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Colin B Begg

Publications and source records attributed to Colin B Begg.

43 records · Page 3Linked to original sources
PubMed2002

Survival of blacks and whites after a cancer diagnosis.

CONTEXT: In recent years a theory that cancer biology is different in blacks and whites has gained prominence in reaction to epidemiologic observations that blacks have poorer survival than whites, even when diagnosed with cancer of similar severity. Yet, few studies have evaluated whether lower-quality treatment and shorter overall life expectancy due to a greater burden of other illnesses may explain the survival discrepancy. OBJECTIVE: To estimate the magnitude of overall and cancer-specific survival differences between blacks and whites who receive comparable treatment for similar-stage cancer. DATA SOURCES: We searched MEDLINE for English-language articles published from 1966 to January 2002 that reported on overall survival for black and white patients treated similarly for cancer. STUDY SELECTION: The abstracts or titles for 891 citations were independently examined by 2 authors. The full text was retrieved if the abstract mentioned both black and white patients, made some comment regarding either similarity of treatment received or presented an analysis based on the treatment received, and commented on survival. Studies were included if they included data for at least 10 black and 10 white patients; specified the cohort ascertainment method and what measures were undertaken to minimize loss to follow-up; summarized survival of both blacks and whites using actuarial measures; presented outcomes within stage, adjusted for stage, or based on cohorts with balanced stage distributions; and specified that blacks and whites in the study received similar treatment. We identified 89 unique cohorts in 54 articles that met our inclusion criteria. DATA EXTRACTION: Overall survival rates and hazard ratios (HRs) for death for blacks relative to whites were calculated. These were subsequently adjusted for rates of death due to causes other than the cancer under study to determine cancer-specific survival and cancer-specific HRs. DATA SYNTHESIS: Results represent 189 877 white and 32 004 black patients with 14 different cancers. Compared with whites, blacks had an overall excess risk of death (HR, 1.16; 95% confidence interval [CI], 1.12-1.20). After correction for deaths due to other causes, the cancer-specific HR was 1.07 (95% CI, 1.02-1.13). Of the 14 cancers, blacks were at a significantly higher risk of cancer-specific death only for cancer of the breast, uterus, or bladder. CONCLUSIONS: Only modest cancer-specific survival differences are evident for blacks and whites treated comparably for similar-stage cancer. Therefore, differences in cancer biology between racial groups are unlikely to be responsible for a substantial portion of the survival discrepancy. Differences in treatment, stage at presentation, and mortality from other diseases should represent the primary targets of research and interventions designed to reduce disparities in cancer outcomes.

Black or African American↗
PubMed2002

Variations in morbidity after radical prostatectomy.

BACKGROUND: Recent studies of surgery for cancer have demonstrated variations in outcomes among hospitals and among surgeons. We sought to examine variations in morbidity after radical prostatectomy for prostate cancer. METHODS: We used the Surveillance, Epidemiology, and End Results-Medicare linked data base to evaluate health-related outcomes after radical prostatectomy. The rates of postoperative complications, late urinary complications (strictures or fistulas 31 to 365 days after the procedure), and long-term incontinence (more than 1 year after the procedure) were inferred from the Medicare claims records of 11,522 patients who underwent prostatectomy between 1992 and 1996. These rates were analyzed in relation to hospital volume and surgeon volume (the number of procedures performed at individual hospitals and by individual surgeons, respectively). RESULTS: Neither hospital volume nor surgeon volume was significantly associated with surgery-related death. Significant trends in the relation between volume and outcome were observed with respect to postoperative complications and late urinary complications. Postoperative morbidity was lower in very-high-volume hospitals than in low-volume hospitals (27 percent vs. 32 percent, P=0.03) and was also lower when the prostatectomy was performed by very-high-volume surgeons than when it was performed by low-volume surgeons (26 percent vs. 32 percent, P<0.001). The rates of late urinary complications followed a similar pattern. Results for long-term preservation of continence were less clear-cut. In a detailed analysis of the 159 surgeons who had a high or very high volume of procedures, wide surgeon-to-surgeon variations in these clinical outcomes were observed, and they were much greater than would be predicted on the basis of chance or observed variations in the case mix. CONCLUSIONS: In men undergoing prostatectomy, the rates of postoperative and late urinary complications are significantly reduced if the procedure is performed in a high-volume hospital and by a surgeon who performs a high number of such procedures.

Aged↗
PubMed2002

Hospital and surgeon procedure volume as predictors of outcome following rectal cancer resection.

