Impact of the COVID-19 pandemic on cancer diagnoses, stage and survival in Alberta

BACKGROUND

The COVID-19 pandemic is suspected to have affected cancer care and outcomes among patients in Canada. In this study, we evaluated the impact of the state of emergency period during the COVID-19 pandemic (Mar. 17 to June 15, 2020) on cancer diagnoses, stage at diagnosis and 1-year survival in Alberta.

METHODS

We included new diagnoses of the 10 most prevalent cancer types from Jan. 1, 2018, to Dec. 31, 2020. We followed patients up to Dec. 31, 2021. We used interrupted time series analysis to examine the impact of the first COVID-19-related state of emergency in Alberta on the number of cancer diagnoses. We used multivariable Cox regression to compare 1-year survival of the patients who received a diagnosis during 2020 after the state of emergency with those who received a diagnosis during 2018 and 2019. We also performed stage-specific analyses.

RESULTS

We observed significant reductions in diagnoses of breast cancer (incidence rate ratio [IRR] 0.67, 95% confidence interval [CI] 0.59-0.76), prostate cancer (IRR 0.64, 95% CI 0.56-0.73) and colorectal cancer (IRR 0.64, 95% CI 0.56- 0.74) and melanoma (IRR 0.57, 95% CI 0.47-0.69) during the state of emergency period compared with the period before it. These decreases largely occurred among early-stage rather than late-stage diagnoses. Patients who received a diagnosis of colorectal cancer, non-Hodgkin lymphoma and uterine cancer in 2020 had lower 1-year survival than those diagnosed in 2018; no other cancer sites had lower survival.

INTERPRETATION

The results from our analyses suggest that health care disruptions during the COVID-19 pandemic in Alberta considerably affected cancer outcomes. Given that the largest impact was observed among early-stage cancers and those with organized screening programs, additional system capacity may be needed to mitigate future impact.

Development of a diffusion-weighted MRI protocol for multicentre abdominal imaging and evaluation of the effects of fasting on measurement of apparent diffusion coefficients (ADCs) in healthy liver

OBJECTIVE

To assess the effect of fasting and eating on estimates of apparent diffusion coefficient (ADC) in the livers of healthy volunteers using a diffusion-weighted MRI protocol with b-values of 100, 500 and 900 s mm(-2) in a multicentre study at 1.5 T.

METHODS

20 volunteers were scanned using 4 clinical 1.5-T MR scanners. Volunteers were scanned after fasting for at least 4 h and after eating a meal; the scans were repeated on a subsequent day. Median ADC estimates were calculated from all pixels in three slices near the centre of the liver. Analysis of variance (ANOVA) was used to assess the difference between ADC estimates in fasted and non-fasted states and between ADC estimates on different days.

RESULTS

ANOVA showed no difference between ADC estimates in fasted and non-fasted states (p = 0.8) nor between ADC estimates on different days (p = 0.8). The repeatability of the measurements was good, with coefficients of variation of 5.1% and 4.6% in fasted and non-fasted states, respectively.

CONCLUSION

There was no significant difference in ADC estimates between fasted and non-fasted measurements, indicating that the perfusion sensitivity of ADC estimates obtained from b-values of 100, 500 and 900 s mm(-2) is sufficiently low that changes in blood flow in the liver after eating are undetectable beyond the variability in the measurements.

ADVANCES IN KNOWLEDGE

Assessment of the effect of prandial state on ADC estimates is critical, in order to determine the appropriate patient preparation for biological validation in clinical trials.

Constraint-Induced Therapy Approach to Restoring Function After Neurological Injury

Traditional rehabilitation programs for persons with neurologic dysfunction emphasize a compensation, true recovery, or substitution approach to improve functional abilities. Constraint-induced (CI) movement therapy substantially increases more-affected extremity use in the life situation due to the influence of two different underlying mechanisms: overcoming learned nonuse and inducing use-dependent cortical reorganization. In this way, it bypasses the debate over whether a compensation, true recovery, or substitution approach should be used. The purposes of this article are to describe the CI therapy approach, discuss its proposed modes of action, and discuss other unique aspects of CI therapy as a rehabilitation technique.

Constraint-induced movement therapy for motor recovery after stroke

A new therapeutic approach to rehabilitation of movement after stroke, termed Constraint-Induced (CI) Movement Therapy, has been derived from basic research with monkeys given somatosensory deafferentation. CI consists of a family of therapies; their common element is that they induce stroke patients to greatly increase the use of a more affected upper extremity for many hours a day over a 10-14 consecutive-day period. These therapies have significantly improved quality of movement and substantially increased amount of use of a more affected extremity in the activities of daily living in the life situation. The purpose of this paper is to describe the protocol used by the investigative team that developed the family of CI therapies and examined them as an effective rehabilitation approach.

Constraint-induced movement therapy: characterizing the intervention protocol

Constraint-induced movement therapy (CI therapy) is a rehabilitation treatment approach that improves more-affected extremity use following a stroke, especially in the life situation. The originators of the approach describe CI therapy as consisting of a family of therapies including a number of treatment components and subcomponents. When thinking of CI therapy, rehabilitation researchers and clinicians frequently cite a restraining mitt on the less affected arm as the main active ingredient behind improvements in motor function. However, substantial data suggest that restraint makes actually a relatively small contribution to treatment outcome. This paper provides a detailed description of the multiple treatment elements included in the CI therapy protocol as used in our research laboratory. Our aim is to improve understanding of CI therapy and the research supporting its use.

Neuroplasticity and constraint-induced movement therapy

Recent years have seen a proliferation of animal and human studies that have associated significant changes in regional brain physiology with sustained altered environmental or somatic stimuli. The behavioral consequences in such instances can be adaptive or maladaptive. As would be expected, constraint-induced movement therapy (CI therapy), which has been found to be beneficial for chronic stroke hemiparesis, has been repeatedly associated with significant plastic brain changes in a variety of studies that have included transcranial magnetic stimulation (TMS), functional magnetic resonance imaging (fMRI), or other approaches. In some instances, the initial degree of brain reorganization occurred in parallel with the improvement in spontaneous, real-world use by the more-affected hand, which suggests that plastic brain changes in some manner support therapeutic effects. However, the studies are also inconsistent with respect to whether the reorganization changes occur more in the lesioned vs unlesioned hemisphere. Interpreting the physiological outcomes post-treatment is compromised by inconsistencies in study design in the nature of treatment administered, participant recruitment, imaging modality, and extent of follow-up. Improved understanding of the biological basis for neuroplasticity in CI therapy may be obtained through rigorous control of study approaches and through evaluating treatment changes with more than one modality in the same patients concurrently. New quantitative structural brain imaging techniques may allow measuring morphological changes following CI therapy to test hypotheses of regional brain recruitment in use-dependent therapy while avoiding the variability of functional imaging and mapping techniques and the difficulties and assumptions imposed by requiring active limb movement during scanning.

