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.

Long-term efficacy and safety of addition of carboplatin with or without veliparib to standard neoadjuvant chemotherapy in triple-negative breast cancer: 4-year follow-up data from BrighTNess, a randomized phase 3 trial

BACKGROUND

Primary analyses of the phase 3 BrighTNess trial showed addition of carboplatin with/without veliparib to neoadjuvant chemotherapy significantly improved pathological complete response (pCR) rates with manageable acute toxicity in patients with triple-negative breast cancer (TNBC). Here, we report 4.5-year follow-up data from the trial.

DESIGN

Women with untreated stage II-III TNBC were randomized (2:1:1) to paclitaxel (weekly for 12 doses) plus either: (a) carboplatin (every 3 weeks for four cycles) plus veliparib (twice daily); (b) carboplatin plus veliparib placebo; or (c) carboplatin placebo plus veliparib placebo. All patients then received doxorubicin and cyclophosphamide (AC) every 2‒3 weeks for four cycles. The primary endpoint was pCR. Secondary endpoints included event-free survival (EFS), overall survival (OS), and safety. Since the co-primary endpoint of increased pCR with carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel was not met, secondary analyses are descriptive.

RESULTS

Of 634 patients, 316 were randomized to carboplatin plus veliparib with paclitaxel, 160 to carboplatin with paclitaxel, and 158 to paclitaxel. With median follow-up of 4.5 years, the hazard ratio [HR] for EFS for carboplatin plus veliparib with paclitaxel versus paclitaxel was 0.63 (95% confidence interval [CI] 0.43‒0.92, P=0.02), but 1.12 (95% CI 0.72‒1.72, P=0.62) for carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel. In post hoc analysis, HR for EFS was 0.57 (95% CI 0.36‒0.91, P=0.02) for carboplatin with paclitaxel versus paclitaxel. OS did not differ significantly between treatment arms, nor did rates of myelodysplastic syndromes, acute myeloid leukemia, or other secondary malignancies.

CONCLUSION

Improvement in pCR with addition of carboplatin was associated with long-term EFS benefit with a manageable safety profile, and without increasing the risk of second malignancies, while adding veliparib did not impact EFS. These findings support the addition of carboplatin to weekly paclitaxel followed by AC neoadjuvant chemotherapy for early stage TNBC.

Adjuvant T-DM1 versus trastuzumab in patients with residual invasive disease after neoadjuvant therapy for HER2-positive breast cancer: subgroup analyses from KATHERINE

BACKGROUND

In the KATHERINE study (NCT01772472), patients with residual invasive early breast cancer (EBC) after neoadjuvant chemotherapy (NACT) plus human epidermal growth factor receptor 2 (HER2)-targeted therapy had a 50% reduction in risk of recurrence or death with adjuvant trastuzumab emtansine (T-DM1) versus trastuzumab. Here, we present additional exploratory safety and efficacy analyses.

PATIENTS AND METHODS

KATHERINE enrolled HER2-positive EBC patients with residual invasive disease in the breast/axilla at surgery after NACT containing a taxane (± anthracycline, ± platinum) and trastuzumab (± pertuzumab). Patients were randomized to adjuvant T-DM1 (n = 743) or trastuzumab (n = 743) for 14 cycles. The primary endpoint was invasive disease-free survival (IDFS).

RESULTS

The incidence of peripheral neuropathy (PN) was similar regardless of neoadjuvant taxane type. Irrespective of treatment arm, baseline PN was associated with longer PN duration (median, 105-109 days longer) and lower resolution rate (∼65% versus ∼82%). Prior platinum therapy was associated with more grade 3-4 thrombocytopenia in the T-DM1 arm (13.5% versus 3.8%), but there was no grade ≥3 hemorrhage in these patients. Risk of recurrence or death was decreased with T-DM1 versus trastuzumab in patients who received anthracycline-based NACT [hazard ratio (HR) = 0.51; 95% confidence interval (CI): 0.38-0.67], non-anthracycline-based NACT (HR = 0.43; 95% CI: 0.22-0.82), presented with cT1, cN0 tumors (0 versus 6 IDFS events), or had particularly high-risk tumors (HRs ranged from 0.43 to 0.72). The central nervous system (CNS) was more often the site of first recurrence in the T-DM1 arm (5.9% versus 4.3%), but T-DM1 was not associated with a difference in overall risk of CNS recurrence.

