Biomedical subjects

P A Groome

Publications and source records attributed to P A Groome.

18 recordsLinked to original sources

PubMed1999

Mortality from myocardial infarction following postlumpectomy radiotherapy for breast cancer: a population-based study in Ontario, Canada.

PURPOSE: To compare the risk of mortality from myocardial infarction (MI) after left-sided postlumpectomy radiotherapy (RT) to the risk after right-sided postlumpectomy RT. METHODS: We conducted a population-based cohort study of cases of invasive female breast cancer in Ontario, diagnosed between January 1, 1982 and December 31, 1987 (n = 25,570). Records of the Ontario Cancer Registry (OCR) were linked to hospital procedure and discharge abstracts and to RT records from Ontario cancer centers. A case was labelled as lumpectomy if this was the maximum breast surgery within 4 months of diagnosis. Postlumpectomy RT occurred up to 1 year postdiagnosis. Laterality was assigned from the laterality descriptor of the RT records. A case was labelled as having had a fatal MI if ICD code 410 (myocardial infarction) was recorded as the cause of death in the OCR. We used logistic regression to compare the likelihood of utilization of: 1. Dose per fraction > 2.00 Gy; 2. cobalt vs. linac; and 3. boost RT. We used life table analysis and the log rank test comparing the time to fatal MI from diagnosis of breast cancer between women who received left-sided postlumpectomy RT and women who received right-sided. We used Cox proportional hazards models to study the relative risk for left-sided cases overall, and stratified by age, RT characteristics, and among conditional survival cohorts. RESULTS: Postlumpectomy RT was received by 1,555 left-sided and 1,451 right-sided cases. With follow-up to December 31, 1995, 2% of women with left-sided RT had a fatal MI compared to 1% of women with right-sided RT. Comparison of the time to failure between women who had left-sided RT and women who had right-sided RT showed the left-sided RT group to be associated with a higher risk of fatal MI (p = 0.02). Adjusting for age at diagnosis, the relative risk for fatal MI with left-sided postlumpectomy RT was 2.10 (1.11, 3.95). CONCLUSION: Among women who received postlumpectomy RT for breast cancer in Ontario between 1982-1987, left-sided postlumpectomy RT was associated with a higher risk of fatal MI compared to right-sided.

Adult↗

PubMed1999

Using TNM staging to predict survival in patients with squamous cell carcinoma of head & neck.

BACKGROUND: There is a need for a classification system for prognosis based on the TNM system for patients with squamous cell carcinoma of the head and neck such that patient groupings are homogeneous within and heterogeneous between. METHODS: Six hundred fifty-five consecutive patients with invasive squamous cell carcinoma of the head and neck followed prospectively are split into a training set and a test set. Using the training set, the Cox Proportional Hazards Model and the outcome of dead with disease, we created homogeneous prognostic levels (PLs) based on RR. Using the test set, we compare our model to others in the literature. RESULTS: Using the training set, we identified five PLs, and using the test set, we demonstrated that our model is superior to others for both within-group homogeneity and between-group heterogeneity. CONCLUSIONS: A simple classification system can be used to group patients for survival and is valid for future study in prognostication.

Adult↗

PubMed1998

Mortality from myocardial infarction after adjuvant radiotherapy for breast cancer in the surveillance, epidemiology, and end-results cancer registries.

