Using Bayesian Adaptive Trial Designs for Comparative Effectiveness Research: A Virtual Trial Execution

BACKGROUND

Bayesian and adaptive clinical trial designs offer the potential for more efficient processes that result in lower sample sizes and shorter trial durations than traditional designs.

OBJECTIVE

To explore the use and potential benefits of Bayesian adaptive clinical trial designs in comparative effectiveness research.

DESIGN

Virtual execution of ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) as if it had been done according to a Bayesian adaptive trial design.

SETTING

Comparative effectiveness trial of antihypertensive medications.

PATIENTS

Patient data sampled from the more than 42 000 patients enrolled in ALLHAT with publicly available data.

MEASUREMENTS

Number of patients randomly assigned between groups, trial duration, observed numbers of events, and overall trial results and conclusions.

RESULTS

The Bayesian adaptive approach and original design yielded similar overall trial conclusions. The Bayesian adaptive trial randomly assigned more patients to the better-performing group and would probably have ended slightly earlier.

LIMITATIONS

This virtual trial execution required limited resampling of ALLHAT patients for inclusion in RE-ADAPT (REsearch in ADAptive methods for Pragmatic Trials). Involvement of a data monitoring committee and other trial logistics were not considered.

CONCLUSION

In a comparative effectiveness research trial, Bayesian adaptive trial designs are a feasible approach and potentially generate earlier results and allocate more patients to better-performing groups.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute.

A meta-analysis platform methodology for determining the comparative effectiveness of antihepatitis C virus regimens

AIM

Many hepatitis C virus regimens are unlikely to be compared head to head. In more difficult to treat populations where there is no standard of care, trials are single arm. We describe a flexible meta-analysis platform in this setting.

METHODS

Our meta-analysis is literature based. We illustrate our methodology and show how inference can be extended to single-arm trials.

RESULTS

As an example, in the single arm setting, a regimen with response rates of 84, 72 and 54% in genotype 1a across treatment naive, previous partial responders and previous null responders, respectively, would have 95% probability of superiority to IFN-α + RBV + TPV.

CONCLUSION

This is a rigorous approach to comparative effectiveness that accounts for varying patient populations and plans for the incorporation of emerging treatments.

The Stroke Hyperglycemia Insulin Network Effort (SHINE) trial: an adaptive trial design case study

Background

The ‘Adaptive Designs Accelerating Promising Trials into Treatments (ADAPT-IT)’ project is a collaborative effort supported by the National Institutes of Health (NIH) and United States Food & Drug Administration (FDA) to explore how adaptive clinical trial design might improve the evaluation of drugs and medical devices. ADAPT-IT uses the National Institute of Neurologic Disorders & Stroke-supported Neurological Emergencies Treatment Trials (NETT) network as a ‘laboratory’ in which to study the development of adaptive clinical trial designs in the confirmatory setting. The Stroke Hyperglycemia Insulin Network Effort (SHINE) trial was selected for funding by the NIH-NINDS at the start of ADAPT-IT and is currently an ongoing phase III trial of tight glucose control in hyperglycemic acute ischemic stroke patients. Within ADAPT-IT, a Bayesian adaptive Goldilocks trial design alternative was developed.

Methods

The SHINE design includes response adaptive randomization, a sample size re-estimation, and monitoring for early efficacy and futility according to a group sequential design. The Goldilocks design includes more frequent monitoring for predicted success or futility and a longitudinal model of the primary endpoint. Both trial designs were simulated and compared in terms of their mean sample size and power across a range of treatment effects and success rates for the control group.

Results

As simulated, the SHINE design tends to have slightly higher power and the Goldilocks design has a lower mean sample size. Both designs were tuned to have approximately 80% power to detect a difference of 25% versus 32% between control and treatment, respectively. In this scenario, mean sample sizes are 1,114 and 979 for the SHINE and Goldilocks designs, respectively.

Conclusions

Two designs were brought forward, and both were evaluated, revised, and improved based on the input of all parties involved in the ADAPT-IT process. However, the SHINE investigators were tasked with choosing only a single design to implement and ultimately elected not to implement the Goldilocks design. The Goldilocks design will be retrospectively executed upon completion of SHINE to later compare the designs based on their use of patient resources, time, and conclusions in a real world setting.

Trial registration

ClinicalTrials.gov NCT01369069 June 2011.

Not too big, not too small: a goldilocks approach to sample size selection

We present a Bayesian adaptive design for a confirmatory trial to select a trial's sample size based on accumulating data. During accrual, frequent sample size selection analyses are made and predictive probabilities are used to determine whether the current sample size is sufficient or whether continuing accrual would be futile. The algorithm explicitly accounts for complete follow-up of all patients before the primary analysis is conducted. We refer to this as a Goldilocks trial design, as it is constantly asking the question, "Is the sample size too big, too small, or just right?" We describe the adaptive sample size algorithm, describe how the design parameters should be chosen, and show examples for dichotomous and time-to-event endpoints.

Predicting clinical trial results based on announcements of interim analyses

Background

Announcements of interim analyses of a clinical trial convey information about the results beyond the trial’s Data Safety Monitoring Board (DSMB). The amount of information conveyed may be minimal, but the fact that none of the trial’s stopping boundaries has been crossed implies that the experimental therapy is neither extremely effective nor hopeless. Predicting success of the ongoing trial is of interest to the trial’s sponsor, the medical community, pharmaceutical companies, and investors. We determine the probability of trial success by quantifying only the publicly available information from interim analyses of an ongoing trial. We illustrate our method in the context of the National Surgical Adjuvant Breast and Bowel (NSABP) trial, C-08.

Methods

We simulated trials based on the specifics of the NSABP C-08 protocol that were publicly available. We quantified the uncertainty around the treatment effect using prior weights for the various possibilities in light of other colon cancer studies and other studies of the investigational agent, bevacizumab. We considered alternative prior distributions.

Results

Subsequent to the trial’s third interim analysis, our predictive probabilities were: that the trial would eventually be successful, 48.0%; would stop for futility, 7.4%; and would continue to completion without statistical significance, 44.5%. The actual trial continued to completion without statistical significance.

Conclusions

Announcements of interim analyses provide information outside the DSMB’s sphere of confidentiality. This information is potentially helpful to clinical trial prognosticators. ‘Information leakage’ from standard interim analyses such as in NSABP C-08 is conventionally viewed as acceptable even though it may be quite revealing. Whether leakage from more aggressive types of adaptations is acceptable should be assessed at the design stage.

