Effect of preoperative chemotherapy on the outcome of women with operable breast cancer

PURPOSE

To determine, in women with primary operable breast cancer, if preoperative doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan; AC) therapy yields a better outcome than postoperative AC therapy, if a relationship exists between outcome and tumor response to preoperative chemotherapy, and if such therapy results in the performance of more lumpectomies.

PATIENTS AND METHODS

Women (1,523) enrolled onto National Surgical Adjuvant Breast and Bowel Project (NSABP) B-18 were randomly assigned to preoperative or postoperative AC therapy. Clinical tumor response to preoperative therapy was graded as complete (cCR), partial (cPR), or no response (cNR). Tumors with a cCR were further categorized as either pathologic complete response (pCR) or invasive cells (pINV). Disease-free survival (DFS), distant disease-free survival (DDFS), and survival were estimated through 5 years and compared between treatment groups. In the preoperative arm, proportional-hazards models were used to investigate the relationship between outcome and tumor response.

RESULTS

There was no significant difference in DFS, DDFS, or survival (P = .99, .70, and .83, respectively) among patients in either group. More patients treated preoperatively than postoperatively underwent lumpectomy and radiation therapy (67.8% v 59.8%, respectively). Rates of ipsilateral breast tumor recurrence (IBTR) after lumpectomy were similar in both groups (7.9% and 5.8%, respectively; P = .23). Outcome was better in women whose tumors showed a pCR than in those with a pINV, cPR, or cNR (relapse-free survival [RFS] rates, 85.7%, 76.9%, 68.1%, and 63.9%, respectively; P < .0001), even when baseline prognostic variables were controlled. When prognostic models were compared for each treatment group, the preoperative model, which included breast tumor response as a variable, discriminated outcome among patients to about the same degree as the postoperative model.

CONCLUSION

Preoperative chemotherapy is as effective as postoperative chemotherapy, permits more lumpectomies, is appropriate for the treatment of certain patients with stages I and II disease, and can be used to study breast cancer biology. Tumor response to preoperative chemotherapy correlates with outcome and could be a surrogate for evaluating the effect of chemotherapy on micrometastases; however, knowledge of such a response provided little prognostic information beyond that which resulted from postoperative therapy.

Circulating tumor DNA (ctDNA) during and after neoadjuvant chemotherapy and prior to surgery is a powerful prognostic factor in triple-negative breast cancer (TNBC)

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Background: TNBC, the most aggressive form of breast cancer, is treated primarily with chemotherapy, even before surgery (neoadjuvant chemotherapy or NAC). The prognosis and need for adjuvant therapy depends greatly on the tumor response assessed by pathology (pCR). Highly sensitive and specific ctDNA assays have been shown to be of prognostic value in the metastatic settingbut not yet in earlier settings. Methods: Tissue was collected from 26 Q-CROC-03 clinical trial TNBC patients before, during and after NAC, prior to surgery. Whole exome sequencing on tumor tissues was used to select single nucleotide variants with high allele frequency (VAF), prioritizing TP53, to generateindividual digital droplet PCR (ddPCR) assays. An average of 5 variants (range 1-12) per patient were tested, for a total of 121 variants. A detection threshold was defined for each variant from a pool of normal controls. Median follow-up was 55 months. Results: ctDNA was detectable in 96% of patients at baseline, but 20% of the 121 variants were not detectable at any time point. At baseline, the mean VAF of all analyzed variants, but not of TP53 variants alone, was significantly correlated (p < 0.05) with tumor factors (tumor size, stage, grade, nodal status before and at surgery, RCB score) but not with patient age or BRCA1/2 mutation status. 87 variants (74%) were detected at baseline and their VAF fell by 86% after 1 cycle of chemotherapy (T1). The detection of ctDNA at T1 was associated with DFS (p = 0.027) while the detection of ctDNA at the last post-chemotherapy pre-surgery time point (T4) was strongly associated with pathological complete response (pCR) and both DFS (p = 0.013) and OS(p = 0.006). At this time point, 5 of 41 variants (12%) were detected in pCR patients vs 42 of 80 (53%) in non-pCR, while only 6 of the 15 (40%) non-pCR patients had detectable TP53 variants. Interestingly, for variants detected at baseline, the positive predictive value of T4 ctDNA for disease recurrence was 69%, similar to that of non-pCR, while the negative predictive value of no ctDNA at T4 was 89% for disease recurrence vs 80% for pCR. Conclusions: ctDNA detection after NAC prior to surgery is strongly predictive of disease-free survival and overall survival and is comparable to pCR as a prognostic factor in our cohort (NCT01276899).

NSABP B-41, a randomized neoadjuvant trial: Genes and signatures associated with pathologic complete response (pCR)

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Background: NSABP B-41 randomly assigned 529 patients (pts) with HER2 positive breast cancer to neoadjuvant trastuzumab (T), lapatinib (L), or combination (T+L), with weekly paclitaxel following doxorubicin and cyclophosphamide. No significant differences in pCR were found, but overall survival was significantly increased for pCR. Methods: RNA was extracted from FFPE tumor specimens, run on the NanoString Breast Cancer 360 Plus panel. Gene counts were normalized to include housekeeping genes, 33 biological signatures from 776 genes across 23 pathways and transformed into logarithm scale with base two. Univariate logistic regression was used to screen candidate genes and signatures that are prognostic of pCR, with false discovery rate controlled at 0.1. Multivariable logistic regression with lasso regularization was used for model selection. Results: 194 core biopsy samples were available; 69 treated with T, 64 with L and 61 with T+L. 20 prognostic genes are selected for trastuzumab-based regimens (TBR), including the epithelial-mesenchymal transition (HEMK1, GRB7, ERBB2, TMPRSS4), adhesion and migration (ITGB6, COL27A1, NRCAM), JAK-STAT (SOCS2), Hedgehog (LRP2), ER signaling (ELOVL2, MAPT), DNA damage and repair (NPEPPS, PRKDC), MAPK (DUSP6, PRKCB), Apoptosis (BCL2), proliferation (TFDP1). ERBB2 expression are associated with pCR in patients on TBR (OR = 1.73), but not for patients on L (interaction p = 0.01). HER2-Enriched correlation (p < 0.001), ESR1 (OR = 0.78, 95% CI = 0.69-0.88, p < 0.001), PD1 (OR = 1.68, 95% CI = 1.12-2.52, p = 0.01) and Tumor Inflammation Score (OR = 1.58, 95% CI = 1.18-2.11, p = 0.002) are associated with pCR in TBR. No genes or signatures were found to be predictive of treatment benefit from L added to T. Conclusions: BC360 highlighted tumor progression and signaling genes prognostic for TBR. HER2-Enriched correlation, ERBB2 and PD1 expression, and immune activation signatures were associated with pCR in TBR and may provide personalized treatment guidance.

Abstract GS3-02: PALLET: A neoadjuvant study to compare the clinical and antiproliferative effects of letrozole with and without palbociclib

Background: CDK4/6 inhibitors, such as palbociclib, are used to treat ER+ metastatic breast cancer in combination with endocrine therapy with trials ongoing in patients with primary disease. No biomarkers exist to identify those who do/do not benefit from added CDK4/6 inhibition. PALLET is an investigator-initiated/led phase II randomized trial collaboration between UK and NSABP investigators evaluating the biological and clinical effects of palbociclib with letrozole combination as neoadjuvant therapy.

Methods: Postmenopausal women with ER+ primary breast cancer and tumors &gt;2.0cm (ultrasound) were randomized to one of 4 treatment groups (3:2:2:2 ratio): Group A: letrozole (2.5mg/d) for 14 weeks; Group B: letrozole for 2 weeks followed by letrozole + palbociclib to 14 weeks; Group C: palbociclib for 2 weeks followed by letrozole + palbociclib to 14 weeks; Group D: letrozole + palbociclib for 14 weeks. Palbociclib was given 125mg/d PO on a 21 days on, 7 days off schedule. Post-14 week treatment was at the discretion of the treating clinician including letrozole until surgery. Core-cut biopsies were taken at baseline, 2 weeks and 14 weeks. Co-primary endpoints for letrozole alone vs palbociclib groups (Group A vs Groups B+C+D) were: (i) change in Ki67 (IHC) between baseline and 14 weeks (log-fold change, Mann-Whitney test); (ii) clinical response (ultrasound) after 14 weeks (4 group, ordinal, Mann-Whitney test). Complete cell-cycle arrest (CCCA) (Ki67≤2.7%) was analyzed using a logistic regression model adjusting for recruitment region. Pre-specified exploratory biomarkers included c-PARP (apoptosis).