PURPOSE: To compare the risk for fatal myocardial infarction (MI) after adjuvant radiotherapy (RT) for left-sided breast cancer with the risk for MI after adjuvant RT for right-sided breast cancer. METHODS: We studied women with local- and regional-stage breast cancer diagnosed from 1973 to 1992 from the Surveillance, Epidemiology, and End-Results (SEER) cancer registries. We performed life-table analysis, the log-rank test, and Cox proportional hazards regression to compare the time to fatal MI from diagnosis between left-sided and right-sided cases, censoring deaths from other causes. RESULTS: Among irradiated patients, the relative risk (RR) for fatal MI in women with left-sided breast cancer was 1.17 (95% confidence interval [CI], 1.01 to 1.36), controlling for age, compared with those with right-sided breast cancer. The RR for fatal MI among left-sided cases was increased for those under the age of 60 years (RR = 1.98; 95% CI, 1.31 to 2.97) compared with right-sided cases, but not at age 60 years or older. Among women with irradiated regional-stage cancer who were younger than 60 years of age, the risk was significantly increased (RR = 2.24; 95% CI, 1.38 to 3.64) for those with left-sided compared with right-sided breast cancer, but not among patients aged 60 years or older. Among irradiated local-stage cases, the risk for those with left-sided breast cancer was not significantly elevated in either age category. Analysis of 5-year conditional survival cohorts showed an increased risk for irradiated left-sided cases among women younger than 60 years of age in the 10- to 15-year conditional survival cohort (RR = 5.28; 95% CI, 1.82 to 15.3). CONCLUSION: Adjuvant RT for left-sided breast cancer diagnosed in women younger than 60 years of age is associated with a higher risk for fatal MI 10 to 15 years later compared with adjuvant RT for right-sided cases.

Adult↗

PubMed1998

Radiotherapy for breast cancer in Ontario: rate variation associated with region, age and income.

OBJECTIVE: To describe the variation in the use of radiotherapy (RT) in women in Ontario within 1 year of diagnosis of breast cancer, from 1982 to 1991, and to identify factors associated with these variations. DESIGN: Retrospective, population-based cohort study. SETTING: Ontario. POPULATION: All women registered by the Ontario Cancer Registry (OCR) with a diagnosis of invasive breast cancer between Jan. 1, 1982, and Dec. 31, 1991. INTERVENTIONS: RT to any anatomic site within 1 year of the diagnosis of breast cancer. OUTCOME MEASURES: Odds of receiving RT within 1 year of diagnosis (from RT files from all radiotherapy departments in Ontario) associated with year and with geographic, age-related and socioeconomic factors. RESULTS: Use of RT within 1 year of diagnosis increased from 21.1% (95% confidence interval [CI] 19.8-22.4) in 1982 to 44.7% (95% CI 43.4-46.0) in 1991 (p < 0.0001). Among the regions of Ontario, the use of RT varied from 24.5% (95% CI 23.5-25.6) to 44.4% (95% CI 43.0-45.9) (p < 0.0001). Increasing age was associated with decreasing likelihood of receiving RT (test for trend p < 0.0001), as was decreasing income (test for trend p < 0.0001). CONCLUSIONS: The use of RT within 1 year of the diagnosis of breast cancer in women in Ontario varies by region, age and income. Despite universal and comprehensive health insurance coverage, women with breast cancer in some populous regions of Ontario were less likely to receive RT within 1 year of their diagnosis than women in other populous regions.

Age Factors↗

PubMed1997

Does a centralized radiotherapy system provide adequate access to care?

PURPOSE: In the Canadian province of Ontario, all radiotherapy is provided by a centrally managed provincial network of nine cancer centers. The primary goal of this study was to determine whether this highly centralized radiotherapy system provides adequate and equitable access to care for the province's dispersed population. METHODS: The Ontario Cancer Registry (OCR) was used to identify 295,386 cases of invasive cancer, excluding nonmelanoma skin cancer, which were diagnosed in Ontario between 1984 and 1991. Electronic radiotherapy records from each of the province's radiotherapy centers were linked to the registry at the level of the individual case. RESULTS: The proportion of incident cases treated with radiotherapy was 18.8% at 4 months after diagnosis, 23.7% at 1 year, 25.8% at 2 years, 28.2% at 5 years, and 29.1% at 8 years. These rates of radiotherapy use are much lower than the accepted national and international targets, and lower than rates reported from other jurisdictions. The rate of radiotherapy use at 1 year varied significantly from county to county across Ontario (range, 18.6% to 32.4%; P < 10(-6)), and the highest rates were recorded in communities close to radiotherapy centers. There was a common geographic pattern of rate variations among several disease groups, including breast cancer, lung cancer, the genitourinary malignancies, and the gastrointestinal malignancies. CONCLUSION: The low and uneven rates of radiotherapy use across the province indicate that Ontario's centralized radiotherapy system does not, at present, provide adequate or equitable access to care.

