Biomedical subjects

D M Rothwell

Publications and source records attributed to D M Rothwell.

6 recordsLinked to original sources

PubMed2001

A comparison of published head and neck stage groupings in carcinomas of the tonsillar region.

BACKGROUND: The combination of T, N, and M classifications into stage groupings was designed to facilitate a number of activities including: the estimation of prognosis and the comparison of therapeutic interventions among similar groups of cases. The authors tested the UICC/AJCC 5th edition stage grouping and seven other TNM-based groupings proposed for head and neck cancer to determine their ability to meet these expectations in a specific site: carcinoma of the tonsillar region. METHODS: The authors defined four criteria to assess each stage grouping scheme: 1) The subgroups defined by T and N comprising a given group within a grouping scheme have similar survival rates (hazard consistency); 2) The survival rates differ across the groups (hazard discrimination); 3) The prediction of cure is high (outcome prediction); and 4) The distribution of patients among the groups is balanced. The authors identified or derived a measure for each criterion and the findings were summarized using a scoring system. The range of scores was from 0 (best) to 7 (worst). Data were from a retrospective chart review on 642 cases of carcinoma of the tonsillar region treated with radiotherapy for cure at the Princess Margaret Hospital from 1970-1991. None of the patients had distant metastases. RESULTS: The scheme proposed by Synderman and Wagner, which was published in Otolaryngology Head and Neck Surgery in 1995 (vol.112, pages 691-4), scored best at 1.2. The UICC/AJCC scheme scored worst at 6.1. The hazard consistency ranged from a 3.1% average survival difference to 6.7% across the 8 schemes. The hazard discrimination measure varied by 28% from the best to worst scheme. Prediction varied by up to almost twofold across the schemes assessed. The distribution of patients varied from expected by between 0.13% and 0.57%. CONCLUSION: UICC/AJCC stage groupings were defined without empirical investigation. When tested, this scheme did not perform as well as any of seven empirically-derived schemes the authors evaluated. The results of the current study suggest that the usefulness of the TNM system can be enhanced by optimizing the design of stage groupings through empirical investigation.

Carcinoma, Squamous Cell↗

PubMed2001

Glottic cancer in Ontario, Canada and the SEER areas of the United States. Do different management philosophies produce different outcome profiles?

We compared the management and outcome of glottic cancer in Ontario, Canada to that in the Surveillance, Epidemiology and End Results (SEER) Program areas in the United States to determine whether the greater use of primary radiotherapy with surgery reserved for salvage in Ontario was associated with similar survival and better larynx retention rates than the U.S. approach where primary surgery is used more often. Electronic, clinical and hospital data were linked to cancer registry data and supplemented by chart review where necessary. Initial treatment and survival in patients diagnosed in the SEER areas from 1988 through 1994 were compared to patients from Ontario diagnosed from 1982 through 1995. Actuarial laryngectomy rates were compared for patients over 65 at diagnosis in the two regions. Analyses were conducted over all cases and stratified by disease stage. In localized disease (T1 or T2), conservative treatment was the most common initial treatment in both regions, although total laryngectomy was used more often in SEER than Ontario (6.2% vs. 0.2%, respectively, P <.001). In advanced disease (T3 or T4), total laryngectomy was more commonly used as initial treatment in SEER (62.9% vs. 21.0% in Ontario, P < or =.001). Over all cases, the relative survival rate was 80% in Ontario at 5 years compared to 78% in SEER (P =.33). In localized disease, the relative survival rates were 4 to 5% higher in Ontario from the second year on, while in advanced disease 2 to 3% higher rates in SEER did not approach statistical significance. Actuarial laryngectomy rates at 3 years differed between the two regions, with a 4% higher rate in SEER (P =.01). In localized disease, 12.6% of Ontario patients had a laryngectomy by 3 years postdiagnosis compared to 17.9% in SEER (P =.05). In advanced disease, the rates were 63.3% and 79.2%, respectively (P =.07). There are large differences in the management of glottic cancer between the SEER areas of the U.S. and Ontario and no evidence that a policy emphasizing radiotherapy with surgery reserved for salvage is associated with worse survival. Ultimate laryngectomy rates are lower in Ontario for localized disease and may be lower for advanced disease. Conservation treatment should be used for localized disease while the treatment decision in advanced disease may be especially sensitive to patient values for voice retention versus initial cure.

Aged↗

PubMed2001

Trends in hormonal management of prostate cancer: a population-based study in Ontario.

OBJECTIVE: To provide a population-based description of current practice in the use of hormonal management of prostate cancer. DESIGN,SETTING & PARTICIPANTS: All men in Ontario, Canada, age 65 and older, with confirmed prostate cancer starting maintained hormonal therapy, from July 1992 through December 1998 (11,435 patients). Data sources included the provincial drug benefit plan, hospital services data, and Ontario Cancer Registry. OUTCOME MEASURES: Rates and trends in the use of: surgical or medical castration; total androgen blockade (TAB); and monotherapies based on steroidal or nonsteroidal antiandrogens. RESULTS: In 5.5 years, use of 'standard' therapy based on surgical or medical castration alone dropped from 36% to 26% of patients, while the use of TAB doubled from 22% to 41%. Approximately 15% of patients received nonsteroidal antiandrogens without evidence of therapy aimed at central androgen blockade. Marked regional differences were observed and not explained by patient age or practitioner specialty. CONCLUSIONS: New hormonal therapies for prostate cancer have implications in terms of disease control, patient survival, side effects, and costs. Rapid growth in prescribing of antiandrogens may represent an unnecessary expense for public or private payers, and observed regional differences likely reflect lack of consensus on the relative merit of TAB. Patients and practitioners must have current information on the advantages and disadvantages of different therapeutic options, and quality-of life, particularly with respect to emerging drug therapies.