Results: 307 patients were recruited between 27 Feb 2015 and 08 Mar 2018; 103 were randomized to letrozole alone and 204 to letrozole + palbociclib. 279 (90.9%) patients were evaluable for 14 week clinical response. Clinical response was not significantly different between letrozole vs letrozole + palbociclib groups [(p=0.20; CR+PR 49.5% (46/93) vs 54.3% (101/186) and PD 5.4% (5/93) vs 3.2% (6/186)] nor was the small proportion of patients with pathological CR (1/87, 1.1% vs 6/180, 3.3%; p=0.43). 190 (61.9%) patients were evaluable for 14 week change in Ki67. The median log-fold change in Ki67 was greater with letrozole + palbociclib vs letrozole alone (-4.1 vs -2.2; p&lt;0.001) corresponding to a geometric mean change of -97.4% vs -88.5%. Similarly, a greater proportion of patients who received letrozole + palbociclib achieved CCCA (90% vs 59%, p&lt;0.001). 146 (47.6%) patients were evaluable for c-PARP and the log-fold change (suppression) was greater with letrozole + palbociclib vs letrozole alone (-0.80 vs -0.42; p=0.003) corresponding to a geometric mean change of -56.8% vs -31.4%. Other biomarkers of response / resistance are being evaluated. A higher proportion of patients had a grade ≥3 toxicity on letrozole + palbociclib than letrozole alone (49.8% vs 17.0%; p&lt;0.001) mainly due to asymptomatic neutropenia.

Conclusion: Adding palbociclib to letrozole markedly enhanced the suppression of malignant cell proliferation as assessed by Ki67 but did not substantially increase the clinical response of primary ER+ breast cancer over a 14-week period. Concurrent reductions in cell death may have reduced the speed of tumor shrinkage.

Citation Format: Dowsett M, Jacobs S, Johnston S, Bliss J, Wheatley D, Holcombe C, Stein R, McIntosh S, Barry P, Dolling D, Snowdon C, Perry S, Batten L, Dodson A, Martins V, Modi A, Cornman C, Puhalla S, Wolmark N, Julian T, Pogue-Geile K, Robidoux A, Provencher L, Boileau JF, Shalaby I, Thirlwell M, Fisher K, Huang Bartlett C, Koehler M, Osborne K, Rimawi M. PALLET: A neoadjuvant study to compare the clinical and antiproliferative effects of letrozole with and without palbociclib [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS3-02.

Abstract PD6-04: Lifestyle intervention study (LISA) in early breast cancer (BC): An RCT of the effects of a telephone-based weight loss intervention (with educational materials) vs educational materials alone on disease-free survival (DFS)

Background: Obesity has been associated with poor BC outcomes. We investigated whether a standardized, telephone-based weight loss lifestyle intervention in recently diagnosed BC patients would lower recurrence and death rates.

Methods: We conducted a multicenter RCT comparing mail-based educational material alone (control arm) or combined with a standardized, telephone-based lifestyle intervention (19 calls over 2 years, (intervention arm) that focused on diet (500-100 kcal/day deficit), physical activity (150-200 minutes of moderate-intensity activity per week) and behavior (compliance, relapse prevention) to achieve up to 10% weight loss. 338 (of 2150 planned) T1-3, N0-3, M0 ER/PgR+ BC patients with body mass index (BMI) ≥ 24 kg/m2 receiving adjuvant letrozole were randomized Aug 2007 to Jan 2010 (enrolment ended due to funding loss). Primary outcome was DFS; secondary outcome OS. Weight loss (5.3 vs 0.7% at 6 months and 3.6 vs 0.4% at 24 months in the intervention vs control arms, respectively) has been reported (JCO 2014;32:2331). At 8 years median follow-up (May 2018), DFS and OS were compared using Cox proportional hazards regression.

Results: Mean age was 61.6 vs 60.4 years, mean BMI 31.4 vs 31.0 kg/m2 and adjuvant chemotherapy was received by 56.1 vs 57.5% in intervention vs controls arms respectively. T1/T2/T3 66.7/27.5/5.9% vs 61.7/33.5/3.6% and N0/1/2+ 62.6/28.7/8.8 vs 63.5/32.3/4.2% in intervention vs controls arms respectively. HER2+ in 8.8 vs 15.0% (intervention vs control). 20 of 171 (11.7%) in the lifestyle intervention arm vs 30 of 167 (18.0%) in the mail-based arm had DFS events, HR 0.71, 95%CI 0.41-1.24, p=0.23). DFS curves separated at 2 yrs; beyond 3-3.5 yrs separation approximated 5%. In a landmark DFS analysis of women alive at 24 months, DFS HR=0.68 (0.34-1.37, p=0.28).

Conclusions: We identified fewer DFS events in the lifestyle intervention arm. Although loss of funding reduced sample size and lowered power, these results are consistent with a potential beneficial effect of a lifestyle intervention on DFS in postmenopausal ER/PgR+ BC patients. They provide strong support for completion of ongoing RCTs (e.g. BWEL) that will provide definitive evidence regarding the effect of lifestyle based weight loss on BC outcomes.

Funded by Novartis Pharmaceuticals Inc.; Sponsored by the Ontario Clinical Oncology Group

Citation Format: Goodwin PJ, Segal R, Vallis M, Ligibel JA, Pond GR, Robidoux A, Findlay BP, Gralow JR, Mukherjee SD, Levine MN, Pritchard KI. Lifestyle intervention study (LISA) in early breast cancer (BC): An RCT of the effects of a telephone-based weight loss intervention (with educational materials) vs educational materials alone on disease-free survival (DFS) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD6-04.

Abstract P5-22-21: Radioactive seed and targeted axillary dissection: A feasibility study

Targeted axillary dissection (TAD) with a radioactive seed is a new and promising technique to evaluate the axillary status in post-neoadjuvant chemotherapy (NACT) node-positive breast cancer patients. This study aims to evaluate the feasibility of TAD with a radioactive seed in a Canadian setting.

We conducted a retrospective observational study of a prospectively gathered database of patients having undergone TAD with a radioactive seed implanted in a proven metastatic axillary node, between 2015 and 2017 in our institution. An iodine-125 radioactive seed was implanted under ultrasound guidance by trained radiologists. Patients then underwent standard sentinel lymph node biopsy (SLNB) using technicium-99 and blue dye, as well as selective removal of the node containing the radioactive seed. Data was gathered from electronic medical records and chart review.

Nine patients with a median age of 54 underwent TAD for unilateral breast cancer post-NACT between 2015 and 2017, three of which were "triple-negative". A median of 3 lymph nodes were removed, including that which contained the radioactive seed. Postoperative pathological evaluation showed 4 patients with positive nodes and 5 pathologic complete responses in the axilla. In all patients, the seed had been accurately positioned in a positive node (no false negatives). The seed also located a positive retropectoral node that would otherwise have been missed using standard dual tracer SLNB. No complications due to the use of the radioactive seed were encountered. All implanted seeds were identified and retrieved within the pathology specimen.

In our experience, TAD with a radioactive seed combined to dual tracer SLNB is an accurate and safe method of evaluating the axillary lymph node status in post-NACT node positive breast cancer patients. Further studies with larger cohorts are warranted to ensure continued feasibility and reproducibility of our positive results.

Citation Format: Boulva K, Rodriguez-Qizilbash S, Guilarte L, Lazizi S, Robidoux A, Younan R, Patocskai E. Radioactive seed and targeted axillary dissection: A feasibility study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-22-21.

Abstract P2-02-02: Dynamics of ctDNA changes during neoadjuvant chemotherapy in triple-negative breast cancer patients

Background:

Liquid biopsies to monitor response to treatment are a minimally invasive and highly attractive method for clinical application. Detection of ctDNA in plasma is now highly sensitive thanks to the use of novel highly sensitive and specific techniques such as ddPCR. In the present study we set out to analyze the utility of using ctDNA to monitor response to treatment in patients receiving standard neoadjuvant chemotherapy in triple negative breast cancer.

Methods:

Serial blood was collected from triple negative breast cancer patients participating in the Q-CROC-03 clinical trial (NCT01276899). The trial recruited triple negative breast cancer patients undergoing standard neoadjuvant chemotherapy. Paired biopsies were collected prior and at the end of treatment and serial bloods collected throughout the study. Whole exome sequencing was performed on tissues collected and we identified mutated genes of interest. Cell free DNA (cfDNA) was extracted from 3 ml of plasma and 4-10 variants per patient were analyzed by ddPCR in serial plasma samples collected before and during treatment. Response was measured by evaluating residual cancer burden (RCB), and non-responders were RCBII-III, responders RCB0-I.

Results:

For the present analysis, we identified 60 variants in tumors from 12 patients (9 RCBII-III and 3 RCB0-I). Except for TP53, none of the genes were shared among the tumors. 20% of the variants were not detected in ctDNA at any time point and we did not find any correlation between cfDNA levels and tumor size or response to treatment. The average variant allele frequency (VAF) of all detected variants at baseline was higher in RCBII-III patients than in RCB0-I patients (7.0 vs 0.7 respectively). Interestingly, variants that were detected either only in the pre-chemo tumor or in the post-chemo tumor were frequently detected throughout neoadjuvant therapy, highlighting the ability of ctDNA to capture tumor heterogeneity. In almost all cases, we observed a dramatic decrease in ctDNA VAF after one cycle of chemotherapy, including 30% to non-detectable levels. By the 5th cycle of chemotherapy 97% of detected variants had decreased (average 95% decrease). This decrease in ctDNA VAF was independent of RCB score. In some RCBII-III cases, ctDNA VAF increased prior to surgery, reflecting residual tumor presence.