CONCLUSIONS

T-DM1 provides clinical benefit across patient subgroups, including small tumors and particularly high-risk tumors and does not increase the overall risk of CNS recurrence. NACT type had a minimal impact on safety.

Evaluation of the change of outcomes over a 10-year period in patients with stage III colon cancer: pooled analysis of 6501 patients treated with fluorouracil, leucovorin, and oxaliplatin in the ACCENT database

BACKGROUND

Since 2004, adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX or FLOX) have been the standard of care for patients with resected colon cancer. Herein we examine the change of outcomes over a 10-year period in patients with stage III colon cancer who received this regimen.

PATIENTS AND METHODS

Individual patient data from the ACCENT database was used to compare the outcomes in older (1998-2003) and newer (2004-2009) treatment eras for patients with stage III colon cancer who received adjuvant FOLFOX or FLOX. The outcomes were compared between the two groups by the multivariate Cox proportional-hazards model adjusting for age, sex, performance score, T stage, N stage, tumor sidedness, and histological grade.

RESULTS

A total of 6501 patients with stage III colon cancer who received adjuvant FOLFOX or FLOX in six randomized trials were included in the analysis. Patients enrolled in the new era group experienced statistically significant improvement in time to recurrence [3-year rate, 76.1% versus 73.0%; adjusted hazard ratio (HRadj) = 0.83 (95% CI, 0.74-0.92), P = 0.0008], disease-free survival (DFS) [3-year rate, 74.7% versus 72.3%; HRadj = 0.88 (0.79-0.98), P = 0.024], survival after recurrence (SAR) [median time, 27.0 versus 17.7 months; HRadj = 0.65 (0.57-0.74), P < 0.0001], and overall survival (OS) [5-year rate, 80.9% versus 75.7%; HRadj = 0.78 (0.69-0.88), P < 0.0001]. The improved outcomes remained in patients diagnosed at 45 years of age or older, low-risk patients (T1-3 and N1), left colon, mismatch repair proficient (pMMR), BRAF, and KRAS wild-type tumors.

CONCLUSION

Improved outcomes were observed in patients with stage III colon cancer enrolled in clinical trials who received adjuvant FOLFOX/FLOX therapy in 2004 or later compared with patients in the older era. Prolonged SAR calls for revalidation of 3-year DFS as the surrogate endpoint of OS in adjuvant clinical trials and reevaluation of optimal follow-up of OS to confirm the trial findings based on the DFS endpoints.

CLINICAL TRIALS NUMBERS

NCT00079274; NCT00096278; NCT00004931; NCT00275210; NCT00265811; NCT00112918.

Prognosis of microsatellite instability and/or mismatch repair deficiency stage III colon cancer patients after disease recurrence following adjuvant treatment: results of an ACCENT pooled analysis of seven studies

BACKGROUND

Microsatellite instable/deficient mismatch repair (MSI/dMMR) metastatic colorectal cancers have been reported to have a poor prognosis. Frequent co-occurrence of MSI/dMMR and BRAFV600E complicates the association.

PATIENTS AND METHODS

Patients with resected stage III colon cancer (CC) from seven adjuvant studies with available data for disease recurrence and MMR and BRAFV600E status were analyzed. The primary end point was survival after recurrence (SAR). Associations of markers with SAR were analyzed using Cox proportional hazards models adjusted for age, gender, performance status, T stage, N stage, primary tumor location, grade, KRAS status, and timing of recurrence.