Cancer Care Facilities↗

PubMed1997

Decision analysis in locally advanced non-small-cell lung cancer: is it useful?

PURPOSE: The optimal management of locally advanced non-small-cell lung cancer (NSCLC) has not been established. While combined-modality treatments have been shown to increase the survival of patients with this illness, the appropriate balance between the benefit of increased quantity of life and the quality-of-life costs of the more toxic treatment combinations remains unresolved. Decision analysis has been promoted as useful when medical decisions must be made under conditions of uncertainty. We consider the potential of this method to guide therapy in locally advanced NSCLC. METHODS: We developed two types of decision models that addressed the choice between radiation alone and combined chemotherapy-radiation therapy in locally advanced NSCLC. The models were constructed using the principles of decision analysis. RESULTS: The models successfully replicated results of relevant clinical trials published in the literature. The analyses of both models showed that the treatment decision was sensitive to patients' values, despite significant increases in survival rates. The models clarified a need for further validation of the three fundamental components: structuring the decision, determining the probabilities of events, and assigning utilities to treatment outcomes. CONCLUSION: In the setting of NSCLC, the models suggest that quality-of-life considerations are important in the treatment choice. Further research is required to identify the health states critical to the decision, the probabilities for occurrence of these health states, and valid measures of their utility.

Carcinoma, Non-Small-Cell Lung↗

PubMed1997

Socioeconomic status and cancer survival in Ontario.

BACKGROUND AND PURPOSE: It is known that the socioeconomic status (SES) of the patient is associated with cancer survival in the United States. The purpose of this study was to determine whether the association between SES and survival is also present in Canada, a society with a comprehensive, universal, health insurance program. METHODS: A population-based cancer registry was used to identify the 357,530 cases of invasive cancer diagnosed in the Canadian province of Ontario between 1982 and 1991. Information from the 1986 Canadian census was linked to the registry and used to describe the SES of the area in which each patient resided. Cox regression was used to describe the association between median household income and survival while controlling for age, sex, and the region in which the patient resided. The Cox model was fitted in a competing risk framework to assess the association between income and the probability of specific causes of death. RESULTS: Lung cancer and cancers of the head and neck region were relatively more common in poor-income communities, and cancers of the breast, CNS, and testis were relatively more common in richer communities. A strong and statistically significant association between community income and survival was observed in cancers of the head and neck region, cervix, uterus, breast, prostate, bladder, and esophagus. Smaller, but significant associations were seen in cancers of the lung and rectum. No significant association between community income and survival was observed in cancers of the stomach, colon, pancreas, or ovary. Analysis of the cause of death showed that community income is associated both with the probability of death from cancer and with the probability of death from other causes. CONCLUSION: Although Canada's health care system was designed to provide equitable access to equivalent standards of care, it does not prevent a difference in cancer survival between rich and poor communities.

Cause of Death↗

PubMed1997

Does TANIS (T And N Integer Score) help predict survival?

OBJECTIVE: This study was conducted to validate the TANIS model as a predictor of survival. DESIGN: Using Cox Proportional Hazards model, we examined the subgroups of the TANIS score levels to see if they were homogeneous on survival. SETTING: The Departments of Otolaryngology and Oncology and the Radiation Oncology Research Unit at Queen's University in Kingston, Ontario. METHODS: Five hundred and ninety-four patients with cancer of the head and neck classified by TNM and TANIS were analyzed for the outcome dead of disease using estimates of relative risk. RESULTS AND CONCLUSION: The stages of TNM and the levels of TANIS contain subgroups of patients with different survival rates.

Adult↗

PubMed1996

Necrosis following radiotherapy for carcinoma of the pinna.