Combining risk difference and risk ratio in noninferiority trials of safety

Prior to marketing, the long-term safety profile of a new therapy is often uncertain. One recommendation for premarket safety studies is to compare the new therapy to an appropriate control to determine whether the 95% confidence interval of the risk ratio is entirely less than a prespecified threshold (e.g., 1.8). The restriction to the risk ratio, however, has consequences that may not be intended. Risk difference may be a more appropriate measure of risk in this setting when event rates are very low. We propose using a suitable combination of risk ratio and risk difference in demonstrating noninferiority.

Bayesian adaptive trials offer advantages in comparative effectiveness trials: an example in status epilepticus

OBJECTIVE

We present a novel Bayesian adaptive comparative effectiveness trial comparing three treatments for status epilepticus that uses adaptive randomization with potential early stopping.

STUDY DESIGN AND SETTING

The trial will enroll 720 unique patients in emergency departments and uses a Bayesian adaptive design.

RESULTS

The trial design is compared to a trial without adaptive randomization and produces an efficient trial in which a higher proportion of patients are likely to be randomized to the most effective treatment arm while generally using fewer total patients and offers higher power than an analogous trial with fixed randomization when identifying a superior treatment.

CONCLUSION

When one treatment is superior to the other two, the trial design provides better patient care, higher power, and a lower expected sample size.

Do Bayesian adaptive trials offer advantages for comparative effectiveness research? Protocol for the RE-ADAPT study

BACKGROUND

Randomized clinical trials, particularly for comparative effectiveness research (CER), are frequently criticized for being overly restrictive or untimely for health-care decision making.

PURPOSE

Our prospectively designed REsearch in ADAptive methods for Pragmatic Trials (RE-ADAPT) study is a 'proof of concept' to stimulate investment in Bayesian adaptive designs for future CER trials.

METHODS

We will assess whether Bayesian adaptive designs offer potential efficiencies in CER by simulating a re-execution of the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) study using actual data from ALLHAT.

RESULTS

We prospectively define seven alternate designs consisting of various combinations of arm dropping, adaptive randomization, and early stopping and describe how these designs will be compared to the original ALLHAT design. We identify the one particular design that would have been executed, which incorporates early stopping and information-based adaptive randomization.

LIMITATIONS

While the simulation realistically emulates patient enrollment, interim analyses, and adaptive changes to design, it cannot incorporate key features like the involvement of data monitoring committee in making decisions about adaptive changes.

CONCLUSION

This article describes our analytic approach for RE-ADAPT. The next stage of the project is to conduct the re-execution analyses using the seven prespecified designs and the original ALLHAT data.

Bayesian hierarchical modeling of patient subpopulations: efficient designs of Phase II oncology clinical trials

BACKGROUND

In oncology, the treatment paradigm is shifting toward personalized medicine, where the goal is to match patients to the treatments most likely to deliver benefit. Treatment effects in various subpopulations may provide some information about treatment effects in other subpopulations.

PURPOSE

We compare different approaches to Phase II trial design where a new treatment is being investigated in several groups of patients. We compare considering each group in an independent trial to a single trial with hierarchical modeling of the patient groups.

METHODS

We assume four patient groups with different background response rates and simulate operating characteristics of three trial designs, Simon's Optimal Two-Stage design, a Bayesian adaptive design with frequent interim analyses, and a Bayesian adaptive design with frequent interim analyses and hierarchical modeling across patient groups.

RESULTS

Simon's designs are based on 10% Type I and Type II error rates. The independent Bayesian designs are tuned to have similar error rates, but may have a slightly smaller mean sample size due to more frequent interim analyses. Under the null, the mean sample size is 2-4 patients smaller. A hierarchical model across patient groups can provide additional power and a further reduction in mean sample size. Under the null, the addition of the hierarchical model decreases the mean sample size an additional 4-7 patients in each group. Under the alternative hypothesis, power is increased to at least 98% in all groups.

LIMITATIONS

Hierarchical borrowing can make finding a single group in which the treatment is promising, if there is only one, more difficult. In a scenario where the treatment is uninteresting in all but one group, power for that one group is reduced to 65%. When the drug appears promising in some groups and not in others, there is potential for borrowing to inflate the Type I error rate.

CONCLUSIONS

The Bayesian hierarchical design is more likely to correctly conclude efficacy or futility than the other two designs in many scenarios. The Bayesian hierarchical design is a strong design for addressing possibly differential effects in different groups.

Abstract TP236: The Stroke Hyperglycemia Insulin Network Effort (SHINE) Trial: A Case Study of a Bayesian Trial Design

Introduction: The “Adaptive Designs Accelerating Promising Trials into Treatments (ADAPT-IT)” project is a collaborative effort supported by the NIH and FDA to explore how adaptive clinical trial design might improve the evaluation of drugs and medical devices. We use the NINDS-supported Neurological Emergencies Treatment Trials network as a "laboratory" in which to study the development of adaptive clinical trial designs. The Stroke Hyperglycemia Insulin Network Effort (SHINE) trial was fully funded by the NIH-NINDS at the start of ADAPT-IT and is a currently ongoing phase III trial of tight glucose control in hyperglycemic acute ischemic stroke patients. Within ADAPT-IT, a Bayesian alternative design was developed. The primary endpoint is a severity-adjusted dichotomized 90-day modified Rankin scale (mRS).

Objective: To present both designs and compare their operating characteristics.

Methods: 10000 trials are simulated under treatment effects ranging from 0% to 7%. We present the mean sample size and probabilities of trial success or futility.

Results: The SHINE trial design includes a group sequential procedure with 4 interim analyses to monitor for early efficacy and futility. A maximum of 1400 patients provide 80% power to detect a 7% absolute difference between treatment arms with an overall Type I error rate of 5%. The expected sample size is 1050 patients. This design also incorporates sample size re-estimation and response adaptive randomization. The Bayesian alternative would enroll a maximum of 1400 patients, equally randomized, but employs more frequent interim looks based on predictive probabilities and incorporates a longitudinal model of the primary endpoint. This design has similar power and Type I error and would enroll a mean of 733 and 979 patients under the null and alternative hypotheses respectively.

Conclusions: Simulations suggest that the designs have similar power and Type I error. The Bayesian alternative, with more frequent looks, has a greater chance of stopping early for overwhelming efficacy or futility. The Bayesian alternative will be retrospectively executed upon completion of SHINE to later compare the designs based on their use of patient resources, time, and strength of conclusions in a real world setting.

