Use of letrozole after aromatase inhibitor-based therapy in postmenopausal breast cancer (NRG Oncology/NSABP B-42): a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: The optimal duration of extended therapy with aromatase inhibitors in patients with postmenopausal breast cancer is unknown. In the NSABP B-42 study, we aimed to determine whether extended letrozole treatment improves disease-free survival after 5 years of aromatase inhibitor-based therapy in women with postmenopausal breast cancer. METHODS: This randomised, double-blind, placebo-controlled, phase 3 trial was done in 158 centres in the USA, Canada, and Ireland. Postmenopausal women with stage I-IIIA hormone receptor-positive breast cancer, who were disease-free after about 5 years of treatment with an aromatase inhibitor or tamoxifen followed by an aromatase inhibitor, were randomly assigned (1:1) to receive 5 years of letrozole (2·5 mg orally per day) or placebo. Randomisation was stratified by pathological node status, previous tamoxifen use, and lowest bone mineral density T score in the lumbosacral spine, total hip, or femoral neck. The primary endpoint was disease-free survival, defined as time from randomisation to breast cancer recurrence, second primary malignancy, or death, and was analysed by intention to treat. To adjust for previous interim analyses, the two-sided statistical significance level for disease-free survival was set at 0·0418. This study is registered with ClinicalTrials.gov, number NCT00382070, is active, and is no longer enrolling patients. FINDINGS: Between Sept 28, 2006, and Jan 6, 2010, 3966 patients were randomly assigned to receive letrozole (n=1983) or placebo (n=1983). Follow-up information was available for 3903 patients for the analyses of disease-free survival. Median follow-up was 6·9 years (IQR 6·1-7·5). Letrozole treatment did not significantly improve disease-free survival (339 disease-free survival events were reported in the placebo group and 292 disease-free survival events were reported in the letrozole group; hazard ratio 0·85, 95% CI 0·73-0·999; p=0·048). 7-year disease-free survival estimate was 81·3% (95% CI 79·3-83·1) in the placebo group and 84·7% (82·9-86·4) in the letrozole group. The most common grade 3 adverse events were arthralgia (47 [2%] of 1933 patients in the placebo group vs 50 [3%] of 1941 patients in the letrozole group) and back pain (44 [2%] vs 38 [2%]). The most common grade 4 adverse event in the placebo group was thromboembolic event (eight [<1%]) and the most common grade 4 adverse events in the letrozole group were urinary tract infection, hypokalaemia, and left ventricular systolic dysfunction (four [<1%] each). INTERPRETATION: After 5 years of aromatase inhibitor-based therapy, 5 years of letrozole therapy did not significantly prolong disease-free survival compared with placebo. Careful assessment of potential risks and benefits is required before recommending extended letrozole therapy to patients with early-stage breast cancer. FUNDING: National Cancer Institute, Korea Health Technology R&D Project, Novartis.

Calmodulin-like protein 3 is an estrogen receptor alpha coregulator for gene expression and drug response in a SNP, estrogen, and SERM-dependent fashion.

BACKGROUND: We previously performed a case-control genome-wide association study in women treated with selective estrogen receptor modulators (SERMs) for breast cancer prevention and identified single nucleotide polymorphisms (SNPs) in ZNF423 as potential biomarkers for response to SERM therapy. The ZNF423rs9940645 SNP, which is approximately 200 bp away from the estrogen response elements, resulted in the SNP, estrogen, and SERM-dependent regulation of ZNF423 expression and, "downstream", that of BRCA1. METHODS: Electrophoretic mobility shift assay-mass spectrometry was performed to identify proteins binding to the ZNF423 SNP and coordinating with estrogen receptor alpha (ERα). Clustered, regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing was applied to generate ZR75-1 breast cancer cells with different ZNF423 SNP genotypes. Both cultured cells and mouse xenograft models with different ZNF423 SNP genotypes were used to study the cellular responses to SERMs and poly(ADP-ribose) polymerase (PARP) inhibitors. RESULTS: We identified calmodulin-like protein 3 (CALML3) as a key sensor of this SNP and a coregulator of ERα, which contributes to differential gene transcription regulation in an estrogen and SERM-dependent fashion. Furthermore, using CRISPR/Cas9-engineered ZR75-1 breast cancer cells with different ZNF423 SNP genotypes, striking differences in cellular responses to SERMs and PARP inhibitors, alone or in combination, were observed not only in cells but also in a mouse xenograft model. CONCLUSIONS: Our results have demonstrated the mechanism by which the ZNF423 rs9940645 SNP might regulate gene expression and drug response as well as its potential role in achieving more highly individualized breast cancer therapy.

