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Biomedical subjects

F L Wong

Publications and source records attributed to F L Wong.

At least 19 recordsLinked to original sources
PubMed2005

An intelligent tutoring system for trauma management (Trauma-Teach): a preliminary report.

Trauma-Teach is an interactive software for tutoring surgical trainees on medical trauma management procedures. Users of the system interact with a virtual patient suffering from trauma injuries. The task of the user is to stabilise the virtual patient, discover the underlying injuries and decide on an appropriate management plan. Artificial intelligence techniques are used to simulate the patient's pulmonary and cardiovascular systems in real time, determine the responses and results of treatments and diagnostics accordingly, model the patient deterioration if wrong actions are taken, and give a measure of reality to the system by selecting actual trauma cases from the hospital's database.

Artificial Intelligence↗
PubMed1999

The importance of hemoglobin levels during radiotherapy for carcinoma of the cervix.

BACKGROUND: It is unclear whether blood transfusion can overcome the negative impact of anemia before or during radiotherapy (RT) in patients with carcinoma of the cervix. The objective of this retrospective study was to examine the impact of anemia and blood transfusion on 605 patients with carcinoma of the cervix treated with radical RT at 7 centers across Canada in 1989, 1990, and 1992. METHODS: The data collected included hemoglobin (Hgb) levels from the time of diagnosis to the end of therapy; blood transfusions administered; and identifiable patient-, tumor-, and treatment-related factors. Survival, disease free survival, and pelvic control analyses were evaluated by univariate and multivariate analysis. RESULTS: The median follow-up was 41 months (range, 0-92 months). Presenting Hgb level, average weekly nadir Hgb (AWNH) during RT, and blood transfusion were correlated significantly with local control, disease free survival, and overall survival on univariate analysis. However, the AWNH remained significant on multivariate analysis, whereas Hgb at presentation and blood transfusion did not. The 5-year survival was 74% for patients with an AWNH >/= 120 g/L, 52% for patients with AWNH levels 110-119 g/L inclusive, and 45% for patients with AWNH levels < 110 g/L (P < 0.0001). At each Hgb level, patients who were transfused and maintained a specific Hgb level had a survival rate that was not significantly different from patients who were at that level spontaneously. There was a significant reduction in both pelvic and distant recurrence (P < 0.0001 and P < 0.0006, respectively) in patients whose AWNH level during RT was >/= 120 g/L compared with < 120 g/L. A reduction in the rate of distant recurrence was observed in patients with and without pelvic recurrence. CONCLUSIONS: AWNH is highly predictive of outcome for patients treated with RT for carcinoma of the cervix. Blood transfusion appears to overcome the negative prognostic effects of low presenting Hgb levels and AWNH levels.

Adenocarcinoma↗
PubMed1999

Cancer of the tonsil: the results of ipsilateral radiation treatment.

BACKGROUND AND PURPOSE: The use of ipsilateral irradiation techniques to treat patients with carcinoma of the tonsil reduces the acute radiation reaction in the contralateral pharynx and late damage to the contralateral salivary tissue. However, this may also spare microscopic disease in apparently uninvolved contralateral lymph nodes. The purpose of this study was to analyse the survival and recurrence rates and sites of recurrance in a group of patients with carcinoma of the tonsil treated with ipsilateral techniques. MATERIALS AND METHODS: Between 1975 and 1993, 271 patients with invasive squamous cell cancer of the tonsil were referred to the Vancouver Cancer Centre (VCC). One hundred and seventy-eight received ipsilateral radiation treatment. Three received surgery only, six post-operative radiation, 12 supportive treatment only and 72 bilateral radiation treatment. In the absence of bilateral neck nodes and extensive lymphodenopathy, field sizes were generally kept small to include the primary tumour and the first echelon of nodes. The most common dose was 60 Gy in 25 daily fractions in 5 weeks (2.4 Gy per day). RESULTS AND DISCUSSION: The disease specific survival for all patients treated by radical radiation treatment was 61% at 5 years. For the 178 patients who received ipsilateral radiation treatment the overall primary tumour control rate by ipsilateral radiation treatment alone was 75% and for T1 and T2 tumours 84%. Eight (7.5%) of 101 of these patients with N0 nodes at presentation and without prior failure at the primary site, developed nodal recurrence (four within the initially radiated high dose volume). Two developed contralateral nodes, and two developed field edge nodal recurrence, one cured by surgery. In 54 patients with N1 disease, five developed nodal recurrence, two within field, two contralateral, one of whom was cured by surgery, and one at field edge. In 23 patients with N2a, N2b or N3 disease node control was achieved from radiation treatment in 11 and two more were cured by surgery. All nodal failures were within the radiated volume. Overall, 10 of the 25 patients with nodal failure were cured by subsequent surgery. CONCLUSIONS: Ipsilateral treatment of patients with carcinoma of the tonsil gives survival results that are at least as good as those reported with bilateral treatment with fewer side effects and a very low risk of failure in the contralateral neck.

