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Rebecca Wong

Publications and source records attributed to Rebecca Wong.

15 recordsLinked to original sources
PubMed2006

Computerized tomographic simulation compared with clinical mark-up in palliative radiotherapy: a prospective study.

PURPOSE: To evaluate the impact of computed tomographic (CT) planning in comparison to clinical mark-up (CM) for palliative radiation of chest wall metastases. METHODS AND MATERIALS: In patients treated with CM for chest wall bone metastases (without conventional simulation/fluoroscopy), two consecutive planning CT scans were acquired with and without an external marker to delineate the CM treatment field. The two sets of scans were fused for evaluation of clinical tumor volume (CTV) coverage by the CM technique. Under-coverage was defined as the proportion of CTV not covered by the CM 80% isodose. RESULTS: Twenty-one treatments (ribs 17, sternum 2, and scapula 2) formed the basis of our study. Due to technical reasons, comparable data between CM and CT plans were available for 19 treatments only. CM resulted in a mean CTV under-coverage of 36%. Eleven sites (58%) had an under-coverage of >20%. Mean volume of normal tissues receiving >/=80% of the dose was 5.4% in CM and 9.3% in CT plans (p = 0.017). Based on dose-volume histogram comparisons, CT planning resulted in a change of treatment technique from direct apposition to a tangential pair in 7 of 19 cases. CONCLUSIONS: CT planning demonstrated a 36% under-coverage of CTV with CM of ribs and chest wall metastases.

Bone Neoplasms↗
PubMed2006

Conformal radiotherapy in the adjuvant treatment of gastric cancer: Review of 82 cases.

BACKGROUND: The Intergroup 0116 study showed a survival benefit with adjuvant chemoradiotherapy (CRT) for resected gastric cancer. We report our experience using conformal radiotherapy (RT). METHODS AND MATERIALS: Eighty-two patients with resected gastric or gastroesophageal junction (GEJ) adenocarcinoma, Stage IB to IV (M0), were treated with 45 Gy in 25 fractions using a 5-field conformal technique. Chemotherapy was in accordance with the Intergroup 0116 study, or infusional 5-fluorouracil and cisplatin in a phase I/II trial. RESULTS: Mean age was 56.4 years. Median follow-up was 22.8 months. Grade 3 or greater acute toxicity (National Cancer Institute Common Terminology Criteria of Adverse Events, version 3.0) was noted in 57% of patients (upper gastrointestinal tract 34%, hematologic 33%). One patient died of neutropenic sepsis. Radiation Therapy Oncology Group Grade 3 late toxicity included esophageal strictures (3 patients) and small bowel obstruction (1 patient). Full course CRT was completed by 67% of patients. Of 26 patients who relapsed, 20 died. Site of first relapse was available on 23 patients: 8 locoregional and distant, 4 locoregional alone, 11 distant alone. Overall and relapse-free survival were 69% and 54% at 3 years. CONCLUSION: Adjuvant CRT for gastric cancer, even with conformal RT, is associated with significant toxicity. Survival was comparable to that reported in the Intergroup 0116 study.

Adenocarcinoma↗
PubMed2005

Preoperative radiation with concurrent chemotherapy for resectable rectal cancer: effect of dose escalation on pathologic complete response, local recurrence-free survival, disease-free survival, and overall survival.

PURPOSE: Three Phase II studies of preoperative radiotherapy and concurrent 5FU chemotherapy were undertaken. The primary endpoints were acute toxicity and pathologic complete response rate (pCR). Secondary endpoints were local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS). METHODS AND MATERIALS: A total of 134 patients with adenocarcinoma of the rectum (clinical T3/T4 or N1/N2) were treated. The initial cohort received 40 Gy in 20 fractions, the second 46 Gy in 23 fractions, and the third 50 Gy in 25 fractions. 5FU (225 mg/m2/day) was given continuously throughout radiotherapy. A total of 121 patients underwent surgical resection. RESULTS: Treatment was well tolerated. Grade 3/4 acute toxicity was observed in 13%, 4%, and 14% of patients in the 40 Gy, 46 Gy, and 50 Gy cohorts, respectively (p = 0.20). pCR was documented in 15%, 23%, and 33% of patients, respectively (p = 0.07). The 2-year actuarial LRFS was 72%, 90%, and 89% (p = 0.02); DFS was 62%, 84%, and 78% (p = 0.02); and OS was 72%, 94%, and 92%, respectively (p = 0.03). CONCLUSIONS: All treatment schedules were well tolerated. There was a trend toward increased pCR with higher doses. A statistically significant increase in LRFS, DFS, and OS was seen with radiation doses of 46 Gy and greater, but there was no difference between 46 Gy and 50 Gy.