Conclusion:

ctDNA could be detected in plasma of all early TNBC patients undergoing neoadjuvant chemotherapy with the majority of variants detected in plasma collected at baseline prior to chemotherapy. Once treatment started, the abundance of ctDNA markedly decreased in plasma independently of tumor response. The effect of chemotherapy on levels of ctDNA needs further investigation.

Citation Format: Cavallone L, Adriana A-M, Aldamry M, Lafleur J, Cathy L, Alirezaie N, Bareke E, Majewski J, Ferrario C, Mihalciou C, Roy J-A, Markus E, Robidoux A, Pelmus M, Aleynikova O, Discepola F, Basik M. Dynamics of ctDNA changes during neoadjuvant chemotherapy in triple-negative breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-02-02.

Chemotherapy (CT) for isolated locoregional recurrence (ILRR) of breast cancer in ER-positive (ER+) and ER-negative (ER-) cohorts: Final analysis of the CALOR trial

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Background: ILRR is associated with a high risk of developing breast cancer distant metastases and death. The CALOR trial (NCT00074152) investigated the effectiveness of CT following local therapy for ILRR. Previously reported results at 5-yrs median follow-up (MFU) showed significant benefit of CT for ER- ILRR, but further follow-up was required in ER+ ILRR. This report presents results at 8.8 yrs MFU within ER status cohorts. Methods: CALOR is an open-label, randomized trial for patients with completely excised ILRR after unilateral breast cancer. Eligible patients were randomized to CT (selected by the investigator; multidrug for at least 3 months recommended) or No-CT, and stratified by prior CT, hormone-receptor (ER, PR) status, and location of ILRR. Patients with ER and/or PR positive ILRR received adjuvant endocrine therapy. Radiation therapy was mandated for patients with microscopically involved margins, and anti-HER2 therapy was optional. Endpoints are disease-free survival (DFS), overall survival (OS) and breast cancer-free interval (BCFI). Results: From August 2003 to January 2010, 162 patients were enrolled: 104 ER+ and 58 ER-. The results at 8.8 years MFU in ER status cohorts are summarized in the Table (40 and 27 DFS events, respectively). The reduction in the hazard of an event associated with CT for the ER- ILRR cohort was sustained, but no benefit was observed for the ER+ cohort; interactions were significant for DFS and BCFI. The reduction in the hazard of an event seen in the ER- cohort was not apparent in ER+, with significant interactions for DFS and BCFI. Results for the 3 endpoints were consistent in multi-variable analyses adjusting for location of ILRR, prior chemotherapy, and interval from primary surgery. Conclusions: The final analysis of CALOR confirms that CT benefits patients with resected ER- ILRR. Long-term CALOR trial results do not support the use of CT for ER+ ILRR. Clinical trial information: NCT00074152. [Table: see text]

Abstract P2-10-04: Using the 21-gene assay from core needle biopsies to choose neoadjuvant therapy for breast cancer: A multi-center trial

Neoadjuvant systemic therapy (NST) can facilitate breast conserving surgery (BCS) for large cancers. While hormone receptor positive (HR+) cancers respond to neoadjuvant chemotherapy (NCT), pathologic complete responses (pCR) are unlikely. Neoadjuvant hormonal therapy (NHT) may make BCS possible with less toxicity than NCT. We hypothesized that the Oncotype Dx® 21-gene Recurrence Score (RS), could guide the decision to treat with NHT versus NCT to facilitate BCS. This hypothesis is based on the ability of the RS to identify ER+ patients (pts) likely to benefit from adjuvant CT vs unlikely to benefit, as well as prior studies showing that pts with a low RS have no pCRs when receiving NCT (Yardley, et al 2015).

Methods: This prospective multi-center study enrolled pts with HR+, HER2-negative, invasive breast cancers not suitable for BCS (size ≥ 2 cm). Diagnosis was made by core needle biopsy (bx). Tissue blocks from the bx's were sent to Genomic Health for RS testing. Pts whose tumors had a RS &lt; 11 were to receive NHT; pts with RS &gt;25 tumors were to receive NCT; pts with midrange RS of 11-25 were randomized to NHT or NCT.

The primary objective was the feasibility of randomizing pts with RS values 11-25 between NHT and NCT. The primary endpoint was whether 1/3 or more of randomized pts would refuse assigned treatment. Secondary endpoints included: clinical partial and complete response (cPR, cCR) rates, overall clinical response rates (CR), pCR in the breast, pCR in the breast and nodes and successful BCS. One-sample binomial test was used to compare the observed refusal rate with 1/3, along with its 95% CI. Fisher's exact test, logistic regression (for a binary endpoint), and/or ordinal regression (for an ordinal endpoint) were used to compare the 4 treatment groups for secondary endpoints.

Results: Seven US and Canadian centers enrolled 64 pts; 5 were excluded (1 delay in RS result, 1 lost block, 1 HR testing discrepancy, 2 not eligible). Of 33 pts with RS 11-25, 5 (15%; 95% CI =2.9% - 27.4%) refused assignment to NCT (2 chose NHT and finished the study). This was significantly lower than the 33% target (binomial test, p=0.0292). Results for other endpoints are shown in the Table (according to treatment received); the total number of pts for the analyses is 55; 1 pt had missing data for clinical response.

Results According to TreatmentTreatment GroupRS&lt;11 NHTRS 11-25 NHTRS 11-25 NCTRS&gt;25 NCTOverall PNN=12N=18N=11N=14 cCR8.3%22.2%36.4%28.6%0.0422cPR75%27.8%36.4%64.3% CR (cCR + cPR)83.3%50%72.7%92.9%0.0490pCR Breast8.3%6%021.4%NSpCR Breast + Nodes00014.3%NSSuccessful BCS75%72.2%63.6%57.1%NS

Conclusions:This pilot showed the feasibility of using the RS to guide NST, with only a 15% refusal rate of randomly assigned treatment. Of greater interest is the finding that pts with a RS &lt;11 had a high CR rate with NHT and that pts with a RS 11-25 who received NHT had a similar rate of BCS success as the pts with RS &lt;11. Conversely, pts with RS&gt;25 treated with NCT had the highest CR (cCR + pCR) and pCR rates. These results demonstrate that conducting a similarly designed larger trial is feasible and suggests that for pts with a low RS, NHT is a potentially effective strategy.

Citation Format: Bear HD, Wan W, Robidoux A, Rubin P, Limentani S, White, Jr. RL, Granfortuna J, Hopkins JO, Oldham D, Rodriguez A, Sing AP. Using the 21-gene assay from core needle biopsies to choose neoadjuvant therapy for breast cancer: A multi-center trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-10-04.

Abstract P6-03-03: The Q-CROC-3 project reveals novel genomic alterations in triple negative breast cancers in residual tumors after neoadjuvant chemotherapy

The prognosis of triple negative breast cancer that shows resistance and/or incomplete response to cytotoxic chemotherapy is poor. In order to understand the mechanisms of resistance to chemotherapy and the genomic evolution of TNBCs treated with chemotherapy, an international multi-center biopsy-driven clinical trial was created for the collection and study of drug-resistant primary and metastatic freshly frozen tumors (Q-CROC-03: NCT01276899). We consented 60 patients with operable TNBC undergoing neoadjuvant Anthracycline/Taxane-based chemotherapy for pre and post-treatment biopsies as well as collection of residual tumor at the time of surgery and serial blood sampling. In 12-15 patients, adequate residual tumor material was available for genomic studies, which included whole exome sequencing, array CGH, gene expression microarray profiling and RNAseq of paired tumors. Whole exome sequencing revealed clonal shifts as well as the relatively infrequent appearance of novel mutations in individual tumors, without any recurrently detected variants. Array CGH revealed a remarkable stability in the number of DNA copy number alterations with a few functional alterations enriched for in the residual tumor, including an amplicon involving the NFIB gene. Finally, gene expression profiling showed shifts towards the immune-modulatory and basal TNBC subtypes after chemotherapy as well as an increase in the expression of several targetable genes, including DUSP1, a dual specificity phosphatase. In the 4 cases of primary and matching metastatic tumors, the post-NAC residual tumor had acquired changes many of which persisted in the metastatic sites, indicating that the analysis of the residual tumors can provide a partial picture of genomic changes present in metastases but not in the primary tumor. In summary, the genomic characterization of residual post-NAC tumor tissue provides important information for the development of novel therapeutic strategies for drug-resistant TNBCs as well as a portrait of genomic evolution of TNBCs subjected to chemotherapy.