Carcinoma, Squamous Cell↗
PubMed1999

Pretreatment assessment and dental management of patients with nasopharyngeal carcinoma.

Patients who present with nasopharyngeal carcinoma (NPC) require through oral and dental assessment prior to treatment of the malignancy. We assessed the oral status of 57 consecutive patients with a diagnosis of NPC. In this study, identified risk factors for NPC were seen to be different in Asian versus non-Asian patients. Epstein-Barr virus seropositivity was seen in all Asian patients and in 69% of non-Asian patients (P = 0.00006), and reported alcohol use was greater in the non-Asian patients. In this study it was found that 68% of dentate patients required dental extractions primarily due to periodontal disease. Even in patients who reported receiving regular dental care (28%) extractions prior to radiation therapy were suggested. Oral complications of radiation therapy were reported by 84% of patients, with the most common being xerostomia. Clinical diagnosis of candidiasis (16%), rampant caries (10% of dentate patients) and difficulties with dentures (25% of denture wearers) were noted. In addition to pretreatment assessment, continuing oral and dental management is needed for patients with NPC.

Adult↗
PubMed1999

Dissemination of an evidence-based intervention manual to improve managed care mammography rates.

After collaborating with the Centers for Disease Control and Prevention to develop an evidence-based mammography intervention manual, the dissemination of the manual in a managed care setting was assessed. Using qualitative methods (in-depth interviews), factors were examined that motivated use of the manual by the quality improvement units of eight Prudential HealthCare health plans. Seven of the plans implemented more intensive interventions after having received the manual than in the previous year. Factors that facilitated use of the manual and implementation of recommendations included: internal motivation, support of senior level management, adequate resources (time, personnel, and funds) to support interventions, and the organization and content of the manual itself.

Aged↗
PubMed1999

Effects of radiation on the longitudinal trends of total serum cholesterol levels in the atomic bomb survivors.

The effects of radiation on the long-term trends of the total serum cholesterol levels of the Hiroshima and Nagasaki atomic bomb survivors were examined using data collected in the Adult Health Study over a 28-year period (1958-1986). The growth-curve method was used to model the longitudinal age-dependent changes in cholesterol levels. For each sex, temporal trends of cholesterol levels were characterized with respect to age, body mass index, city and birth year. We then examined whether the temporal trends differed by radiation dose. We showed that the mean growth curve of cholesterol levels for the irradiated subjects were significantly higher than that for the unirradiated subjects, and that the increase was greater for women than for men. No difference in dose response was detected between Hiroshima and Nagasaki. An increased mean level of cholesterol was evident for irradiated women in general, but a notable increase was apparent in males only for the youngest birth cohort of 1935-1945. The difference in the mean cholesterol levels between the irradiated and unirradiated subjects diminished past 70 years of age. It is not known whether this is due to natural progression or is an artifact of nonrandom variation in the rate of participation in the examinations. The maximum predicted increase at 1 Gy for women occurred at age 52 years for the 1930 cohort: 2.5 mg/dl (95% CI 1.6-3.3 mg/dl) for Hiroshima and 2.3 mg/dl (95% CI 1.5-3.1 mg/dl) for Nagasaki. The corresponding increase for men occurred at age 29 years for the 1940 cohort: 1.6 mg/dl (95% CI 0.4-2.8) for Hiroshima and 1.4 mg/dl (95% CI 0.3-2.6) for Nagasaki. Controlling for cigarette smoking did not alter the dose-response relationship. Although the difference in the mean growth curves of the irradiated and unirradiated groups was statistically significant, there was a considerable overlap in the individual growth curves of the two groups. The significant sex difference and the greater magnitude of radiation effects in women suggest that hormonal changes resulting from radiation exposure, such as accelerated menopause, is an area worth investigating to delineate the mechanisms underlying the increased cholesterol levels of the irradiated female subjects. This increase may also partially explain the increased rate of coronary heart disease seen in the atomic bomb survivors.