Antimetabolites, Antineoplastic↗
PubMed2005

Primary radical external beam radiotherapy of rectal adenocarcinoma: long term outcome of 271 patients.

BACKGROUND AND PURPOSE: To assess local control, survival and toxicity following primary radical external beam radiotherapy of rectal adenocarcinoma treated between 1978 and 1997, and to compare practices and outcomes between the two decades of study. PATIENTS AND METHODS: A retrospective review of 271 patients who underwent primary radical external beam radiotherapy, without prior or concurrent chemotherapy, was conducted. All patients received radiation doses of at least 40 Gy. Most patients (82%) were followed until death. RESULTS: Tumor fixation was the only significant prognostic factor for complete response by multivariate analysis. Complete response rates for mobile, partially fixed and fixed tumors were 49, 22 and 9%, respectively. For patients with mobile, partially fixed and fixed tumors, overall 5 year survival was 48, 26 and 6%, respectively, and cancer specific 5 year survival was 59, 33 and 9%, respectively. On multivariate analysis, tumor fixation and CEA higher than 8.7 microg/L at presentation were associated with significantly shortened survival. Outcomes did not change significantly during the two decades of the study. RTOG grade 3 or higher acute (1.8%) and late (1.5%) toxicity occurred only in the first decade of study. CONCLUSIONS: Radical external beam radiotherapy is a reasonable treatment option for rectal carcinoma for patients who are not surgical candidates or refuse surgery. However in patients with fixed tumors in this study, the outcome is poor and treatment should be considered palliative. Severe radiation toxicity is infrequent with current schedules and techniques of radiotherapy.

Adenocarcinoma↗
PubMed2005

IMRT for adjuvant radiation in gastric cancer: a preferred plan?

PURPOSE: To assess the potential advantage of intensity-modulated radiotherapy (IMRT) over conformal planning for postoperative adjuvant radiotherapy in patients with gastric carcinoma. METHODS AND MATERIALS: Twenty patients who had undergone treatment planning with conformal beam arrangements for 4500 cGy adjuvant radiotherapy between 2000 and 2001 underwent repeat planning using IMRT techniques. Conformal five-field plans were compared with seven- to nine-field coplanar sliding-window IMRT plans. For each patient, the cumulative dose-volume histograms and organ-dose summaries (without distributions or digitally reconstructed radiographs) were provided to two independent, "blinded" GI radiation oncologists. The oncologists indicated which plan provided better planning target volume coverage and critical organ sparing, any safety concerns with either plan, and which plan they would choose to treat the patient. RESULTS: In 18 (90%) of 20 cases, both oncologists chose the same plan. Cases with disagreement were given to a third "blinded" reviewer. A "preferred plan" could be determined in 19 (95%) of 20 cases. IMRT was preferred in 17 (89%) of 19 cases. In 4 (20%) of 20 IMRT plans at least one radiation oncologist had safety concerns because of the spinal cord dose (3 cases) or small bowel dose (2 cases). Of 42 ratings, IMRT was thought to provide better planning target volume coverage in 36 (86%) and better sparing of the spinal cord in 31 (74%) of 42, kidneys in 29 (69%), liver in 30 (71%), and heart in 29 (69%) of 42 ratings. The median underdose volume (1.7 vs. 4.1 cm3), maximal dose to the spinal cord (36.85 vs. 45.65 Gy), and dose to 50% of the liver (17.29 vs. 27.97), heart (12.89 vs. 15.50 Gy), and left kidney (15.50 vs. 16.06 Gy) were lower with IMRT than with the conformal plans. CONCLUSION: Compared with the conformal plans, oncologists frequently preferred IMRT plans when using dose-volume histogram data. The advantages of IMRT plans include both improved planning target volume coverage and improved sparing of critical organs. We are currently studying organ motion in the upper abdomen as a prerequisite to using IMRT for actual patient treatment.

