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E Chow

Publications and source records attributed to E Chow.

At least 19 recordsLinked to original sources
PubMed2006

Whole brain radiotherapy for the treatment of multiple brain metastases.

BACKGROUND: Brain radiotherapy is used to treat cancer patients who have brain metastases resulting from various primary malignancies. OBJECTIVES: To assess the effectiveness and adverse effects of whole brain radiotherapy (WBRT) in adult patients with multiple metastases to the brain. SEARCH STRATEGY: CENTRAL (The Cochrane Library), MEDLINE, EMBASE, CANCERLIT, and CINAHL were searched. SELECTION CRITERIA: Randomized controlled trials (RCTs) in which adult patients with multiple metastases to the brain from any primary cancer and treated with WBRT were included. Trials of prophylactic WBRT were excluded as well as trials that dealt with surgery or WBRT, or both, for the treatment of a single brain metastasis. DATA COLLECTION AND ANALYSIS: Two review authors independently abstracted information for each predetermined outcome: overall survival at six months, intracranial progression-free duration, local brain response, local brain control, quality of life, symptom control, neurological function, and the proportion of patients able to reduce the daily dexamethasone dose. Adverse effects were also collected. MAIN RESULTS: Eight published reports (nine trials) showed no benefit of altered dose-fractionation schedules as compared to control fractionation (3000 cGy in 10 fractions) of WBRT on the probability of survival at six months. These studies also showed no difference in symptom control nor neurologic improvement among the different dose-fractionation schemes. The addition of radiosensitizers, in five RCTs, did not confer additional benefit to WBRT in either overall median survival times or brain tumor response rates. The addition of the radiosensitizer motexafin gadolinium did not improve quality of life nor time to neurologic progression overall. For the radiosensitizer misonidazole, there was no improvement in Karnofsky performance score outcomes. Three RCTs found no benefit in overall survival with the use of WBRT and a radiosurgery boost as compared to WBRT alone for selected patients with multiple brain metastases (up to four brain metastases). Overall, however, there was a statistically significant improvement in local brain control favoring the whole brain radiotherapy and radiosurgery boost arm. Only one trial of radiosurgery boost with WBRT reported an improved Karnofsky performance score outcome and improved ability to reduce dexamethasone dose. One RCT examined the use of WBRT and prednisone versus prednisone alone and produced inconclusive results. AUTHORS' CONCLUSIONS: None of the RCTs with altered dose-fractionation schemes as compared to standard delivery (3000 cGy in ten fractions) found a benefit in terms of overall survival, neurologic function, or symptom control. The use of radiosensitizers or chemotherapy in conjunction with WBRT remains experimental. A radiosurgery boost with WBRT may improve local disease control in selected patients, although survival remains unchanged. The benefit of WBRT as compared to supportive care alone has not been studied in RCTs. It may be that supportive care alone, without WBRT, may be appropriate for some patients, particularly those with advanced disease and poor performance status.

Adult↗
PubMed2006

An updated mutation spectrum in an Australian series of PJS patients provides further evidence for only one gene locus.

The genetic predisposition Peutz-Jeghers Syndrome (PJS) has been shown to be associated with mutations in the serine threonine kinase 11 (STK11) gene but only a proportion of probands have been shown to harbour changes in the gene. The remaining patients were proposed to be either associated with a second PJS gene or they harboured more cryptic mutations within the STK11 gene itself. With the introduction of the multiplex ligation probe amplification (MLPA) assay, large sequence losses or gains can be more readily identified. In this report we have screened 33 PJS patients from unrelated families, employing a combination of denaturing high-performance liquid chromatography, direct DNA sequencing and the MLPA assay to identify deleterious changes in the STK11 gene. The results revealed that 24 (73%) of patients diagnosed with PJS-harboured pathogenic mutations in the STK11 gene, including 10 (36%) with exonic or whole-gene deletions. No phenotypic differences were identified in patients harbouring large deletions in the STK11 gene compared to patients harbouring missense or nonsense mutations. Mutation analysis in PJS should include techniques such as MLPA to identify large exonic or whole-gene deletions and rearrangements. The high proportion of families with identifiable mutations in the STK11 gene using this range of techniques suggests that most, if not all PJS, is attributable to mutations in the STK11 gene, perhaps including as yet undiscovered changes in promoter or enhancer sequences or other cryptic changes.

AMP-Activated Protein Kinase Kinases↗
PubMed2005

An innovative rapid response radiotherapy program to reduce waiting time for palliative radiotherapy.