Age and associated fibrocystic changes are prognostically significant in patients with small node-negative (T1a,bN0) invasive breast cancer

Some patients with small (≤1.0 cm) node-negative (T1a,bN0) invasive breast cancer (IBC) who undergo only local therapy experience recurrences. There is limited information on prognostic factors in these patients. We sought to identify prognostic factors associated with disease-free survival (DFS) and overall survival (OS) in patients with T1a,bN0 IBC. Histologic sections from 273 T1a,bN0 IBC patients treated at M. D. Anderson Cancer Center (MDACC) between 1980 and 1999 were reviewed. Microscopic tumor size; multifocality; histologic type, grade of tumor; presence, type, grade of associated ductal carcinoma in situ (DCIS); presence of fibrocystic changes (FCC) with/without atypia; and lymphovascular invasion were identified. The Kaplan-Meier method was used to evaluate DFS and OS. Median patient age was 58 years, median follow-up period was 10.8 years, and median tumor size was 0.8 cm. Multifocal disease was identified in 26% of cases. At 10 years, the DFS and OS rates were 91% and 88%, respectively. Twenty-one percent of patients had extensive (>50%), and 30% had grade 3 DCIS. Nonproliferative FCC and proliferative FCC with/without atypia were present in 80%, 36%, and 38% of patients, respectively. In univariate analysis, age at diagnosis (p < 0.0001), grade (p = 0.015), and percent (p = 0.046) of DCIS were significantly associated with DFS; presence of FCC was associated with longer DFS and OS. In multivariable models, age and presence of FCC remained significantly associated with survival. Age at diagnosis and associated FCC are significant factors in predicting recurrence in patients with T1a,bN0 IBC. Adjuvant systemic therapy should be discussed with and considered for young patients with T1a,bN0 IBC.

Addressing the incremental benefit of histamine dihydrochloride when added to interleukin-2 in treating acute myeloid leukemia: a Bayesian meta-analysis

IL-2 has been investigated as maintenance therapy for patients with AML in five randomized trials. None has shown a statistically significant benefit. A randomized trial of HDC + IL-2 showed a statistically significant benefit for leukemia-free survival (LFS) in comparison with standard of care. Because HDC + IL-2 has not been randomized against IL-2 alone, the question remains as to whether and to what extent HDC + IL-2 is an improvement compared to IL-2 alone. This is a literature-based meta-analysis. We employ two versions of a Bayesian hierarchical model to compare HDC + IL-2 versus IL-2 alone on the basis of LFS in patients in remission from AML.

Daily oral sodium bicarbonate preserves glomerular filtration rate by slowing its decline in early hypertensive nephropathy

In most patients with hypertensive nephropathy and low glomerular filtration rate (GFR), the kidney function progressively declines despite the adequate control of the hypertension with angiotensin-converting enzyme inhibition. Previously we found that 2 years of oral sodium citrate slowed GFR decline in patients whose estimated GFR (eGFR) was very low (mean 33 ml/min). This treatment also slowed GFR decline in an animal model of surgically reduced nephron mass. Here, we tested if daily oral sodium bicarbonate slowed GFR decline in patients with hypertensive nephropathy with reduced but relatively preserved eGFR (mean 75 ml/min) in a 5-year, prospective, randomized, placebo-controlled, and blinded interventional study. Patients matched for age, ethnicity, albuminuria, and eGFR received daily placebo or equimolar sodium chloride or bicarbonate while maintaining antihypertensive regimens (including angiotensin-converting enzyme inhibition) aiming for their recommended blood pressure targets. After 5 years, the rate of eGFR decline, estimated using plasma cystatin C, was slower and eGFR was higher in patients given sodium bicarbonate than in those given placebo or sodium chloride. Thus, our study shows that in hypertensive nephropathy, daily sodium bicarbonate is an effective kidney protective adjunct to blood pressure control along with angiotensin-converting enzyme inhibition.

Detecting an overall survival benefit that is derived from progression-free survival

BACKGROUND

Whether progression-free survival (PFS) or overall survival (OS) is the more appropriate endpoint in clinical trials of metastatic cancer is controversial. In some disease and treatment settings, an improvement in PFS does not result in an improved OS.

METHODS

We partitioned OS into two parts and expressed it as the sum of PFS and survival postprogression (SPP). We simulated randomized clinical trials with two arms that had respective medians for PFS of 6 and 9 months. We assumed no treatment difference in median SPP. We found the probability of a statistically significant benefit in OS for various median SPP and observed P values for PFS. We compared the sample sizes required for PFS vs OS for various median SPP. We compare our results with the literature regarding surrogacy of PFS for OS by use of the correlation between hazard ratios for PFS and OS. All statistical tests were two-sided.

RESULTS

For a trial with observed P value for improvement in PFS of .001, there was a greater than 90% probability for statistical significance in OS if median SPP was 2 months but less than 20% if median SPP was 24 months. For a trial requiring 280 patients to detect a 3-month difference in PFS, 350 and 2440 patients, respectively, were required to have the same power for detecting a real difference in OS that is carried over from the 3-month benefit in PFS when the median SPP was 2 and 24 months.

CONCLUSIONS

Addressing SPP is important in understanding treatment effects. For clinical trials with a PFS benefit, lack of statistical significance in OS does not imply lack of improvement in OS, especially for diseases with long median SPP. Although there may be no treatment effect on SPP, its variability so dilutes the OS comparison that statistical significance is likely lost. OS is a reasonable primary endpoint when median SPP is short but is too high a bar when median SPP is long, such as longer than 12 months.

High risk of recurrence for patients with breast cancer who have human epidermal growth factor receptor 2-positive, node-negative tumors 1 cm or smaller

PURPOSE

To evaluate the risk of recurrence in women diagnosed with T1a and T1b, node-negative, human epidermal growth factor receptor 2 (HER2) -positive breast cancer.

METHODS

We reviewed 965 T1a,bN0M0 breast cancers diagnosed at our institution between 1990 and 2002. Dedicated breast pathologists confirmed HER2 positivity if 3+ by immunohistochemistry or if it had a ratio of 2.0 or greater by fluorescence in situ hybridization (FISH). Patients who received adjuvant chemotherapy or trastuzumab were excluded. Kaplan-Meier product was used to calculate recurrence-free survival (RFS) and distant recurrence-free survival (DRFS). Cox proportional hazard models were fit to determine associations between HER2 status and survival after adjustment for patient and disease characteristics. Additionally, 350 breast cancers from two other institutions were used for validation.