Adult↗
PubMed2005

Accuracy of survival prediction by palliative radiation oncologists.

PURPOSE: To examine the accuracy of survival prediction by palliative radiation oncologists. METHODS AND MATERIALS: After consultation of cancer patients with metastatic disease for referral of palliative radiotherapy, radiation oncologists estimated the survival of the patients. These were compared with the actual dates of death obtained from the Cancer Death Registry. The time to death from all causes was the outcome. The survival times were measured from the date of the first consultation at the palliative radiotherapy clinics. RESULTS: Six radiation oncologists provided estimates for 739 patients. Of the 739 patients, 396 were men and 343 were women (median age, 69 years). The median survival of all patients was 15.9 weeks. The mean difference between the actual survival (AS) and the clinician predicted survival (i.e., actual survival minus clinician predicted survival) was -12.3 weeks (95% confidence interval, -15.0 to -9.5) for the entire population. The mean difference was -21.9 weeks when the actual survival was < or =12 weeks, -19.2 weeks when the AS was 13-26 weeks, -9.7 weeks when the AS was 27-52 weeks, and +23.0 weeks when the AS was >52 weeks. CONCLUSION: In this study, the prediction of survival by radiation oncologists was inaccurate and tended to be overly optimistic.

Adult↗
PubMed2005

Assessing perfusion changes during whole brain irradiation for patients with cerebral metastases.

PURPOSE: To assess perfusion changes within brain and correlate these with clinical symptoms during whole brain radiotherapy (WBRT) for cerebral metastases. MATERIALS AND METHODS: Fourteen patients with cerebral metastases underwent dynamic CT perfusion scans during palliative whole brain irradiation. Perfusion scans were performed on Day 1 prior to initial radiotherapy treatment, then on Day 2, and on Day 5 immediately after completion of radiotherapy. Measurements of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and capillary surface area permeability product (PS) were performed for each perfusion scan, and daily symptom assessment was taken prior to initial perfusion scan and thereafter prior to each daily radiation treatment. RESULTS: Utilizing Day 1 as baseline, a 19% increase (P = 0.033) was noted in PS at Day 2, (median 1.47 ml/100 g/min), which returned to Day 1 range at Day 5 (median 1.31 ml/100 g/min). When symptoms were correlated with perfusion parameters, a statistically significant association between change in MTT with change in headache scores was observed, baseline to Day 2 (P = 0.019), and a trend between change in nausea scores with change in CBV (P = 0.059) as well as change in MTT (P = 0.098), baseline to Day 5. CONCLUSION: This study has demonstrated the feasibility of a non-invasive technique to assess changes occurring within the human brain during a course of radiation treatment. Dynamic perfusion tomography provides insight into the pathophysiological processes taking place and allows correlation with patient symptomatology.

Adult↗
PubMed2004

Phase I study of 5-fluorouracil and leucovorin by continuous infusion chronotherapy and pelvic radiotherapy in patients with locally advanced or recurrent rectal cancer.

PURPOSE: To determine the maximal tolerated dose of chronomodulated 5-fluorouracil (5-FU) and leucovorin (LV) given concurrently with radiotherapy in patients with rectal cancer. METHODS AND MATERIALS: Forty-five patients with T3, T4 or recurrent rectal cancer received concurrent radiotherapy to a minimal dose of 4500 cGy. Chemotherapy was administered by a programmable pump in chronomodulated fashion, with 62.5% of the total dose given within 7 hours around 9:30 pm. The starting doses were LV at 5 mg/m2/d and 5-FU at 150 mg/m2/d. LV was escalated in 5-mg/m2 increments to 20 mg/m2/d; 5-FU was then escalated in 25 mg/m2 increments to the maximal tolerated dose. RESULTS: Diarrhea and stomatitis were dose limiting, with Grade 3 or worse toxicity occurring in 16% and 5% of patients, respectively. Thirty-seven patients (84%) received their scheduled dose of radiotherapy (range, 4500-6000 cGy). Thirty-two patients had clinical T3 disease; all were treated with definitive surgery; 23 (71%) underwent sphincter-sparing surgery with complete resection in 28 (87%). Ten patients (31%) had no evidence of tumor in the pathologic specimen. CONCLUSION: Preoperative chemoradiotherapy in rectal cancer using chronomodulated 5-FU and LV is feasible. The recommended Phase II dose is 5-FU 200 mg/m2 and LV 20 mg/m2 daily for 5 weeks.