BACKGROUND: Waiting for radiation therapy (RT) in Ontario has been a major problem for the past decade. In 1996, the Toronto-Sunnybrook Regional Cancer Centre (TSRCC) initiated a Rapid Response Radiotherapy Program (RRRP) to provide timely palliative RT for symptom relief of patients with terminal cancer. PURPOSE: This study reviews the clinical activity of the RRRP over the past 8 years to evaluate if we are meeting the objectives of the program. MATERIALS AND METHODS: From the TSRCC oncology patient information system (OPIS) database, we retrieved the number of patients referred to the RRRP, their demographics, diagnosis and treatment for the calendar years 1996 to 2003 inclusive. We calculated the time interval between referral to consultation, consultation to simulation and the percentage of cases who started RT on their initial consultation for all new cases referred to the RRRP. RESULTS: From 1996 to 2003, the number of cases seen in consultation increased from just over 200 cases annually in the first 2 years to about 500 cases per year in the last 4 years, for a total of 3,290. There were 1,792 (54%) men and 1,498 (46%) women; median age was 69 years (range, 21-95 years). Breast, lung, genitourinary and gastrointestinal primaries accounted for over 80% of all referrals. The majority was referred for palliative treatment of symptomatic bone (70%) or brain (14%) metastases. The dose fractionation for bone metastases was a single 8-Gy fraction in 45%, 20 Gy in five fractions in 42%, 30 Gy in ten fractions in 4% and other dose fractionations in 9%. Nearly 90% were seen within 2 weeks of referral (38% within 1 week). Eighty-five percent were simulated on the day of their initial consultation. Sixty percent started their RT treatment on the day of their consultation visit. The overall median interval from referral to treatment was 8 days. CONCLUSION: Over the past 8 years, the annual number of new cases referred to the RRRP has doubled. The overall median interval from referral to consultation was 8 days. Sixty percent were simulated, planned and started treatment on the day of their initial consultation. We therefore are meeting our goal of providing rapid access to palliative RT for symptomatic cancer patients.

Adult↗
PubMed2005

Disrupted compaction of CNS myelin in an OSP/Claudin-11 and PLP/DM20 double knockout mouse.

OSP/claudin-11 and PLP are both tetraspan proteins concentrated in CNS myelin. It has been proposed that they have a structural role in myelin formation and maintenance due to their localization and concentration in membrane sheaths. This hypothesis is not supported by the fact that both OSP/claudin-11- and PLP-null mice have relatively normal-appearing myelin and mild neurological deficits. Since both OSP/claudin-11 and PLP are abundant in myelin and have similar structures, the mild phenotypes of the knockout mice are likely due to compensatory mechanisms. Here we show that when both OSP/claudin-11 and PLP genes are knocked out, mice had severe neurological deficits, markedly abnormal myelin compaction, and smaller axon diameters. Interestingly, when either of these genes was knocked out, the expression of the other protein was increased. These data demonstrate that OSP/claudin-11 and PLP have essential structural functions in maintaining normal compact myelin and there is redundancy in their functions.

Adaptation, Physiological↗
PubMed2004

Subacute sclerosing panencephalitis in the differential diagnosis of encephalitis.

The authors describe five cases of subacute sclerosing panencephalitis (SSPE) identified through the California Encephalitis Project that emphasize the importance of considering SSPE in the differential diagnosis of encephalitis, particularly among pediatric patients. SSPE was not suspected in the differential diagnosis of three of the cases until results of measles testing were known. The diagnosis of SSPE is often not considered by clinicians because of its rarity in the United States and the nonspecific clinical manifestations at onset.

Adolescent↗
PubMed2004

Ultracompact biochemical sensor built with two-dimensional photonic crystal microcavity.

We report an experimental demonstration of an ultracompact biochemical sensor based on a two-dimensional photonic crystal microcavity. The microcavity, fabricated on a silicon-on-insulator substrate, is designed to have a resonant wavelength (lambda) near 1.5 microm. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n = 1.0 to n = 1.5. From observation of the shift in resonant wavelength, a change in ambient refractive index of delta(n) = 0.002 is readily apparent. The correspondence between absolute refractive index and resonant wavelength agrees with numerical calculation to within 4% accuracy. The evaporation of water in a 5% glycerol mixture is also used to demonstrate the capability for in situ time-resolved sensing.

Biosensing Techniques↗
PubMed2004

Prognostic factors in brain metastases: can we determine patients who do not benefit from whole-brain radiotherapy?