Novel T*2-weighted contrast preparation scheme for segmented k-space myocardial imaging

A novel T*(2)-weighted contrast-preparation scheme is described for use with segmented k-space cardiac sequences. This approach frees the imaging phase from the requirement of a long TE and, hence, a relatively long TR. A [90 degrees (x)-tau-90 degrees (rho)] preparation scheme is used to acquire four image data sets with the phase rho of the second pulse set to x, y, -x, and -y. The rho = x raw data is subtracted from the rho = -x data to form the "x" image, with a similar subtraction to generate the "y" image. These images are added in quadrature to obtain the T*(2)-weighted image. The method results in reduced artifact compared to a simple two-image scheme with rho = x, and y. T*(2) was measured in the myocardial septum in six normal volunteers by comparing tau = 7 and 28 ms images, and it was found to be 44 +/- 5 ms at 0.95 T.

Constraint-induced movement therapy to enhance recovery after stroke

A therapeutic approach to rehabilitation of movement after stroke, termed constraint-induced (CI) movement therapy, has been derived from basic research with monkeys given somatosensory deafferentation. CI therapy consists of a family of therapies; their common element is that they induce persons with stroke to greatly increase the use of a more-affected upper extremity (UE) for many hours a day over a 2- to 3-week period. These therapies have significantly improved quality of movement and substantially increased amount of use of a more-affected UE in the activities of daily living in life situations. A number of neuroimaging and transcranial magnetic stimulation studies have shown that the massed practice of CI therapy produces a massive use-dependent cortical reorganization that increases the area of cortex involved in the innervation of movement of the more-affected UE. The intensity and schedule of delivery of this very efficacious therapy is quite different from that of more traditional physical rehabilitation approaches. As a result, to be clinically applicable, the CI therapy approach to rehabilitation will likely require a paradigm shift in the delivery of physical rehabilitation services.

The reliability of the wolf motor function test for assessing upper extremity function after stroke

OBJECTIVE

To examine the reliability of the Wolf Motor Function Test (WMFT) for assessing upper extremity motor function in adults with hemiplegia.

DESIGN

Interrater and test-retest reliability.

SETTING

A clinical research laboratory at a university medical center.

PATIENTS

A sample of convenience of 24 subjects with chronic hemiplegia (onset >1yr), showing moderate motor impairment.

INTERVENTION

The WMFT includes 15 functional tasks. Performances were timed and rated by using a 6-point functional ability scale. The WMFT was administered to subjects twice with a 2-week interval between administrations. All test sessions were videotaped for scoring at a later time by blinded and trained experienced therapists.

MAIN OUTCOME MEASURE

Interrater reliability was examined by using intraclass correlation coefficients and internal consistency by using Cronbach's alpha.

RESULTS

Interrater reliability was.97 or greater for performance time and.88 or greater for functional ability. Internal consistency for test 1 was.92 for performance time and.92 for functional ability; for test 2, it was.86 for performance time and.92 for functional ability. Test-retest reliability was.90 for performance time and.95 for functional ability. Absolute scores for subjects were stable over the 2 test administrations.

CONCLUSION

The WMFT is an instrument with high interrater reliability, internal consistency, test-retest reliability, and adequate stability.

Kidney and breast cysts: a comparative study of fluids

The contributions of amino acids to the overall osmotic activity of cyst fluids were sought in this comparative study of fluids from the cysts of autosomal dominant polycystic disease (ADPKD) and gross cystic disease of the breast (GCDB). Fluids (n = 18) from 18 women with GCDB and from 8 patients with ADPKD (n = 25), grouped on the basis of sodium concentrations, were analyzed for potassium, chloride, protein, and osmolality by routine methods and for amino acids by reversed-phase high-pressure liquid chromatography. Similarities between kidney and breast cyst fluids included relative isosmolality, a wide range of sodium concentrations, an inverse relationship between sodium and potassium concentrations, higher concentrations of amino acids in low-sodium fluids, and significant correlations between sequential concentrations of amino acids in cyst fluids versus blood and some of its components. Therefore, cyst fluids in ADPKD and GCDB share compositional characteristics, and amino acids, possibly of blood protein origin, accumulate in small but osmotically significant amounts in some, particularly low-sodium, cysts of kidney and breast.

Prospective CYP2D6 genotyping as an exclusion criterion for enrollment of a phase III clinical trial

A phase III study was performed to compare the efficacy and safety of lamotrigine (Lamictal), desipramine (Norpramin), and placebo in the treatment of unipolar depression. Desipramine is extensively metabolized by cytochrome P450 2D6 (CYP2D6), and kinetics of this compound are altered in poor metabolizers. Genotyping was utilized to exclude poor metabolizers in order to increase subject safety and to eliminate the need to continuously monitor plasma desipramine levels. As part of screening, subjects were genotyped for the *3(A), *4(B), and *5(D) alleles, which identify approximately 95% of poor metabolizers. Extensive metabolizers were eligible for randomization to the lamotrigine, desipramine, or placebo arm. Follow-up genotyping for the *6(T) and *7(E) alleles was performed after study enrollment and was used to identify poor metabolizers who may have been incorrectly identified as extensive metabolizers upon initial three-allele screening. Of 628 subjects screened for *3(A), *4(B), *5(D) alleles, 590 (93.9%) were classified as extensive metabolizers. The remaining 38 (6.1%) subjects were poor metabolizers and excluded. Subsequent *6(T) and *7(E) testing revealed that two poor metabolizers had been enrolled, and the follow-up genotyping provided an explanation for the high desipramine plasma concentrations in one subject. No differences in phenotypic or allelic frequencies were found between the study population and literature populations. However, the frequency of poor metabolizers varied among clinical sites (0-15%). For a compound that is extensively metabolized by CYP2D6, prescreening subjects for *3(A), *4(B), *5(D), *6(T) and *7(E) alleles can increase subject safety and eliminate the need to continuously monitor drug plasma concentrations.