PURPOSE: Radiation therapy is often the preferred modality of treatment for carcinoma of the pinna because it avoids the cosmetic defect of surgery. However, radiation oncologists are sometimes reluctant to irradiate the ear because of the risk of subsequent necrosis. The goal of this study was to establish the long-term disease control and necrosis rates following irradiation of the external ear. METHODS AND MATERIALS: A retrospective analysis was undertaken of 138 courses of curative radiotherapy given to 128 patients for biopsy-proven basal (70 courses), squamous (62 courses), or mixed (6 courses) tumors of the pinna between January 1, 1982, and December 31, 1991, at the Kingston Regional Cancer Center. RESULTS: The median age of the patients was 73 (range 43-94) and the median size of the tumors was 12 mm (range 3-50 mm). Treatment was given using orthovoltage X rays (79) or electrons (59). The most common dose prescription was 35 Gy/5 fractions; total doses ranged from 17.50 to 64 Gy. The median follow-up is 58 months (range 6-149). The actuarial 5-year local control rate is 93%; the actuarial necrosis rate at 5 years is 13%. Most necroses healed with conservative management; only two patients required surgery for necrosis. We analyzed the following factors as possible predictors of radiation necrosis: patient age, size of lesion, histology, fraction size, total dose, overall time, and beam energy. Only daily fraction sizes > 6 Gy (p = 0.0093) and treatment times < 5 days (p = 0.0053) were significantly associated with an increased risk of necrosis. CONCLUSION: To reduce the risk of necrosis, radiation therapy for external ear cancer should be given using protracted fractionation.

Adult↗

PubMed1996

Does N stage predict survival?

OBJECTIVE: To examine the relationship between N stage and survival in head and neck cancer to see if N stage has prognostic value. DESIGN: Database analysis using the Cox Proportional Hazards Model. METHOD: Five hundred and twenty-three consecutive patients with squamous cell carcinoma of the head and neck prospectively entered into a clinical database are analyzed for the outcome of dead with disease. RESULTS: There is no difference in survival between some increments of N stage, specifically N1 and N2, controlling for T stage and site. CONCLUSION: A modified N stage system consisting of N0, N(limited), and N(extended) appears to have a better prognostic value.

Carcinoma, Squamous Cell↗

PubMed1994

Outmigrant ascertainment for bias assessment in environmental epidemiology.

BACKGROUND: In the summer of 1985, the McGill Epidemiology Rapid Response Unit undertook a study comparing two areas exposed to emissions of 'sour gas' refineries to an unexposed area. One operational objective of the project was the identification and survey of all the people who had lived in the study area but had since moved (outmigrants). METHODS: We estimated the number of outmigrants (people who had ever lived in the area during the period 1957 to 1985) to be 3363 by using information obtained from our cross-sectional survey and from population statistics for the area of interest. Ten different methods combined lead to the identification of approximately 87% of all the outmigrants who left the study area during that period. We used vital statistics to identify the outmigrants who had died and mailed questionnaires to obtain the necessary information from the others. RESULTS: We confirmed the vital status of approximately 46% of them (1532/3363). The results from the outmigrant survey showed that they were younger than area residents, that they experienced lower rates of heart disease and hypertension and that they had moved for health reasons in only 1.3% of the cases. These findings were similar across comparison areas. CONCLUSION: We concluded that there was no effect due to migration bias on the cross-sectional study results. This evidence considerably strengthened the conclusions regarding the effects of exposure, a benefit that largely justified the cost of identifying and surveying the outmigrants.

Adolescent↗

PubMed1994

Quality adjusted life years added by treatment of obstructive sleep apnea.

