Breast cancer screening: controversy of impact

Few medical issues have been as controversial--or as political, at least in the United States-as the role of mammographic screening for breast cancer. The advantages of finding a cancer early seem obvious. Indeed, randomized trials evaluating screening mammography demonstrate a reduction in breast cancer mortality, but the benefits are less than one would hope. Moreover, the randomized trials are themselves subject to criticism, including that they are irrelevant in the modern era because most were conducted before chemotherapy and hormonal therapy became widely used. In this article I chronicle the evidence and controversies regarding mammographic screening, including attempts to assess the relative contributions of screening and therapy in the substantial decreases in breast cancer mortality that have been observed in many countries over the last 20-25 years. I emphasize the trade-off between harms and benefits depending on the woman's age and other risk factors. I also discuss ways for communicating the associated risks to women who have to decide whether screening (and what screening strategy) is right for them.

Biomarker-based adaptive trials for patients with glioblastoma--lessons from I-SPY 2

The traditional clinical trials infrastructure may not be ideally suited to evaluate the numerous therapeutic hypotheses that result from the increasing number of available targeted agents combined with the various methodologies to molecularly subclassify patients with glioblastoma. Additionally, results from smaller screening studies are rarely translated to successful larger confirmatory studies, potentially related to a lack of efficient control arms or the use of unvalidated surrogate endpoints. Streamlining clinical trials and providing a flexible infrastructure for biomarker development is clearly needed for patients with glioblastoma. The experience developing and implementing the I-SPY studies in breast cancer may serve as a guide to developing such trials in neuro-oncology.

Lumpectomy plus tamoxifen with or without irradiation in women age 70 years or older with early breast cancer: long-term follow-up of CALGB 9343

PURPOSE

To determine whether there is a benefit to adjuvant radiation therapy after breast-conserving surgery and tamoxifen in women age ≥ 70 years with early-stage breast cancer.

PATIENTS AND METHODS

Between July 1994 and February 1999, 636 women (age ≥ 70 years) who had clinical stage I (T1N0M0 according to TNM classification) estrogen receptor (ER) -positive breast carcinoma treated by lumpectomy were randomly assigned to receive tamoxifen plus radiation therapy (TamRT; 317 women) or tamoxifen alone (Tam; 319 women). Primary end points were time to local or regional recurrence, frequency of mastectomy, breast cancer-specific survival, time to distant metastasis, and overall survival (OS).

RESULTS

Median follow-up for treated patients is now 12.6 years. At 10 years, 98% of patients receiving TamRT (95% CI, 96% to 99%) compared with 90% of those receiving Tam (95% CI, 85% to 93%) were free from local and regional recurrences. There were no significant differences in time to mastectomy, time to distant metastasis, breast cancer-specific survival, or OS between the two groups. Ten-year OS was 67% (95% CI, 62% to 72%) and 66% (95% CI, 61% to 71%) in the TamRT and Tam groups, respectively.

CONCLUSION

With long-term follow-up, the previously observed small improvement in locoregional recurrence with the addition of radiation therapy remains. However, this does not translate into an advantage in OS, distant disease-free survival, or breast preservation. Depending on the value placed on local recurrence, Tam remains a reasonable option for women age ≥ 70 years with ER-positive early-stage breast cancer.

Clinical and translational results of CALGB 40601: A neoadjuvant phase III trial of weekly paclitaxel and trastuzumab with or without lapatinib for HER2-positive breast cancer