Pathological complete response and long-term clinical benefit in breast cancer: the CTNeoBC pooled analysis.

BACKGROUND: Pathological complete response has been proposed as a surrogate endpoint for prediction of long-term clinical benefit, such as disease-free survival, event-free survival (EFS), and overall survival (OS). We had four key objectives: to establish the association between pathological complete response and EFS and OS, to establish the definition of pathological complete response that correlates best with long-term outcome, to identify the breast cancer subtypes in which pathological complete response is best correlated with long-term outcome, and to assess whether an increase in frequency of pathological complete response between treatment groups predicts improved EFS and OS. METHODS: We searched PubMed, Embase, and Medline for clinical trials of neoadjuvant treatment of breast cancer. To be eligible, studies had to meet three inclusion criteria: include at least 200 patients with primary breast cancer treated with preoperative chemotherapy followed by surgery; have available data for pathological complete response, EFS, and OS; and have a median follow-up of at least 3 years. We compared the three most commonly used definitions of pathological complete response--ypT0 ypN0, ypT0/is ypN0, and ypT0/is--for their association with EFS and OS in a responder analysis. We assessed the association between pathological complete response and EFS and OS in various subgroups. Finally, we did a trial-level analysis to assess whether pathological complete response could be used as a surrogate endpoint for EFS or OS. FINDINGS: We obtained data from 12 identified international trials and 11 955 patients were included in our responder analysis. Eradication of tumour from both breast and lymph nodes (ypT0 ypN0 or ypT0/is ypN0) was better associated with improved EFS (ypT0 ypN0: hazard ratio [HR] 0·44, 95% CI 0·39-0·51; ypT0/is ypN0: 0·48, 0·43-0·54) and OS (0·36, 0·30-0·44; 0·36, 0·31-0·42) than was tumour eradication from the breast alone (ypT0/is; EFS: HR 0·60, 95% CI 0·55-0·66; OS 0·51, 0·45-0·58). We used the ypT0/is ypN0 definition for all subsequent analyses. The association between pathological complete response and long-term outcomes was strongest in patients with triple-negative breast cancer (EFS: HR 0·24, 95% CI 0·18-0·33; OS: 0·16, 0·11-0·25) and in those with HER2-positive, hormone-receptor-negative tumours who received trastuzumab (EFS: 0·15, 0·09-0·27; OS: 0·08, 0·03, 0·22). In the trial-level analysis, we recorded little association between increases in frequency of pathological complete response and EFS (R(2)=0·03, 95% CI 0·00-0·25) and OS (R(2)=0·24, 0·00-0·70). INTERPRETATION: Patients who attain pathological complete response defined as ypT0 ypN0 or ypT0/is ypN0 have improved survival. The prognostic value is greatest in aggressive tumour subtypes. Our pooled analysis could not validate pathological complete response as a surrogate endpoint for improved EFS and OS. FUNDING: US Food and Drug Administration.

A polygenic risk score for breast cancer in women receiving tamoxifen or raloxifene on NSABP P-1 and P-2.

Recent genetic studies have identified common variation in susceptibility loci that stratify lifetime risks of breast cancer and may inform prevention and screening strategies. However, whether these loci have similar implications for women treated with tamoxifen or raloxifene (SERMs) is unknown. We conducted a matched case-control study of 592 cases who developed breast cancer and 1,171 unaffected women from 32,859 participants on SERM therapy enrolled on NSABP P-1 and P-2 breast cancer prevention trials. We formed a quantitative polygenic risk score (PRS) using genotypes of 75 breast cancer-associated single nucleotide polymorphisms and examined the PRS as a risk factor for breast cancer among women treated with SERMs. The PRS ranged from 3.98 to 7.74, with a one-unit change associated with a 42 % increase in breast cancer (OR = 1.42; P = 0.0002). The PRS had a stronger association with breast cancer among high-risk women with no first-degree family history (OR = 1.62) compared to those with a positive family history (OR = 1.32) (P intx = 0.04). There was also suggestion that PRS was a stronger risk factor for ER-positive (OR = 1.59, P = 0.0002) than ER-negative (OR = 1.05, P = 0.84) breast cancer (P intx = 0.10). Associations did not differ by tamoxifen or raloxifene treatment, age at trial entry, 5-year predicted Gail model risk or other clinical variables. The PRS is a strong risk factor for ER-positive breast cancer in moderate to high-risk individuals treated with either tamoxifen or raloxifene for cancer prevention. These data suggest that common genetic variation informs risk of breast cancer in women receiving SERMs.

