated prymidines during radiation and Procarbazine, CCNU, and Vincristine (PCV) as adjuvant chemotherapy.

Adolescent↗
PubMed1998

Survival and functional status after resection of recurrent glioblastoma multiforme.

OBJECTIVE: To determine the selection factors for and results of second resections performed to treat recurrent glioblastoma multiforme (GM), we studied 301 patients with GM who were treated from the time of diagnosis using two prospective clinical protocols. METHODS: The patients were prospectively followed from the time of diagnosis, using clinical and radiographic criteria after maximal surgical resection and external beam radiotherapy with or without adjuvant chemotherapy. Resection of recurrent GM was performed at the recommendation of the treating clinicians. The results of the second resections were retrospectively reviewed and analyzed using multivariate logistic regression, Kaplan-Meier-Turnbull survival analysis, Cox regression, and propensity score stratification. RESULTS: Forty-six patients underwent second resections during the study period. The actuarial rate of the second resections was 15% of the patients 1 year after diagnosis and 31% 2 years after diagnosis. Younger age (P = 0.01) and more extensive initial resection (P = 0.02), but not Karnofsky Performance Scale (KPS) score at the time of diagnosis or recurrence, predicted a higher chance of selection for reoperation after initial tumor recurrence. Twenty-eight percent of the patients had improved KPS scores after undergoing reoperation, 49% were stable, and 23% had declines in KPS scores of 10 to 30 points. There was no operative mortality. After reoperation, 85% of the patients received chemotherapy, 11% received brachytherapy or underwent stereotactic radiosurgery, and 17% underwent third resections. The median survival period after reoperation was 36 weeks. Higher preoperative KPS scores predicted longer survival periods after reoperation (P = 0.03). Age and interval since diagnosis were not significant prognostic factors. The median high-quality survival period (KPS score, > or =70) was 18 weeks. The median survival period after first tumor progression was 23 weeks for 130 patients treated using the same protocols who did not undergo reoperations. Patients who did undergo reoperations experienced clinically and statistically significantly longer survival periods. However, this was determined to be partially because of selection bias. CONCLUSION: Survival after resection of recurrent GM remains poor despite advances in imaging, operative technique, and adjuvant therapies. High-quality survival after resection of recurrence to treat GM seems to have increased significantly since an earlier report from our institution.

Adolescent↗
PubMed1997

Age and the risk of anaplasia in magnetic resonance-nonenhancing supratentorial cerebral tumors.

BACKGROUND: It is often assumed that a cerebral lesion that is nonenhancing on a magnetic resonance imaging study with gadolinium contrast is a low grade tumor. Some physicians recommend observation rather than biopsy for such lesions. METHODS: The authors prospectively evaluated the incidence of anaplastic tumor histology in a consecutive series of patients who presented to a neuro-oncology service with a nonenhancing mass of the cerebral hemisphere. RESULTS: During a 5-month period, the authors evaluated 31 patients who had a nonenhancing lesion in the cerebral hemisphere on initial magnetic resonance images. Thirty patients underwent stereotactic biopsy (27%) or open resection (73%). The median patient age was 36 years (range, 6-63 years). There was no mortality or permanent neurologic morbidity from surgery. Twenty-eight patients had pathologic confirmation of diagnosis while their lesions were still nonenhancing. Of these patients, 9 (32%) had Grade 3 lesions (anaplastic astrocytoma or oligoastrocytoma), 13 (43%) had Grade 2 lesions (astrocytoma, oligodendroglioma, or oligoastrocytoma), and 2 (7%) had Grade 1 lesions (dysembryoplastic neuroepithelial tumors). Two additional patients (ages 33 and 59 years) who developed enhancement within their lesions during preoperative periods of observation had glioblastomas at surgery. Logistic regression was used to relate patient age to the risk of anaplasia in a nonenhancing cerebral mass lesion. Older age predicted a significantly higher risk of anaplasia (P = 0.025). The model predicted that nonenhancing cerebral masses in patients older than 44 years were more likely to be anaplastic tumors than low grade tumors. There was no "safe" age below which low grade histology could be confidently assumed. CONCLUSIONS: Magnetic resonance-nonenhancing cerebral lesions may be histologically anaplastic, even in young patients. The risk of anaplasia in magnetic resonance-nonenhancing lesions increases significantly with patient age.

Adolescent↗