OBJECTIVE: To compare surgeon and hospital procedure volume as predictors of outcomes for patients with rectal cancer. SUMMARY BACKGROUND DATA: Although a "volume-outcome" relationship exists for several major cancer operations, the impact of procedure volume on outcomes following rectal cancer surgery remains uncertain, and it has not been determined whether hospital or surgeon volume is a more important predictor of outcomes. METHODS: A retrospective population-based cohort study utilizing the Surveillance, Epidemiology and End Results (SEER)-Medicare linked database identified 2,815 rectal cancer patients aged 65 and older who had surgery for a primary tumor diagnosed in 1992-1996 in a SEER area. Hospital- and surgeon-specific procedure volume was ascertained based on the number of claims submitted over the 5-year study period. Outcome measures were mortality at 30 days and 2 years, overall survival, and the rate of abdominoperineal resections. Age, sex, race, comorbid illness, cancer stage, and socioeconomic status were used to adjust for differences in case mix. RESULTS: Neither hospital- nor surgeon-specific procedure volume was significantly associated with 30-day postoperative mortality or rates of rectal sphincter-sparing operations. Although an association between hospital volume and mortality at 2 years was evident, this finding was no longer significant once surgeon-specific volume was controlled for. In contrast, surgeon-specific volume was associated with 2-year mortality and remained an important predictor even after adjustment for hospital volume. Surgeon volume was also better than hospital procedure volume at predicting long-term survival. CONCLUSIONS: Surgeon-specific experience as measured by procedure volume can have a significant impact on survival for patients with rectal cancer.

Aged↗
PubMed2002

Reporting participation in case-control studies.

Although low participation in case-control studies may threaten their validity, it is difficult to evaluate the potential problem of nonresponse across studies because the level of participation among subjects is not reported in a consistent manner. This commentary presents a proposal for standard reporting of the process by which control subjects are recruited to a study and the outcomes of recruitment attempts. We encourage authors to provide a description of the sampling frame, the method of selecting units from the frame, and the number of units selected. For each unit selected, an outcome should be classified into four broad categories: ineligible sampling unit, unable to determine eligibility, respondent not eligible, and respondent screened and eligible. Details should be provided in each category; these details would differ according to the method used to contact potential respondents (by random-digit dialing, by telephone from a list, in person, or by mail). The proportion who participated can be reported as the investigator sees fit, as long as reporting of the components is complete. The sampling frame and outcomes should be reported separately for various parts of the study, such as controls from different sources or those who gave biological specimens. Standardized reporting will allow an evaluation of the success of various methods in recruiting potential participants, and will contribute important information for assessing the validity of individual studies.

Case-Control Studies↗
PubMed2002

Measuring complications of cancer treatment using the SEER-Medicare data.

BACKGROUND: The linkage of SEER registry data with Medicare claims allows the longitudinal tracking of health care and outcomes for patients after a cancer diagnosis. One category of outcomes amenable to research using Medicare claims is complications of cancer treatments: the unintentional, adverse side effects or sequelae of interventions used to treat or palliate cancer patients. RESEARCH DESIGN: The authors review some of the methods and limitations of using Medicare claims to identify both acute and chronic complications of cancer treatments, and present an original analysis comparing survey-based and claims-based complications following radical prostatectomy for prostate cancer to illustrate some of the potential limitations inherent in using claims for this purpose. RESULTS: Utility of the Medicare claims for identifying postdischarge complications varies by the patient type, the initial treatment used, and any subsequent treatment of complications. For patients undergoing surgical interventions, Medicare claims can be used to identify most acute inpatient complications. However, claims data cannot be used as effectively in the long-term to capture chronic complications, particularly when the complication does not consistently prompt an intervention. CONCLUSION: Researchers who use the SEER-Medicare-linked database to assess long-term complications of cancer treatments should exercise caution when designing and interpreting studies. Ideally, for studies of most chronic complications of cancer care, validation studies similar to the one performed here would provide valuable additional evidence to assess the credibility of conclusions based on claims data.

Aged↗
PubMed2002

Two-stage designs for gene-disease association studies.

The goal of this article is to describe a two-stage design that maximizes the power to detect gene-disease associations when the principal design constraint is the total cost, represented by the total number of gene evaluations rather than the total number of individuals. In the first stage, all genes of interest are evaluated on a subset of individuals. The most promising genes are then evaluated on additional subjects in the second stage. This will eliminate wastage of resources on genes unlikely to be associated with disease based on the results of the first stage. We consider the case where the genes are correlated and the case where the genes are independent. Using simulation results, it is shown that, as a general guideline when the genes are independent or when the correlation is small, utilizing 75% of the resources in stage 1 to screen all the markers and evaluating the most promising 10% of the markers with the remaining resources provides near-optimal power for a broad range of parametric configurations. This translates to screening all the markers on approximately one quarter of the required sample size in stage 1.

Breast Neoplasms↗