Selective oestrogen receptor modulators in prevention of breast cancer: an updated meta-analysis of individual participant data.

BACKGROUND: Tamoxifen and raloxifene reduce the risk of breast cancer in women at elevated risk of disease, but the duration of the effect is unknown. We assessed the effectiveness of selective oestrogen receptor modulators (SERMs) on breast cancer incidence. METHODS: We did a meta-analysis with individual participant data from nine prevention trials comparing four selective oestrogen receptor modulators (SERMs; tamoxifen, raloxifene, arzoxifene, and lasofoxifene) with placebo, or in one study with tamoxifen. Our primary endpoint was incidence of all breast cancer (including ductal carcinoma in situ) during a 10 year follow-up period. Analysis was by intention to treat. RESULTS: We analysed data for 83,399 women with 306,617 women-years of follow-up. Median follow-up was 65 months (IQR 54-93). Overall, we noted a 38% reduction (hazard ratio [HR] 0·62, 95% CI 0·56-0·69) in breast cancer incidence, and 42 women would need to be treated to prevent one breast cancer event in the first 10 years of follow-up. The reduction was larger in the first 5 years of follow-up than in years 5-10 (42%, HR 0·58, 0·51-0·66; p<0·0001 vs 25%, 0·75, 0·61-0·93; p=0·007), but we noted no heterogeneity between time periods. Thromboembolic events were significantly increased with all SERMs (odds ratio 1·73, 95% CI 1·47-2·05; p<0·0001). We recorded a significant reduction of 34% in vertebral fractures (0·66, 0·59-0·73), but only a small effect for non-vertebral fractures (0·93, 0·87-0·99). INTERPRETATION: For all SERMs, incidence of invasive oestrogen (ER)-positive breast cancer was reduced both during treatment and for at least 5 years after completion. Similar to other preventive interventions, careful consideration of risks and benefits is needed to identify women who are most likely to benefit from these drugs. FUNDING: Cancer Research UK.

Using the gene ontology to scan multilevel gene sets for associations in genome wide association studies.

Gene-set analyses have been widely used in gene expression studies, and some of the developed methods have been extended to genome wide association studies (GWAS). Yet, complications due to linkage disequilibrium (LD) among single nucleotide polymorphisms (SNPs), and variable numbers of SNPs per gene and genes per gene-set, have plagued current approaches, often leading to ad hoc "fixes." To overcome some of the current limitations, we developed a general approach to scan GWAS SNP data for both gene-level and gene-set analyses, building on score statistics for generalized linear models, and taking advantage of the directed acyclic graph structure of the gene ontology when creating gene-sets. However, other types of gene-set structures can be used, such as the popular Kyoto Encyclopedia of Genes and Genomes (KEGG). Our approach combines SNPs into genes, and genes into gene-sets, but assures that positive and negative effects of genes on a trait do not cancel. To control for multiple testing of many gene-sets, we use an efficient computational strategy that accounts for LD and provides accurate step-down adjusted P-values for each gene-set. Application of our methods to two different GWAS provide guidance on the potential strengths and weaknesses of our proposed gene-set analyses.

National Surgical Adjuvant Breast and Bowel Project Study of Tamoxifen and Raloxifene trial: advancing the science of recruitment and breast cancer risk assessment in minority communities.