Adolescent↗
PubMed1998

Topical bleomycin for the treatment of dysplastic oral leukoplakia.

BACKGROUND: Because malignant transformation of dysplastic oral leukoplakia has been reported in up to 43% of cases, these lesions must be managed. METHODS: This study evaluated the use of topical 1% bleomycin in dimethylsulfoxide for the treatment of dysplastic oral lesions. Bleomycin was applied once daily for 14 consecutive days to lesions of the oral mucosa in 19 patients. Immediate posttreatment biopsies and the clinical response were evaluated and clinical follow-up was conducted for as long as possible. RESULTS: The mean age of the patients at diagnosis was 59.4 years and 74% were tobacco users. Seventy-five percent of patients had resolution of dysplasia at follow-up biopsy, with a mean improvement of two histologic grades of dysplasia after topical chemotherapy. Ninety-four percent of the patients attained at least partial responses. After a mean follow-up period of 3.4 years, 31.6% of patients had no clinically visible lesions and 47.4% of patients had clinically benign lesions of homogeneous leukoplakia or minimal visible leukoplakia. In 2 patients (11%) malignant transformation occurred a mean of 1.75 years after bleomycin treatment. CONCLUSIONS: Topical bleomycin may prevent the potential progression of leukoplakia through dysplasia to carcinoma. Close follow-up of all patients with dysplasia is required.

Administration, Topical↗
PubMed1997

Cancer incidence after retinoblastoma. Radiation dose and sarcoma risk.

CONTEXT: There is a substantial risk of a second cancer for persons with hereditary retinoblastoma, which is enhanced by radiotherapy. OBJECTIVE: To examine long-term risk of new primary cancers in survivors of childhood retinoblastoma and quantify the role of radiotherapy in sarcoma development. DESIGN: Cohort incidence study of patients with retinoblastoma followed for a median of 20 years, and nested case-control study of a radiation dose-response relationship for bone and soft tissue sarcomas. SETTING/PARTICIPANTS: A total of 1604 patients with retinoblastoma who survived at least 1 year after diagnosis, identified from hospital records in Massachusetts and New York during 1914 to 1984. RESULTS: Incidence of subsequent cancers was statistically significantly elevated only in the 961 patients with hereditary retinoblastoma, in whom 190 cancers were diagnosed, vs 6.3 expected in the general population (relative risk [RR], 30 [95% confidence interval, 26-47]). Cumulative incidence (+/-SE) of a second cancer at 50 years after diagnosis was 51.0% (+/-6.2%) for hereditary retinoblastoma, and 5.0% (+/-3.0%) for nonhereditary retinoblastoma. All 114 sarcomas of diverse histologic types occurred in patients with hereditary retinoblastoma. For soft tissue sarcomas, the RRs showed a stepwise increase at all dose categories, and were statistically significant at 10 to 29.9 Gy and 30 to 59.9 Gy. A radiation risk for all sarcomas combined was evident at doses above 5 Gy, rising to 10.7-fold at doses of 60 Gy or greater (P<.05). CONCLUSIONS: Genetic predisposition has a substantial impact on risk of subsequent cancers in retinoblastoma patients, which is further increased by radiation treatment. A radiation dose-response relationship is demonstrated for all sarcomas and, for the first time in humans, for soft tissue sarcomas. Retinoblastoma patients should be examined for new cancers and followed into later life to determine whether their extraordinary cancer risk extends to common cancers of adulthood.

Adolescent↗
PubMed1997

Longitudinal trends in total serum cholesterol levels in a Japanese cohort, 1958-1986.

The 28-year follow-up of a Japanese cohort, having collected vast amounts of data collected on total serum cholesterol (TC), provided an exceptional opportunity to examine TC temporal trends. The longitudinal statistical method of growth-curve analysis was used to elucidate the age-related changes in TC levels and to characterize these trends in relation to sex, birth cohort, time period, place of residence, and body mass index (BMI). Japanese TC levels at initial examination were remarkably lower than those in western countries. During the study period from 1958 to 1986, TC levels increased dramatically with age in both sexes. The slope of the cholesterol growth curve was steeper for women than for men, with the difference growing larger after age 40 years. Drastic changes in Japanese behavior and lifestyle, especially westernization of the diet, are thought to have affected the TC values as time-period effects. As a result of this temporal change, which affected different cohorts at different ages, TC values were higher in members of the younger cohort. The increase of the TC values as time-period effects were larger in earlier period than in later period. These time-period effects appeared to be almost similar in men and women. The TC growth curves also varied by city of residence. Subjects in urban areas had higher TC values than subjects in rural areas. Changes associated with BMI from 1958 to 1986 were only partially responsible for the increased steepness of the TC growth curve.