Are antioxidant levels measured immediately postoperatively an indicator of magnitude of injury?

BACKGROUND

Little is known about the changes that occur in antioxidant levels in response to surgical trauma. The antioxidant system may influence recovery and healing after operation. Miller et al described a reliable assay for total antioxidant capacity of serum. We studied changes in antioxidant levels secondary to operation using this assay.

METHODS

Twenty-seven patients were studied: 14 abdominal and 13 breast cancer operations. Initial blood samples were obtained when starting the preoperative intravenous line, the second in the recovery room, and every 6 hours thereafter.

RESULTS

Levels did not correlate with diagnosis, extent of operation, age, body mass index, or complications. Differences between preoperative and postoperative values in the down and up groups were significant at P = 0.002 and P = 0.023, respectively. Differences in initial levels between the down and up groups were significant at P = 0.005. Levels 12 hours after operation were stable.

CONCLUSIONS

Rapid return to a baseline of approximately 1 micromole/L, regardless of the direction of initial response, supports the concept of a set point for regulation of serum's antioxidant capacity.

The effects of breathing supplemental oxygen during altitude training on cycling performance

To compare the training effects of doing high intensity intervals at 1,840 m in a normoxic vs. hyperoxic environment, eight cyclists (NORM) performed intervals on ergometers 3d/wk while breathing normoxic gas (P1O2 = 128 Torr), and seven subjects (HYPER) performed identical intervals at the same relative workload while breathing hyperoxic gas (P1O2 = 156 Torr). HYPER subjects were able to train at a higher percentage of their altitude lactate inflection point than were NORM subjects (HYPER = 126+/-2%, NORM = 109+/-3% p<0.05). Improvements in power output at maximal steady state (NORM = 8 W, HYPER = 20 W,) and improvement in time to complete a 120 kJ cycling performance test (NORM = 2 s, HYPER = 15 s) were significant in the HYPER group pre- vs. post-training (p<0.05) while the NORM group exhibited no significant changes. No significant changes in power output at lactate inflection point were seen in either group (NORM = -12 W, HYPER = +11 W). The results demonstrate that while training at moderate altitude, breathing hyperoxic gas vs. ambient air allows for higher training intensities and this higher intensity training results in significant improvements in maximal steady state power output and time to complete a 120 kJ performance test.

Differential effects of heparin on the early and late phases of hepatic ischemia and reperfusion injury in the pig

The mechanisms by which heparin protects the liver during induced episodes of liver ischemia-reperfusion are poorly understood. Previous work in a swine model demonstrated that serum levels of glycohydrolases and lipid peroxide peaked within 3 h after 45 minutes of hepatic ischemia followed by reperfusion. Serum levels of lactate dehydrogenase and aspartate aminotransferase peaked 20-24 h later. The aim of this study was to evaluate the effect of heparin on these two-phases of enzyme release, using a pig model of hepatic ischemia-reperfusion injury. Twenty male swine were divided into control (n = 8) and heparin (n = 12) groups. In the heparin group, heparin was administered prior to and concurrent with ischemia-reperfusion. Following 45 min of hepatic ischemia, the levels of beta-galactosidase, beta-glucosidase, acid phosphatase, purine nucleoside phosphorylase, lipid peroxides, lactate dehydrogenase, and aspartate aminotransferase in serum were monitored for up to 166 h and compared to pre-ischemic and control levels. With heparin infusion, the peak levels of beta-galactosidase, beta-glucosidase, and the lipid peroxide were reduced to 50-60% of the control levels. Acid phosphatase and purine nucleoside phosphorylase activities in serum were reduced to 25% and 60%, respectively. The peak concentrations of lactate dehydrogenase and aspartate aminotransferase were reduced to about 25% of the control level. In addition, the serum enzymes of control pigs did not return to pre-ischemic levels until 2 weeks after hepatic ischemia, while they normalized in less than 1 week in the heparin-treated animals. Systemic heparinization had different protective effects on the first and secondary phases of liver injury. These differences may reflect heparin protection of different types of liver cells. The protection of the parenchymal cells may be the combined result of reduced sinusoidal cell injury and the anticoagulant properties of heparin.

Lamivudine/zidovudine as a combined formulation tablet: bioequivalence compared with lamivudine and zidovudine administered concurrently and the effect of food on absorption

A single-center, open-label, three-way crossover study was conducted in 24 healthy subjects to assess (1) the bioequivalence of a combined lamivudine 150 mg/zidovudine 300 mg tablet relative to the separate brand-name components administered concurrently and (2) the effect of food on the bioavailability of the drugs from the combination tablet. The subjects were randomly assigned to receive each of the following three treatments, separated by a 5- to 7-day washout period: one lamivudine/zidovudine combination tablet after an overnight fast, one lamivudine 150 mg tablet and one zidovudine 300 mg tablet simultaneously after an overnight fast, or one lamivudine/zidovudine combination tablet 5 minutes after completing a standardized high-fat breakfast (67 g fat, 58 g carbohydrate, and 33 g protein). Serial blood samples were collected up to 24 hours postdose for the determination of lamivudine and zidovudine plasma concentrations. Standard pharmacokinetic parameters were estimated. Treatments were considered bioequivalent if 90% confidence intervals for the ratio of least squares (LS) means for the lamivudine and zidovudine area under the plasma concentration-time curve (AUC infinity) and maximum observed plasma concentration (Cmax) fell entirely within 0.80 to 1.25 for log-transformed parameters. The combined lamivudine/zidovudine tablet was bioequivalent in the extent (AUC infinity) and rate of absorption (Cmax and time of Cmax [tmax]) to the individual brand-name drug components administered concurrently under fasted conditions. Geometric LS mean ratios and 90% confidence intervals for AUC infinity and Cmax were 0.97 (0.92, 1.03) and 0.94 (0.84, 1.06), respectively, for lamivudine and 0.99 (0.91, 1.07) and 0.97 (0.82, 1.15), respectively, for zidovudine. The extent of absorption of lamivudine and zidovudine from the combination tablet was not altered by administration with meals, indicating that this formulation may be administered with or without food. However, food slowed the rate of absorption, delayed the tmax, and reduced the Cmax of lamivudine and zidovudine. These changes were not considered clinically important. All formulations were well tolerated under fasted and fed conditions.