Citation Format: Basik M, Aguilar-Mahecha A, Lafleur J, Bareke E, Przybytkowski E, Alirezaie N, Discepola F, Légaré S, Kovacina B, Lan C, Mihalcioiu CL, Robidoux A, Marcus E, Roy J-A, Pelmus M, Aleynikova O, Nabavi S, Tonellato P, Majewski J. The Q-CROC-3 project reveals novel genomic alterations in triple negative breast cancers in residual tumors after neoadjuvant chemotherapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-03-03.

Early breast cancer response to neoadjuvant chemotherapy: Defining the optimal timing and response rate using clinical tumor measurement

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Background: Breast cancer pathological complete response (pCR) following neoadjuvant therapy (NAT) is associated with better survival in some tumor subtypes. There is interest in identifying methods to increase early prediction of pCR during NAT. A simple and inexpensive technique such as early clinical breast examination has been shown to correlate with pCR during NAT in some studies. However, the optimal timing of the measurement and the best tumor response (TR) rate to predict pCR still need to be defined. Methods: We conducted a retrospective cohort study of patients prospectively enrolled in the following NSABP trials in one academic center (Montreal, Canada): B-40, B-41, FB-AX-003, FB-4, FB-5 and FB-6. Patients with T4 disease or disease progression were excluded. Clinical tumor measurements were recorded before each cycle of NAT. TR was measured as the percentage decrease in the largest tumor diameter. ROC curves for TR measurements at each time point were generated, comparing areas under the curve using the DeLong method. P-value ² 0.05 was considered significant. Results: We analyzed data of 155 patients recruited from Aug. 2005 to May 2011. Results are presented in Table 1. The best time point to predict pCR was after cycle 2. At this time point, a TR of 46% was the best cutoff value to predict for pCR. Among hormone receptor positive (HR+) and HER-2 positive (HER-2+) breast cancer patients, a TR of 47% after cycle 2 was significantly predictive for pCR. These findings were similar using a 50% TR cutoff after 2 cycles. Conclusions: Observing a 50% reduction in largest tumour diameter on clinical breast examination after cycle 2 of NAT is predictive for pCR in HR+ and HER-2+ breast cancer patients. We recommend using this definition of clinical response in future trials evaluating novel methods to improve early prediction of pCR during NAT. [Table: see text]

Sentinel node biopsy after neoadjuvant chemotherapy in biopsy-proven node-positive breast cancer: the SN FNAC study

PURPOSE

An increasing proportion of patients (> 30%) with node-positive breast cancer will obtain an axillary pathologic complete response after neoadjuvant chemotherapy (NAC). If sentinel node (SN) biopsy (SNB) is accurate in this setting, completion node dissection (CND) morbidity could be avoided.

PATIENTS AND METHODS

In the prospective multicentric SN FNAC study, patients with biopsy-proven node-positive breast cancer (T0-3, N1-2) underwent both SNB and CND. Immunohistochemistry (IHC) use was mandatory, and SN metastases of any size, including isolated tumor cells (ypN0[i+], ≤ 0.2 mm), were considered positive. The optimal SNB identification rate (IR) ≥ 90% and false-negative rate (FNR) ≤ 10% were predetermined.

RESULTS

From March 2009 to December 2012, 153 patients were accrued to the study. The SNB IR was 87.6% (127 of 145; 95% CI, 82.2% to 93.0%), and the FNR was 8.4% (seven of 83; 95% CI, 2.4% to 14.4%). If SN ypN0(i+)s had been considered negative, the FNR would have increased to 13.3% (11 of 83; 95% CI, 6.0% to 20.6%). There was no correlation between size of SN metastases and rate of positive non-SNs. Using this method, 30.3% of patients could potentially avoid CND.

CONCLUSION

In biopsy-proven node-positive breast cancer after NAC, a low SNB FNR (8.4%) can be achieved with mandatory use of IHC. SN metastases of any size should be considered positive. The SNB IR was 87.6%, and in the presence of a technical failure, axillary node dissection should be performed. We recommend that SN evaluation with IHC be further evaluated before being included in future guidelines on the use of SNB after NAC in this setting.

Duration of tamoxifen use and the risk of contralateral breast cancer in BRCA1 and BRCA2 mutation carriers

Women with a mutation in BRCA1 or BRCA2 face a lifetime risk of breast cancer of approximately 80 %. Tamoxifen treatment of the first cancer has been associated with a reduction in the risk of a subsequent contralateral cancer. We studied 1,504 women with a known BRCA1 or BRCA2 mutation, 411 women with bilateral breast cancer (cases) and 1,093 women with unilateral breast cancer (controls) in a matched case-control study. Control women were of similar age and had a similar age of diagnosis of first breast cancer as the cases. For each woman who used tamoxifen, the starting and stopping dates were abstracted and the duration of tamoxifen use was calculated. Three hundred and thirty-one women had used tamoxifen (22 %); of these 84 (25 %) had completed four or more years of tamoxifen, the remainder stopped prematurely or were current users. For women with up to 1 year of tamoxifen use, the odds ratio for contralateral breast cancer was 0.37 (95 % CI 0.20-0.69; p = 0.001) compared to women with no tamoxifen use. Among women with 1-4 years of tamoxifen use the odds ratio was 0.53 (95 % CI 0.32-0.87; p = 0.01). Among women with four or more years of tamoxifen use the odds ratio was 0.83 (95 % CI 0.44-1.55; p = 0.55). Short-term use of tamoxifen for chemoprevention in BRCA1 and BRCA2 mutation carriers may be as effective as a conventional 5-year course of treatment.

Randomised, phase II, placebo-controlled, trial of fulvestrant plus vandetanib in postmenopausal women with bone only or bone predominant, hormone-receptor-positive metastatic breast cancer (MBC): the OCOG ZAMBONEY study

Biomarkers of bone turnover, including urine N-telopeptide (uNTx), have been used as surrogate measures of response to bone-targeted therapies. Vascular endothelial growth factor (VEGF) levels correlate with extent of bone metastases. We assessed whether vandetanib, an inhibitor of VEGF, epidermal growth factor receptor and RET signalling, improved uNTx response when added to fulvestrant (F) in breast cancer patients with bone metastases. Postmenopausal patients with bone predominant, hormone-receptor-positive metastatic breast cancer were randomised to F (500 mg IM days 1, 15, 29, then monthly) with either vandetanib (100 mg PO OD) (FV) or placebo (FP). The primary objective was uNTx response. Secondary objectives included PFS, OS, RECIST response, pain scores and toxicity. Sixty-one patients were allocated to FV and 68 to FP. Out of 127 analyzable patients, an uNTx response occurred in 66 % for FV and 54 % for FP (p = 0.21). No difference was detected between groups for PFS; HR = 0.95 (95 % CI 0.65-1.38) or OS HR = 0.69 (95 % CI 0.37-1.31). For the 62 patients with measurable disease, clinical benefit rates were 41 and 43 %, respectively (p = 0.47). Serious adverse events were similar, 3.3 % for FV versus 5.9 % for FP. Elevated baseline uNTx (>65 nM BCE/mmol Cr) was prognostic for PFS, HR = 1.55 (95 % CI 1.04-2.30) and for OS, HR = 2.32 (95 % CI 1.25-4.33). The addition of vandetanib to fulvestrant did not improve biomarker response, PFS or OS in patients with bone metastases. Baseline bone turnover was prognostic for PFS and OS.

Sentinel node biopsy after neoadjuvant therapy: Relevance of sentinel node micrometastases, isolated tumor cells, and value of immunohistochemistry

52

Background: Sentinel node biopsy (SNB) is used in breast cancer patients that present with clinically negative nodes. In this setting, most guidelines do not support the use of immunohistochemistry (IHC) and recommend against completion node dissection (CND) when only isolated tumor cells (pN0(i+)) or micrometasases (pN1mi) are identified. When SNB is used after neoadjuvant therapy (NAT), the relevance of ypN0(i+) and ypN1mi sentinel nodes (SNs) and the value of IHC are not well established. The goals of this study are to determine if CND should be recommended in the presence of ypN0(i+) or ypN1mi SNs and if IHC should be used to evaluate SNs after NAT. Methods: From March 2009 to December 2012, 152 women with biopsy proven node positive breast cancer were accrued to the multicentric prospective SN FNAC trial. After NAT, SNB was followed by a CND in all participants. SNs were cut in serial slices no thicker than 2 mm. Hematoxylin and eosin stains (H and E) were done on all slices, and if negative, IHC was used. The size of the largest SN metastasis and the primary method of identification (H and E or IHC) were recorded. ypN0(i+), ypN1mi and ypN1 SNs were considered as positive. Pathology was centrally reviewed. Results: 145 women were eligible for the trial. Axillary pathologic complete response rate = 34% (49/145). SNB success rate = 88% (127/145). False negative rate = 8.4% (7/83). If ypN0(i+) SNs are classified as node negative, the false negative rate is increased to 13.3% (11/83). For patients with ypN0(i+) (n=7), ypN1mi (n=8) and ypN1 (n=61) SNs, the rates of non-SN involvement are 57%, 38% and 56% respectively (p=NS). 40% (27/68) of positive SNBs are primarily detected by IHC. This is increased to 64% (9/14) for the identification of SN metastases ≤ 2mm. Conclusions: After NAT, particularly when presenting with biopsy proven node positive breast cancer, patients with ypN0(i+) and ypN1mi SNs have a significant rate of non-SN involvement. In the absence of evidence to show that a CND can be safely avoided, efforts should be made to identify even minimal amounts of disease when SNBs are done following NAT. IHC is useful to increase the detection of small SN metastases in this setting. Clinical trial information: NCT00909441.