RESULTS

Ten percent of patients had HER2-positive tumors. At a median follow-up of 74 months, there were 72 recurrences. The 5-year RFS rates were 77.1% and 93.7% in patients with HER2-positive and HER2-negative tumors, respectively (P < .001). The 5-year DRFS rates were 86.4% and 97.2% in patients with HER2-positive and HER2-negative tumors, respectively (P < .001). In multivariate analysis, patients with HER2-positive tumors had higher risks of recurrence (hazard ratio [HR], 2.68; 95% CI, 1.44 to 5.0; P = .002) and distant recurrence (HR, 5.3; 95% CI, 2.23 to 12.62; P < .001) than those with HER2-negative tumors. Patients with HER2-positive tumors had 5.09 times (95% CI, 2.56 to 10.14; P < .0001) the rate of recurrences and 7.81 times (95% CI, 3.17 to 19.22; P < .0001) the rate of distant recurrences at 5 years compared with patients who had hormone receptor-positive tumors.

CONCLUSION

Patients with HER2-positive T1abN0M0 tumors have a significant risk of relapse and should be considered for systemic, anti-HER2, adjuvant therapy.

Scientific writing training for academic physicians of diverse language backgrounds

Research articles are the coin of the realm for anyone working in academia, and success or failure to publish determines a biomedical researcher's career path. At the same time, the dramatic increase in foreign faculty and trainees in U.S. academia, as well as in international scientific collaboration, adds another dimension to this developmental vacuum: limited English-language skills. Paradoxically, few programs exist to develop and support the skills needed to accomplish the vital task of writing English-language research articles, which does not come naturally to most. To better prepare all trainees for research careers, editors in the Department of Scientific Publications at The University of Texas M. D. Anderson Cancer Center created an in-depth training program that would target the writing skills gap effectively. Instruction focused on structure, rhetorical organization, and the conventions of biomedical publishing. More than 300 trainees have participated in 22 workshops. Results of a survey of 46 participants at 6 months to 2.5 years after workshop completion indicated that participants from all language backgrounds believed the course to have improved their writing (97.8% strongly agreed or agreed), made it easier to begin a manuscript (80.4%), and helped them to get published (56.8%), with nonnative speakers of English reporting somewhat greater perceived benefit than native English speakers. On the basis of these results, the authors conclude that researchers of varied linguistic backgrounds appreciate the need for, and benefit from, instruction in the conventions of scientific writing.

High prevalence of preinvasive lesions adjacent to BRCA1/2-associated breast cancers

Mutations in BRCA1 and BRCA2 increase a woman's lifetime risk of developing breast cancer by 43% to 84%. It was originally postulated that BRCA1/2-associated breast cancers develop more rapidly than sporadic cancers and may lack preinvasive lesions. More recent studies have found preinvasive lesions in prophylactic mastectomy specimens from mutation carriers; however, there is little information on the presence of preinvasive lesions in tissue adjacent to breast cancers. Our aim is to investigate the role of preinvasive lesions in BRCA-associated breast carcinogenesis. We retrospectively compared BRCA1/2-associated breast cancers and sporadic breast cancers for the prevalence of preinvasive lesions [ductal carcinoma in situ (DCIS), lobular carcinoma in situ, and atypical lobular hyperplasia] in tissue adjacent to invasive breast cancers. Pathology was reviewed for 73 BRCA1/2-associated tumors from patients with breast cancer. We selected 146 patients with mutation-negative breast cancer as age-matched controls. Among the BRCA1/2-associated breast cancers, 59% had at least one associated preinvasive lesion compared with 75% of controls. Preinvasive lesions were more prevalent in BRCA2 mutation carriers than in BRCA1 mutation carriers (70% versus 52%, respectively). The most common preinvasive lesion in both groups was DCIS; 56% of BRCA1/2-associated breast cancers and 71% of the sporadic breast cancers had adjacent intraductal disease, respectively. Preinvasive lesions, most notably DCIS, are common in BRCA1/2-associated breast cancers. These findings suggest that BRCA1/2-associated breast cancers progress through the same intermediate steps as sporadic breast cancers, and that DCIS should be considered as a part of the BRCA1/2 tumor spectrum.

Residual risk of breast cancer recurrence 5 years after adjuvant therapy

There is limited prognostic information to identify breast cancer patients who are at risk for late recurrences after adjuvant or neoadjuvant systemic therapy (AST). We evaluated the residual risk of recurrence and prognostic factors of 2838 patients with stage I-III breast cancer who were treated with AST between January 1, 1985, and November 1, 2001, and remained disease free for 5 years. Residual recurrence-free survival was estimated from the landmark of 5 years after AST to date of first recurrence or last follow-up using the Kaplan-Meier method. The log-rank test (two-sided) was used to compare groups. Residual recurrence-free survival rates at 5 and 10 years were 89% and 80%, respectively, and 216 patients developed a recurrence event. The 5-year residual risks of recurrence for patients with stage I, II, and III cancers were 7% (95% confidence interval [CI] = 3% to 15%), 11% (95% CI = 9% to 13%), and 13% (95% CI = 10% to 17%), respectively (P = .02). In multivariable analysis, stage, grade, hormone receptor status, and endocrine therapy were associated with late recurrences. Breast cancer patients have a substantial residual risk of recurrence, and selected tumor characteristics are associated with late recurrences.

Factors predicting additional disease in the axilla in patients with positive sentinel lymph nodes after neoadjuvant chemotherapy

BACKGROUND

The utility of sentinel lymph node (SNL) biopsy (SLNB) as a predictor of axillary lymph node status is similar in patients who receive neoadjuvant chemotherapy and patients who undergo surgery first. The authors of this study hypothesized that patients with positive SLNs after neoadjuvant therapy would have unique clinicopathologic factors that would be predictive of additional positive non-SLNs distinct from patients who underwent surgery first.

METHODS

One hundred four patients were identified who received neoadjuvant chemotherapy, had a positive SLN, and underwent axillary dissection between 1997 and 2005. At the time of presentation, 66 patients had clinically negative lymph nodes by ultrasonography, and 38 patients had positive lymph nodes confirmed by fine-needle aspiration. Eighteen factors were assessed for their ability to predict positive non-SLNs using chi-square and logistic regression analysis with a bootstrapped, backwards elimination procedure. The resulting nomogram was tested by using a patient cohort from another institution.

RESULTS

Patients with clinically negative lymph nodes at presentation were less likely than patients with positive lymph nodes to have positive non-SLNs (47% vs 71%; P=.017). On multivariate analysis, lymphovascular invasion, the method for detecting SLN metastasis, multicentricity, positive axillary lymph nodes at presentation, and pathologic tumor size retained grouped significance with a bootstrap-adjusted area under the curve (AUC) of 0.762. The resulting nomogram was validated in the external patient cohort (AUC, 0.78).