BACKGROUND: One of the first chemoprevention trials conducted in the western hemisphere, the National Surgical Adjuvant Breast and Bowel Project's (NSABP) Breast Cancer Prevention Trial (BCPT), demonstrated the need to evaluate all aspects of recruitment in real time and to implement strategies to enroll racial and ethnic minority women. PURPOSE: The purpose of this report is to review various patient recruitment efforts the NSABP developed to enhance the participation of racial and ethnic minority women in the Study of Tamoxifen and Raloxifene (STAR) trial and to describe the role that the recruitment process played in the implementation and understanding of breast cancer risk assessment in minority communities. METHODS: The NSABP STAR trial was a randomized, double-blinded study comparing the use of tamoxifen 20 mg/day to raloxifene 60 mg/day, for a 5-year period, to reduce the risk of developing invasive breast cancer. Eligible postmenopausal women were required to have a 5-year predicted breast cancer risk of 1.66% based on the modified Gail Model. For the current report, eligibility and enrollment data were tabulated by race/ethnicity for women who submitted STAR risk assessment forms (RAFs). RESULTS: A total of 184,460 RAFs were received, 145,550 (78.9%) from white women and 38,910 (21.1%) from minority women. Of the latter group, 21,444 (11.6%) were from African Americans/blacks, 7913 (4.5%) from Hispanics/Latinas, and 9553 (5.2%) from other racial or ethnic groups. The percentages of risk-eligible women among African Americans, Hispanics/Latinas, others, and whites were 14.2%, 23.3%, 13.7%, and 57.4%, respectively. Programs targeting minority enrollment submitted large numbers of RAFs, but the eligibility rates of the women referred from those groups tended to be lower than the rates among women referred outside of those programs. The average number of completed risk assessments increased among minority women over the course of the recruitment period compared to those from whites. LIMITATIONS: We have not addressed all identified barriers to the recruitment of minorities in clinical research. Our risk assessments and recruitment results do not reflect the modified Gail Model for African Americans. CONCLUSIONS: Recruitment strategies used in STAR for racial and ethnic minorities contributed to doubling the minority enrollment compared to that in the BCPT and increased the awareness of breast cancer risk assessment in minority communities. Incorporation of new information into models to improve the risk estimation of diverse populations should prove beneficial.

Gene Expression and Benefit of Chemotherapy in Women With Node-Negative, Estrogen Receptor-Positive Breast Cancer.

PURPOSE: The 21-gene recurrence score (RS) assay quantifies the likelihood of distant recurrence in women with estrogen receptor-positive, lymph node-negative breast cancer treated with adjuvant tamoxifen. The relationship between the RS and chemotherapy benefit is not known. METHODS: The RS was measured in tumors from the tamoxifen-treated and tamoxifen plus chemotherapy-treated patients in the National Surgical Adjuvant Breast and Bowel Project (NSABP) B20 trial. Cox proportional hazards models were utilized to test for interaction between chemotherapy treatment and the RS. RESULTS: A total of 651 patients were assessable (227 randomly assigned to tamoxifen and 424 randomly assigned to tamoxifen plus chemotherapy). The test for interaction between chemotherapy treatment and RS was statistically significant (P = .038). Patients with high-RS (≥ 31) tumors (ie, high risk of recurrence) had a large benefit from chemotherapy (relative risk, 0.26; 95% CI, 0.13 to 0.53; absolute decrease in 10-year distant recurrence rate: mean, 27.6%; SE, 8.0%). Patients with low-RS (< 18) tumors derived minimal, if any, benefit from chemotherapy treatment (relative risk, 1.31; 95% CI, 0.46 to 3.78; absolute decrease in distant recurrence rate at 10 years: mean, -1.1%; SE, 2.2%). Patients with intermediate-RS tumors did not appear to have a large benefit, but the uncertainty in the estimate can not exclude a clinically important benefit. CONCLUSION: The RS assay not only quantifies the likelihood of breast cancer recurrence in women with node-negative, estrogen receptor-positive breast cancer, but also predicts the magnitude of chemotherapy benefit.

Breast cancer incidence in postmenopausal women with osteoporosis or low bone mass using arzoxifene.

The Generations trial, a multicenter, placebo-controlled, double-blind trial, compared arzoxifene 20 mg/day and placebo in 9,354 postmenopausal women with osteoporosis (N=5,252) or low bone mass (N=4,102). Primary outcomes were vertebral fracture in the osteoporotic population and invasive breast cancer in all study participants. Here, we report the detailed breast cancer findings from the trial. Breast cancers were detected by annual mammograms and clinical examination. After 48 months follow-up, breast cancer incidence was compared between treatment groups by estrogen receptor (ER) and progesterone receptor (PR) status and baseline risk factors. Baseline breast cancer risk factors, including age, estimated Gail risk, and bone mineral density, were well balanced between treatment groups. A total of 75 breast cancers occurred 53 in the placebo group and 22 in the arzoxifene group (HR 0.41, 95% CI 0.25-0.68, P<0.001). There were 62 invasive breast cancers, 39 identified as invasive ER-positive (placebo 30, arzoxifene 9; HR 0.30, 95% CI 0.14-0.63, P=0.001) and 30 identified as invasive PR-positive (placebo 23, arzoxifene 7; HR 0.30, 95% CI 0.13-0.71, P=0.003). Breast cancer risk reduction with arzoxifene was similar between Gail risk groups (P interaction=0.31) and between low bone mass and osteoporosis groups (P interaction=0.35). Although generally well tolerated, there was a significant increase in venous thromboembolism, vasomotor symptoms, muscle cramps, and some gynecological events with arzoxifene. These findings demonstrate that in this study arzoxifene reduced the risk of ER-positive breast cancer in this population of postmenopausal women with low bone mass or osteoporosis, an effect similar to that seen with other SERMs.