RESULTS

Among 2630 patients with cancer recurrence (1491 men [56.7%], mean age, 58.5 [19-85] years), multivariable analysis revealed that patients with MSI/dMMR tumors had significantly longer SAR than did patients with microsatellite stable/proficient MMR tumors (MSS/pMMR) (adjusted hazard ratio [aHR], 0.82; 95% CI [confidence interval], 0.69-0.98; P = 0.029). This finding remained when looking at patients treated with standard oxaliplatin-based adjuvant chemotherapy regimens only (aHR, 0.76; 95% CI, 0.58-1.00; P = 0.048). Same trends for SAR were observed when analyzing MSI/dMMR versus MSS/pMMR tumor subgroups lacking BRAFV600E (aHR, 0.84; P = 0.10) or those harboring BRAFV600E (aHR, 0.88; P = 0.43), without reaching statistical significance. Furthermore, SAR was significantly shorter in tumors with BRAFV600E versus those lacking this mutation (aHR, 2.06; 95% CI, 1.73-2.46; P < 0.0001), even in the subgroup of MSI/dMMR tumors (aHR, 2.65; 95% CI, 1.67-4.21; P < 0.0001). Other factors associated with a shorter SAR were as follows: older age, male gender, T4/N2, proximal primary tumor location, poorly differentiated adenocarcinoma, and early recurrence.

CONCLUSIONS

In stage III CC patients recurring after adjuvant chemotherapy, and before the era of immunotherapy, the MSI/dMMR phenotype was associated with a better SAR compared with MSS/pMMR. BRAFV600E mutation was a poor prognostic factor for both MSI/dMMR and MSS/pMMR patients.

TRIAL IDENTIFICATION NUMBERS

NCT00079274, NCT00265811, NCT00004931, NCT00004931, NCT00026273, NCT00096278, NCT00112918.

Abstract GS4-04: Primary results of NSABP B-39/RTOG 0413 (NRG Oncology): A randomized phase III study of conventional whole breast irradiation (WBI) versus partial breast irradiation (PBI) for women with stage 0, I, or II breast cancer

Background: Conventional WBI after lumpectomy for early-stage breast cancer decreases ipsilateral breast tumor recurrence (IBTR), yielding comparable results to mastectomy. Accelerated PBI appears effective in reducing IBTR by treating only the tumor bed area. As the majority of IBTR occur at or in the vicinity of the tumor bed, we hypothesized that PBI would be as effective as WBI in controlling IBTR. The primary aim of NSABP B-39/RTOG 0413 was to determine if PBI provides equivalent local tumor control post lumpectomy compared to WBI in pts with early-stage breast cancer. The equivalency test was based on a 50% margin of increase in the hazard ratio (HR=1.5). Secondary endpoints included: overall survival (OS), recurrence-free interval (RFI), distant disease-free interval (DDFI), and toxicity.

Methods: Eligible pts had lumpectomy with histologically-free margins and 0-3 positive axillary nodes. Pts were stratified by stage, menopausal status, hormone receptor status, and intent to receive chemotherapy and then randomized to PBI or WBI. PBI was 10 fractions of 3.4-3.85 Gy, given twice daily with either brachytherapy or 3D external beam radiation. WBI was 50 Gy in 2 Gy fractions given daily with a sequential boost to the surgical cavity. Follow-up was every 6 mos for 5 yrs and then annually. All analyses were by intent-to-treat.

Results: From 3-21-05 to 4-16-13, 4216 pts were randomized: 2107 PBI; 2109 WBI. 61% were postmenopausal; 81% were hormone receptor-positive; 29% intended to receive chemotherapy. Stage distribution was: DCIS, 24%; invasive pN0, 65%; invasive pN1, 10%. As of 7-31-18, median follow-up was 10.2 yrs. There were 161 IBTRs as first events: 90 PBI v 71 WBI (HR 1.22; 90%CI 0.94-1.58). Per protocol-defined margin, to declare PBI and WBI equivalent regarding IBTR risk, the 90% CI for the observed HR had to lie entirely between 0.667 and 1.5. The percent of pts IBTR-free at 10 yrs was 95.2% PBI v 95.9% WBI. A statistically significant difference in the 10-yr RFI rate favored WBI (91.9% PBI v 93.4% WBI; HR 1.32; 95%CI 1.04-1.68; p=0.02). No statistically significant differences existed between PBI and WBI in DDFI (HR 1.31; 95%CI 0.91-1.91; p=0.15), OS (HR 1.10; 95%CI 0.90-1.35; p=0.35), or DFS (HR 1.12; 95%CI 0.98-1.29; p=0.11). Grade 3 toxicity was 9.6% PBI v 7.1% WBI, and grade 4-5 toxicity was 0.5% v 0.3%, respectively.