Repair of fascial defects in dogs using carbon fibers

Hernia repair may involve the use of an implant to augment or replace autologous tissue, but the best material for use in this application has not been established. We developed a dog model to evaluate the mechanical strength of fascial defects repaired using carbon fibers, compared with the strength of similar defects repaired using polypropylene mesh (Marlex). Unrepaired defects were included as an additional control. Bilateral defects (1 cm square) were made in the fascia of the back, and the ultimate mechanical strength and stiffness at the repair sites were measured 3-12 months after operation. Defects repaired with carbon fibers were significantly stronger 12 months after operation compared with defects repaired with polypropylene mesh and compared with unrepaired defects. It is concluded that carbon fibers are biocompatible and significantly increase mechanical strength at the repair site. A randomized clinical trial involving patients undergoing hernia repair seems justified to determine whether carbon fibers are superior to standard therapy.

Localized well-differentiated thyroid carcinoma: survival analysis of prognostic factors and (131)I therapy

BACKGROUND

Recommendations regarding therapeutic use of (131)I for patients with well-differentiated thyroid cancer remain controversial. Between 1969 and 1993, 1171 patients with papillary (including mixed) or follicular thyroid cancer were reported to the New Mexico Tumor Registry. Of these, 1075 cases (77.6% female, median age 41 years) were available for analysis of survival plots and previously recognized risk factors. Extent of operation was documented for 344 patients.

METHODS

One hundred twenty-seven (37%) patients underwent postoperative (131)I ablation. Median follow-up was 99 months. A proportional hazards model was constructed using age, gender, stage, histology, and use of radioiodine. The same variables plus extent of operation were examined in the smaller group.

RESULTS

Kaplan-Meier survival estimates at 12 years were 96.2% for patients younger than 45 years and 68.6% for those older than 45 years. Age, gender, and histology, but not stage, were important survival variables (P <.05). Adjusting for other risk factors, there was no apparent survival benefit associated with radioiodine following clinically appropriate thyroidectomy. Findings from the small group mirrored those of the large group.

CONCLUSIONS

(131)I may not be as efficacious as previously believed for patients with well-differentiated thyroid cancer confined to the neck.

Evaluation of a commercial accelerometer (Tritrac-R3 D) to measure energy expenditure during ambulation

This study evaluated the ability of a commercially available accelerometer (Tritrac-R3 D) to measure energy expenditure in 16 subjects at rest (pre- and post-exercise) and during three different intensities of steady-state exercise (40-70% of peak oxygen consumption [VO2peak]) while ambulating on a treadmill (no grade). Oxygen consumption and the respiratory exchange ratio from indirect calorimetry and the vector magnitude of triaxial accelerations were used to estimate energy expenditure using the manufacturers' equations. There was a significant relationship between indirect calorimetry-derived energy expenditure and the energy expenditure derived from the accelerometer (r=0.96). Using analysis of variance, there was no difference in the energy expenditure derived by the two methods at rest before exercise and during the three different intensities of ambulatory exercise. There was a significant difference between energy expenditure derived via indirect calorimetry and with the accelerometer during rest after exercise, probably due to the failure of the accelerometer to accurately estimate the energy expenditure associated with the progressive decline in post-exercise oxygen consumption. Thus, this commercially available accelerometer appears to provide statistically acceptable estimates of energy expenditure at rest and during zero-grade treadmill ambulation up to about 70% VO2peak. This may indicate its acceptable utility for large-scale population studies of physical activity involving this mode of movement. The failure of the accelerometer to accurately estimate energy expenditure during recovery from exercise may contribute to an underestimation of energy expenditure in some physically active individuals.

Benefit plans in a changing practice environment

Managed care is affecting the business of medical practices. Many physicians are joining with larger organizations and employee benefits are even more significant in each physician's financial security. Background on benefit issues and common areas of caution when contemplating joining a large entity are addressed.

The effects of bicycle crank arm length on oxygen consumption

The purpose of this investigation was to determine the effects of various crank arm lengths on oxygen consumption for trained cyclists. Secondary purposes were, if optimal crank arm lengths existed, to determine if these lengths could be predicted based on an individual's leg length. Six trained cyclists completed four experimental protocols riding at a workload of approximately 68% of VO2 max using crank arm lengths of 165, 170, and 175 mm. During each protocol, the cadence, oxygen consumption, and distance traveled were determined, and values were combined to give a VO2.m-1.min-1 value. The values then were placed in either a high, medium, or low efficiency category. Significant differences were found among the three protocols. No significant correlations were found between each subject's most efficient crank arm length and leg length. The results of the study suggest that each subject has a most efficient crank arm length, but it does not appear that optimal crank arm length can be predicted by leg length.

Prognostic factors for thyroid carcinoma. A population-based study of 15,698 cases from the Surveillance, Epidemiology and End Results (SEER) program 1973-1991

BACKGROUND

A number of prognostic factors for thyroid carcinoma have been identified, including sociodemographic characteristics, such as age and gender, and tumor characteristics, such as histology and stage. The relative importance of these factors as independent predictors of survival for patients with papillary, follicular, anaplastic, and medullary thyroid carcinoma has been extensively studied but remains uncertain.

METHODS

The authors used data collected by the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute between 1973 and 1991 to investigate prognostic factors for each of the major histologic types of thyroid carcinoma in a population-based patient series and to assess the effect of these factors as predictors of survival.

RESULTS

Both tumor and sociodemographic characteristics were independently associated with survival. Patients with papillary carcinoma had the highest 10-year relative survival (0.98), followed by those with follicular carcinoma (0.92) and medullary carcinoma (0.80). Anaplastic tumors had the lowest 10-year relative survival (0.13). Stage at diagnosis and differentiation status were strong independent prognostic factors for each histologic type. Advanced stage at diagnosis was a stronger prognostic factor for medullary carcinoma than for other histologic types. Increasing age was associated with lower relative survival for each histologic type. Gender, marital status, and ethnicity were significant, but weaker, predictors of survival.

CONCLUSIONS

Survival varied markedly among patients with different histologic types of thyroid carcinoma. Stage at diagnosis and tumor differentiation were important prognostic factors for each histologic type. Age at diagnosis was a stronger predictor of survival for patients with follicular and medullary carcinoma than for patients with papillary carcinoma.