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Background: Recent trials in HER2-positive (HER2+) breast cancer (BrCa) demonstrate increased pathological complete response (pCR) using dual HER2-targeting in the neoadjuvant setting and increased progression-free survival in metastatic disease. CALGB 40601 aimed to further quantify the pCR rates of weekly paclitaxel (T) and trastuzumab (H) alone or combined HER2-blockade of H with the small molecule lapatinib (L), and to identify biomarkers of sensitivity to these HER2-targeted agents. Methods: Eligible patients had newly diagnosed, noninflammatory stage II-III HER2+ BrCa and were randomized to receive T (80mg/m2/week IV) + H (4mg/kg then 2mg/kg/week IV) alone (TH) or with the addition of L (750 mg/d PO) (THL) for 16 weeks preoperatively. A third arm, T + L (1500 mg/d) (TL), was closed early when negative efficacy and toxicity data emerged from preliminary analysis of ALTTO. After surgery, 4 cycles of adjuvant dose-dense AC and 1 year H was recommended. Tumors were biopsied for research before therapy; post-Rx samples of residual disease were requested. The primary endpoint was in-breast pCR rate; the study had 85% power to detect an increase from 30% (TH) to 50% (THL). Results: 305 patients were randomized (118 THL, 120 TH, 67 TL); 68% were clinical stage II and 59% hormone receptor-positive. Grade 3+ toxicity was higher among L-containing arms, including neutropenia (12% TL, 7% THL, 2% TH), rash (15% TL, 14% THL, 2% TH), and diarrhea (20% TL, 20% THL, 2% TH). Breast pCR rates with 95% confidence limits were: 51% (42-60%) THL, 40% (32-49%) TH, 32% (22-44%) TL. pCR rate in the TH arm was higher than previous studies, and was not significantly different from THL (p=0.11). We will present molecular subtype, sequence and gene copy number abnormalities in primary tumors and residual disease. Conclusions: pCR rate was higher with combined THL compared with standard TH but did not reach statistical significance. These results are qualitatively similar to other neoadjuvant studies in HER2+ BrCa, and contribute to estimates of pCR rates after these agents. Tissue-based studies may illuminate which patients benefit from HER2-targeting using these agents. Clinical trial information: NCT00770809.

Impact of neoadjuvant chemotherapy plus HER2-targeting on breast conservation rates: Surgical results from CALGB 40601 (Alliance)

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Background: Neoadjuvant systemic therapy improves breast conserving therapy (BCT) rates, but the magnitude of this benefit is unknown in operable breast cancer. We sought to quantify this benefit in CALGB 40601, a phase III trial of paclitaxel (T) + HER2 blockade with either trastuzumab (TH), lapatinib (TL), or both (THL), by requiring the treating breast surgeon to determine BCT eligibility before and after neoadjuvant therapy and examining surgical results. Methods: Eligible patients (pts) had operable, newly diagnosed, noninflammatory stage II-III HER2+ breast cancer randomized to receive TH, TL or THL. Prior to, and again after neoadjuvant therapy, the treating breast surgeon determined whether the patient was a BCT candidate based on clinical and radiographic criteria, but the subsequent breast cancer operation was at the discretion of the surgeon and patient. Two endpoints examined were: (1) the conversion rate from BCT-ineligible to BCT-eligible and (2) the rate of successful BCT as determined by tumor-free surgical margins. Results: Of 305 pts randomized (118 THL, 120 TH, 67 TL), 294 were evaluable. Prior to neoadjuvant therapy, 136 (46%) patients were candidates and 158 (54%) were non-candidates for BCT. 107/136 (79%) remained BCT candidates following neoadjuvant therapy and 78 chose BCT, of whom 69 (88%) were successful. 29 pts (21%) initially thought to be BCT candidates became non-candidates after neoadjuvant therapy. Conversely, 76/158 (48%) pts considered non-BCT candidates prior to neoadjuvant therapy down-sized sufficiently to be considered BCT candidates; 40 of these opted for BCT with a 75% (30/40) BCT success rate. In total, 183 pts were deemed BCT candidates after neoadjuvant therapy, yet 65 (36%) proceeded directly to mastectomy. Conclusions: This is the first neoadjuvant trial to prospectively quantify a nearly 50% conversion rate from BCT-ineligible to BCT-eligible in HER2+ breast cancer pts treated with modern systemic therapy. Neoadjuvant chemotherapy combined with targeted anti-HER2 treatment permits potential BCT in approximately 80% of properly selected patients. Clinical trial information: NCT00770809.

Comparison of doxorubicin and cyclophosphamide (AC) versus single-agent paclitaxel (T) as adjuvant therapy for breast cancer in women with 0-3 positive axillary nodes: CALGB 40101