We assessed the impact of treatment with nasal continuous positive airway pressure (nCPAP) on the quality of life of 19 patients with obstructive sleep apnea (OSA). We measured the utility for the patients' health states before and with treatment using the standard gamble approach. The study group had an average age of 57 years and had been on treatment for a mean of 9.5 months. For all the patients, the polysomnographic indicators of OSA disease severity improved markedly with treatment. For nine of the 12 symptoms most commonly associated with OSA, the patients reported improvement during treatment. The mean utility and the standard deviation obtained with the standard gamble method were 0.87 +/- 0.17 on treatment and 0.63 +/- 0.29 pretreatment. The difference in utility between treatment and pretreatment health states was combined with the life expectancy of each patient to generate the number of quality adjusted life years (QALYs) considered equivalent to the impact of treatment. This resulted in an average gain of 5.4 QALYs. When we related this impact to the cost of treatment, we obtained a cost-utility ratio between Can $3,397 and Can $9,792 per QALY added. These costs are relatively small when compared to the cost per QALY for many other clinical interventions. Hence, nCPAP clearly offers the prospect for a well-tolerated therapy with a very favorable cost-utility ratio.

Adult↗

PubMed1993

Atrial fibrillation and anticoagulation: from randomised trials to practice.

Randomised trials confirm that anticoagulants reduce the risk of emboli in atrial fibrillation. To apply this evidence to practice, we developed an expression relating all relevant factors. Trial-based estimates of the risks of emboli and haemorrhage, and of the effects of anticoagulants on these risks were used to derive the extent to which haemorrhage has to be seen to be more detrimental than emboli to justify not using anticoagulants. Information from other studies was used to assess the risks for the types of patients not included in the trials. Haemorrhage needs to be assessed as being at least six times more detrimental than emboli to warrant withholding anticoagulants from patients like those in the trials. Only in patients with lone atrial fibrillation and in those with features suggesting a bleeding risk six times higher than the trials' average would a perception of equal detriment risk justify not giving anticoagulation.

Anticoagulants↗

PubMed1993

The morbidity of abdominal hysterectomy.

OBJECTIVE: To determine the morbidity of abdominal hysterectomy. DESIGN: Descriptive. Physician billings to the Quebec Health Care Plan in the 1-month period after abdominal hysterectomy were examined. SETTING: Operations performed in 102 hospitals in the Province of Quebec between Jan. 1, 1989, and Mar. 31, 1989, were selected. PATIENTS: The study group included 3322 patients who had abdominal hysterectomy. Patients who had vaginal or abdominal hysterectomy for invasive cancer or pregnancy-related complications were excluded. A patient was considered to be morbid if the physician's intervention indicated concern for the patient's well-being. MAIN OUTCOME MEASURES: Multiple logistic regression analysis to determine the adjusted rate ratio for inclusion in a categorical list of morbid patients among different subsets of surgeons, hospitals and patients. RESULTS: Postoperative morbidity occurred in 646 patients (19.5%), who spent an average of 1.7 days longer in the hospital than patients with no postoperative morbidity. There were two postoperative deaths (0.1%). Forty-nine patients (1.5%) had postoperative surgical intervention. On 119 occasions (3.6%), patients were treated in the intensive care unit. A consultation was given by a medical specialist in 303 cases (9.1%). The rate ratio for postoperative morbidity was not significantly affected by years in practice or specialty of the surgeon but was increased for operations performed in mid-sized hospitals. The strongest predictor of postoperative morbidity was pre-existing medical disorder (RR). CONCLUSION: The major causes of morbidity in patients who undergo abdominal hysterectomies are medical rather than surgical.

Female↗

PubMed1991

Factors relevant to preventing embolic stroke in patients with non-rheumatic atrial fibrillation.

Whether or not to treat patients with non-rheumatic atrial fibrillation with anticoagulants to prevent embolic stroke is a dilemma for physicians. If randomized trials, currently underway, demonstrate a beneficial effect, the dilemma will not be solved because not all of the relevant factors can be addressed by trials. We used current knowledge about non-rheumatic atrial fibrillation and a method of obtaining patient-derived weights for avoiding stroke from eight medically trained subjects, to determine the overall benefit of anticoagulants and to see what factors were relevant and what effect each might have in deciding whether to use anticoagulant therapy. Using standard assumptions, anticoagulants gave an expected benefit for all subjects. The expected benefit (expressed in terms of lives per 1000 saved due to anticoagulants) varied between 5.4 and 46.7. This benefit remained for all subjects when we did a sensitivity analysis for different rates of stroke prevented by anticoagulants and different rates of intracranial hemorrhage caused by anticoagulants. When we used different baseline rates of stroke and different impacts of major hemorrhagic complications the benefit disappeared for 3 and 4 subjects respectively. We found the factors that were most crucial to the decision will not be included in randomized trials; the weight that an individual would place on avoiding embolic stroke vs the risk of intracranial bleeding from anticoagulant therapy; and the rate of embolic stroke that could be expected for the subject at risk. Factors which will be measured in randomized trials, will change results less substantially: the increased risk of major hemorrhages; the proportion of strokes that could be prevented by treatment; the increase in risk of intracranial hemorrhage. This method of analysis suggests that for most patients anticoagulants are beneficial and that the most important factor in determining this result is the value that subjects put on different outcomes.