Adult↗
PubMed1996

Benign thyroid tumors: general risk factors and their effects on radiation risk estimation.

The authors examined risk factors for benign thyroid nodules and their influence on radiation effects among 544 subjects who were exposed to childhood radiation treatment for benign head and neck conditions at a Chicago, Illinois hospital during 1939-1962. In follow-up through 1991, benign thyroid nodules were diagnosed in 131 patients. The risk of benign nodules was elevated in women (relative risk (RR) = 2.2, 95% confidence interval (CI) 1.6-3.2), Jews (RR = 1.7, 95% CI 1.2-2.5), college graduates (RR = 1.8, 95% CI 1.2-2.8), and subjects whose mother had cancer (RR = 1.7, 95% CI 1.2-2.5). There were increasing trends for risk with increasing body mass index in women and decreasing height in men. Risk was increased for women who never married (RR = 3.7, 95% CI 1.6-7.3) or who never had a full-term pregnancy (RR = 2.0, 95% CI 1.1-3.3). A significant radiation dose-response relationship was observed that was not modified by sex, education, Jewish religion, or reproductive factors. The data suggest that there are genetic, life-style (including ascertainment), and hormonal factors associated with the development of benign thyroid nodules.

Cohort Studies↗
PubMed1995

Incidence of benign gastrointestinal tumors among atomic bomb survivors.

Using the Hiroshima and Nagasaki tumor and tissue registries, benign tumors of the stomach, colon, and rectum were identified among members of the Life Span Study cohort of atomic bomb survivors. During the period 1958-1989, a total of 470 cases with histologically confirmed benign gastrointestinal tumors (163 stomach, 215 colon, and 92 rectum) were identified among approximately 80,000 Life Span Study members with known radiation doses, who were alive in 1958. Restricting the analysis to adenomatous tumors not detected at autopsy, a dose-response relation was observed for stomach tumors (excess relative risk at 1 sievert (ERR1Sv) = 0.53; 95% confidence interval (CI) -0.01 to 1.43). However, there was little evidence of a dose response for colon tumors (ERR1Sv = 0.14; 95% CI -0.20 to 0.76), and no evidence was present for rectal tumors (ERR1Sv = -0.25; 95% CI undetermined to 0.80). The excess relative risk (ERR) for benign tumors of the stomach is consistent with the excess found for stomach cancer. For cancer of the rectum, the dose response was not significant, but the point estimate of the excess relative risk was positive. The excess relative risk for benign colon tumors is less than that reported for colon cancer (ERR1Sv = 0.72). The authors observed a dramatic increase in colon tumors detected after 1985, suggesting that the relatively recent introduction of colonoscopy may be influencing these results.

Cohort Studies↗
PubMed1995

Relationship between cataracts and epilation in atomic bomb survivors.

Among 1713 atomic bomb survivors who underwent ophthalmological examinations from 1963-1964, the risk of cataract formation per unit dose of radiation was significantly greater for those who reported hair loss of 67% or more after exposure (the epilation group) than for those who reported less or no hair loss (the no-epilation group) (P < 0.01). Such an epilation effect has also been associated with leukemia mortality and the frequency of chromosome aberrations. Although this might be interpreted as indicating differential sensitivity to radiation between the epilation group and the no-epilation group, it could also be explained by imprecision in dose estimates. We have calculated that a 48% random error in DS86 dose estimates could be in accordance with the dose-response relationship for the prevalence of cataracts in the epilation group or the no-epilation group. Possible mechanisms for variation in radiosensitivity are discussed.

Alopecia↗
PubMed1994

Endometrial adenocarcinoma presenting as an isolated calcaneal metastasis. A rare entity with good prognosis.

A 59-year-old woman presented with progressive pain, swelling, and erythema of her right foot. Biopsy of a destructive calcaneal lesion revealed a metastatic adenoacanthoma with focal adenosquamous carcinoma consistent with an endometrial origin. This was confirmed on hysterectomy. Postoperative treatment consisted of systemic chemotherapy, hormonal therapy, and local radiotherapy to the foot. She has now experienced 5 years of complete remission. This is a case of an endometrial adenocarcinoma presenting as an isolated calcaneal metastasis with an excellent outcome.