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Background: Determining optimal adjuvant chemotherapy for early stage breast cancer depends on efficacy and toxicity. We sought to determine if T is equivalent to AC but with reduced toxicity. Methods: Pts with operable breast cancer with 0-3 positive nodes were enrolled on a 2x2 factorial design study which addressed (1) superiority of 6 vs. 4 cycles of therapy (previously reported, Shulman, JCO 2012) and (2) equivalence of single-agent T to standard AC, defined as upper bound of 95% confidence interval (CI) of hazard ratio (HR) of T vs. AC < 1.30 for the primary endpoint of relapse-free survival (RFS). A planned target of 567 RFS events required 4,646 pts with 4 yrs FU. At activation in 2002, T (80mg/m2) was q1wk for 12 or 18 wks and AC (60/600 mg/m2) was q3wk for 4 or 6 cycles. In 2003 (570 pts enrolled) schedules were revised to 4 or 6 cycles q2wk for both T (175 mg/m2) and AC. The 6-cycle arms were dropped in 2008 (3,171 pts enrolled) due to slow accrual. Relative effectiveness of T to AC is shown by hazard ratio (HR). Logrank p-values are measures of discordance but are not relevant for the equivalence question and are not adjusted for multiple comparisons. Results: After enrolling 3,871 pts, the study closed in 2010 due to slowing accrual. With a median follow-up of 6.1 yrs there are 437 RFS events. The HR of 1.26 (95% CI: 1.05-1.53; p = 0.02) does not allow a conclusion of equivalence of T with AC. With 266 deaths the HR for overall survival (OS) is 1.27 (95% CI=1.00-1.62; p = 0.05), favoring AC. The estimated absolute advantage of AC at 5 yrs is 3% (91 vs. 88%) for RFS and 1% (95 vs. 94%) for OS. All 9 treatment-related deaths were in pts receiving AC and are included in the survival analysis. The incidence of Grade 3+ toxicity for AC vs T was 33% vs. 4% for hematologic toxicity and 36% vs 22% for non-hematologic toxicity. Conclusions: This trial did not show equivalence of T to AC, a conclusion that is very unlikely to change with additional follow-up. T was less toxic than AC. Clinical trial information: CDR0000069444/NCT00041119.

Developing safety criteria for introducing new agents into neoadjuvant trials

New approaches to drug development are critically needed to lessen the time, cost, and resources necessary to identify and optimize active agents. Strategies to accelerate drug development include testing drugs earlier in the disease process, such as the neoadjuvant setting. The U.S. Food and Drug Administration (FDA) has issued guidance designed to accelerate drug approval through the use of neoadjuvant studies in which the surrogate short-term endpoint, pathologic response, can be used to identify active agents and shorten the time to approval of both efficacious drugs and biomarkers identifying patients most likely to respond. However, this approach has unique challenges. In particular, issues of patient safety are paramount, given the exposure of potentially curable patients to investigational agents with limited safety experience. Key components to safe drug development in the neoadjuvant setting include defining a study population at sufficiently poor prognosis with standard therapy to justify exposure to investigational agents, defining the extent and adequacy of safety data from phase I, detecting potentially harmful interactions between investigational and standard therapies, improving study designs, such as adaptive strategies, that limit patient exposure to ineffective agents, and intensifying safety monitoring in the course of the trial. The I-SPY2 trial is an example of a phase II neoadjuvant trial of novel agents for breast cancer in which these issues have been addressed, both in the design and conduct of the trial. These adaptations of phase II design enable acceleration of drug development by reducing time and cost to screen novel therapies for activity without compromising safety.

PAM50 proliferation score as a predictor of weekly paclitaxel benefit in breast cancer

To identify a group of patients who might benefit from the addition of weekly paclitaxel to conventional anthracycline-containing chemotherapy as adjuvant therapy of node-positive operable breast cancer. The predictive value of PAM50 subtypes and the 11-gene proliferation score contained within the PAM50 assay were evaluated in 820 patients from the GEICAM/9906 randomized phase III trial comparing adjuvant FEC to FEC followed by weekly paclitaxel (FEC-P). Multivariable Cox regression analyses of the secondary endpoint of overall survival (OS) were performed to determine the significance of the interaction between treatment and the (1) PAM50 subtypes, (2) PAM50 proliferation score, and (3) clinical and pathological variables. Similar OS analyses were performed in 222 patients treated with weekly paclitaxel versus paclitaxel every 3 weeks in the CALGB/9342 and 9840 metastatic clinical trials. In GEICAM/9906, with a median follow up of 8.7 years, OS of the FEC-P arm was significantly superior compared to the FEC arm (unadjusted HR = 0.693, p = 0.013). A benefit from paclitaxel was only observed in the group of patients with a low PAM50 proliferation score (unadjusted HR = 0.23, p < 0.001; and interaction test, p = 0.006). No significant interactions between treatment and the PAM50 subtypes or the various clinical–pathological variables, including Ki-67 and histologic grade, were identified. Finally, similar OS results were obtained in the CALGB data set, although the interaction test did not reach statistical significance (p = 0.109). The PAM50 proliferation score identifies a subset of patients with a low proliferation status that may derive a larger benefit from weekly paclitaxel.