CONCLUSIONS

A significant proportion of patients with positive SLNs after neoadjuvant chemotherapy had no positive non-SLNs. The use of a nomogram based on 5 predictive variables that were identified in this study may be useful for predicting the risk of positive non-SLNs in patients who have positive SLNs after chemotherapy.

Overall survival and cause-specific mortality of patients with stage T1a,bN0M0 breast carcinoma

PURPOSE

With mammographic screening, the frequency of diagnosis of stage T1a,bN0M0 breast cancer has increased. Prognosis after locoregional therapy and benefit from adjuvant systemic therapy are poorly defined. We reviewed T1a,bN0M0 breast cancer cases registered in the Surveillance, Epidemiology, and End Results (SEER) Program to investigate the impact of prognostic factors on breast cancer-specific (BCSM) and non-breast cancer-related mortality.

METHODS

We identified T1a,bN0M0 breast cancer cases registered in the SEER Program from 1988 to 2001, and used the Kaplan-Meier product limit method to describe overall survival (OS). We estimated the probabilities of death resulting from breast cancer and from other causes, and analyzed associations of patient and tumor characteristics with OS, BCSM, and non-breast cancer-related mortality using the log-rank test, Cox proportional hazards models, and a competing-risk model. We constructed nomograms to assist physicians in adjuvant therapy decision making.

RESULTS

We identified 51,246 T1a,bN0M0 cases. Median follow-up was 64 months (range, 1 to 167 months). Median age at diagnosis was 65 years (range, 20 to 101 years). Ten-year probabilities of all-cause mortality and BCSM were 24% and 4%, respectively. Characteristics associated with increased probability of BCSM included age younger than 50 years at diagnosis, high tumor grade, estrogen receptor-negative status, progesterone receptor-negative status, and fewer than six nodes removed at axillary dissection. The constructed nomograms allow a comparison of predicted breast cancer-specific survival and non-breast cancer-specific survival in individual patients.

CONCLUSION

Overall, the prognosis of patients with T1a,bN0M0 breast cancer is excellent. However, subgroups of patients who are at higher risk of BCSM and who should be considered for adjuvant systemic therapy can be identified.

BRCA1 and BRCA2 genetic testing in Hispanic patients: mutation prevalence and evaluation of the BRCAPRO risk assessment model

PURPOSE

The BRCAPRO model, used to predict a family's likelihood of carrying a BRCA1 or BRCA2 mutation, was designed using mutation frequencies of white and Ashkenazi Jewish populations, and may not be applicable to other populations. BRCAPRO was recently validated in African Americans, although has yet to be examined in Hispanics. This retrospective study reports the mutation frequency and spectrum of BRCA1 and BRCA2 mutations in a Hispanic population and evaluates the BRCAPRO model in Hispanics.

PATIENTS AND METHODS

A descriptive analysis of mutation frequency and spectrum was performed for Hispanic patients who underwent BRCA1 and BRCA2 genetic testing at a single institution. For comparative analysis of the BRCAPRO risk model, Hispanic patients who underwent comprehensive analysis were compared with white controls using area under the receiver operating characteristic curves (AUROC).

RESULTS

Fourteen Hispanic individuals who underwent comprehensive analysis were identified to carry a mutation in BRCA1 or BRCA2 (17.9%; 95% CI, 10.2% to 28.3%) and seven individuals had a variant of uncertain significance (9.0%; 95% CI, 12.0% to 30.8%). A total of eight different mutations and three variants were observed within the entire Hispanic population. When evaluating the performance of the BRCAPRO model, the AUROC for Hispanics was 0.774 (95% CI, 0.63 to 0.90), compared with the AUROC of 0.770 (95% CI, 0.65 to 0.89) for whites.

CONCLUSION

Deleterious BRCA1 and BRCA2 mutations occur at considerable frequency within the Hispanic population, many of which have been identified previously in other ethnic populations. The BRCAPRO model appears to perform equally well in Hispanics as in whites.

Inflammatory breast cancer (IBC) and patterns of recurrence: understanding the biology of a unique disease

BACKGROUND

Inflammatory breast cancer (IBC) is the most aggressive manifestation of primary breast cancer. The authors compared the prognostic features of IBC and non-IBC locally advanced breast cancer (LABC) to gain insight into the biology of this disease entity.

METHODS

This retrospective analysis consisted of 1071 patients, comprising 240 patients with IBC and 831 patients with non-IBC LABC who were enrolled in 10 consecutive clinical trials (5 from each disease group). All patients received similar multidisciplinary treatment. The authors measured time to disease recurrence for each individual site from the start of treatment to the date of disease recurrence or last follow-up (recurrence-free survival) and overall survival rates to the date of last follow-up or death.

RESULTS

The median follow-up period was 69 months (range, 1-367 months). Pathologically complete response rates were 13.9% and 11.7% in the IBC and non-IBC LABC groups, respectively (P = .42). The 5-year estimates of cumulative incidence of recurrence were 64.8 % and 43.4% (P < .0001), respectively, for IBC and non-IBC LABC. IBC had significantly higher cumulative incidence of locoregional recurrence and distant soft-tissue and bone disease. The 5-year overall survival (OS) rate was 40.5% for the IBC group (95% CI, 34.5%-47.4%) and 63.2% for the non-IBC LABC group (95% CI, 60.0%-66.6%; P < .0001).

CONCLUSIONS

IBC was associated with a worse prognosis and a distinctive pattern of early recurrence compared with LABC. These data suggested that investigating factors affecting "homing" of cancer cells may provide novel treatment strategies for IBC.

Neoadjuvant therapy with paclitaxel followed by 5-fluorouracil, epirubicin, and cyclophosphamide chemotherapy and concurrent trastuzumab in human epidermal growth factor receptor 2-positive operable breast cancer: an update of the initial randomized study population and data of additional patients treated with the same regimen

PURPOSE

Findings from our previously published phase III randomized trial showed a high pathologic complete remission (CR) rate in patients with human epidermal growth factor receptor 2-positive breast cancer after the concurrent administration of trastuzumab and paclitaxel, followed by concurrent trastuzumab and 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) preoperative chemotherapy. The safety and efficacy data of initial population were updated, with inclusion of additional experience with the same therapy.

STUDY DESIGN

The initial randomized study population of 42 patients were randomly assigned to either four cycles of paclitaxel followed by four cycles of FEC or to the same chemotherapy with simultaneous weekly trastuzumab for 24 weeks. All data were updated through November 2005.