Comparison of the prognostic and predictive utilities of the 21-gene Recurrence Score assay and Adjuvant! for women with node-negative, ER-positive breast cancer: results from NSABP B-14 and NSABP B-20.

The Oncotype DX Recurrence Score (RS) is a validated genomic predictor of outcome and response to adjuvant chemotherapy in ER-positive breast cancer. Adjuvant! was developed using SEER registry data and results from the Early Breast Cancer Clinical Trialists' overview analyses to estimate outcome and benefit from adjuvant hormonal therapy and chemotherapy. In this report we compare the prognostic and predictive utility of these two tools in node-negative, ER-positive breast cancer. RS and Adjuvant! results were available from 668 tamoxifen-treated NSABP B-14 patients, 227 tamoxifen-treated NSABP B-20 patients, and 424 chemotherapy plus tamoxifen-treated B-20 patients. Adjuvant! results were also available from 1952 B-20 patients. The primary endpoint was distant recurrence-free interval (DRFI). Cox proportional hazards models were used to compare the prognostic and predictive utility of RS and Adjuvant!. Both RS (P < 0.001) and Adjuvant! (P = 0.002) provided strong independent prognostic information in tamoxifen-treated patients. Combining RS and individual clinicopathologic characteristics provided greater prognostic discrimination than combining RS and the composite Adjuvant!. In the B-20 cohort with RS results (n = 651), RS was significantly predictive of chemotherapy benefit (interaction P = 0.031 for DRFI, P = 0.011 for overall survival [OS], P = 0.082 for disease-free survival [DFS]), but Adjuvant! was not (interaction P = 0.99, P = 0.311, and P = 0.357, respectively). However, in the larger B-20 sub-cohort (n = 1952), Adjuvant! was significantly predictive of chemotherapy benefit for OS (interaction P = 0.009) but not for DRFI (P = 0.219) or DFS (P = 0.099). Prognostic estimates can be optimized by combining RS and clinicopathologic information instead of simply combining RS and Adjuvant!. RS should be used for estimating relative chemotherapy benefit.

Gynecologic conditions in participants in the NSABP breast cancer prevention study of tamoxifen and raloxifene (STAR).

OBJECTIVE: This study reports the gynecologic conditions in postmenopausal women (intact uterus on enrollment) in the National Surgical Adjuvant Breast and Bowel Project (NSABP) study of tamoxifen and raloxifene (STAR)/P-2 trial. STUDY DESIGN: This study, with a median follow-up period of 81 months, evaluated the incidence rates/risks of gynecologic conditions among women who were treated with tamoxifen and raloxifene. RESULTS: Compared with women who received tamoxifen therapy, women who received raloxifene therapy had a lower incidence of uterine cancer (relative risk, 0.55)/endometrial hyperplasia (relative risk, 0.19), leiomyomas (relative risk, 0.55), ovarian cysts (relative risk, 0.60), and endometrial polyps (relative risk, 0.30) and had fewer procedures performed. Women receiving tamoxifen therapy had more hot flashes (P < .0001), vaginal discharge (P < .0001), and vaginal bleeding (P < .0001). CONCLUSION: Our results suggest that tamoxifen has more of an estrogenic effect on the gynecologic reproductive organs. These effects should be considered in counseling women on options for breast cancer prevention.

Hazard of recurrence and adjuvant treatment effects over time in lymph node-negative breast cancer.