Prognostic factors for thyroid carcinoma. A population-based study of 15,698 cases from the Surveillance, Epidemiology and End Results (SEER) program 1973-1991

BACKGROUND

A number of prognostic factors for thyroid carcinoma have been identified, including sociodemographic characteristics, such as age and gender, and tumor characteristics, such as histology and stage. The relative importance of these factors as independent predictors of survival for patients with papillary, follicular, anaplastic, and medullary thyroid carcinoma has been extensively studied but remains uncertain.

METHODS

The authors used data collected by the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute between 1973 and 1991 to investigate prognostic factors for each of the major histologic types of thyroid carcinoma in a population-based patient series and to assess the effect of these factors as predictors of survival.

RESULTS

Both tumor and sociodemographic characteristics were independently associated with survival. Patients with papillary carcinoma had the highest 10-year relative survival (0.98), followed by those with follicular carcinoma (0.92) and medullary carcinoma (0.80). Anaplastic tumors had the lowest 10-year relative survival (0.13). Stage at diagnosis and differentiation status were strong independent prognostic factors for each histologic type. Advanced stage at diagnosis was a stronger prognostic factor for medullary carcinoma than for other histologic types. Increasing age was associated with lower relative survival for each histologic type. Gender, marital status, and ethnicity were significant, but weaker, predictors of survival.

CONCLUSIONS

Survival varied markedly among patients with different histologic types of thyroid carcinoma. Stage at diagnosis and tumor differentiation were important prognostic factors for each histologic type. Age at diagnosis was a stronger predictor of survival for patients with follicular and medullary carcinoma than for patients with papillary carcinoma.

Determination of the novel sialic acid analog GG167 (GR121167X) in human urine by liquid chromatography: direct injection with column switching

GG167 is a novel compound which selectively inhibits viral neuraminidase and has demonstrated activity against influenza A and B. A liquid chromatography (LC) method for the determination of GG167 in human urine has been developed and validated. The method allows direct injection of urine (7 microliters) using LC column switching followed by UV detection. Initial chromatography is performed using a Nucleosil-Diol column (7 microns, 250 mm x 4.6 mm), eluted with 20 mM phosphate buffer (pH 2.5):acetonitrile (18:82, v/v) at 2.0 ml min-1. GG167 is "heart-cut" to a Spherisorb-SCX column (5 microns, 100 mm x 4.6 mm) and eluted with 35 mM phosphate buffer (pH 2.5):acetonitrile (50:50, v/v) at 1.5 ml min-1 for final separation. GG167 is detected by UV absorbance at lambda = 238 nm. UV detection and peak shape are enhanced at pH < 2.5. The quantitation range of the assay is 0.3-100 micrograms ml-1. The method has demonstrated sufficient ruggedness to be used in support of GG167 clinical trials.

Pharmacokinetics, absolute bioavailability, and absorption characteristics of lamivudine

Lamivudine is a novel cytosine nucleoside analog, reverse transcriptase inhibitor that has shown activity against human immunodeficiency virus (HIV) types 1 and 2 and hepatitis B virus in vitro. This study was conducted to compare the absolute bioavailability, pharmacokinetics, and absorption characteristics of oral solution, 100-mg capsule, and 100-mg tablet formulations of lamivudine with those of intravenous lamivudine. Twelve patients with HIV were enrolled in a single-center, randomized, open-label, four-way cross-over study. Treatment arms consisted of 100 mg intravenous lamivudine (administered over 1 hour), 100 mg oral lamivudine (1 mg/mL), a 100-mg capsule, and a 100-mg tablet, each followed by a 3- to 14-day washout period. Serial blood samples over 24 hours were obtained after each dose administration. Serum concentration data were analyzed to determine pharmacokinetic parameter estimates including area under the curve (AUC), terminal half-life (t1/2), mean residence time (MRT) for each formulation, systemic clearance, oral clearance, and apparent volume of distribution (Vd). Absolute bioavailability and in vivo mean absorption time (MAT) and mean dissolution time (MDT) were calculated for the oral formulations. Deconvolution techniques were used to calculate the input rate for the oral solution, capsule, and tablet. The two one-sided t test was used to determine bioequivalency among oral formulations with respect to logarithmic transformed estimates of AUC and maximum peak concentration (Cmax). Mean (CV) systemic clearance and Vdss after intravenous administration of lamivudine were 22.6 L/h (15%) and 99 L (28%), respectively; mean t1/2 ranged from 8.41 to 9.11 hours for all formulations; and MRT ranged from 4.42 to 5.77 hours for all formulations. Mean absolute bioavailability ranged from 86% to 88% for the oral solution, capsule, and tablet. All oral formulations were considered bioequivalent for AUC and Cmax. The MAT was 1.32 hour for the oral solution, and MDT was 0.03 and -0.11 hours for the capsule and the oral solution, respectively. The oral formulations of lamivudine examined in this study demonstrated acceptable bioavailability for oral administration. The solid oral formulations (capsule and tablet) show rapid dissolution properties with an absorption rate similar to or exceeding those observed with the oral solution. This suggests that dissolution is not an important factor for the rate of absorption of lamivudine. The use of deconvolution techniques using PCDCON provides valuable insight into the absorption characteristics of lamivudine.

Coexistent thyroid cancer and pregnancy

OBJECTIVE

A study was performed to determine the appropriate time for the initiation of therapy for thyroid carcinoma first diagnosed during pregnancy.

DATA SOURCES

Material on thyroid cancer cases was obtained from the New Mexico Tumor Registry, Albuquerque, a computerized population-based registry for the state of New Mexico, and the Indian reservation facilities in New Mexico and Arizona (a Surveillance, Epidemiology, and End Results Registry funded by the National Cancer Institute, Bethesda, Md) for the period 1970 to 1991.

STUDY SELECTION

All cases of thyroid cancer, except medullary and anaplastic, in patients aged 18 to 46 years were evaluated. Subgroups were established for (1) all women who were noted to be pregnant at the time of their initial diagnosis and (2) all women with thyroid cancer in the 18- to 46-year-old age group.

DATA EXTRACTION

The information was extracted by a certified tumor registrar for age, sex, thyroid cancer, specific type of thyroid cancer, period, race, year of diagnosis, accession date, last date seen, tumor status, treatment, and patient status.

DATA SYNTHESIS

There have been no deaths in the pregnant group with a follow-up ranging from 0.5 to 20 years. There was no statistically significant difference in observed survival rates between the pregnant group and 465 women, aged 18 to 46 years, with comparable thyroid cancers or in the death rates of women aged 18 to 67 years in the general population.