RESULTS

Pretreatment characteristics of the initial patients and of the second cohort were similar. In the second cohort, pathologic CR rate was 54.5% (95% confidence interval, 32.2-75.6%) and the pathologic CR rate among all patients treated with chemotherapy plus trastuzumab was 60% (95% confidence interval, 44.3-74.3%). Three patients in the chemotherapy only group have recurred, and one has died. There has been no recurrences in the patients randomized to chemotherapy plus trastuzumab, and the estimated disease-free survival at 1 and 3 years was 100% (P = 0.041). In additional cohort treated with chemotherapy and trastuzumab at the median follow-up of 16.3 months, no patients had recurred. No new safety concerns were observed in this study.

CONCLUSION

Our expanded cardiac safety data and the updated efficacy data showed that the natural history of this subset of breast cancer patients can be substantially modified by this treatment approach.

Expression of growth factor and chemokine receptors: new insights in the biology of inflammatory breast cancer

PURPOSE

Recent studies have indicated that expression of chemokine receptors CXCR4 and CCR7 could be an indicator of the metastatic potential of breast cancer. Expression of CXCR4 and CCR7 along with the biomarkers HER2-neu and epidermal growth factor receptor (EGFR) was investigated in inflammatory breast cancer (IBC) to evaluate their prognostic implications.

EXPERIMENTAL DESIGN

CXCR4, CCR7, and EGFR were evaluated by immunohistochemical staining (IHC) of paraffin-embedded tissue sections. HER2-neu amplification was assessed by FISH and/or IHC. All patients received chemotherapy, surgery, and radiation.

RESULTS

Forty-four cases diagnosed with IBC from 1994 to 2002 were included in the study. In all, 18 (40.9%) patients had positive CXCR4, 10 (22.7%) had positive CCR7, 21 (47.7%) had positive HER2-neu, and EGFR was positive in 12 of 40 patients (30%). The 5-year overall survival (OS) was 24.8% for CXCR4-positive disease versus 42.3% for CXCR4-negative patients (P = 0.53) and 20.0% for CCR7-positive disease versus 41.9% for CCR7-negative patients (P = 0.24). EGFR-positive disease had significantly worse OS compared with EGFR-negative disease (P = 0.01).

CONCLUSIONS

These data demonstrate the expression of growth factor and chemokine receptors in IBC. The expression of these receptors is associated with increased risk of recurrence and death, and thus, they may represent potential therapeutic targets in IBC.

Novel clinical trial designs for treatment of ductal carcinoma in situ of the breast with trastuzumab (herceptin)

Because ductal carcinoma in situ (DCIS) avidly expresses Her2/neu, the target of the monoclonal antibody trastuzumab, and because trastuzumab has been shown to be effective against invasive breast cancer, trastuzumab may be effective for reducing the tumor burden and abrogating or reversing the hypothesized transition from in situ to invasive disease in patients with DCIS. To test this hypothesis, a trial of neoadjuvant trastuzumab for DCIS has been opened at our institution. Because trastuzumab has been shown to act as a radiosensitizing agent for Her2/neu-overexpressing cancer and because there are currently no systemic treatments for estrogen-receptor-negative DCIS, it makes sense to investigate whether use of trastuzumab concurrently with postoperative radiation therapy improves local control of DCIS. The National Surgical Adjuvant Breast and Bowel Project (NSABP) is planning a trial to test this hypothesis. The risk of cardiac toxicity associated with the doses of trastuzumab planned for these trials (cumulative doses of 8 mg/kg for our trial and 14 mg/kg in the NSABP trial) is believed to be minimal, but the safety profile of these approaches will need to be closely monitored.

Circulating tumor cells in metastatic breast cancer: biologic staging beyond tumor burden

BACKGROUND

The detection of circulating tumor cells (CTCs) predicts overall survival in patients with metastatic breast cancer (MBC). However, it is unknown whether CTCs have superior value compared with other standard prognostic factors. We compared the prognostic significance of CTCs with clinical and laboratory measures of tumor burden and phenotypic subtype of disease.

PATIENTS AND METHODS

One hundred fifty-one patients with MBC evaluated between 2000 and 2006 were included in this retrospective analysis. Circulating tumor cells were isolated and enumerated in whole blood using an immunomagnetic bead system (CellSearch System). Overall survival was evaluated according to the level of CTCs (negative: <5 CTCs per 7.5 mL of blood; positive: >or=5 CTCs per 7.5 mL of blood), Swenerton score, cancer antigen 27-29 level, age (<50 years vs. >or=50 years), hormone-receptor status and HER2 status, metastatic site, and type and line of therapy.

RESULTS

The median age of patients was 53 years (range, 24-88 years), and 44% of the patients had >5 CTCs. The median overall survival for negative versus positive CTCs were 29.3 months and 13.5 months, respectively (P<0.0001). In the multivariable Cox model, the detection of>or=5 CTCs demonstrated the highest hazard ratio with 2.2 times the risk of death (P=0.003). The prognostic value was independent of measure of tumor burden and type and line of therapy, and phenotypic subtype of the disease.

CONCLUSION

Circulating tumor cells have superior and independent prognostic value of tumor burden and disease phenotype and might represent an important marker of tumor biology in MBC. Detection of CTCs should be considered for new staging stratification of patients with MBC.

Bortezomib (VELCADE®) in metastatic breast cancer: pharmacodynamics, biological effects, and prediction of clinical benefits

BACKGROUND

Bortezomib (VELCADE) is a potent inhibitor of the 26S proteasome with broad antitumor activity. We performed a phase II study of bortezomib to evaluate its clinical effects in patients with metastatic breast cancer.

PATIENTS AND METHODS

Twelve patients with metastatic breast cancer were treated with bortezomib (VELCADE) at a dosage of 1.5 mg/m(2) administered biweekly for 2 weeks with 1 week of rest in a 21-day cycle. The primary objective was clinical response rate. Toxicity and pharmacodynamics data were also obtained.

RESULTS

No objective responses were observed. One patient had stable disease, and 11 others experienced disease progression. The median survival time was 4.3 months (range, 0.9-37 months). The most common grade 3 or 4 toxicities included fatigue (58%; n = 7) and skin rash (33%; n = 4). The mean inhibition of specific chymotryptic activity was 53.1% (+/- 13.33%). A statistically significant reduction in the plasma interleukin-6 level was seen (P = 0.0354).

CONCLUSION

Bortezomib was well tolerated but showed limited clinical activity against metastatic breast cancer when used as a single agent. The future development of this agent for the treatment of breast cancer should be guided by in vivo models that optimize activity in combination with other antitumor agents.