An overview of the adaptive designs accelerating promising trials into treatments (ADAPT-IT) project

Randomized clinical trials, which aim to determine the efficacy and safety of drugs and medical devices, are a complex enterprise with myriad challenges, stakeholders, and traditions. Although the primary goal is scientific discovery, clinical trials must also fulfill regulatory, clinical, and ethical requirements. Innovations in clinical trials methodology have the potential to improve the quality of knowledge gained from trials, the protection of human subjects, and the efficiency of clinical research. Adaptive clinical trial methods represent a broad category of innovations intended to address a variety of long-standing challenges faced by investigators, such as sensitivity to previous assumptions and delayed identification of ineffective treatments. The implementation of adaptive clinical trial methods, however, requires greater planning and simulation compared with a more traditional design, along with more advanced administrative infrastructure for trial execution. The value of adaptive clinical trial methods in exploratory phase (phase 2) clinical research is generally well accepted, but the potential value and challenges of applying adaptive clinical trial methods in large confirmatory phase clinical trials are relatively unexplored, particularly in the academic setting. In the Adaptive Designs Accelerating Promising Trials Into Treatments (ADAPT-IT) project, a multidisciplinary team is studying how adaptive clinical trial methods could be implemented in planning actual confirmatory phase trials in an established, National Institutes of Health-funded clinical trials network. The overarching objectives of ADAPT-IT are to identify and quantitatively characterize the adaptive clinical trial methods of greatest potential value in confirmatory phase clinical trials and to elicit and understand the enthusiasms and concerns of key stakeholders that influence their willingness to try these innovative strategies.

Outcomes of phase II clinical trials with single-agent therapies in advanced/metastatic non-small cell lung cancer published between 2000 and 2009

PURPOSE

We analyzed the outcomes of single-agent phase II clinical trials in non-small cell lung cancer (NSCLC) to determine trial parameters that predicted clinical activity.

EXPERIMENTAL DESIGN

Data on response rate (RR), progression-free survival (PFS), and overall survival (OS) from all English language, single-agent phase II trials in advanced/metastatic NSCLC indexed by PubMed (January 2000 through December 2009) were abstracted.

RESULTS

A total of 143 single-agent phase II trials (7,701 patients) were identified. The median RR was 10%, PFS 2.8 months, and OS 7.6 months. RR and PFS correlated with OS (r = 0.46, P < 0.001, r = 0.52, P < 0.001, respectively) and RR correlated with PFS (r = 0.61, P < 0.001). Treatment arms enriched for patients with molecular targets had a higher median RR (48.8% vs. 9.7%, P = 0.005), longer median PFS (6 vs. 2.8 months, P = 0.005), and OS (11.3 vs. 7.5 months, P = 0.05) as compared with those of unselected patients. In multivariate analysis, only studies enriched for patients with molecular targets or including drugs that eventually gained FDA/EMA approval were associated with a higher RR, and longer PFS/OS.

CONCLUSIONS

In phase II trials in NSCLC, RR and PFS correlated with OS. Studies enriched for patients with putative molecular drug targets were associated with higher therapeutic benefit as compared with those of unselected populations.

From drug discovery to biomarker-driven clinical trials in lymphoma

Over the past three decades, the pathological classification of lymphoma has substantially improved. The early Rappaport classification included a handful of subtypes that did not reflect the cell of origin and, not surprisingly, resulted in diagnostic inaccuracies. The WHO currently classifies lymphoma into 30 major distinctive types. While this classification improved the accuracy and consistency of the histological diagnosis of lymphoma, it had little impact on advancing drug development or improving the cure rate of this disease. One reason for this lack of improvement is that recent developments in cancer genomics show these histopathological subtypes to be heterogeneous. Basing treatment decisions on histopathological subtypes is inefficient as it groups different underlying molecular characteristics into one category. Such a strategy exposes many patients to potentially toxic drugs without providing benefits. The recent approval of two new cancer drugs with companion diagnostics to allow selection and treatment of patients with melanoma and non-small-cell lung cancer has raised hope that a similar approach may also expedite successful drug development in lymphoma. We review the current status of biomarker development in lymphoma, and discuss novel biomarker-directed clinical trial designs for lymphoma.