Adult↗
PubMed2004

Computed tomography (CT) evaluation of breast cancer patients with osteolytic bone metastases undergoing palliative radiotherapy--a feasibility study.

Twenty-five patients with osteolytic metastases had computed tomography (CT) scans before and 3 months after palliative radiotherapy. The median % density change following single 8Gy, 20Gy/5#, 30Gy/10# were: 128 (range 98-255), 141 (79-342), and 145 (65-235), respectively. It is feasible to evaluate remineralization of osteolytic lesions with palliative radiotherapy.

Adult↗
PubMed2003

The success of data collection in the palliative setting--telephone or clinic follow-up?

Assessment of outcomes is essential in order to improve available palliative treatments. Collecting follow-up information can be a challenging task in the palliative setting. We compared the effectiveness of data collection by telephone contact and clinic visit in 112 patients with brain metastases treated with whole-brain radiotherapy. The first 56 patients (group A) were followed by telephone only. The second 56 patients (group B) were asked to attend an outpatient clinic appointment 4 weeks after radiotherapy. Successful contact was defined as obtaining data at week 4. Patients in the two groups did not differ significantly with regard to age, sex, performance status, primary site, number of brain metastases, or the treatment given. The proportions of patients with successful follow-up contact at week 4 were 45% and 61% in groups A and B, respectively ( P = 0.09). The quality of the collected data did not differ significantly between the two groups. The side effects and responses to therapy were similar. However, there were significantly more patients with a reduced dose of dexamethasone among the successful contacts in group B, which probably reflected the better condition of the patients coming back to clinic at week 4. In conclusion, there was a trend towards more successful data collection in our clinic follow-up. Some of the observed outcome data suggest that the two methods of follow-up might be reaching different populations of patients; considering this and the high attrition rate, a combined follow-up strategy of clinic and telephone contacts might be the best strategy.

Ambulatory Care↗
PubMed2003

Meta-analysis of dose-fractionation radiotherapy trials for the palliation of painful bone metastases.

PURPOSE: To compare pain relief among various dose-fractionation schedules of localized radiotherapy (RT) in the treatment of painful bone metastases. METHODS AND MATERIALS: A systematic search for randomized trials of localized RT on bone metastases using different dose fractionations was performed using Medline (1966 to February 2001) and other sources. The primary outcomes of interest were complete and overall pain relief. The studies were divided into three groups: comparisons of doses given as a single fraction, single vs. multiple fractions, and comparisons of doses given as multiple fractions. The complete and overall pain responses for studies comparing single vs. multiple fractions were pooled. Exploratory analyses of the dose-response relationship, using the biologic effective dose (alpha/beta = 10), were performed using results from all three groups of trials. RESULTS: Two trials comparing single vs. single, eight trials comparing single vs. multiple, and six trials comparing multiple vs. multiple fractions were included. The complete and overall response rates from studies comparing single-fraction RT (median 8 Gy, range 8-10 Gy) against multifraction RT (median 20 Gy in 5 fractions, range 20 Gy in 5 fractions to 30 Gy in 10 fractions) were homogeneous and allowed pooling of data. Of 3260 randomized patients in seven studies, 539 (33.4%) of 1613 and 523 (32.3%) of 1618 patients achieved a complete response after single and multifraction RT, respectively, giving a risk ratio of 1.03 (95% confidence interval 0.94-1.14; p = 0.5). The overall response rate was in favor of single-fraction RT (1011 [62.1%] of 1629) compared with multifraction (958 [58.7%] of 1631; risk ratio 1.05, 95% confidence interval 1.00-1.11, p = 0.04), reaching statistical significance. However, when the analysis was restricted to evaluated patients alone, the overall response rates were similar for single fraction and multifraction RT, at 1011 (72.7%) of 1391 and 958 (72.5%) of 1321, respectively (risk ratio 1.00; p = 0.9). Exploratory analyses by biologic effective dose did not reveal any dose-response relationship among the fractionation schedules used (single 8 Gy to 40 Gy in 15 fractions). Of the other results and observations reported in the trials, only the re-irradiation rates were consistently different between the treatment arms (more frequent re-irradiation in lower dose arms among trials reporting re-irradiation rates). CONCLUSION: Meta-analysis of reported randomized trials shows no significant difference in complete and overall pain relief between single and multifraction palliative RT for bone metastases. No dose-response relationship could be detected by including data from the multifraction vs. multifraction trials. Additional data are needed to evaluate the role of re-irradiation and the impact of RT on other treatment end points such as quality of life.