Discussion: PBI did not meet the criteria for equivalence to WBI in controlling IBTR based on the upper limit of the hazard ratio confidence interval. However, the absolute difference in 10-yr rate of IBTR was &lt;1% (4.8% PBI v 4.1% WBI). The risk of an RFI event was statistically significantly higher for PBI compared to WBI, but the absolute difference in 10-yr RFI rate was also small (8.1% PBI v 6.6% WBI). DDFI, OS, and DFS were not statistically different for PBI v WBI. Grade 3-5 toxicities, although low, were more common for PBI than WBI. The trial population was heterogeneous, ranging from Stage 0-2 breast cancer, and outcome by risk categories are being analyzed.

Support: U10CA180868, -180822, UG1CA189867.

Citation Format: Vicini FA, Cecchini RS, White JR, Julian TB, Arthur DW, Rabinovitch RA, Kuske RR, Parda DS, Ganz PA, Scheier MF, Winter KA, Paik S, Kuerer HM, Vallow LA, Pierce LJ, Mamounas EP, Costantino JP, Bear HD, Germaine I, Gustafson G, Grossheim L, Petersen IA, Hudes RS, Curran, Jr. WJ, Wolmark N. Primary results of NSABP B-39/RTOG 0413 (NRG Oncology): A randomized phase III study of conventional whole breast irradiation (WBI) versus partial breast irradiation (PBI) for women with stage 0, I, or II breast cancer [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 GS4-04.

Abstract OT3-05-01: A randomized double-blind phase III clinical trial of neoadjuvant chemotherapy (NAC) with atezolizumab or placebo in patients (pts) with triple negative breast cancer (TNBC) followed by adjuvant atezolizumab or placebo: NSABP B-59/GBG 96-GeparDouze

Background:

TNBC is associated with higher percentages of pathological complete response (pCR) to neoadjuvant chemotherapy (NAC), and women with a pCR have a favorable prognosis. However, Liedtke (2008) and Loibl (2017) found that women with residual disease have a substantially higher risk of recurrence than women with other subtypes of breast cancer. Additionally, Adams (2017) and Schmid (2017) found that therapeutic blockade of PD-L1 binding by atezolizumab has resulted in relevant anti-tumor efficacy.

Methods:

Design

This is a phase III, double blind, placebo-control trial evaluating neoadjuvant atezolizumab with NAC followed by adjuvant atezolizumab in TNBC. Pts are stratified by region (North America; Europe), tumor size (1.1-3.0cm; &gt;3.0cm), AC/EC schedule (q2w; q3w), and nodal status (positive; negative), then randomized 1:1 to receive atezolizumab/placebo 1200 mg IV every 3 wks concurrently with both sequential regimens of weekly paclitaxel 80 mg/m2 IV for 12 doses with every 3-wk carboplatin AUC of 5 IV for 4 doses followed by AC/EC every 2-3 wks (per investigator discretion) for 4 cycles. Following surgery, pts resume atezolizumab/placebo 1200 mg IV every 3 wks as adjuvant therapy for 6 months. Radiotherapy based on local standards is co-administered with atezolizumab/placebo.

Eligibility criteria

Centrally-confirmed ER-neg, PR-neg, HER2-neg invasive breast cancer by ASCO/CAP guidelines. Primary tumor must be stage T2 or T3 if cN0 or cN1 with negative biopsy or T1c, T2, or T3 if cN1 with positive biopsy or cN2 or cN3. LVEF &gt;55% and no significant cardiac history.