Sentinel node biopsy following neoadjuvant chemotherapy in biopsy proven node positive breast cancer: The SN FNAC study

1018

Background: A significant and increasing proportion of patients (>30%) with biopsy proven node positive breast cancer will obtain a pathological complete response (pCR) in the axilla after neoadjuvant chemotherapy (NAC). If sentinel node biopsy (SNB) can accurately identify these patients, they could potentially avoid the morbidity of an axillary node dissection. The primary aim of this study is to evaluate the identification rate (IR), false negative rate (FNR) and accuracy of SNB in this setting. The accuracy of post NAC axillary ultrasound and clinical examination are evaluated as secondary endpoints. Methods: Patients with biopsy proven node positive breast cancer (T0-3, N1-2, M0) treated with NAC were eligible to participate in this multi-centre prospective trial. Following NAC, axillary ultrasound and clinical examination results were obtained. At time of surgery, all participants underwent both a SNB and a completion node dissection. A SNB IR greater than 90% and a FNR of less than 10% were pre-determined as being optimal. Results: From September 2009 to December 2012, 153 patients were accrued to the study. 7 patients were not eligible and 5 patients had not yet undergone surgery at the time of analysis. Axillary pCR rate = 34.0% (48/141). SNB IR = 87.2% (123/141), 95% CI [81.7%-92.7%] and FNR = 9.9% (8/81), 95% CI [3.4%-16.4%]. If only one sentinel node was removed, FNR = 19.0%(4/21); if there were 2 or more sentinel nodes, FNR = 6.6% (4/61) (p < 0.0001). Accuracy of SNB, axillary ultrasound and clinical examination were 93.5%, 63.2%, and 45.5% respectively. Conclusions: SNB following NAC in biopsy proven node positive breast cancer is associated with a suboptimal IR. FNR (less than 10%) and accuracy of SNB in this study are comparable to that of patients that present with clinically negative nodes. The FNR decreases when more than one sentinel node is identified. However, in an era where regional nodal radiation is increasingly used, the relevance of leaving residual disease in the undissected axilla after NAC is unknown and remains to be investigated. Clinical trial information: NCT00909441.

Randomized phase II placebo-controlled trial of fulvestrant plus vandetanib in postmenopausal women with bone only or bone predominant, hormone receptor-positive metastatic breast cancer (MBC): OCOG Zamboney study—NCT00811369

574

Background: Biomarkers of bone turnover, including urine N-telopeptide (uNTx) and serum C-telopeptide (sCTx) reflect tumor-related bone breakdown and have been used as surrogate measures of response to therapy in trials. Vascular endothelial growth factor (VEGF) levels correlate with extent of bone metastases (BM). We assessed whether vandetanib, an inhibitor of VEGF, epidermal growth factor receptor and RET signalling, improved uNTx response when added to fulvestrant (F) in patients with BM. Methods: Postmenopausal patients with bone only, or bone predominant, hormone receptor positive MBC were randomised to F (500mg IM day 1, 14, 28, then monthly) with either vandetanib (100mg PO OD) (FV) or placebo (FP) until progression. The primary objective was uNTx response (>30% reduction from baseline). uNTx was collected at baseline, weekly to wk 4, at wk 12 and then every 12 wks. Secondary objectives included PFS, OS, RECIST response, pain and toxicity. Results: 61 patients were allocated to FV and 68 to FP. Median age was 59. 18% had received 1 prior chemotherapy regime and 73% prior endocrine therapy for MBC. uNTx response (n=124 pts) was 64% for FV vs. 52% for FP (p=0.20). No difference was detected between groups for median PFS; 6 months for FV vs. 4.8 months for FP, HR=0.93 (95% CI: 0.64 to 1.36). 16 patients died in FV arm vs. 21 in the FP arm, HR=0.71 (95% CI: 0.37 to 1.36). For those patients with measurable disease, clinical benefit rates were 41% and 43%, respectively, p=1.00. Serious adverse events were similar, 3.3% for FV vs. 5.9% for FP. Elevated baseline uNTx (>65 nM BCE/mmol Cr) was prognostic for PFS, HR=1.62 (95% CI: 1.08 to 2.43 and for mortality, HR= 2.4 (95% CI: 1.2 to 4.6). In an exploratory analysis uNTx was predictive of responsiveness to FV for PFS, HR=0.60 when uNTx >65 vs. HR=1.37 when uNTx <65, P = 0.025 for interaction. Conclusions: The addition of vandetanib to F did not improve biomarker response, PFS or OS compared to F alone in patients with bone predominant disease. Exploratory analyses confirmed that baseline bone turnover markers are prognostic for PFS and OS. Clinical trial information: NCT00811369.

Biopsy-driven study to identify biomarkers of drug resistance in patients with triple-negative breast cancer

87

Background: Resistance to chemotherapy is the underlying cause of death in most patients dying of breast cancer. Patients with early stages of breast cancer whose tumor is or becomes resistant to chemotherapy have a poor prognosis, while women with advanced breast cancer live as long as their tumors respond to chemotherapy. Because of the great difficulty of obtaining clinical samples from drug resistant tumors in patients, there is scant information about molecular factors from actual drug resistant tumors. This project aims to systematically profile resistant triple negative breast cancers (TNBCs) in order to discover molecular “resistance” genes/proteins as a first step to develop strategies to overcome drug resistance. Methods: Paired biopsies are collected from TNBC patients (NCT01276899). Four needle core biopsies are collected before the initiation of treatment and 2 weeks before surgery or at the time of progression in the neoadjuvant and metastatic settings respectively. Paired biopsies will undergo Next Gen Sequencing, flow sorted aCGH analysis, gene expression and miRNA profiling as well as phosphoproteomic profiling using reverse phase protein arrays. Results: We have currently enrolled 28 patients in the neoadjuvant setting and 3 metastatic patients. We have standardized the methods of collection and processing of tissue and blood specimens to ensure their molecular integrity and compatibility with different genomic and proteomic molecular platforms. Analysis of tumor cellularity has been incorporated into our quality control and we have optimized the extraction of nucleic acids to obtain high yields and optimal quality. In parallel, we have generated acquired resistance to paclitaxel in a panel of TNBC cell lines. These cell lines will also undergo genomic profiling and exome sequencing to identify molecular markers of resistance that will be correlated with the markers found in patient samples. Conclusions: This project will allow us to identify the molecular factors responsible for drug resistance in TNBCs and enable the elaboration of strategies to overcome resistance.

NSABP B-38: Definitive analysis of a randomized adjuvant trial comparing dose-dense (DD) AC→paclitaxel (P) plus gemcitabine (G) with DD AC→P and with docetaxel, doxorubicin, and cyclophosphamide (TAC) in women with operable, node-positive breast cancer

LBA1000

Background: The primary aims were to determine whether adjuvant DD AC→PG will be superior to DD AC→P as well as to TAC in DFS and to compare the relative DFS of TAC and DD AC→P. Secondary endpoints include survival and toxicity. Methods: From Nov 3, 2004 to May 3, 2007, 4894 women were randomized; 1630 to TAC (docetaxel [T] 75 mg/m2, doxorubicin [A] 50 mg/m2, cyclophosphamide [C] 500 mg/m2 q3 wks x 6), 1634 to DD AC→P (A 60 mg/m2 and C 600 mg/m2 q2 wks x 4 followed by P 175 mg/m2 q2 wks x 4), and 1630 to DD AC→PG (A 60 mg/m2 and C 600 mg/m2 q2 wks x 4 → P 175 mg/m2 + G 2000 mg/m2q2 wks x 4). Primary G-CSF support was required and erythropoiesis-stimulating agents (ESA) were used at investigator discretion. 52% were postmenopausal, 65% had 1 - 3 positive nodes, and 80% had HR+ breast cancer. Log-rank tests were used for pair-wise comparisons of the primary (DFS) and secondary (OS) endpoints among the three treatment arms. Results: With 64 months median follow-up, 5-year DFS in DD AC→PG group was 80.6% compared with 82.2% in DD AC→P group (HR=1.1; p=0.27) and 80.1 % (HR=0.97; p=0.71) in TAC group. 5-year OS was 90.8% in DD AC→PG group as compared with 89.1% (HR=.89; p=0.25) in DD AC→P group and 89.6 % (HR=0.90; p=0.32) in TAC group. HR for DFS and OS of DD AC→P vs. TAC were 0.89 (p=0.14) and 1.01 (p=0.92) respectively. Toxicities for TAC, DD AC→P, DD AC→PG, respectively: febrile neutropenia (Gr 3/4: 9%, 4%, 4% [p<0.001]), sensory neuropathy (Gr 3/4: <1%, 7%, 6% [p<0.001]), diarrhea (Gr 3/4: 8 %, 2%, 2% [p<0.001]). Hgb was <10 in 12%, 26%, 33% with ESA use in 35.2%, 47%, 51.6% and transfusions in 3.7%, 6.3%, 9.4%. Deaths on treatment: N=13, 5, 7 (p=0.2). AML/MDS: N=5, 8, 11. All cycles completed in 91% for TAC and 88% for DD regimens. Conclusions: Addition of G to DD AC→P did not improve outcomes. No significant differences in efficacy endpoints were identified between DD AC→P and TAC, though toxicity profiles differed. Funding: NCI PHS U10-CA-37377, -69974, -12027, -69651 and NCCTG U10-CA25224, with additional funding from Eli Lilly & Company, and Amgen, Inc.