Pathologic complete response predicts recurrence-free survival more effectively by cancer subset: results from the I-SPY 1 TRIAL--CALGB 150007/150012, ACRIN 6657

PURPOSE

Neoadjuvant chemotherapy for breast cancer provides critical information about tumor response; how best to leverage this for predicting recurrence-free survival (RFS) is not established. The I-SPY 1 TRIAL (Investigation of Serial Studies to Predict Your Therapeutic Response With Imaging and Molecular Analysis) was a multicenter breast cancer study integrating clinical, imaging, and genomic data to evaluate pathologic response, RFS, and their relationship and predictability based on tumor biomarkers.

PATIENTS AND METHODS

Eligible patients had tumors ≥ 3 cm and received neoadjuvant chemotherapy. We determined associations between pathologic complete response (pCR; defined as the absence of invasive cancer in breast and nodes) and RFS, overall and within receptor subsets.

RESULTS

In 221 evaluable patients (median tumor size, 6.0 cm; median age, 49 years; 91% classified as poor risk on the basis of the 70-gene prognosis profile), 41% were hormone receptor (HR) negative, and 31% were human epidermal growth factor receptor 2 (HER2) positive. For 190 patients treated without neoadjuvant trastuzumab, pCR was highest for HR-negative/HER2-positive patients (45%) and lowest for HR-positive/HER2-negative patients (9%). Achieving pCR predicted favorable RFS. For 172 patients treated without trastuzumab, the hazard ratio for RFS of pCR versus no pCR was 0.29 (95% CI, 0.07 to 0.82). pCR was more predictive of RFS by multivariate analysis when subtype was taken into account, and point estimates of hazard ratios within the HR-positive/HER2-negative (hazard ratio, 0.00; 95% CI, 0.00 to 0.93), HR-negative/HER2-negative (hazard ratio, 0.25; 95% CI, 0.04 to 0.97), and HER2-positive (hazard ratio, 0.14; 95% CI, 0.01 to 1.0) subtypes are lower. Ki67 further improved the prediction of pCR within subsets.

CONCLUSION

In this biologically high-risk group, pCR differs by receptor subset. pCR is more highly predictive of RFS within every established receptor subset than overall, demonstrating that the extent of outcome advantage conferred by pCR is specific to tumor biology.

Six cycles of doxorubicin and cyclophosphamide or Paclitaxel are not superior to four cycles as adjuvant chemotherapy for breast cancer in women with zero to three positive axillary nodes: Cancer and Leukemia Group B 40101

PURPOSE

The ideal duration of adjuvant chemotherapy for patients with lower risk primary breast cancer is not known. Cancer and Leukemia Group B trial 40101 was conducted using a phase III factorial design to define whether six cycles of a chemotherapy regimen are superior to four cycles. We also sought to determine whether paclitaxel (T) is as efficacious as doxorubicin/cyclophosphamide (AC), but with reduced toxicity.

PATIENTS AND METHODS

Between 2002 and 2008, the study enrolled women with operable breast cancer and zero to three positive nodes. Patients were randomly assigned to either four or six cycles of either AC or T. Study stratifiers were estrogen receptor/progesterone receptor (ER/PgR), human epidermal growth factor receptor 2 (HER2), and menopausal status. After 2003, all treatment was administered in dose-dense fashion. The primary efficacy end point was relapse-free survival (RFS).

RESULTS

A total of 3,171 patients were enrolled; 94% were node-negative and 6% had one to three positive nodes. At a median follow-up of 5.3 years, the 4-year RFS was 90.9% and 91.8% for six and four cycles, respectively. The adjusted hazard ratio (HR) of six to four cycles regarding RFS was 1.03 (95% CI, 0.84 to 1.28; P=.77). The 4-year OS was 95.3% and 96.3% for six and four cycles, respectively, with an HR of six to four cycles of 1.12 (95% CI, 0.84 to 1.49; P=.44). There was no interaction between treatment duration and chemotherapy regimen, ER/PgR, or HER2 status on RFS or OS.

CONCLUSION

For women with resected primary breast cancer and zero to three positive nodes, we found no evidence that extending chemotherapy regimens of AC or single-agent T from four to six cycles improves clinical outcome.