CCR7 and CXCR4 as novel biomarkers predicting axillary lymph node metastasis in T1 breast cancer

PURPOSE

The chemokine receptors CCR7 and CXCR4 have been shown to play an important role in cancer metastasis. We therefore studied the differential expression of CCR7 and CXCR4, along with that of the biomarker HER2-neu, to evaluate whether these biomarkers could predict axillary lymph node metastasis in breast cancer.

EXPERIMENTAL DESIGN

Biomarker expression levels were evaluated using paraffin-embedded tissue sections of lymph node-negative (n = 99) and lymph node-positive (n = 98) T1 breast cancer by immunohistochemical staining.

RESULTS

Lymph node-positive tumors showed higher rates of high cytoplasmic CCR7 staining (21.5% versus 8.5%, P = 0.013) and HER2-neu overexpression (21.5% versus 9.3%, P = 0.019) than did lymph node-negative tumors. Similarly, high cytoplasmic CXCR4 expression occurred more commonly in lymph node-positive tumors (11.2% versus 5.1%, P = 0.113). In contrast, predominantly nuclear CXCR4 staining was more likely to be found in lymph node-negative tumors (54.5% versus 37.8%, P = 0.018). Furthermore, cytoplasmic CXCR4 coexpressed with HER2-neu was the only factor associated with involvement of four or more lymph nodes (16.7% versus 1.2%, P = 0.04) among lymph node-positive tumors. When all three biomarkers (CCR7, CXCR4, HER2-neu) were utilized together, 50.0% of lymph node-positive tumors highly expressed one of these biomarkers compared with 18.8% of the lymph node-negative tumors (P < 0.0001).

CONCLUSIONS

Our results suggest that the chemokine receptor CCR7 is a novel biomarker that can predict lymph node metastases in breast cancer. Utilization of additional markers, such as CXCR4 and HER2-neu, further improves the prediction of the presence and extent of lymph node involvement.

Combined-modality treatment for isolated recurrences of breast carcinoma: update on 30 years of experience at the University of Texas M.D. Anderson Cancer Center and assessment of prognostic factors

BACKGROUND

In three prospective, single-arm studies, the authors previously showed an improved outcome for anthracycline-naïve patients with isolated sites of recurrent breast carcinoma (BC) who were treated with doxorubicin-based chemotherapy after local therapy (surgery and/or radiotherapy). In the current report, the initial results are presented from a Phase II trial of docetaxel (100 mg/m(2) every 21 days for 6 cycles) given after local therapy for recurrent BC (Stage IV BC with no evidence of clinically measurable disease) in patients who received prior adjuvant anthracycline-based chemotherapy, and the authors provide an update of the 3 previous studies. An analysis of prognostic factors for these patients also is presented.

METHODS

Eligibility criteria for all studies included histologic proof of recurrent BC that had been resected and/or irradiated with curative intent. Survival was calculated using the Kaplan-Meier method. Univariate survival analyses were performed to test for associations between patient characteristics and outcome (log-rank test). Cox proportional hazards models were used to determine the multivariable correlations between patient characteristics and outcome.

RESULTS

The median follow-up for the docetaxel-based trial (n = 26 patients) was 45 months. Early outcomes for this study are promising. The median disease-free survival (DFS) was 44 months, and the 3-year DFS and overall survival (OS) rates were 58% and 87%, respectively. In the 3 doxorubicin-based studies, the median follow-up was 121.5 months for all living patients, and the estimated 20-year DFS and OS rates were both 26%. On multivariable analysis of patients from all 4 studies, the only significant prognostic factor for DFS and OS (P = 0.0006) was the number of involved axillary lymph nodes at initial diagnosis.

CONCLUSIONS

A proportion of patients with isolated BC recurrences achieved prolonged DFS with combined-modality treatment. Patients who receive anthracycline-based chemotherapy at primary diagnosis may benefit from local treatment followed by docetaxel-based chemotherapy for isolated recurrences. The only significant independent prognostic factor was the number of involved axillary lymph nodes at initial diagnosis.

High rate of durable remissions after treatment of newly diagnosed aggressive mantle-cell lymphoma with rituximab plus hyper-CVAD alternating with rituximab plus high-dose methotrexate and cytarabine

PURPOSE

To determine the response, failure-free survival (FFS), and overall survival rates and toxicity of rituximab plus an intense chemotherapy regimen in patients with previously untreated aggressive mantle-cell lymphoma (MCL).

PATIENTS AND METHODS

This was a prospective phase II trial of rituximab plus fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (hyper-CVAD; considered one cycle) alternating every 21 days with rituximab plus high-dose methotrexate-cytarabine (considered one cycle) for a total of six to eight cycles.

RESULTS

Of 97 assessable patients, 97% responded, and 87% achieved a complete response (CR) or unconfirmed CR. With a median follow-up time of 40 months, the 3-year FFS and overall survival rates were 64% and 82%, respectively, without a plateau in the curves. For the subgroup of patients < or = 65 years of age, the 3-year FFS rate was 73%. The principal toxicity was hematologic. Five patients died from acute toxicity. Four patients developed treatment-related myelodysplasia/acute myelogenous leukemia, and three patients died while in remission from MCL. A total of eight treatment-related deaths (8%) occurred.

CONCLUSION

Rituximab plus hyper-CVAD alternating with rituximab plus high-dose methotrexate and cytarabine is effective in untreated aggressive MCL. Toxicity is significant but expected. Because of the shorter FFS concurrent with significant toxicity in patients more than 65 years of age, this regimen is not recommended as standard therapy for this age subgroup. Larger prospective randomized studies are needed to define the role of this regimen in the treatment of MCL patients compared with existing and new treatment modalities.

Adult glioma incidence trends in the United States, 1977-2000

BACKGROUND

Several authors have reported an increase in the incidence of brain tumors, especially among the elderly. A more complete understanding of adult glioma incidence trends might provide indications of risk factors for gliomas and contribute to the search for improved therapies.

METHODS

The authors used the Surveillance, Epidemiology, and End Results (SEER) registry public use data tapes, which included data on patients with cancer diagnosed between 1973 and 2000. For 3 histologies as well as for 12 histology categories combined, the authors used Poisson regression to model incidence as a function of year of diagnosis, age at diagnosis, race (white or African American), and gender. They used cubic splines to fit age at diagnosis and year of diagnosis and tested for all pair-wise interactions.

RESULTS

The interaction between year of diagnosis and age at diagnosis was significant in all four groups modeled. In glioblastoma, there was also a significant interaction between gender and age at diagnosis. In anaplastic astrocytoma, there was a significant interaction between gender and year of diagnosis. In oligodendroglioma, there was a significant interaction between race and gender. In the 12 histology categories combined, there was a significant interaction between gender and age at diagnosis.