Evaluation of lapatinib as a component of neoadjuvant therapy for HER2+ operable breast cancer: NSABP protocol B-41

LBA506

Background: The purposes of this trial are to determine the effect of substituting lapatinib (L) for trastuzumab (T) in combination with weekly paclitaxel (WP) following AC as well as adding L to T with WP following AC on pathologic complete response (pCR) rates. Methods: Women with HER2-positive operable breast cancer received standard AC q3wks x 4 cycles followed by WP (80 mg/m2) on days 1, 8, and 15 q28 days x 4 cycles. Concurrently with WP, patients received either T (4 mg/kg load, then 2 mg/kg) weekly until surgery, L (1250 mg) daily until surgery, or weekly T plus L (750 mg) daily until surgery. Following surgery, patients received trastuzumab to complete 52 wks of HER2-targeted therapy. The primary endpoint is pCR breast. For each of the two primary comparisons, the Fisher’s exact test was used to test the equality of pCR rates. A Hochberg-type step-up procedure was applied to address multiple testings and to control the family-wise error rate at 0.05. Results: 51% were clinically node positive and 63% had HR+ tumors. pCR assessments were available from 519 of 529 patients. pCR percentage was 52.5% for AC→WP+T, 53.2% (p=0.9) for AC→WP+L, and 62% (p=0.075) for AC→WP+TL. pCR percentages in the HR+ subset were 46.7%, 48% (p=0.85), and 55.6% (p=0.18), respectively, and were 65.5%, 60.6% (p=0.57), and 73% (p=0.37) in the HR- cohort. The corresponding pCR breast and nodes percentages were 49.1%, 47.4% (p=0.74), and 60.4% (p=0.04). Grade 3/4 toxicities include diarrhea in 2%, 20%, 27% (p<0.001), and symptomatic Gr 3/4 left ventricular systolic dysfunction in 4%, 4%, and 2% (p=0.49). Conclusions: Substitution of lapatinib for trastuzumab in combination with the chemotherapy program employed in this study resulted in similar high percentages of pCR in both HR+ and HR- cohorts. Combined HER2-targeted therapy produced a numerically higher pCR percentage than single agent HER2-directed therapy, but the difference was not statistically significant. Central review of HER2 and ER is being conducted to determine if subsets benefiting from the combined HER2-targeted therapy can be identified. Funding: GlaxoSmithKline.

Evaluation of lapatinib as a component of neoadjuvant therapy for HER2+ operable breast cancer: NSABP protocol B-41

LBA506

The full, final text of this abstract will be available at abstract.asco.org at 12:01 AM (EDT) on Sunday, June 3, 2012, and in the Annual Meeting Proceedings online supplement to the June 20, 2012, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Sunday edition of ASCO Daily News.

NSABP B-38: Definitive analysis of a randomized adjuvant trial comparing dose-dense (DD) AC followed by paclitaxel (P) plus gemcitabine (G) with DD AC followed by P and with docetaxel, doxorubicin, and cyclophosphamide (TAC) in women with operable, node-positive breast cancer

LBA1000

The full, final text of this abstract will be available at abstract.asco.org at 12:01 AM (EDT) on Monday, June 4, 2012, and in the Annual Meeting Proceedings online supplement to the June 20, 2012, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

Can MRI accurately identify which patients with operable breast cancer will have a pathologic complete response after neoadjuvant therapy?

616

Background: With the introduction of targeted therapy based on tumor subtypes, an increasing number of patients that receive neoadjuvant chemotherapy achieve a pathologic complete response (pCR). Previous studies have shown that the accuracy of MRI is poor at predicting the response to neoadjuvant chemotherapy in locally advanced and often non-resectable breast cancers, where the rate of pCR is low. The purpose of this study is to evaluate MRI’s ability to predict a pCR in operable breast cancers after neoadjuvant therapy. Methods: All patients enrolled in the NSABP B-40, B-41, FB-5 and FB-6 protocols in a single tertiary care centre, that had an MRI done before and after neoadjuvant therapy were reviewed. A radiologist, blinded to the pathology results, interpreted the pre- and post- treatment MRI’s and made a prediction as to whether or not patients would have a pCR. In this study, a true negative was defined as a reading of a complete response on MRI that was confirmed as a pCR on final pathology. pCR was defined as having no residual invasive or in situ disease in the breast. Results: 129 women with a median age of 51 years were identified. 90% had invasive ductal carcinoma; 8% had invasive lobular. 58% were ER+, 21% were triple negative and 21% were Her2+. 16% of patients had a pCR. 25% of patients had no residual invasive cancer in the breast. pCR rates for ER+ tumors was 5%, triple negative 37%, and Her2+ 26%. 19% of patients that had a pCR had a total mastectomy. The sensitivity and specificity of MRI for predicting residual disease were 88% and 52% respectively. The positive predictive value was 90% and the negative predictive value was 46% with an accuracy of 82%. Conclusions: MRI has limited value for determining which patients had a pCR after neoadjuvant chemotherapy, even in operable breast cancers. When residual disease is suspected on MRI, it is unlikely that a pCR has been achieved. Surgical excision following neoadjuvant therapy remains the gold standard to identify which patients have achieved a pCR. Other modalities will need to be used in order to accurately determine which patients would be eligible for studies evaluating non operative management following neoadjuvant therapy.

NSABP FB-6: Phase II trial of weekly paclitaxel (WP) and pazopanib following doxorubicin and cyclophosphamide (AC) as neoadjuvant therapy for HER2-negative locally advanced breast cancer (LABC)

1025

Background: Pazopanib is an oral, small molecule inhibitor of VEGFR-1, -2, and-3, PDGFR-α, and -β, and c-kit tyrosine kinases. The purpose of this trial was to determine the activity and safety profile of pazopanib when added to neoadjuvant WP following AC in LABC. The primary endpoint was pathologic complete response in the breast and nodes (pCR-BN). Methods: Women with HER2-negative stage IIIA-IIIC breast cancer were treated with AC (60 mg/m2/600 mg/m2) for 4 cycles every 3 weeks followed by WP 80 mg/m2 on days 1, 8, and 15 every 28 days for 4 cycles concurrently with pazopanib 800 mg orally daily prior to surgery. Postoperatively, pazopanib was given for 6 months. The regimen would be considered active if ≥14 responses (16% pCR rate in breast and nodes) were observed in 87 evaluable patients. Patients were considered evaluable if they received at least 1 dose of pazopanib. Results: Between July 2009 and March 2011, 101 pts (median age 51 yrs, range 30-71) were enrolled; 56% had stage IIIA, 34% stage IIIB, and 10% stage IIIC disease. 74 pts (73%) had ER-and/or PR-positive tumors and 27 pts (27%) were triple negative. 8 patients did not begin pazopanib. The pCR-BN rate in evaluable patients for whom surgical information was known was 18% (16/89). The pCR-BN rate in ER positive disease was 9% (6/65) and was 42% (10/24) in TNBC. Toxicities observed with WP and pazopanib included diarrhea (gr 2/3, 10%/5%), hand-foot syndrome (gr 2/3, 11%/1%), hypertension (gr 2/3, 12%/3%), neuropathy (gr 2/3, 14%/1%), and neutropenia (gr 3/4, 25%/1%). Liver toxicity during WP and pazopanib included ALT (gr 2/3/4, 13%/7%/1%), AST (gr 2/3, 7%/7%), and total bilirubin (gr 2, 2%). Conclusions: A regimen of WP and pazopanib following AC was active as neoadjuvant therapy in women with LABC and met the pre-specified criteria of interest. The activity in TNBC was notable. The toxicity profile of WP and pazopanib was consistent with previous experience. Support: GlaxoSmithKline.