CONCLUSIONS

Surgical treatment for patients with well-differentiated thyroid cancer diagnosed during pregnancy can be delayed until after parturition.

High-performance liquid chromatographic assay for 2'-deoxy-3'-thiacytidine in human serum

A high-performance liquid chromatographic method for the determination of 2'-deoxy-3'-thiacytidine (3TC), a novel dideoxy-nucleoside analogue, in human serum is described. 3TC was extracted from serum samples using Bond Elut Certify solid-phase extraction cartridges prior to reversed-phase chromatography with UV detection. The method has been shown to be valid over the concentration range 10-5000 ng/ml using a 1-ml sample volume, both before and after heat treatment of the samples at 60 degrees C for 3 h. The method has been automated using a Zymark robot and used in the analysis of serum samples from HIV positive patients.

Peritoneal cultures and antibiotic therapy in pediatric perforated appendicitis

We retrospectively reviewed 70 cases of perforated appendicitis in children to examine the relationship between postoperative antibiotic selection and culture results from the peritoneal cavity. Initial antibiotic therapy chosen for the children consisted of a three-drug combination in 54 (77%) patients. Peritoneal cultures were performed in 58 (83%) patients. Escherichia coli and Bacteriodes fragilis were the most common bacterial isolates from the peritoneal culture. Only 7 (10%) patients had their antibiotic regimen changed after the culture results were available, of which 2 changes brought drug therapy into compliance with the cultures and 5 changes were inappropriate with respect to the peritoneal cultures. Of the remaining 51 patients with culture data available, 39 should have had changes to bring the antibiotic therapy into compliance with the observed culture results. These data indicate that surgeons select antibiotic therapy for perforated appendicitis in children based on assumptions of which organisms should be present in the infection and not on culture data. There appears to be no clinical usefulness to the routine culturing of the peritoneal cavity in children with perforated appendicitis.

Determination of 2'-deoxy-3'-thiacytidine (3TC) in human urine by liquid chromatography: direct injection with column switching

3TC (GR109714X) is a cytidine dideoxynucleoside analogue which has been shown to have in vitro activity against a variety of strains of HIV-1 and is currently being investigated in clinical trials as a treatment for HIV infection. An HPLC method for the determination of 3TC in human urine has been developed and validated. The method allows direct injection of urine (10 microliters) using HPLC column switching followed by UV detection. On-line extraction is performed using a Spherisorb-SCX (5 microns, 20 x 4.0 mm) eluted with deionized water at 1 ml min-1. 3TC is retained while the bulk of urine constituents are eluted to waste. The SCX column is then backflushed to a BDS-Hypersil-C18 (5 microns, 250 x 4.6 mm) and eluted with 100 mM acetate pH 4.5-methanol (95:5, v/v) for final separation. 3TC is detected by UV absorbance at lambda = 285. The quantitation range of the assay was 0.5-500 micrograms ml-1. The method has demonstrated sufficient ruggedness to be used in support of 3TC clinical trials. Application to other cytidine analogues including DDC has been demonstrated.

Aquatic rehabilitation for the treatment of neurological disorders

Patients with neurological disorders present therapists with complex challenges for treatment, including weakness, hypertonicity, voluntary movement deficit, limited range of motion, sensory loss, incoordination, and postural instability. The presence of one or more of these impairments negatively influences these patients by contributing to problems in walking, transferring, and reaching. Aquatic rehabilitation offers a unique, versatile approach to the treatment of these disabilities. This article examines the problems encountered by patients with neurological disorders, general principles guiding neurotreatment, and aquatic neurorehabilitation approaches.

Electrical potential measurements in human breast cancer and benign lesions

Electrical potentials were measured on the breast and at other sites in 110 women with palpable breast masses. The tumor site was significantly electropositive compared with control sites only when the tumor was a cancer, as determined by a subsequent biopsy; the electrical potentials were not influenced by age or menstrual cycle. The results indicate that, on average, altered electrical potentials detected by a noninvasive measurement on the skin reflect the presence of transformed cells in patients with breast cancer. Previous in vitro studies of breast tissue and breast epithelial cells suggest that the observed effect was due to a change in interstitial K+ concentration that arose from alterations in the activity of K+ channels. Electrical potentials may be suitable for diagnosis of individual patients if refinements are made in the measurement technique.

Sustained pulmonary hypertension in surgical patients

Twenty-two consecutive critically ill surgical patients who had a Swan-Ganz thermodilution catheter inserted as part of their intensive care unit therapy were studied prospectively. Patients were divided into two groups. Group I consisted of 17 patients whose pulmonary artery diastolic pressure minus pulmonary artery wedge pressure (PADP-PAWP) gradient was less than 5 mm Hg or if greater than 5 mm Hg persisted for less than 12 hours. Group II was composed of 5 patients whose PADP-PAWP gradient was greater than 5 mm Hg for at least 12 hours or more. The two groups were equally matched in terms of risk factors that predispose to an elevated gradient or factors that falsely lower the gradient. Nine other physiologic parameters were measured in patients in Group II during the period of the elevated gradient and were compared with the same parameters measured in patients in Group I. An elevated pulmonary vascular resistance was the only parameter associated with an elevated gradient. An elevated PADP-PAWP gradient greater than 5 mm Hg that persisted for 12 hours or more was associated with a 60 per cent mortality rate.

Pancreaticogastrostomy: preferred reconstruction for Whipple resection

Anastomotic leak is the main complication after Whipple procedures. We reviewed retrospectively our experience with pancreatic cancer patients treated with Whipple resection and reconstruction with a pancreaticogastrostomy (PG) or a pancreaticojejunostomy (PJ). Ten patients operated between 1966 and 1990 composed the PJ group. Eight patients operated recently made up the PG group. Data on age, length of stay (LOS), survival, and complications (early and late) were noted from patient's charts. Patients in the PJ group had an average age of 58.3 years, a mean LOS of 60.3 days (median, 48 days), and a mean survival of 14.5 months. PG group patients had a mean age of 64.5 years, an average LOS of 14.3 days (median, 14 days), and an average survival of 10+ months. None of these differences were significant. Major complications in the PJ group included 2 leaks, 2 cases of pancreatic insufficiency, and 2 deaths related to the anastomotic leaks. Eleven other major complications occurred. The PG group patients did not have any leaks. One developed pancreatic insufficiency. Complications in the PG group were much less serious than those in PJ group. The longest hospital stay in the PG group was 20 days (range, 2-20) and 144 days (range, 11-144) in the PJ group. We conclude that PG is superior to PJ because of the decreased incidence of anastomotic leaks and the less serious nature of the complications associated with PG.