CONCLUSIONS

The results in the current study were consistent with other published reports that showed an increase in the incidence of brain tumors using SEER data. Although others have observed increasing incidence trends among the elderly, the authors formally tested and found a statistically significant interaction between age at diagnosis and year of diagnosis.

Central nervous system metastases in patients with high-risk breast carcinoma after multimodality treatment

BACKGROUND

The current study was performed to determine the incidence of central nervous system (CNS) metastases and to examine associated disease characteristics in a group of patients with locally advanced breast carcinoma (LABC) or inflammatory breast carcinoma (IBC) treated at The University of Texas M. D. Anderson Cancer Center (Houston, TX).

METHODS

Seven hundred sixty-eight patients treated with multimodality therapy between 1982 and 2000 in any of 6 neoadjuvant trials were eligible for the current study. Five hundred ninety-two patients (77%) had LABC, and 176 (23%) had IBC. CNS disease was defined as the presence of brain metastases or leptomeningeal disease. Time to detection of CNS disease and overall survival were estimated using the Kaplan-Meier product-limit method, and differences were evaluated using log-rank tests.

RESULTS

The median patient age was 48 years. Most tumors were classified as T4 lesions (58%) and exhibited lymph node involvement (78%). Fifty-one percent of all tumors had positive hormone receptor status. At a median follow-up duration of 9.5 years, 61 patients (8%) had developed CNS metastases, with the CNS representing the first site of recurrence for 38 of these 61 (63%). Characteristics associated with the development of CNS metastases over time included negative hormone receptor status (P = 0.03), Grade 3 disease (P = 0.01), and larger tumor size (P = 0.02). The median time to detection of CNS metastases was 2.3 years. Ten patients (16%) remained alive after treatment for CNS metastases. The median survival from the time of diagnosis of CNS metastases was 8 months.

CONCLUSIONS

CNS metastases from breast carcinoma were relatively uncommon and were strongly associated with more aggressive clinical presentation. Survival from the time of diagnosis of such metastases generally was short.

Recurrence and outcomes following hepatic resection, radiofrequency ablation, and combined resection/ablation for colorectal liver metastases

OBJECTIVE

To examine recurrence and survival rates for patients treated with hepatic resection only, radiofrequency ablation (RFA) plus resection or RFA only for colorectal liver metastases.

SUMMARY BACKGROUND DATA

Thermal destruction techniques, particularly RFA, have been rapidly accepted into surgical practice in the last 5 years. Long-term survival data following treatment of colorectal liver metastasis using RFA with or without hepatic resection are lacking.

METHODS

Data from 358 consecutive patients with colorectal liver metastases treated for cure with hepatic resection +/- RFA and 70 patients found at laparotomy to have liver-only disease but not to be candidates for potentially curative treatment were compared (1992-2002).

RESULTS

Of 418 patients treated, 190 (45%) underwent resection only, 101 RFA + resection (24%), 57 RFA only (14%), and 70 laparotomy with biopsy only or arterial infusion pump placement ("chemotherapy only," 17%). RFA was used in operative candidates who could not undergo complete resection of disease. Overall recurrence was most common after RFA (84% vs. 64% RFA + resection vs. 52% resection only, P < 0.001). Liver-only recurrence after RFA was fourfold the rate after resection (44% vs. 11% of patients, P < 0.001), and true local recurrence was most common after RFA (9% of patients vs. 5% RFA + resection vs. 2% resection only, P = 0.02). Overall survival rate was highest after resection (58% at 5 years); 4-year survival after resection, RFA + resection and RFA only were 65%, 36%, and 22%, respectively (P < 0.0001). Survival for "unresectable" patients treated with RFA + resection or RFA only was greater than chemotherapy only (P = 0.0017).

CONCLUSIONS

Hepatic resection is the treatment of choice for colorectal liver metastases. RFA alone or in combination with resection for unresectable patients does not provide survival comparable to resection, and provides survival only slightly superior to nonsurgical treatment.

Lack of association between amplification ofher-2 and response to preoperative taxanes in patients with breast carcinoma

BACKGROUND

The objective of the current study was to determine whether her-2 amplification was associated with a pathologic response to preoperative chemotherapy with taxanes in patients with early-stage breast carcinoma.

METHODS

The authors evaluated 71 patients treated for AJCC Stage II and III breast carcinoma with preoperative taxanes whose tissue specimens were still available. Fifty-seven patients (80%) had received paclitaxel and 14 (20%) had received docetaxel (4 cycles of either drug). Amplification of the her-2 gene was determined using fluorescence in situ hybridization.

RESULTS

The median patient age was 49 years (range, 21-70 years). Forty-eight patients (68%) had Stage II breast carcinoma and 23 (32%) had Stage III disease. her-2 gene amplification was detected in 19 tumor specimens (28%). Hormone receptors (estrogen and/or progesterone) were detected in 11 her-2-positive tumor specimens (58%) and in 31 her-2-negative tumor specimens (85%). Eight pathologic complete responses (pCR; breast and axillary lymph nodes) occurred, 3 (16%) in patients with her-2-positive tumor specimens and five (10%) in patients with her-2-negative tumor specimens (P = 0.68). Twelve patients achieved pCR in the breast, 5 (26%) in patients with her-2-positive tumors and 7 (15%) in patients with her-2-negative tumors (P = 0.3). At a median follow-up of 61 months, none of the patients with a pCR developed recurrent disease, regardless of their her-2 status. The progression-free and overall survival rates were similar in both HER-2-positive and her-2-negative groups (P = 0.45 and P = 0.14, respectively).

CONCLUSIONS

her-2 gene amplification was not found to be predictive of a pathologic response to preoperative taxanes in patients with early-stage breast carcinoma.

A dynamic Markov model for forecasting diabetes prevalence in the United States through 2050

This study develops forecasts of the number of people with diagnosed diabetes and diagnosed diabetes prevalence in the United States through the year 2050. A Markov modeling framework is used to generate forecasts by age, race and ethnicity, and sex. The model forecasts the number of individuals in each of three states (diagnosed with diabetes, not diagnosed with diabetes, and death) in each year using inputs of estimated diagnosed diabetes prevalence and incidence; the relative risk of mortality from diabetes compared with no diabetes; and U.S. Census Bureau estimates of current population, live births, net migration, and the mortality rate of the general population. The projected number of people with diagnosed diabetes rises from 12.0 million in 2000 to 39.0 million in 2050, implying an increase in diagnosed diabetes prevalence from 4.4% in 2000 to 9.7% in 2050.