Q-CROC-03: A prospective biopsy driven clinical trial to study the mechanisms of resistance to chemotherapy in triple-negative breast cancer patients

TPS1139

Background: Resistance to chemotherapy or targeted agents is the cause of death in most patients dying of breast cancer and one of the major challenges presently faced by oncologists. In triple negative breast cancers (TNBCs), drug resistance emerges quicker than in other breast cancer subtypes and contributes to the poor prognosis seen in these patients. The lack of targeted therapies to treat TNBC highlights the important need to better understand the molecular mechanisms contributing to chemotherapy resistance in order to develop new therapeutic strategies. However, the difficulty in obtaining tissue samples from drug resistant tumors has been one of the limiting factors in this field of study. Methods: We have designed a prospective phase II clinical trial where paired biopsies are collected from chemotherapy resistant TNBCs (NCT01276899). Four needle core biopsies are collected before the initiation of treatment and 2 weeks before surgery or at the time of progression in the neoadjuvant and metastatic settings respectively. Metastatic sites eligible for biopsy include liver, lung, skin and lymph nodes. This study is presently recruiting at 5 major health centers in Quebec and will soon open in the USA. We have currently enrolled 13 patients in the neoadjuvant setting and 2 metastatic patients. Major challenges in patient enrolment will be discussed. We have standardized the methods of collection and processing of tissue and blood specimens to ensure their molecular integrity and compatibility with different genomic and proteomic molecular platforms. Analysis of tumor cellularity has been incorporated into our quality control and we have optimized the extraction of nucleic acids to obtain high yields and optimal quality. Paired biopsies will undergo Next Gen Sequencing, flow sorted aCGH analysis, gene expression and miRNA profiling as well as phosphoproteomic profiling using reverse phase protein arrays. Collection of clinical data will allow molecular profiling data to be linked to clinical response data so as to determine DNA, RNA and protein factors correlated with tumor resistance to chemotherapy.

A prospective pilot study investigating the musculoskeletal pain in postmenopausal breast cancer patients receiving aromatase inhibitor therapy

BACKGROUND

Although arthralgia is a known adverse effect of aromatase inhibitor (ai) treatment in postmenopausal breast cancer patients, few studies have carried out a comprehensive evaluation of the nature, onset, and incidence of musculoskeletal (msk) pain in these patients. We therefore used a pilot study to identify conditions or markers predictive of pain.

METHODS

For 24 weeks, we monitored 30 eligible postmenopausal women starting ai therapy. Pre-existing and incident msk conditions and pain were assessed clinically and with ultrasonography of the hands and wrists. In addition, patient questionnaires were used to assess pain before and during ai therapy. Biochemical markers were measured at baseline and at regular intervals after anastrozole therapy began. Gene profiling studies were carried out before and 48 hours after the initial ai administration.

RESULTS

Over the 24-week study period, 20 participants (67%) showed no pain symptoms; 5 (17%) experienced low or moderate pain at baseline, which did not increase with ai treatment; and during therapy, 5 (17%) showed exacerbation of pain attributable to osteoarthritis of the hand and to finger flexor tenosynovitis. Although all 30 participants had some degree of msk conditions before anastrozole therapy started, the pre-existing conditions did not necessarily predispose the women to increased pain during anastrozole treatment. Higher levels of urinary N-telopeptides of type i collagen were associated with the groups presenting pain, suggesting a higher extent of pre-existing bone resorption, without significant evolution over the 24-week treatment period. Slightly higher levels of 1,25(OH)(2) vitamin D(3) were observed at baseline in patients with pain increase, but did not significantly change during treatment; however, average levels of 25(OH) vitamin D(3) increased, likely because of supplementation. Although biochemical markers did not discriminate efficiently between pain groups, a signature of 166 genes in peripheral blood mononuclear cells was identified that could stratify patients into the various groups observed in this pilot study. The gene signature was enriched in components of inflammatory signalling and chemokine expression, of antitumoural immunity pathways, and of metabolic response to hormones and xenobiotics, although no clinically significant association could be made in the present study, considering the small number of patients. Nevertheless, the observed trend suggests the feasibility of developing surrogate predictive markers of msk pain. Patient compliance was high in this study and was not affected by pain exacerbation.

CONCLUSIONS

Baseline msk assessment showed pre-existing causes for pain in most of the study patients before initiation of the ai. Exacerbation of existing osteoarthritis pain and tenosynovial symptoms was the primary cause of pain increase. Musculoskeletal pain assessment at baseline and prompt treatment of pain symptoms may help to optimize adherence to ai therapy. The value of routinely assessing inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate was not supported by our pilot study. Gene expression profiles in peripheral blood mononuclear cells may be further explored in larger-scale studies as stratification markers to identify patients at risk of developing arthralgia.

The effect on pCR of bevacizumab and/or antimetabolites added to standard neoadjuvant chemotherapy: NSABP protocol B-40

LBA1005

Background: The addition of capecitabine (X), gemcitabine (G), and bevacizumab (B) to taxanes have each improved PFS in metastatic breast cancer. The primary aims of this trial were to determine if adding X or G to docetaxel (T) → AC will increase breast pathologic complete response (pCR) rates in operable, HER2-negative breast cancer and if adding B to T-based regimens →AC will increase pCR rates. Secondary aims included assessment of clinical complete response (cCR) rates. Methods: Pts received one of 3 T-based regimens, with or without B, 15mg/kg, q3wks x 4: T 100 mg/m2 day 1; T 75 mg/m2 day 1 and X 825 mg/m2 BID days 1-14; or T 75 mg/m2 day 1 and G 1000 mg/m2 days 1 and 8. Pts then received preoperative AC x 4, with or without B for the initial 2 cycles of AC. Pts randomized to B resumed B for 10 postop doses. The primary endpoint was pCR in the breast. The maximum of the standardized pairwise differences between pCR rate for the T → AC regimen and for the other 2 T-based regimens was used as the test statistic to adjust for multiple comparisons. Fisher’s exact test was used to compare the arms with and without B. Results: The groups were balanced, with 47% clinically node+, 56% poorly differentiated, and 59% HR+. Assessments for pCR were available from 1180 of 1206 randomized patients. pCR for TX and TG were 29.7% and 32% vs. 32.7% for T. Neither TX nor TG increased cCR rates relative to T (58.3% and 60.4% vs. 61.5%). TX and TG increased toxicity. Addition of B increased the pCR rate (28.4 vs. 34.5%, p=0.027) and the cCR rate (55.8 vs. 64.3%, p=0.007). The effect of B was predominantly in the HR+ subset (15.2 vs. 23.3%, p=0.008) with minimal effect in the HR- subset (47.3% vs. 51.3%, p=0.44). Grades 2/3/4 toxicities increased with B were HTN (1/<1/0% vs. 13/9/<1%), HFS (11/7/0% vs. 15/11/0%), and mucositis (10/3/0% vs. 20/5/0%). Conclusions: The addition of B to neoadjuvant chemotherapy improved pCR and cCR rates, but the addition of X or G to T did not improve outcomes. Follow-up for wound healing issues and DFS will help define the role of B in the treatment of early breast cancer. Funded by NCI PHS grants U10-CA-37377, U10-CA-69974, U10-CA-12027, U10-CA-69651, and U10-CA-44066, and F. Hoffmann La-Roche, Ltd., Genentech, USA, and Eli Lilly.

Canadian Initiatives for Locally Advanced Breast Cancer Research and Treatment: Inaugural Meeting of the Canadian Consortium for LABC

The inaugural Canadian Consortium for LABC (locally advanced breast cancer) conference was held at Langdon Hall, Cambridge, Ontario, April 11–12, 2010. The meeting focused on current and future directions in labc treatment and research, the specific benefits of labc as a model for clinical and translational research, strategies for increased national and international collaboration, and ongoing clinical trials. Exciting Canadian initiatives in labc research are underway, focusing on identifying molecular signatures that will allow for the development of new tailored therapies. The challenge of identifying patient subgroups for accrual is being addressed through strategies to foster and improve national collaboration. This meeting report includes highlights from each presentation at the conference.

Use of aromatase inhibitors and bisphosphonates as an anticancer therapy in postmenopausal breast cancer

Breast cancer is a major cause of morbidity and mortality in postmenopausal women worldwide. Reducing the risk of distant disease recurrence is a primary goal of adjuvant endocrine therapy. As we await data from ongoing Phase III comparison trials, an emerging body of evidence demonstrates important differences between third-generation aromatase inhibitors, particularly with respect to potency and prevention of early distant metastases. Furthermore, a growing body of evidence demonstrates anticancer benefits of bisphosphonates in adjuvant breast cancer and other settings. This article outlines the proceedings from an Expert Panel meeting of regionally diverse breast cancer specialists regarding the appropriate use of aromatase inhibitors in postmenopausal hormone-responsive early breast cancer and bisphosphonates as anticancer therapy in adjuvant breast cancer.