Bone Neoplasms↗
PubMed2003

Food insecurity and low income in an English inner city.

BACKGROUND: Low incomes may not provide the minimum requirements for healthy living. We evaluated experiences of food insecurity in relation to income in inner London. METHODS: Subjects attending 10 general medical practices completed a short self-administered questionnaire, including the short form Household Food Security Scale and a short food frequency questionnaire. RESULTS: Responses were obtained from 431/495 (87 per cent) subjects. Overall 87 (20 per cent) of subjects were classified as food insecure. Food insecurity was negatively associated with household income (p = 0.004). University-educated subjects (8 per cent) were less often food insecure than all others (26 per cent). Subjects who were food insecure were less likely to report eating fruit daily (food secure 48 per cent, food insecure 33 per cent, p = 0.017) or vegetables or salads daily (food secure 56 per cent, food insecure 34 per cent, p = 0.002). CONCLUSIONS: Experiences of food insecurity may be common in households with incomes at the level of the UK national minimum wage or lower.

Adolescent↗
PubMed2003

Multidisciplinary radiation oncology palliative care rounds as a continuing educational activity implementing the rapid response radiotherapy program at the toronto sunnybrook regional cancer centre.

BACKGROUND: This paper describes the development of the Rapid Response Radiotherapy Program and evaluates the continuing medical education (CME) series, in the form of multidisciplinary monthly Radiation Oncology Palliative Care Rounds at the Toronto Sunnybrook Regional Cancer Centre. METHODS: Palliative care rounds were initiated by the multidisciplinary committee in September, 1998. From January, 2000, to June, 2002, attendees used a standard 5- point Likert rating scale to conduct formal evaluations. RESULTS: A total of 203 evaluation forms examining 20 rounds have been collected. Findings indicated that 86.8, 96.0, 87.1, and 90.8% of participants thought the material of the presentation was relevant to their practice, interesting, and instructional. Overall 90.1% of the respondents highly rated the grand rounds (rating of 4 or 5). CONCLUSION: The grand rounds are an effective CME activity at our hospital.

Attitude of Health Personnel↗
PubMed2002

Improving the consistency in cervical esophageal target volume definition by special training.

PURPOSE: Three-dimensional conformal radiation therapy requires the precise definition of the target volume. Its potential benefits could be offset by the inconsistency in target definition by radiation oncologists. In a previous survey of radiation oncologists, a large degree of variation in target volume definition of cervical esophageal cancer was noted for the boost phase of radiotherapy. The present study evaluated whether special training could improve the consistency in target volume definitions. METHODS AND MATERIALS: A pre-training survey was performed to establish baseline values. This was followed by a special one-on-one training session on treatment planning based on the RTOG 94-05 protocol to 12 radiation oncologists. Target volumes were redrawn immediately and at 1-2 months later. Post-training vs. pre-training target volumes were compared. RESULTS: There was less variability in the longitudinal positions of the target volumes post-training compared to pre-training (p < 0.05 in 5 of 6 comparisons). One case had more variability due to the lack of a visible gross tumor on CT scans. Transverse contours of target volumes did not show any significant difference pre- or post-training. CONCLUSION: For cervical esophageal cancer, this study suggests that special training on protocol guidelines may improve consistency in target volume definition. Explicit protocol directions are required for situations where the gross tumor is not easily visible on CT scans. This may be particularly important for multicenter clinical trials, to reduce the occurrences of protocol violations.

Education, Medical, Continuing↗