Statistical methods

Co-primary endpoints are event-free survival (EFS) and pCR breast/nodes. Secondary endpoints include pCR breast, overall survival, distant disease-free survival, safety and toxicity. Trial is an academic collaboration between NSABP and GBG with support from Genentech/Roche.

NCT03281954

Support: Genentech/Roche

Citation Format: Geyer, Jr. CE, Loibl S, Rastogi P, Seiler S, Costantino JP, Nekljudova VN, Cortazar P, Lucas PC, Denkert C, Mamounas EP, Jackisch C, Wolmark N. A randomized double-blind phase III clinical trial of neoadjuvant chemotherapy (NAC) with atezolizumab or placebo in patients (pts) with triple negative breast cancer (TNBC) followed by adjuvant atezolizumab or placebo: NSABP B-59/GBG 96-GeparDouze [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 OT3-05-01.

Abstract P3-10-04: The fully validated NSABP/NRG 8-gene signature which predicted the degree of benefit in the adjuvant setting (B-31 and NCCTG N9831) associates with pCR in the neoadjuvant setting in NSABP clinical trial FB-7

Background: We previously described a predictive signature for trastuzumab benefit which was validated in the adjuvant setting in an independent cohort within NSABP B-31 (the 8-gene signature) (Pogue-Geile et al JNCI, 2013) and in Alliance/NCCTG N9831 (SABCs 2017). The 8-gene signature subtyped B-31 patients into three trastuzumab benefit groups: high HR=0.27, intermediate HR=0.56 and no benefit HR=1.56 based on disease free survival. The 8 gene signature was also predictive of trastuzumab benefit in N9831. HRs were 0.47, P&lt;0.001, 0.6, P=0.02, and 1.54, P=0.375 in the predicted-high, -intermediate and -no benefit groups, respectively based on recurrence free survival (SABCS 2017). The interaction P-value was significant at 0.019 in adjusted Cox models. The RFS at 10 years for trastuzumab-treated pts was 83%, 83% and 72% in the high, intermediate and no benefit groups, respectively. Now we have tested the association of the 8-gene signature groups with pCR in FB-7 which was a 3 arm neoadjuvant study testing the pCR rate of HER2+ breast cancer patients treated with paclitaxel in combination with trastuzumab (T) or neratinib (N) or the combination (T + N).

Methods: RNA-Seq data from FB-7 pretreatment biopsies was used to predict the trastuzumab benefit groups (high, intermediate, and no) for each patient's tumor using the 8 gene signature using methods and cut-offs as previously described (Pogue-Geile et al 2013). The pCR rates (percentages) were tested for treatment interaction with a chi-square test.

Results: The pCR rates were 75%, 53%, and 22%, in the high (N=12), intermediate (N=32) and no benefit groups (N=9), respectively, when analyzed without regard to treatment arm. The pCR rates for the no benefit group and the high benefit groups were significantly different (p=0.030) and there was a significant treatment interaction with the 8-gene benefit group (intp=0.0081). The predicted low and intermediate groups were combined to test whether the 8 gene signature could identify a group of patients whose pCR rates might improve by adding N to T, and referred to it as the low benefit group. This was necessary due to the small numbers of patients in each group. The pCR rate in the low benefit group was higher in patients treated with T+N (9/15, 60%) than in the T arm (6/11, 45%) but these differences were not significant.

Conclusions: This is the first test of the 8-gene signature in the neoadjuvant setting and interpretations of these data should be interpreted cautiously due to the small numbers. However, if these results were validated in another neoadjuvant trial then the 8 gene signature could provide a rationale for selecting patients who would be appropriate for the addition of neratinib or other TKIs to trastuzumab and chemotherapy.

SUPPORT: PUMA Biotechnology, NCI U10CA180868, -180822, UG1-189867, and U24-196067; The Pennsylvania Department of Health. The Department specifically disclaims responsibility for any analysis,interpretations, or conclusions.