Adult↗

PubMed1991

ESRD treatment modality selection: which factors are important in the decision?

UNLABELLED: The purpose of this study was to determine which factors are most important in choosing between ESRD treatments and to assess if patients, R.N.'s and M.D.'s agree or differ as to the level of importance of different factors. METHODS: 22 patients, 11 R.N.'s and 10 M.D.'s were interviewed to determine which factors should be considered. Forty-three factors were identified relevant to CAPD and hemodialysis. Then 14 patients, 8 R.N.'s and M.D.'s were asked to rate each of these factors on a scale of 1-10 (10 being most important) and the average score for each was computed. The factors were then ranked in order of importance (1 being most important). The results revealed that peritonitis ranked as overall the most important factor in determining treatment modality choice. In general, life style considerations ranked higher than medical consequences of a specific therapy. There was concordance amongst the three groups in some areas but there were also differences between patients, R.N.'s and M.D.'s. This raises important issues with regards to the adequacy of patient counselling.

Attitude of Health Personnel↗

PubMedDate not supplied

Content of a decision analysis for treatment choice in end-stage renal disease: who should be consulted?

For an illness whose treatment options lead to similar survival, quality-of-life issues determine the choice. If the patient has not yet experienced the treatments, then the information provided regarding the options plays a crucial role in the patient's choice. The authors interviewed 43 people who are intimately involved with the treatments for end-stage renal disease (ESRD) (ten physicians, 11 nurses, and 22 patients) with a view to determining what information needs to be considered when choosing between the various treatment options for this illness. They compared the three groups based on the items obtained from the interviews to determine whether the inclusion of patients in the process changed the content of the treatment descriptions. They were also interested in determining whether the use of the frequency with which an item is mentioned in the interviews is a valid measure of its relative importance to other items. 1,269 relevant items were obtained from the interviews and categorized into 51 areas of concern (subject domains). The health professionals (physicians and nurses) were found to have mentioned seven subject domains more often than the patients, and no domain was mentioned more often by the patients than by the health professionals. The frequency that an item was mentioned was correlated (r = 0.55) with direct measures of its importance. These results imply that careful consultation with health professionals to determine the content of a decision analysis or informational materials that address treatment choice is sufficient to address patient concerns and that items can be chosen for inclusion based on the relative frequencies with which they are mentioned.

Decision Support Techniques↗

PubMedDate not supplied

Using the TNM system to predict survival in squamous cell carcinoma of the head and neck.

PURPOSE: To create a classification system for prognosis based on the TNM system for patients with squamous cell carcinoma of the Head and Neck such that patient groupings are homogeneous within and heterogenous between. METHOD: 655 consecutive patients with invasive squamous cell carcinoma of the Head and Neck followed prospectively are split into a training set and a test set. Using the training set, the Cox Proportional Hazards Model and the outcome of dead with disease, we create homogenous prognostic levels based on relative risk. Using the test set, we compare our model to others in the literature. RESULTS: Using the training set we identify 5 prognostic levels and using the test set we demonstrate that our model is superior to others for both within group homogeneity and between group heterogeneity. CONCLUSIONS: A simple classification system can be used to group patients for survival and is valid for future study in prognostication.

Carcinoma, Squamous Cell↗