Electrochemical modification of tumor growth in mice

We evaluated the effect of direct electrical current on large tumors in mice. Lewis lung carcinoma greater than 1 cm in the shortest dimension was treated percutaneously with 20 mA for 15 min. Separate groups were given one or more than one (two or three) percutaneous electrical treatments (PET). A third group was given sham electrical treatment, and a fourth group had surgical excision of the tumor. Animals in both PET groups survived longer and had smaller primary tumors at death compared with the sham group. PET did not alter the systemic course of the disease, judged by lung and spleen weights and by histological observation of the extent of metastatic burden in the lung. Surgery resulted in long-term survival of 17% and an increase in average survival time compared with both PET and sham treatment. PET produced rapid and polarity-dependent alterations in physiological solutions in vitro, and it is likely that similar electrochemical processes mediated the observed reduction in tumor growth. PET is potentially useful as an adjuvant modality because it reduces local tumor mass but does not alter the extent of metastasis.

Work-site nutrition intervention and employees' dietary habits: the Treatwell program

In a randomized, controlled study of the Treatwell work-site nutrition intervention program, which focused on promoting eating patterns low in fat and high in fiber, 16 work sites from Massachusetts and Rhode Island were recruited to participate and randomly assigned to either an intervention or a control condition. The intervention included direct education and environmental programming tailored to each work site; control work sites received no intervention. A cohort of workers randomly sampled from each site was surveyed both prior to and following the intervention. Dietary patterns were assessed using a semiquantitative food frequency questionnaire. Adjusting for work site, the decrease in mean dietary fat intake was 1.1% of total calories more in intervention sites than in control sites (P less than .005). Mean changes in dietary fiber intake between intervention and control sites did not differ. This study provides evidence that a work-site nutrition intervention program can effectively influence the dietary habits of workers.

Diagnosis and management of esophageal perforations

Esophageal perforation remains a difficult diagnostic and management problem. Recommendations regarding treatment remain controversial. A 15-year experience with perforation of the esophagus from all causes was reviewed at Louisiana State University and Veterans Administration, Medical Centers (Shreveport, LA). The majority of the injuries involved the thoracic esophagus (28 or 54%), followed by the cervical (21 or 40%), and the intraabdominal esophagus (3 or 6%). Iatrogenic causes constituted most of the injuries (52%), followed by external trauma (23%), barogenic rupture (15%), and ingested foreign bodies (10%). Diatrizoate methylglucamine 66 per cent, sodium diatrizoate 10 per cent (Gastrografin; Squibb, Princeton, NJ) contrast studies and flexible esophagoscopy were performed in 44 and 22 patients, respectively. In the cervical esophagus, contrast studies were more sensitive and specific than endoscopy (P less than .01), but both studies were equally effective as diagnostic methods in thoracic perforations. Cervical perforations were treated with either drainage alone (7 patients) or primary repair with drainage (14 patients) with an operative mortality of 4.8 per cent. Several procedures were used in thoracic perforations, which carried a mortality of 36 per cent and were more lethal than cervical tears (P less than 0.2). Any thoracic esophageal perforation treated more than 24 hours after the onset of symptoms, irrespective of what procedure was used, was associated with a significantly higher mortality than if operated on earlier (P less than .001). Five patients with perforated carcinomas were treated by esophageal resection with no mortality. Significantly higher mortality was seen with a delay in diagnosis, thoracic perforations, and Boerhaave's Syndrome. A subset of patients with perforated carcinomas may benefit from esophageal resection with delayed reconstruction.

Antibiotic treatment for surgical peritonitis

The charts of 480 patients with secondary bacterial peritonitis were reviewed. The antibiotics used were compared with the culture and sensitivity data obtained at surgery, and the outcomes of patients were evaluated. Patients treated with a single broad-spectrum antibiotic had a better outcome than patients treated with multiple drug treatment. Inadequate empiric antibiotic treatment was associated with poorer outcome than any other type of treatment. The outcome of this inadequate treatment group could not be improved by any antibiotic response to culture and sensitivity information after operation. Those patients treated with antibiotic coverage for anticipated organisms and having no cultures taken did as well as patients having cultures taken. Surgeons typically ignore culture data after operation, and only 8.8% of patients in this study had an appropriate change in antibiotic treatment after operation. A benefit from obtaining operative cultures could not be identified.

Loop colostomies are totally diverting in adults

Temporary colostomy is a mainstay in the treatment of patients with colon injuries. Common teaching is that loop colostomies are not totally diverting. We performed this study to determine whether loop colostomies are totally diverting. Twenty-three patients presenting for closure of loop colostomies were given barium by mouth. Serial abdominal films were obtained at intervals over 24 hours. Scout films were obtained after bowel preparation to see if flushing the colon could cause passage of barium into distal bowel. We could not demonstrate passage of barium into the distal limb of the colon in any patient studied. This was true even in long-established loop colostomies. Bowel preparation did not cause passage of barium into the distal colon. Loop colostomies constructed over a rod and matured immediately totally divert the fecal stream. Most surgeons would agree that this type of colostomy is more easily and quickly created and closed. Since it fulfills the criteria for fecal diversion, the use of divided colostomies should be abandoned when a loop colostomy can be utilized.

Unresectable pancreatic cancer: what is the optimal procedure?

We retrospectively reviewed cases of pancreatic cancer to determine the benefit of various methods of biliary decompression and the role of prophylactic gastroenterostomy (GE) in management. Twenty-seven patients had only biliary bypass, and 26 had biliary bypass and GE. Operative mortality was similar for both groups (22% and 19%, respectively). The complication rates were almost identical (37% and 35%). Differences in operative mortality, incidence of cholangitis, and recurrence of jaundice were not statistically significant between patients having biliary decompression via the common bile duct or the gallbladder. Operative mortality associated with choledochoenterostomy was 33% versus 17% for cholecystoenterostomy. Gastric outlet obstruction developed in 5% of patients who did not have GE. We conclude that cholecystojejunostomy is an effective method of biliary bypass. Because its addition did not seem to increase operative morbidity or mortality, we advocate GE at the initial exploration to prevent gastric outlet obstruction.