Elacytarabine has single-agent activity in patients with advanced acute myeloid leukaemia

Elacytarabine is a novel cytotoxic nucleoside analogue, independent of nucleoside transporters (e.g. human Equilibrative Nucleoside Transporter 1 [hENT1]) for cell uptake, and mechanisms of action similar to those of cytarabine. This Phase II study assessed the efficacy and safety of elacytarabine in patients with advanced stage acute myeloid leukaemia (AML). Patients received 2000 mg/m(2) per d continuously i.v. during days 1-5 every 3 weeks. Patients were matched by six risk factors with historical controls; remission rate (assessed after 1 or 2 cycles) and 6-month survival were compared. Sixty-one patients, median age 58 years, were enrolled; 52% had five or six risk factors. The remission rate was 18% (95% confidence interval: 9-30%) vs. 4% in controls (P < 0·0001), 6-month survival rate was 43%, median overall survival was 5·3 months (vs. 1·5 months); 10 patients (16%) were referred for stem cell transplantation after treatment. Side effects were predictable and manageable. The most common grade 3/4 non-haematological adverse events were febrile neutropenia, hypokalemia, fatigue, hyponatraemia, dyspnoea and pyrexia. Thirty-day all-cause mortality, after start of treatment, was 13% vs. 25% in controls. Elacytarabine has monotherapy activity in patients with advanced AML. This study provides proof-of-concept that lipid esterification of nucleoside analogues is clinically relevant.

Benefits and harms of CT screening for lung cancer: a systematic review

CONTEXT

Lung cancer is the leading cause of cancer death. Most patients are diagnosed with advanced disease, resulting in a very low 5-year survival. Screening may reduce the risk of death from lung cancer.

OBJECTIVE

To conduct a systematic review of the evidence regarding the benefits and harms of lung cancer screening using low-dose computed tomography (LDCT). A multisociety collaborative initiative (involving the American Cancer Society, American College of Chest Physicians, American Society of Clinical Oncology, and National Comprehensive Cancer Network) was undertaken to create the foundation for development of an evidence-based clinical guideline.

DATA SOURCES

MEDLINE (Ovid: January 1996 to April 2012), EMBASE (Ovid: January 1996 to April 2012), and the Cochrane Library (April 2012).

STUDY SELECTION

Of 591 citations identified and reviewed, 8 randomized trials and 13 cohort studies of LDCT screening met criteria for inclusion. Primary outcomes were lung cancer mortality and all-cause mortality, and secondary outcomes included nodule detection, invasive procedures, follow-up tests, and smoking cessation.

DATA EXTRACTION

Critical appraisal using predefined criteria was conducted on individual studies and the overall body of evidence. Differences in data extracted by reviewers were adjudicated by consensus.

RESULTS

Three randomized studies provided evidence on the effect of LDCT screening on lung cancer mortality, of which the National Lung Screening Trial was the most informative, demonstrating that among 53,454 participants enrolled, screening resulted in significantly fewer lung cancer deaths (356 vs 443 deaths; lung cancer−specific mortality, 274 vs 309 events per 100,000 person-years for LDCT and control groups, respectively; relative risk, 0.80; 95% CI, 0.73-0.93; absolute risk reduction, 0.33%; P = .004). The other 2 smaller studies showed no such benefit. In terms of potential harms of LDCT screening, across all trials and cohorts, approximately 20% of individuals in each round of screening had positive results requiring some degree of follow-up, while approximately 1% had lung cancer. There was marked heterogeneity in this finding and in the frequency of follow-up investigations, biopsies, and percentage of surgical procedures performed in patients with benign lesions. Major complications in those with benign conditions were rare.

CONCLUSION

Low-dose computed tomography screening may benefit individuals at an increased risk for lung cancer, but uncertainty exists about the potential harms of screening and the generalizability of results.

Chemotherapy response and recurrence-free survival in neoadjuvant breast cancer depends on biomarker profiles: results from the I-SPY 1 TRIAL (CALGB 150007/150012; ACRIN 6657)

Neoadjuvant chemotherapy for breast cancer allows individual tumor response to be assessed depending on molecular subtype, and to judge the impact of response to therapy on recurrence-free survival (RFS). The multicenter I-SPY 1 TRIAL evaluated patients with ≥ 3 cm tumors by using early imaging and molecular signatures, with outcomes of pathologic complete response (pCR) and RFS. The current analysis was performed using data from patients who had molecular profiles and did not receive trastuzumab. The various molecular classifiers tested were highly correlated. Categorization of breast cancer by molecular signatures enhanced the ability of pCR to predict improvement in RFS compared to the population as a whole. In multivariate analysis, the molecular signatures that added to the ability of HR and HER2 receptors, clinical stage, and pCR in predicting RFS included 70-gene signature, wound healing signature, p53 mutation signature, and PAM50 risk of recurrence. The low risk signatures were associated with significantly better prognosis, and also identified additional patients with a good prognosis within the no pCR group, primarily in the hormone receptor positive, HER-2 negative subgroup. The I-SPY 1 population is enriched for tumors with a poor prognosis but is still heterogeneous in terms of rates of pCR and RFS. The ability of pCR to predict RFS is better by subset than it is for the whole group. Molecular markers improve prediction of RFS by identifying additional patients with excellent prognosis within the no pCR group.