Citation Format: Pogue-Geile KL, Wang Y, Srinivasan A, Gavin PG, Kim RS, Song N, Feng H, Lipchik C, Costantino JP, Wolmark N, Lucas PC, Paik S, Jacobs SA. The fully validated NSABP/NRG 8-gene signature which predicted the degree of benefit in the adjuvant setting (B-31 and NCCTG N9831) associates with pCR in the neoadjuvant setting in NSABP clinical trial FB-7 [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 P3-10-04.

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 OT2-04-01: Phase III trial to determine if chest wall and regional nodal radiotherapy (CWRNRT) post mastectomy (Mx) or the addition of RNRT to whole breast RT post breast-conserving surgery (BCS) reduces invasive breast cancer recurrence-free interval (IBCR-FI) in patients (pts) with pathologically positive axillary (PPAx) nodes who are ypN0 after neoadjuvant chemotherapy (NC): NRG Oncology/NSABP B-51/RTOG 1304

This phase III post-NC trial evaluates if CWRNRT post-Mx or whole breast irradiation (WBI) with RNRT after BCS significantly reduces the IBCR-FI rate in pts with PPAx nodes that are pathologically negative after NC. Secondary aims are OS, LRR-FI, DR-FI, DFS-DCIS, second primary cancer, and comparison of RT effect on cosmesis in reconstructed Mx pts. Correlative science examines RT effect by tumor subtype, molecular outcome predictors for residual disease, and predictors for the degree of reduction in loco-regional recurrence.

Methods: Clinical T1-3, N1 IBC PPAx nodes (FNA or core needle biopsy) pts complete ≥8 weeks of NC (anthracycline and/or taxane). HER2+ pts receive anti-HER2 therapy. Following NC, BCS or Mx, sentinel node biopsy (≥2 nodes) and/or Ax dissection with histologically negative nodes is performed. ER/PR and HER-2neu status before NC is required. Pts may receive appropriate adjuvant systemic therapy. Radiation credentialing with a facility questionnaire/case benchmark is required. Random assignment for Mx pts is to no CWRNRT or CWRNRT and for BCS pts to WBI or WBI+RNRT.

Statistics: 1,636 pts are to be enrolled over 5 yrs (definitive analysis at 7.5 yrs). Study is powered at 80% to test that RT reduces the annual hazard rate of events for IBCR-FI by 35% for an absolute risk reduction of 4.6% (5-yr cumulative rate). Intent-to-treat analysis with 3 interim analyses (43, 86, and 129 events) and a 4th/final analysis at 172 events. Pt-reported outcomes focusing on RT effect will be provided by 736 pts before random assignment and at 3, 6, 12, and 24 mos. Accrual as of 6-21-18 is 967 (59.11%).

Contacts: Protocol: CTSU member website https://www.ctsu.org. Questions: NRG Oncology Pgh Clin Coord Dpt: 1-800-477-7227 or ccd@nsabp.org. Pt entry: OPEN at https://open.ctsu.org or the OPEN tab on CTSU member website.

NCT01872975

Support: U10 CA-2166; -180868, -180822; 189867; Elekta

Citation Format: Mamounas EP, Bandos H, White JR, Julian TB, Khan AJ, Shaitelman SF, Torres MA, Vicini FA, Ganz PA, McCloskey SA, Paik S, Gupta N, Li XA, DiCostanzo DJ, Curran WJ, Wolmark N. Phase III trial to determine if chest wall and regional nodal radiotherapy (CWRNRT) post mastectomy (Mx) or the addition of RNRT to whole breast RT post breast-conserving surgery (BCS) reduces invasive breast cancer recurrence-free interval (IBCR-FI) in patients (pts) with pathologically positive axillary (PPAx) nodes who are ypN0 after neoadjuvant chemotherapy (NC): NRG Oncology/NSABP B-51/RTOG 1304 [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 OT2-04-01.