Inhibition of peripheral aromatization in the male cynomolgus monkey by a novel nonsteroidal aromatase inhibitor (R 76713)

R 76713 (6-[(4-chlorophenyl)(1-H-1,2,4-trizol-1-yl)methyl]1-H benzotriazole) is a highly potent and selective inhibitor of the aromatase enzyme both in vitro and in vivo. The ability of R 76713 to inhibit peripheral aromatization of androstenedione (A) to estrone (E1) in vivo was studied in male cynomolgus monkeys (Macaca fascicularis). Peripheral aromatization was measured using a primed constant infusion of [3H] A and [14C]E1 for 3.5 h. Blood samples, collected during the final hour of infusion, were analyzed for plasma radioactivity as infused and product steroids. MCRs, conversion ratios (CR), and percent conversion of A to E1 were calculated. R 76713 (0.03-10 microgram/kg) or vehicle (10% hydroxypropyl-beta-cyclodextrin) were administered iv 90 min before beginning the infusion of radiolabeled steroids. In vehicle-treated monkeys, the aromatization of A (mean +/- SEM, 1.35 +/- 0.11%) was similar to that previously reported for cynomolgus and rhesus monkeys, baboons, and humans. Aromatization of A, measured 4-5 h after injection of R 76713, was dose-dependently decreased from the control value by 87 +/- 3%, 85 +/- 2%, 61 +/- 5%, and 33 +/- 8% (all P less than 0.05) at doses of 10.0, 3.0, 0.3, and 0.03 micrograms/kg, respectively, with an ID50 of 0.13 microgram/kg, iv (95% confidence interval, 0.06-0.21). When measured 15-16 h after iv administration of 3.0 micrograms/kg R 76713, aromatization (0.55 +/- 0.13%) was significantly inhibited by 53 +/- 11% compared to that in control monkeys (1.16 +/- 0.18%). The CRs between androgens, the CRs between estrogens, and the MCRs of A and E1 were not significantly altered by R 76713 compared to those after vehicle treatment. R 76713 potently decreased peripheral conversion of androgen to estrogen in vivo in male cynomolgus monkeys and may be a useful therapeutic agent in treating estrogen-dependent diseases, including post-menopausal breast cancer.

Hormonal receptors in locally advanced breast cancer: change with response to neoadjuvant chemotherapy?

Twenty-one cancers in 20 patients with locally advanced breast cancer were studied. Incisional biopsy was performed without using electrocautery. Tissue was obtained for histology and estrogen (ER) and progesterone (PR) receptors. Patients received chemotherapy after biopsy. All responded and had radical mastectomy performed. Tissue was removed from the mastectomy specimen to confirm residual tumor and for repeat receptor measurements. Initial receptor levels were negative in 13 cancers. Following chemotherapy, both ER and PR levels were unchanged in 11 cancers. Levels in one cancer changed from ER-PR- to ER+PR- and one changed from ER-PR- to ER+PR+. Six cancers were ER+PR+ at initial examination. Repeat receptor levels after chemotherapy were ER+PR+ in three. One ER+PR+ tumor became ER-PR+, one changed to ER+PR-, and one to ER-PR-. One ER+PR- cancer remained ER+PR- after treatment and an ER-PR+ cancer became ER-PR- after treatment. Chemotherapy dose not significantly alter hormonal levels in breast cancer tissue.

Preoperative chemotherapy is beneficial for geriatric patients with locally advanced and metastatic breast cancer

The relationship between aging and drug toxicity has been documented. We reviewed patients with Stage IIIB and Stage IV breast cancer with the primary tumor intact at presentation to compare the toxicity secondary to chemotherapy, the disease-free survival, and the survival in both young and elderly women. Fifty-three patients were studied. All received preoperative chemotherapy and mastectomy as part of treatment for breast cancer. Sixty years was used arbitrarily to divide the patients into two groups. Data were analyzed by unpaired T-test. Hematologic, nutritional, infectious, and cardiac toxicities were noted and compared between groups. Disease-free survival was studied in patients with Stage IIIB disease. Survival was examined in patients with Stage IIIB and Stage IV disease. We could not detect any statistically significant differences between young and elderly patients in any of these groups. The elderly patients in this study seemed to derive as much benefit from chemotherapy as did younger patients.

Use of carbon fibers for repair of abdominal-wall defects in rats

Carbon in the form of 8-micron fibers induces growth of connective tissue. The purpose of this study was to measure and histologically characterize tissue ingrowth occurring in carbon fibers implanted for up to 12 months in abdominal-wall defects in rats, compared with polypropylene mesh. Carbon fibers induced significantly more tissue ingrowth than polypropylene mesh at 6 to 12 months postoperatively. The predominant tissues associated with carbon fibers and polypropylene mesh were dense connective tissue and fat, respectively. Fragmentation of the implants did not occur, and implant debris was not found in the regional lymph nodes. Carbon fibers are potentially useful for reinforcing abdominal-wall defects.

Hydraulic bedscale lift for retracting and holding large lesions

Extremely large bulky lesions are not often encountered in modern surgical practice. The use of a hydraulic bedscale lift to elevate and position these large lesions, so that the base can be approached, makes it much easier to obtain and maintain exposure.

Cardiac complications of aneurysm repair

To assess the early morbidity and mortality from coronary artery disease (CAD), we reviewed the charts of 49 patients who had elective resection of infrarenal abdominal aortic aneurysms between September 1978 and February 1986 at the VA and LSU medical centers in Shreveport. On the basis of history, physical examination, and resting electrocardiogram, patients were divided into two groups--those with clinical evidence of coronary artery disease (group 1, n = 21) and those without clinical evidence of coronary artery disease (group 2, n = 28). End points measured were perioperative (30-day) myocardial infarction (MI) rate and death. A definite MI was diagnosed when an abnormally elevated CPK-MB was accompanied by a new electrocardiographic abnormality or a reversal of the normal LDH isoenzyme pattern. A possible MI was diagnosed when an elevated CPK-MB was the only abnormality. In group 1, one definite (4.5%) and two possible (9.5%) MIs occurred. In group 2, there were no definite or possible MIs. All cardiac events were discovered by measurements of cardiac enzymes, since none of the patients had cardiac symptoms. This retrospective study reveals a low incidence of clinically significant cardiac events after resection of abdominal aortic aneurysms, even in patients with clinical evidence of coronary artery disease. Prophylactic coronary artery bypass surgery does not appear to be necessary for most patients needing repair of an abdominal aortic aneurysm.