Reports from the 2010 Clinical and Translational Cancer Research Think Tank meeting: design strategies for personalized therapy trials

It has long been evident that cancer is a heterogeneous disease, but only relatively recently have we come to realize the extent of this heterogeneity. No single therapy is effective for every patient with tumors having the same histology. A clinical strategy based on a single-therapy approach results in overtreatment for the majority of patients. Biomarkers can be considered as knives that dissect the disease ever more finely. The future of clinical research will be based on learning whether certain therapies are more appropriate than others for biomarker-defined subsets of patients. Therapies will eventually be tailored to narrow biomarker subsets. The ability to determine which therapies are appropriate for which patients requires information from biological science as well as empirical evidence from clinical trials. Neither is easy to achieve. Here we describe some nascent approaches for designing clinical trials that are biomarker-based and adaptive. Our focus is on adaptive trials that address many questions at once. In a way, these clinical experiments are themselves part of a much larger experiment: learning how (or whether it is possible) to design experiments that match patients in small subsets of disease with therapies that are especially effective and possibly even curative for them.

PD06-08: Projecting the Impact of Adopting Trial Results

Background: There is often a substantial delay between the presentation of clinical trial results and change in practice. Reasons for slow adoption include the disruption of practice routines, doubt about the validity of results, financial disincentive, and resistance to change. We propose a decision-making process to inform adoption that considers three factors: likelihood the trial's conclusions will not change with longer follow up, and consequences of early and late adoption. We apply this framework to the published 4-year results of the international TARGIT-A trial, which compares intraoperative radiation therapy (IORT) to external beam radiation therapy (EBRT).

Methods: To find whether the trial results will remain robust, we reviewed the TARGIT-A trial's annual hazards for local recurrence (LR). We then reviewed 5–10 year LR rates from recent clinical trials with similar patient populations undergoing RT, no RT or partial breast RT. To assess the impact of an early change in practice, a Markov model was used to evaluate life expectancy, quality adjusted life years (QALYs), and cost. Sensitivity analysis estimated the impact of varying the LR rate 1–20x the TARGIT-A 4 year results. To estimate the impact of late adoption, we generated the expected number of N0, grades 1 & 2, ductal cancers in postmenopausal women (&gt;50 yrs) from SEER and US Census Bureau data. Using Medicare rates, costs of EBRT vs. IORT were compared and potential savings to the health care system calculated.

Results: The TARGIT-A peak hazard for LR for IORT and EBRT occurred at 3 years. In the START and ATAC trials, the peak local recurrence Kaplan Meier estimates are between 2 and 3 years. In other trials (ATAC, and in the 2005 RT Lancet overview) there is no second peak of recurrence, making it unlikely that longer follow up will change the conclusion of the TARGIT-A results. The LRR in similar trials have dropped steadily over time for post menopausal, stage I patients with or without RT. Impact of early adoption: If treatment were adopted early, the impact on life expectancy and QALYs would be minimal unless IORT LR rate exceeds 20% over a 10 year period of time. Impact of late adoption: In the US, 45% of new breast cancer cases fit the described population. EBRT costs $6,400 more than IORT per patient on average. If adoption were delayed 5 years to allow the trial results to mature, 70,136 patients per year are expected to receive EBRT resulting in a societal burden of &gt;$2.2 billion barring the capital investment required for new technology. This also assumes that patients have equal utility for a single dose of IORT as they do for 3–6 weeks of postoperative radiation therapy. If IORT utility is higher than that of EBRT, then the IORT strategy is both more effective and less costly.

Conclusion: The process of modeling the impact of both early and late adoption when considering the stability of trial results can serve as a tool to evaluate whether to change practice. This analysis was tested on the results of the TARGIT-A trial, and demonstrated that prompt adoption of the IORT intervention would cause minimal harm, provide an improved quality of life, and offer significant societal savings.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD06-08.