AIMS: Whole-brain radiotherapy (WBRT) is a standard treatment recommendation for patients with brain metastases. The goal of treatment is symptom control, which in the short run can be often achieved by steroids. Patients with a short life expectancy may not derive benefit from the addition of radiation. The ability to identify this group would aid the decision of whether to recommend WBRT. MATERIALS AND METHODS: Data on all patients referred for WBRT to palliative radiotherapy teams at two comprehensive cancer centres were prospectively collected over a 2-year period. The most frequent radiation dose and fractionation was 2000 cGy in 5 fractions over 1 week. Multivariate logistic regression analysis using forward stepwise selection process was used to develop a prediction model for early death (before 8 weeks). The variables considered were sex, performance status, primary disease, weight loss, age, time from primary diagnosis to brain metastases diagnosis, number of metastatic sites and Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) status. RESULTS: Two hundred and seventy-five patients with brain metastases were assessed. The median follow-up was 19 weeks, and estimated median overall survival was 5.3 months. Multivariate regression revealed Eastern Cooperative Oncology Group (ECOG) performance status and number of metastatic sites to be significant predictors of early death. The odds ratios were 2.38 (95% confidence interval [CI] 1.77-3.19) and 1.39 (95% CI 1.07-1.81), respectively. Sixty-eight per cent of patients could be correctly classified; however, 55% would have been incorrectly predicted to die early. CONCLUSIONS: Poor performance status and number of metastatic sites are useful predictors of early death. A regression model was highly predictive overall, but this was primarily due to a high negative predictive value of 86%. The ability to predict patients who would die early (positive predictive value) was only 45%. Thus, despite the understanding that we are over-treating a subset of patients, further research is required to identify patients who do not require radiotherapy.

Adult↗
PubMed2004

A link between irritable bowel syndrome and fibromyalgia may be related to findings on lactulose breath testing.

BACKGROUND: An association between irritable bowel syndrome (IBS) and small intestinal bacterial overgrowth (SIBO) has been found. OBJECTIVE: To compare the prevalence and test results for bacterial overgrowth between IBS and fibromyalgia. METHODS: Subjects with independent fibromyalgia and IBS were compared with controls in a double blind study. Participants completed a questionnaire, and a lactulose hydrogen breath test was used to determine the presence of SIBO. The prevalence of an abnormal breath test was compared between study participants. Hydrogen production on the breath test was compared between subjects with IBS and fibromyalgia. The somatic pain visual analogue score of subjects with fibromyalgia was compared with their degree of hydrogen production. RESULTS: 3/15 (20%) controls had an abnormal breath test compared with 93/111 (84%) subjects with IBS (p<0.01) and 42/42 (100%) with fibromyalgia (p<0.0001 v controls, p<0.05 v IBS). Subjects with fibromyalgia had higher hydrogen profiles (p<0.01), peak hydrogen (p<0.0001), and area under the curve (p<0.01) than subjects with IBS. This was not dependent on the higher prevalence of an abnormal breath test. The degree of somatic pain in fibromyalgia correlated significantly with the hydrogen level seen on the breath test (r = 0.42, p<0.01). CONCLUSIONS: An abnormal lactulose breath test is more common in fibromyalgia than IBS. In contrast with IBS, the degree of abnormality on breath test is greater in subjects with fibromyalgia and correlates with somatic pain.

Breath Tests↗
PubMed2003

A consensus development approach to define national research priorities in bone metastases: proceedings from NCIC CTG workshop.

AIMS: A 1-day workshop was conducted to gather interested Canadian radiation oncologists to identify priority research questions that could be answered through clinical trials under the auspices of the National Cancer Institute of Canada--Clinical Trials Group (NCIC-CTG) Symptom Control committee. MATERIALS AND METHODS: In preparation for the workshop, a survey of Canadian radiation oncologists resulted in four research areas in symptom control, including radiation-induced mucosal reactions, fatigue, radiotherapy for brain metastases and radiotherapy for bone metastases. The first half of the workshop consisted of plenary sessions where the research setting and perspective was defined for each area. This was followed by deliberations by a subgroup of researchers with special interest in the topic area. The bone-metastases subgroup deliberated the clinical context, the scientific merits and the required methodology of research questions related to the role of radiotherapy in early treatment of bone metastases, the role of re-irradiation, the role of systemic radiotherapy and patient selection for different fractionation schedules. A list of prioritised clinical studies was proposed. RESULTS: The question of single vs multi-fraction re-irradiation for symptomatic bone metastases was identified as most pertinent to the Canadian radiation oncologists present. A multi-centre, international intergroup study is undergoing protocol development. Other study concepts, such as an alternative dose-schedule of 17 Gy/2 fractions/1 week for intermediate-prognosis patients, and early referral for radiation oncologist assessment of early or mildly symptomatic bone metastases for good-prognosis patients, require further methodological development before a clinical trial can be proposed. CONCLUSION: An NCIC-CTG workshop provided an update on current evidence-based knowledge in palliative radiotherapy for bone metastases. New trial concepts were discussed among practitioners and clinical investigators to promote dialogue and collaboration. The proposal of an international intergroup randomised trial of single vs multiple fraction re-irradiation for painful bone metastases received the most support among participants.