Adenocarcinoma↗
PubMed1994

The efficacy of sucralfate suspension in the prevention of oral mucositis due to radiation therapy.

PURPOSE: The purpose of this study was to assess the value of sucralfate suspension in prevention of oral mucositis and for reduction of oral pain in patients who develop mucositis during radiation therapy. METHODS AND MATERIALS: The study was a double-blind, placebo-controlled, randomized prospective trial of a sucralfate suspension in the prevention and management of oral mucositis during radiation therapy. Oral mucositis was assessed using a quantitative scale and symptoms were assessed using visual analogue scales. The statistical model was developed to detect a 40% reduction in mucositis. RESULTS: No statistically significant reduction in mucositis was seen. Early during radiation therapy less oral pain was reported in the sucralfate group, but as treatment progressed all patients experienced pain. Patients in the sucralfate group were prescribed topical and systemic analgesics later in the course of radiation therapy. CONCLUSION: Prophylactic oral rinsing with sucralfate did not prevent oral ulcerative mucositis. Sucralfate may reduce the experience of pain during radiation therapy.

Adult↗
PubMed1993

Mortality from second tumors among long-term survivors of retinoblastoma.

BACKGROUND: Children diagnosed with retinoblastoma, a rare cancer of the eye, tend to develop and die of second primary cancers in childhood and adolescence, but few investigations have followed patients into adulthood. Retinoblastoma is frequently caused by inherited mutations of the RB1 tumor suppressor gene. Most patients with germline (hereditary) mutations have bilateral disease. PURPOSE: We sought to quantify the mortality from second malignancies among long-term survivors of retinoblastoma and to identify factors that predispose to these deaths. METHODS: A retrospective cohort study examined mortality among 1603 patients enrolled at 1 year after diagnosis of retinoblastoma during the period 1914-1984. Data on demography, family history, and retinoblastoma treatment were collected by medical chart review and questionnaire interview. Number of deaths, by cause, was compared with the corresponding expected figure based on U.S. mortality data for the general population for 1925-1990. RESULTS: Follow-up was complete for 1458 patients (91%) for a median of 17 years after retinoblastoma diagnosis. A total of 305 deaths occurred, 167 of them from retinoblastoma. There were 96 deaths from second primary tumors (relative risk [RR] = 30), 21 from other known causes (RR = 1.0), and 21 from ill-defined or unknown causes. Statistically significant excess mortality was found for second primary cancers of bone, connective tissue, and malignant melanoma and benign and malignant neoplasms of brain and meninges. Among 919 children with bilateral retinoblastoma, 90 deaths from second primary tumors occurred (RR = 60). Deaths from second tumors were more frequent among females (RR = 39) than males (RR = 22) (P = .007). The cumulative probability of death from second primary neoplasms was 26% at 40 years after bilateral retinoblastoma diagnosis, and additional cancer deaths occurred thereafter. Radiotherapy for retinoblastoma further increased the risk of mortality from second neoplasms. An excess of mortality from a second cancer, not seen in prior studies, was found among the 684 children with unilateral disease (RR = 3.1; 95% confidence interval = 1.0-7.3). CONCLUSIONS: These findings implicate germinal mutations in the retinoblastoma gene in second cancer mortality. Radiotherapy treatment for retinoblastoma appears to further enhance the inborn susceptibility to development of a second cancer. IMPLICATIONS: Patients with retinoblastoma, particularly bilateral retinoblastoma, should have careful follow-up, and interventions should be developed to reduce mortality from a second cancer.

Adolescent↗
PubMed1993

Hyperbaric oxygen and postradiation osteonecrosis of the mandible.

The clinical and dental records of 26 patients with the clinical diagnosis of postradiation osteonecrosis (PRON) managed with hyperbaric oxygen (HBO) were reviewed to determine the efficacy of HBO. 19 patients were male and 7 were female; age at the first HBO session ranged from 28 to 80 years (median 57.5 years). All but 8 patients reviewed had some form of surgical management; 7 had mandibulectomy for PRON. As part of management, a total of 9-84 HBO sessions (median 35 sessions) was administered. 18 of the 26 patients ultimately achieved persistent mucosal and cutaneous coverage 1-84 months (median 24 months) after the first HBO session. 13 of the 26 patients met strict criteria for resolution of their disease; fully 21 of 26 patients had improved PRON status following HBO therapy. HBO treatment as part of a comprehensive management plan is safe and effective in the management of PRON.

Adult↗