BACKGROUND: For patients with axillary lymph node-negative breast cancer, benefits from adjuvant therapy are smaller than in node-positive disease and thus more selective use is warranted, prompting development of risk profiling to identify those most likely to benefit. Examination of the magnitude and changes in the hazard of failure over time in node-negative breast cancer may also be informative in this regard. METHODS: Among 9,444 participants from five randomized trials (accrual 1982-1998) investigating chemotherapy and tamoxifen for node-negative breast cancer, we estimated recurrence hazards over time by tumor estrogen receptor (ER) status and adjuvant treatment. RESULTS: In patients treated by surgery only, we observed the previously noted larger hazard peak followed by a rapid decrease in ER-negative patients and smaller but more persistent hazard in ER-positive patients. After approximately 48 months, the ER-positive hazard is greater. For adjuvant treatment, while tamoxifen decreases the early hazard in ER-positive patients to that of the chemotherapy-treated ER-negative group, in later follow-up (beyond 5 years) the hazard for ER-positive patients again exceeds that of ER-negative patients. Adding chemotherapy to tamoxifen in ER-positive patients results in large early hazard reduction, but in later follow-up the hazard converges with those of patients treated by surgery only or tamoxifen. CONCLUSIONS: Recurrence hazards over time reveal changes in risk that may have biologic and therapeutic strategy relevance. In ER-negative tumors, a large early chemotherapy benefit is followed by a consistently low recurrence hazard over time. In ER-positive patients, the chemotherapy benefit appears concentrated mostly in earlier follow-up, and a greater recurrence risk remains.

The use of tamoxifen and raloxifene for the prevention of breast cancer.

The NSABP Study of Tamoxifen and Raloxifene (STAR), launched in 1999, compared tamoxifen with raloxifene in a population of healthy postmenopausal women at increased risk for breast cancer to determine the relative effects on the risk of invasive breast cancer. To be eligible for participation, a woman had to be healthy with at least a 5-year predicted breast cancer risk of 1.66% based on the Gail model or a history of lobular carcinoma in situ (LCIS) treated by local excision alone. All participants were at least 35 years of age and postmenopausal. Between July 1999 and November 2004, 19,747 participants were randomized to receive either tamoxifen (20 mg, plus placebo) or raloxifene (60 mg, plus placebo) daily for a 5-year period. The mean age of the participants was 58.5 years; 93% were white and 51.6% had a hysterectomy prior to entering the study. Of the women, 71% had one or more first degree female relatives (mother, sister, daughter) with a history of breast cancer and 9.2% of the women had a personal history of LCIS. A history of atypical hyperplasia of the breast was noted in 22.7% of the participants. The mean predicted 5-year risk of developing breast cancer among the study population was 4.03% (SD, 2.17%) with a lifetime predicted risk of 16%. The mean time of follow-up is 3.9 years (SD, 1.6 years). There was no difference between the effect oftamoxifen and the effect of raloxifene on the incidence of invasive breast cancer; there were 163 cases of invasive breast cancer in the tamoxifen-treated group and 168 cases in those women assigned to raloxifene (incidence 4.30 per 1,000 vs 4.41 per 1,000; RR 1.02; 95% CI, 082-1.28). There were fewer cases of noninvasive breast cancer (LCIS and ductal carcinoma in situ [DCIS]) in the tamoxifen group (57 cases) than in the raloxifene group (80 cases), although the difference is not yet statistically significant (incidence 1.51 vs 2.11 per 1,000; RR, 1.40; 95% CI, 0.98-2.00). There were 36 cases of uterine cancer with tamoxifen and 23 cases with raloxifene (RR, 0.63; 95% CI, 0.35-1.08).

Stromal Tumor-infiltrating Lymphocytes in NRG Oncology/NSABP B-31 Adjuvant Trial for Early-Stage HER2-Positive Breast Cancer.

We retrospectively assessed association of stromal tumor-infiltrating lymphocytes (sTILs) with clinical outcomes and molecular variables reportedly predictive of trastuzumab-benefit in National Surgical Adjuvant Breast and Bowel Project B-31 (N = 2130). sTILs were assessed in 1581 eligible B-31 cases utilizing all available hematoxylin and eosin slides. Mean concordance between main reviewer and six other pathologists was 90.8% in 100 cases. Cox regressions were used to calculate hazard ratios (HRs). In chemotherapy and trastuzumab added to chemotherapy arms, increases in sTILs, as a semicontinuous variable (combined arms HR = 0.42, 95% confidence interval = 0.27 to 0.64, two-sided P < .001) or as lymphocyte-predominant breast cancer with more than 50% sTILs (combined arms HR = 0.65, 95% confidence interval = 0.49 to 0.86, two-sided P = .003) were statistically significantly associated with improved disease-free survival. There was no association of sTILs with trastuzumab benefit. However, higher sTILs were statistically significantly associated with higher trastuzumab benefit groups by 8-gene prediction model (two-sided P < .001). Neither PIK3CA mutations nor Fc-gamma-receptor polymorphisms were associated with sTILs. sTILs may have utility as a prognostic biomarker identifying HER2-positive early breast cancer at low recurrence risk.