Aged↗

PubMed2001

Chiropractic manipulation and stroke: a population-based case-control study.

BACKGROUND AND PURPOSE: Several reports have linked chiropractic manipulation of the neck to dissection or occlusion of the vertebral artery. However, previous studies linking such strokes to neck manipulation consist primarily of uncontrolled case series. We designed a population-based nested case-control study to test the association. METHODS: Hospitalization records were used to identify vertebrobasilar accidents (VBAs) in Ontario, Canada, during 1993-1998. Each of 582 cases was age and sex matched to 4 controls from the Ontario population with no history of stroke at the event date. Public health insurance billing records were used to document use of chiropractic services before the event date. RESULTS: Results for those aged <45 years showed VBA cases to be 5 times more likely than controls to have visited a chiropractor within 1 week of the VBA (95% CI from bootstrapping, 1.32 to 43.87). Additionally, in the younger age group, cases were 5 times as likely to have had >/=3 visits with a cervical diagnosis in the month before the case's VBA date (95% CI from bootstrapping, 1.34 to 18.57). No significant associations were found for those aged >/=45 years. CONCLUSIONS: While our analysis is consistent with a positive association in young adults, potential sources of bias are also discussed. The rarity of VBAs makes this association difficult to study despite high volumes of chiropractic treatment. Because of the popularity of spinal manipulation, high-quality research on both its risks and benefits is recommended.

Adult↗

PubMed2000

A Canadian comparison of data sources for coronary artery bypass surgery outcome "report cards".

BACKGROUND: Prior comparisons of administrative versus clinical data for creating coronary artery bypass graft (CABG) surgery outcome "report cards" are all from the United States and yield inconsistent conclusions regarding the validity of administrative data report cards. In this study, we compared 2 CABG surgery outcome report cards for Ontario, Canada: one derived from clinical data from the Cardiac Care Network of Ontario and one derived from administrative data from the Canadian Institute for Health Information. METHODS: Data from 4 fiscal years, 1992-93 through 1995-96, were used. The Canadian Institute for Health Information report card was derived from administrative data only. The Cardiac Care Network report card drew on prospectively collected clinical information that included variables such as left ventricular ejection fraction but also required linkages to the Canadian Institute for Health Information data for ascertainment of selected comorbidities and in-hospital mortality rates. Logistic regression models were used to calculate risk-adjusted death rates for each of the 9 hospitals performing CABG surgery in Ontario. RESULTS: The risk-adjusted death rates were quite similar between data sources for 7 of the 9 hospitals. For 2 hospitals, rather large absolute differences in adjusted death rates of 0.58% and 0.64% were seen between report cards. There was a strong correlation between data sources for risk-adjusted hospital death rates (intraclass correlation coefficient = 0.927, P <.001) and for rankings of adjusted hospital death rates (Spearman correlation coefficient = 0.828, P =.02). CONCLUSION: These results from Ontario, Canada, reveal general similarities between administrative and clinical data report cards for CABG surgery. However, clinical data are likely needed if individual hospitals are to be publicly scrutinized in outcome report cards.

Adult↗

PubMed2000

Management and outcome of glottic cancer: a population-based comparison between Ontario, Canada and the SEER areas of the United States. Surveillance, Epidemiology and End Results.

OBJECTIVE: We compared treatment practice and outcome in glottic cancer in Ontario, Canada to that in the Surveillance, Epidemiology and End Results (SEER) program areas in the United States to determine whether the Ontario emphasis on the use of delayed combined therapy was associated with similar survival and better laryngectomy-free survival than the U.S. approach, which emphasizes greater use of surgery. METHODS: Electronic, clinical, and hospital data were linked to cancer registry data. The study groups compared on survival comprised all patients diagnosed from 1982 to the end of 1991 in Ontario (2324 patients) and in the SEER areas (5715 patients). Comparisons on initial treatment, laryngectomy rates, and laryngectomy-free survival were limited to subsets of these study populations due to data availability. Initial treatment data were provided by the SEER registries in the U.S. and by the cancer clinic and hospitalization data in Ontario. Information about laryngectomies performed subsequent to initial treatment was available from Medicare hospitalization data in the U.S. and from Canadian Institute for Health Information hospitalization data in Ontario. RESULTS: Although radiotherapy was the most common initial treatment in both areas, it was used more often in Ontario (84.4% versus 63.2% in the U.S. [p < 0.001]). Relative survival was not statistically different with a relative risk comparing SEER to Ontario of 1.09, 95% confidence interval (CI) (0.93, 1.29). Laryngectomy rates were similar with a relative risk of 1.01, 95% CI (0.67, 1.52), and it follows from the survival and laryngectomy rate comparisons that the laryngectomy-free survival was not statistically different (p = .95). CONCLUSIONS: There are large differences in the management of glottic cancer between the U.S. and Ontario and no corresponding differences in survival or laryngectomy-free survival. This work highlights a need for more clinical investigation into the relative merits of differing management policies in glottic cancer.

Aged↗