The contribution of founder mutations to early-onset breast cancer in French-Canadian women

In an ethnically-homogeneous population, it is valuable to identify founder mutations in cancer-predisposing genes. Founder mutations have been found in four breast-cancer-predisposing genes in French-Canadian breast cancer families. The frequencies of the mutant alleles have been measured neither in a large series of unselected breast cancer patients from Quebec, nor in healthy controls. These estimates are necessary to measure their contribution to the hereditary burden of breast cancer in Quebec and to help develop genetic screening policies which are appropriate for the province. We studied 564 French-Canadian women with early-onset invasive breast cancer who were treated at a single Montreal hospital. Patients had been diagnosed at age 50 or less, and were ascertained between 2004 and 2008. We screened all 564 patients for nine founder mutations: four in BRCA1, three in BRCA2 and one each in PALB2 and CHEK2. We also studied 6433 DNA samples from newborn infants from the Quebec City area to estimate the frequency of the nine variant alleles in the French-Canadian population. We identified a mutation in 36 of the 564 breast cancer cases (6.4%) and in 35 of 6443 controls (0.5%). In the breast cancer patients, the majority of mutations were in BRCA2 (54%). However, in the general population (newborn infants), the majority of mutations were in CHEK2 (54%). The odds ratio for breast cancer to age 50, given a BRCA1 mutation, was 10.1 (95% CI: 3.7-28) and given a BRCA2 mutation was 29.5 (95% CI: 12.9-67). The odds ratio for breast cancer to age 50, given a CHEK2 mutation, was 3.6 (95% CI: 1.4-9.1). One-half of the women with a mutation had a first- or second-degree relative diagnosed with breast or ovarian cancer. Thus, it can be concluded that a predisposing mutation in BRCA1, BRCA2, CHEK2 or PALB2 is present in approximately 6% of French-Canadian women with early-onset breast cancer. It is reasonable to offer screening for founder mutations to all French-Canadian women with breast cancer before age 50. The frequency of these mutations in the general population (0.5%) is too low to advocate population-based screening.

The Contribution of Founder Mutations to Early-Onset Breast Cancer in French-Canadian Women

Background: In an ethnically-homogeneous population, it is valuable to identify founder mutations in cancer-predisposing genes. Founder mutations have been found in four breast cancer predisposing genes in French-Canadian breast cancer families. The frequencies of the mutant alleles have not been measured in a large series of unselected breast cancer patients from Quebec, nor in healthy controls. These estimates are necessary to measure their contribution to the hereditary burden of breast cancer in Quebec and to help develop genetic screening policies which are appropriate for the province.Methods: We studied 564 French-Canadian women with early-onset invasive breast cancer who were treated at a single Montreal hospital. Patients had been diagnosed at age 50 or less, and were ascertained between 2004 and 2008. We screened all 564 patients for nine founder mutations; four in BRCA1, three in BRCA2 and one each in PALB2 and CHEK2. We also studied 6433 DNA samples from newborn infants from the Quebec City area to estimate the frequency of the nine variant alleles in the French-Canadian population.Results: We identified a mutation in 36 of the 564 breast cancer cases (6.4%) and in 35 of 6443 controls (0.5%). In the breast cancer patients, the majority of mutations were in BRCA2 (54%). However, in the general population (newborn infants), the majority of mutations were in CHEK2 (54%). The odds ratio for breast cancer to age 50, given a BRCA1 mutation was 10.1 (95% CI: 3.7 to 28) and given a BRCA2 mutation was 29.5 (95% CI: 12.9 – 67). The odds ratio for breast cancer to age 50, given a CHEK2 mutation was 3.6 (95% CI: 1.4 – 9.1). One-half of the women with a mutation had a first or second-degree relative diagnosed with breast or ovarian cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 902.

Bevacizumab beginning concurrently with a sequential regimen of doxorubicin and cyclophosphamide followed by docetaxel and capecitabine as neoadjuvant therapy followed by postoperative bevacizumab alone for women with HER2-negative locally advanced breast cancer (LABC): A phase II trial of the NSABP Foundation Research Group

584

Background: Bevacizumab with chemotherapy improves outcomes in patients with metastatic breast cancer. The purpose of this trial was to determine the activity and safety profile of bevacizumab with chemotherapy in women with LABC. Methods: Between November 2006 and August 2007, 45 women with HER-2 negative LABC initiated preoperative standard AC x 4 followed by docetaxel 75 mg/m2 IV and capecitabine 825 mg/m2 BID days 1–14 (TX) every 21 days for 4 cycles. Bevacizumab 15 mg/kg IV was given concurrently with chemotherapy every 21 days for a total of 6 preoperative doses. Postoperatively, bevacizumab was resumed for a total of 10 doses. Primary endpoint was pathologic complete response rate (pCR) in the breast. The secondary endpoints include clinical response rates and toxicity. Results: The median age was 50 yrs (range 30–78). 30 patients had stage IIIA (67%), 12 stage IIIB (27%), and 3 stage IIIC (7%) disease. Of these, 10 (22%) had inflammatory breast cancer. 27 patients (60%) had ER-positive disease. A pCR in the breast was documented in 4/44 (9%) patients, which included negative axillary nodes. A complete clinical response was noted in 14/45 (31%). One patient did not have surgery due to progression. Toxicities included hand-foot (grade 2/3–33%/22%), mucositis (grade 2/3–49%/27%), and febrile neutropenia (grade 3–24%). Conclusions: This regimen demonstrated only modest activity with substantial toxicity, and does not appear to warrant further evaluation. This clinical trial is being conducted through the support of Genentech and Roche.

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Lifestyle, weight history, nutrition and breast cancer among non-gene carriers: a case-control study

Abstract #6084

We conducted a nested case-control study of 280 French-Canadian women with breast cancer who were non-gene carriers (BRCA) and 280 women without cancer who were also non-gene carriers. A validated lifestyle questionnaire and a food frequency questionnaire were administered to obtain relevant information. It was found that age at the time the subjects reached maximum body mass index (BMI) was significantly associated with breast cancer risk [OR=2.83; 95% CI: (2.34-2.81)]. In addition, a significant association was noted between maximum weight gain at age 20 years [OR=1.68; 95% CI: (1.10-2.58)], 30 years [OR=1.96; 95% CI: (1.46-3.06)], and 40 years [OR=2.50; 95% CI: (1.72-3.97)] and breast cancer risk. Women who smoked more than 9 pack-years of cigarettes had a higher risk of breast cancer [OR=1.59; 95% CI: (1.57-2.87)]. Subjects who engaged in moderate physical activity had a 52% decreased risk of breast cancer [OR=0.48; 95% CI: (0.31-0.74)], but this was not evident for vigorous physical activity. It was observed that total energy intake was significantly associated with breast cancer risk [OR=2.54; 95% CI: (1.67-3.84)]. Women who drank more than 8 cups of coffee per day had 40% more chance of developing breast cancer [OR=1.40 (95% CI: (1.09-2.24)]. Subjects who consumed more than 9 grams of alcohol (ethanol) per day had the highest risk of breast cancer [OR=1.55 (95% CI: (1.02-2.37)]. None of the other nutrients and dietary components was significantly associated with non-gene carrier breast cancer risk. This study suggests that BMI, maximum weight gain during the second, third and fourth decades, smoking, total energy intake, and high intake of both alcohol and coffee may increase the risk of breast cancer among non-gene carrier French-Canadian women, while moderate physical activities may reduce the risk.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6084.

Germline RAP80 mutations and susceptibility to breast cancer

Most of the breast cancer susceptibility genes identified to date are involved in DNA repair, including BRCA1, BRCA2, PALB2, CHEK2 and BRIP1. RAP80 works upstream of BRCA1 and is essential for the localization of BRCA1 to the site of damaged DNA. To investigate whether or not RAP80 is also a breast cancer susceptibility gene, we sequenced the entire exonic regions of RAP80 in the germline DNA of 152 women with familial breast cancer, who were previously found to be negative for BRCA1 and BRCA2 mutations. No truncating mutation was identified. Eleven potentially deleterious RAP80 variants were identified; these 11 variants were genotyped in 424 more familial cases and in 726 healthy controls. Three novel p.Ala342Thr, p.Met353Thr and p.Tyr575Asp rare missense variants and a novel haplotype composed of two variants in the CpG island (c.-24149G > T and c.-24001A > G) and a variant in the 5'UTR (c.-8A > G) and a variant in the 3'UTR (c.*27A > C) were detected in 26 of 571 (4.6%) individuals with familial breast cancer, compared to 14 of 725 (1.9%) controls (P = 0.01; OR = 2.4, 95% CI = 1.2-5.1). In summary, we did not find truncating mutations of the RAP80 gene to be a cause of familial breast cancer. A novel RAP80 haplotype or rare missense mutations may be associated with a modest increased risk of breast cancer, but this observation needs to be confirmed by additional studies.