The half century of clinical trials of the National Surgical Adjuvant Breast And Bowel Project.

The supplanting of radical mastectomy by simple mastectomy and then by lumpectomy plus radiation, the use of adjuvant therapy to alter the natural course of breast and colorectal cancer, the use of tamoxifen for the prevention of breast cancer, and the dramatic improvement in survival demonstrated with the use of the monoclonal antibody trastuzumab in women with HER2-positive breast cancer are all the direct results of research that has been carried out over the past 50 years by the National Surgical Adjuvant Breast and Bowel Project (NSABP). This National Cancer Institute-supported clinical cooperative trials group based in Pittsburgh, PA, currently has 200 member institutions and 700 satellite centers located throughout the United States, Canada, Puerto Rico, and Ireland. The NSABP's mandate is to conduct large randomized phase III trials to evaluate therapies designed to improve the treatment and prevention of breast and colorectal cancer. Over the past half century, the NSABP has entered more than 150,000 patients and participants into clinical studies that have changed the treatment of colorectal cancer and have revolutionized the treatment and prevention of breast cancer.

21-Gene assay as predictor of chemotherapy benefit in HER2-negative breast cancer.

The NSABP B-20 prospective-retrospective study of the 21-gene Oncotype DX Breast Cancer Recurrence Score® test predicted benefit from addition of chemotherapy to tamoxifen in node-negative, estrogen-receptor positive breast cancer when recurrence score (RS) was ≥31. HER2 is a component of the RS algorithm with a positive coefficient and contributes to higher RS values. Accrual to B-20 occurred prior to routine testing for HER2, so questions have arisen regarding assay performance if HER2-positive patients were identified and excluded. We report an exploratory reanalysis of the B-20, 21-gene study following exclusion of such patients. Patients were considered HER2 positive if quantitative RT-PCR for HER2 was ≥11.5 units, and excluded from re-analyses performed using the original cutoffs: <18, 18-30, ≥31, and the TAILORx cutoffs: <11, 11-25, >25. The endpoint remained distant recurrence-free interval (DRFI) as in the original study. Distribution was estimated via the Kaplan-Meier method and compared via log-rank test. Multivariate Cox proportional hazards models estimated chemotherapy benefit in each group. In the RS < 18 and 18-30 groups, 1.7 and 6.7% were HER2 positive. In the RS ≥ 31 group, 41% were HER2 positive. Exclusion resulted in fewer events, with loss of significance for benefit from chemotherapy in the overall HER2-negative cohort (log-rank P = 0.06), but substantial benefit from chemotherapy remained in the RS ≥ 31 cohort (HR = 0.18; 95% CI: 0.07-0.47) and the RS > 25 cohort (HR = 0.28; 95% CI: 0.12-0.64). No benefit from chemotherapy was evident in the other RS groups. Following exclusion of HER2-positive patients based on RT-PCR expression, substantial benefit of chemotherapy remained for RS ≥ 31 as originally employed, and with RS > 25 employed in TAILORx.

A multigene assay to predict recurrence of tamoxifen-treated, node-negative breast cancer.

BACKGROUND: The likelihood of distant recurrence in patients with breast cancer who have no involved lymph nodes and estrogen-receptor-positive tumors is poorly defined by clinical and histopathological measures. METHODS: We tested whether the results of a reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay of 21 prospectively selected genes in paraffin-embedded tumor tissue would correlate with the likelihood of distant recurrence in patients with node-negative, tamoxifen-treated breast cancer who were enrolled in the National Surgical Adjuvant Breast and Bowel Project clinical trial B-14. The levels of expression of 16 cancer-related genes and 5 reference genes were used in a prospectively defined algorithm to calculate a recurrence score and to determine a risk group (low, intermediate, or high) for each patient. RESULTS: Adequate RT-PCR profiles were obtained in 668 of 675 tumor blocks. The proportions of patients categorized as having a low, intermediate, or high risk by the RT-PCR assay were 51, 22, and 27 percent, respectively. The Kaplan-Meier estimates of the rates of distant recurrence at 10 years in the low-risk, intermediate-risk, and high-risk groups were 6.8 percent (95 percent confidence interval, 4.0 to 9.6), 14.3 percent (95 percent confidence interval, 8.3 to 20.3), and 30.5 percent (95 percent confidence interval, 23.6 to 37.4). The rate in the low-risk group was significantly lower than that in the high-risk group (P<0.001). In a multivariate Cox model, the recurrence score provided significant predictive power that was independent of age and tumor size (P<0.001). The recurrence score was also predictive of overall survival (P<0.001) and could be used as a continuous function to predict distant recurrence in individual patients. CONCLUSIONS: The recurrence score has been validated as quantifying the likelihood of distant recurrence in tamoxifen-treated patients with node-negative, estrogen-receptor-positive breast cancer.