Bone Neoplasms↗
PubMed2003

A population-based study of surgery for spinal metastases. Survival rates and complications.

The management of spinal metastases is palliative and aimed at improving quality of life at an acceptable risk. This population study uses administrative databases and measures survivorship and complication rates after surgery for spinal metastases. The effects of various potential predictor variables were evaluated. We identified 987 patients with a median survival for all types of cancer of 227 days. The one and three-month mortality was 9% and 29%, respectively. Increasing age, male gender and primary lung cancer were significant risk factors for death within 30 days of surgery. A preoperative neurological deficit contributed a 19% increase in mortality and a 71% increase in the risk of postoperative wound infection. We found an overall major complication rate of 27%. This information will provide patients, families and clinicians with objective data which will help in the choice of treatment and the understanding of the surgical risk and outcome.

Adult↗
PubMed2001

Phase II study assessing the effectiveness of Biafine cream as a prophylactic agent for radiation-induced acute skin toxicity to the breast in women undergoing radiotherapy with concomitant CMF chemotherapy.

PURPOSE: To assess the efficacy of Biafine cream in preventing Grade 2 acute radiation dermatitis, according to the National Cancer Institute of Canada skin radiation toxicity criteria in patients undergoing concomitant adjuvant chemotherapy and radiotherapy to the breast. METHODS AND MATERIALS: Sixty patients participated in this study. Patients were treated with a lumpectomy followed by concomitant chemotherapy and radiotherapy to the breast. Biafine cream was applied daily, starting on the first day and ending 2 weeks post-radiotherapy. Patients underwent weekly skin assessments throughout radiotherapy and at 2 and 4 weeks after treatment. Outcome measures were assessed using a Skin Assessment Questionnaire that was scored according to the National Cancer Institute of Canada skin radiation toxicity criteria and a self-administered questionnaire that evaluated skin symptoms. RESULTS: The maximum skin toxicity observed during the course of treatment was as follows: less than Grade 2 toxicity, 15% (9 patients); Grade 2, 83% (50 patients); Grade 3, 2% (1 patient); Grade 4, 0% (0 patients). The majority of the radiation dermatitis was observed after 3 weeks of radiotherapy. CONCLUSION: The majority of patients who underwent concomitant chemo- and radiotherapy for breast cancer developed Grade 2 radiation dermatitis with the use of Biafine cream. However, no treatment delays or interruptions were observed because of skin toxicity.

Adult↗
PubMed2001

Prospective patient-based assessment of effectiveness of palliative radiotherapy for bone metastases.

PURPOSE: The primary objective of this report is to prospectively evaluate pain control provided by palliative radiotherapy for all irradiated patients with bone metastases by using their own assessments. MATERIALS AND METHODS: A prospective database was set up for all patients referred for palliative radiotherapy for bone metastases. Patients were asked to rate their pain intensity using an 11 categorical point scale (0=lack of pain, 10=worst pain imaginable). Analgesic consumption during the preceding 24 h was recorded and converted into equivalent total daily dose of oral morphine. For those who received radiotherapy, follow-up was conducted via telephone interviews at week 1, 2, 4, 8 and 12 post treatment using the same pain scale and analgesic diary. Radiotherapy outcome was initially assessed by pain score alone. Complete response (CR) was defined as a pain score of 0. Partial response (PR) was defined as a reduction of score > or =2 or a> or =50% reduction of the pre-treatment pain score. We further analyzed outcomes using integrated pain and analgesic scores. Response was defined as either a reduction of pain score > or =2 with at least no increase in analgesics or at least stable pain score with a > or =50% reduction in analgesic intake. RESULTS: One hundred and five patients were treated with palliative radiotherapy. When response evaluation was by pain score alone, the PR rates at 2, 4, 8 and 12 weeks were 44, 42, 30 and 38%, respectively; while the CR rates were 24, 32, 31 and 29%, respectively. The overall response rate at 12 weeks was 67%. When assessed by the integrated pain and analgesic scores, the response rates were 50, 46, 43 and 43%, respectively. CONCLUSION: The response rate in our patient population is comparable with those reported in clinical trials. This is important when counselling our patients on the expected effectiveness of radiotherapy outside of clinical trials. Our observations confirm the generalizability of the trials conducted to date. While randomized trials still remain the gold standard of research, observational studies can serve as useful adjuncts to randomized trials to confirm the efficacy and guide the design of new controlled trials.

