Biomedical subjects

M E Nierengarten

Publications and source records attributed to M E Nierengarten.

4 recordsLinked to original sources

PubMed2000

The need for long-term surveillance for patients treated with curative radiotherapy for Hodgkin's disease: University of Minnesota experience.

PURPOSE: To examine the long-term outcome of Stage I, II, and III patients treated with curative radiotherapy for Hodgkin's disease at the University of Minnesota Hospital, with particular focus on long-term treatment-related complications and the need for long-term surveillance after treatment. METHODS AND MATERIALS: A total of 210 Stage I, II, and III patients (98 female, 112 male) treated at the University of Minnesota since 1970 were included in this study. All patients were laparotomy staged. Between 1970 and 1974, 35 high-risk patients (i.e., patients with large mediastinal mass, and/or hilar disease, and/or splenic involvement) and 40 low-risk patients were treated with standard field radiotherapy. From 1975 on, 67 high-risk patients received radical radiotherapy because of poor outcomes with standard radiotherapy, and 68 low-risk patients received standard radiotherapy. Salvage chemotherapy was given to 62 patients who recurred. Median follow-up for all patients was 15.6 years (range 0. 35-26.5 years). Long-term complications after treatment were assessed using standardized incidence ratios (SIR) and mortality ratios (SMR), with particular focus on cardiac complications and secondary malignancies. RESULTS: By study end, 70% of the patients are alive and 70% had never recurred. Complications included 33 second malignancies and 75 cardiovascular events. Patients treated for Hodgkin's disease had about 7 times the risk of dying from cardiac problems (SMR = 7.2) and 10 times the risk of dying from a second malignancy (SMR = 10.3) compared to the general population. In terms of absolute risk, Hodgkin's disease would cause seven additional deaths from secondary malignancies per year among 1000 patients and four additional deaths from cardiac problems. CONCLUSION: Hodgkin's disease patients treated successfully with radiotherapy are at an increased risk for developing long-term treatment-related cardiac disease and/or second malignancies. Careful monitoring of these patients is essential to manage morbidity and minimize mortality from these complications. Suggestions for the establishment of worldwide surveillance programs for these patients are proposed.

Adolescent↗

PubMed1996

The impact of radiation on early breast carcinoma survival. A Bayesian analysis.

BACKGROUND: A Bayesian statistical approach was used to examine the effect of local control on survival of patients with early breast carcinoma. METHODS: The effect of radiation on overall survival was examined in the four published randomized trials on conservation surgery with or without radiation: the Uppsala-Orebro, Canadian, NSABP-B06, and Milan III trials. Classical and Bayesian statistical approaches were used to evaluate the effect of sample size and follow-up on the results. RESULTS: Combined 5-year survival results of patients with negative lymph nodes and surgical margins in the Uppsala-Orebro, Canadian, and NSABP-B06 trials indicated a 79% probability of a positive benefit with the addition of radiation and a 9.6% relative reduction in the annual mortality rate in favor of the irradiated patients. For the same subgroup of patients in the NSABP-B06 trial, the probability of a positive benefit with radiation increased from 65% at 5 years to 87% at 10 years, and is reflected in the change of the relative reduction in annual mortality from 8.2% at 5 years to 17.5% at 10 years. For all patients who accepted randomized treatment in the NSABP-B06 trial, the probability of a positive survival benefit with radiation was 80%, 98%, and 91% at 5, 10, and 12 years, respectively, with corresponding relative reductions in the annual mortality rates of 12.8%, 20.5%, and 15.2%. CONCLUSIONS: The addition of radiation to lumpectomy offers a small but important survival advantage, even in patients with negative surgical margins and lymph nodes. Because locoregional control and breast preservation are significantly improved with radiation, even a small survival advantage substantiates the importance of radiation in the treatment of patients with early breast carcinoma.

Bayes Theorem↗

PubMed1995

The importance of local control in the conservative treatment of breast cancer.

The purpose of this study was to examine the meaning of local control, especially on survival, in breast cancer patients treated by lumpectomy with or without radiotherapy. We analyzed the survival results of four major published randomized trials that compare conservation surgery with or without radiation using three different statistical approaches: p-values, confidence intervals, and Bayesian techniques. All four trials report statistically significant increased local control and improved survival for the irradiated patients. Survival based on p-values and confidence intervals shows statistical significance for long-term follow-up of the NSABP-B06 trial, but not for the other trials, probably because of small sample sizes and short follow-up. At 10 years, the overall survival rates for the NSABP-B06 were 65% and 71% for lumpectomy alone or with radiation respectively. Interpreted in a Bayesian framework, the expected advantage in 10-year survival was 6% (the mean of NSABP-B06 10-year survival) with an 83% probability that the 10-year survival difference may lie between 2% and 10%. An 85% probability that 3% of patients will survive at 10 years because of irradiation translates into a 30% reduction in annual odds of death several years after treatment in stage I good prognosis patients and 15% in stage I poor prognosis patients. Analysis of the randomized trials comparing lumpectomy with or without radiation indicate a clear improvement in survival for the irradiated patients associated with increased local control. Combination of improved survival with the reduced psychological and economic costs associated with local recurrence argues well for the inclusion of radiation for many breast cancer patients.

Bayes Theorem↗

PubMed1993

Influences on inferences. Effect of errors in data on statistical evaluation.

BACKGROUND: Inadvertent random and systemic errors introduced into data sets and manipulation of data are well-defined sources of discrepancies in statistical evaluation of clinical trials. In this study, the authors show the influence of errors on the widely used statistical result, P values. METHODS: Using data from a retrospective study of patients with Hodgkin disease treated at the University of Minnesota between 1970 and 1984 and observed to 1988, we introduced various errors into the data to study the impact on results. RESULTS: Inadvertent random and systemic errors affect statistical results. Data entry and transcription errors, vague definitions of endpoints and prognostic factors, and the omission and selection of patients are examples of frequent errors that affect statistical evaluation. CONCLUSION: The results and inferences of many studies are sensitive to systemic errors and data manipulation. Great care must be given to the clear definitions of terms, exclusion and inclusion criteria, group assignments, treatment protocols, and the subgroups on which statistical analysis is performed. Clinicians and statisticians must work together to improve the performance and interpretation of clinical trials.

Clinical Trials as Topic↗