Pathologic variables predictive of breast events in patients with ductal carcinoma in situ.

Central pathology review of ductal carcinoma in situ from 1,456 patients enrolled in National Surgical Adjuvant Breast and Bowel Project (NSABP) protocol B-24 was performed to determine predictors for ipsilateral breast tumor recurrences and contralateral breast cancers. Findings after a median follow-up time of 10.5 years revealed ductal comedo necrosis, micropapillary histologic tumor type, and multifocality to be independent high risk factors for ipsilateral breast tumor recurrence. Risk increased for slight comedo necrosis vs absent and for moderate to marked comedo necrosis vs slight. The presence of a micropapillary tumor type and gross tumor size (> or = 1.0 cm) were independently found as risk factors for contralateral breast cancers. Although 47% of ipsilateral and 66% of contralateral events were invasive carcinomas, overall mortality was only 2.3%, a conundrum possibly related to the small size of the latter. The similar predictive role of comedo necrosis in this study and that reported previously from NSABP B-17 (total of 2,079 patients) strongly supports its role as a simple high-risk predictor for ipsilateral breast tumor recurrences.

Milestone clinical trials of the National Surgical Adjuvant Breast and Bowel Project (NSABP).

The National Surgical Adjuvant Breast and Bowel Project (NSABP) has made significant contributions in reducing the extent of breast surgery and in improving outcomes of patients with early-stage breast cancer through the conduct of large randomized clinical trials evaluating local and systemic therapy. In 2014, the NSABP merged with two other US National Cancer Institute-funded cooperative groups, the Radiation Therapy Oncology Group (RTOG) and the Gynecologic Oncology Group (GOG), to form NRG Oncology. The combined organization has 218 member institutions with more than 600 affiliate centers located throughout the United States, Canada, Puerto Rico, and other international sites. Over the past half century, the NSABP has entered more than 150,000 women into clinical trials of breast cancer treatment and breast cancer prevention. Many of these trials have been instrumental in establishing new standards of care for patients with breast cancer.

NRG Oncology/National Surgical Adjuvant Breast and Bowel Project Decision-Making Project-1 Results: Decision Making in Breast Cancer Risk Reduction.

Selective estrogen receptor modulators (SERMs) reduce breast cancer risk. Adoption of SERMs as prevention medication remains low. This is the first study to quantify social, cultural, and psychologic factors driving decision making regarding SERM use in women counseled on breast cancer prevention options. A survey study was conducted with women counseled by a health care provider (HCP) about SERMs. A statistical comparison of responses was performed between those who decided to use and those who decided not to use SERMs. Independent factors associated with the decision were determined using logistic regression. Of 1,023 participants, 726 made a decision: 324 (44.6%) decided to take a SERM and 402 (55.4%) decided not to. The most important factor for deciding on SERM use was the HCP recommendation. Other characteristics associated with the decision included attitudes and perceptions regarding medication intake, breast cancer worry, trust in HCP, family members with blood clots, and others' experiences with SERMs. The odds of SERM intake when HCP recommended were higher for participants with a positive attitude toward taking medications than for those with a negative attitude (Pinteraction = 0.01). This study highlights the importance of social and cultural aspects for SERM decision making, most importantly personal beliefs and experiences. HCPs' recommendations play a statistically significant role in decision making and are more likely to be followed if in line with patients' attitudes. Results indicate the need for developing interventions for HCPs that not only focus on the presentation of medical information but, equally as important, on addressing patients' beliefs and experiences. Cancer Prev Res; 10(11); 625-34. ©2017 AACRSee related editorial by Crew, p. 609.