Adult↗
PubMed2001

Use of the CAGE questionnaire for screening problem drinking in an out-patient palliative radiotherapy clinic.

To determine the positive rate of the CAGE questionnaire in an outpatient palliative radiotherapy clinic and to examine the association between problem drinking, pain control, and analgesic consumption, patients referred for palliative radiotherapy were screened with the CAGE questionnaire and asked to rate their symptom distress using the modified Edmonton Symptom Assessment System (ESAS). The latter instrument uses 11-point numeric scales (0 = best, 10 = worst). Their daily analgesic consumption in oral morphine equivalent was recorded. A total of 128 patients participated in the study. Only 9 patients answered one of the four CAGE questions affirmatively (positive group). All the rest answered negatively (negative group). The mean pain intensity at index site/overall pain was 4.97 +/- 3.31/3.27 +/- 2.76 for the negative group and 6.29 +/- 4.42/2.89 +/- 3.37 for the positive group. The mean total daily oral morphine equivalent for the negative and positive group were 112.35 +/- 233.58 mg and 36.82 +/- 58.85 mg, respectively. There was no significant difference found in other symptoms in the modified ESAS between these two groups. The positive rate of the CAGE in patients with advanced cancer attending an out-patient radiotherapy clinic was only 7%, and analyses were limited by the small sample size of those with a positive CAGE. Whether our observed low positive rate of CAGE represents the true prevalence of problem drinking or the CAGE questionnaire is an insensitive tool for screening problem drinking in an outpatient palliative radiotherapy clinic requires further investigation. We did not find a statistically significant worse pain intensity nor higher analgesic consumption in patients who screened positive for CAGE questionnaire.

Adult↗
PubMed2001

Prospective assessment of symptom palliation for patients attending a rapid response radiotherapy program. feasibility of telephone follow-up.

Clinical trials generally include motivated patients with relatively good performance status. This can result in an overestimation of the effectiveness of an intervention. Clinic follow-up protocols for outcome assessment after palliative treatments suffer from high attrition rates. In this study, the feasibility of telephone follow-up for the assessment of symptom palliation in patients receiving outpatient palliative radiotherapy as a tool to evaluate outcome was examined. Patients referred for palliative radiotherapy were asked to rate their symptom distress using the modified Edmonton Symptom Assessment System (ESAS) at initial consultation. Patient demographics and analgesic consumption were collected. For those who received radiotherapy, follow-up was conducted through telephone interviews at week 1, 2, 4, 8, and 12 post-treatment using the same modified ESAS and analgesic diary. One hundred ninety patients received radiotherapy to 256 sites from January to August 1999. Seventy-eight patients (41%) died during the 12-week follow-up period. The percentage of surviving patients responding to the telephone interview ranged from 63% to 68% during the 12-week study. Telephone follow-up is a feasible tool for the prospective outcome assessment of symptom palliation in this population. It compares well to clinic visits or mailed questionnaires. However, to improve the follow-up rates, other modalities may also need to be implemented.

Adult↗
PubMed2001

Patients with advanced cancer: a survey of the understanding of their illness and expectations from palliative radiotherapy for symptomatic metastases.

We conducted a pilot study to examine patients' understanding of their illness and their expectations for palliative radiotherapy for symptomatic metastases. Participants were asked to complete a survey consisting of seven questions prior to the initial consultation. Demographic details and information on extent of disease were collected. Patients were asked to score their symptom distress using the modified Edmonton Symptom Assessment System. Sixty patients participated in the pilot study between January and April 1999. Their median age was 68 years (range 46-90). The most common primary tumours were lung, prostate and breast. Twenty-one patients (35%) believed that their cancer was curable. Twelve (20%) expected that palliative radiotherapy would cure their advanced cancer and 23 (38%) believed that palliative radiotherapy would prolong their lives. Twenty-one patients (35%) had concerns about the effectiveness of radiation therapy and twenty (33%) had concerns about the side-effects of radiotherapy. Fifty-two (87%) were not familiar with the concept of radiation treatment. Forty-seven patients (78%) reported that they were not given information about the radiation treatment; 51 (85%) were not satisfied with the information that their own doctors had provided regarding radiation treatment prior to the consultation at our clinic. A significant proportion of the patients in this pilot study had misconceptions regarding their illness and unrealistic expectations from palliative radiotherapy. We plan to provide educational pamphlets for use in referring doctors' surgeries and clinics in order to inform patients of the nature, rationale and anticipated benefits and side-effects of palliative radiotherapy.

Aged↗