Abstract OT2-03-01: NRG oncology/NSABP B-51/RTOG 1304: A phase III superiority clinical trial designed to determine if chest wall and regional nodal radiotherapy (CWRNRT) post mastectomy (Mx) or the addition of RNRT to breast RT post breast-conserving surgery (BCS) will reduce invasive cancer events in patients (pts) with positive axillary (Ax) nodes and convert to ypN0 after neoadjuvant chemotherapy (NC)

Background:

This phase III post-NC trial evaluates if CWRNRT post Mx or whole breast irradiation (WBI) with RNRT after BCS significantly reduces the invasive breast cancer recurrence-free interval (IBC-RFI) rate in pts presenting with positive Ax nodes that are pathologically negative after NC. Secondary aims are OS, LRRFI, DRFI, DFS-DCIS, and second primary cancer, as well as comparing RT effect on cosmesis in reconstructed Mx pts.

Correlative science studies examine RT effect by tumor subtype, molecular outcome predictors for residual disease pts, and predictors for the degree of reduction in loco-regional recurrence.

Methods:

Clinical T1-3, N1 IBC pts with positive Ax nodes (FNA or core needle biopsy) complete ≥8 wks of NC (anthracycline and/or taxane). HER2-positive pts receive anti-HER2 therapy (tx). After NC, BCS or Mx is performed with a sentinel node biopsy (≥2 nodes) and/or Ax dissection with histologically negative nodes. ER/PR and HER2 neu status before NC is required. Pts receive required systemic tx. Radiation credentialing with a facility questionnaire and a case benchmark is required. Randomization for Mx pts is to no CWRNRT or CWRNRT and for BCS pts to WBI or WBI+RNRT.

Statistics:

1636 pts to be enrolled over 5 yrs with definitive analysis at 7.5 yrs. Study is powered at 80% to test that RT reduces the annual hazard rate of events for IBCR-FI by 35% for an absolute risk reduction in the 5-yr cumulative rate of 4.6%. Intent-to-treat analysis with 3 interim analyses at 43, 86, and 129 events, with a 4th/final analysis at 172 events will occur. Accrual as of 6/13/16 is 356. Pt-reported outcomes focusing on RT effect will be obtained from 736 pts before randomization and at 3, 6, 12, and 24 months.

Contacts:

Protocol: CTSU member website https://www.ctsu.org. Questions: NRG Oncology Pgh Clin Coord Dpt: 1-800-477-7227 or ccd@nsabp.org. Pt entry: OPEN at https://open.ctsu.org or the OPEN tab on CTSU member website.

Support: U10 CA-2166; -180868, -180822; -189867; Elekta.

Citation Format: Mamounas EP, Bandos H, White JR, Julian TB, Khan AJ, Shaitelman SF, Torres MA, Vicini FA, Ganz PA, McCloskey SA, Paik S, Gupta N, Li XA, DiCostanzo DJ, Curran, Jr WJ, Wolmark N. NRG oncology/NSABP B-51/RTOG 1304: A phase III superiority clinical trial designed to determine if chest wall and regional nodal radiotherapy (CWRNRT) post mastectomy (Mx) or the addition of RNRT to breast RT post breast-conserving surgery (BCS) will reduce invasive cancer events in patients (pts) with positive axillary (Ax) nodes and convert to ypN0 after neoadjuvant chemotherapy (NC) [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 OT2-03-01.

Abstract S6-04: Patient-reported outcome (PRO) results, NRG Oncology/NSABP B-35: A clinical trial of anastrozole (A) vs tamoxifen (tam) in postmenopausal patients with DCIS undergoing lumpectomy plus radiotherapy

Background

The clinical results of NSABP B-35, phase III trial comparing 1 mg/day A to 20 mg/day tam, each given for 5 years, were reported at ASCO 2015. B-35 demonstrated a statistically significant benefit in breast cancer free interval for women assigned to A, primarily in women &lt;60 years. A secondary endpoint of B-35 was quality of life (QOL) and symptom (SX) outcomes in the two treatment groups. The primary hypotheses of the PRO study were that there would be no differences in QOL between the two treatments, and that patients receiving A would report higher rates of hot flashes compared to patients receiving tam. Other SX comparisons were secondary endpoints.

Methods

QOL and SX were assessed at baseline (prior to randomization), and every 6 months thereafter for 5 years of treatment and in the following 12 months. QOL was measured with the SF-12 Physical Component Summary (PCS) and Mental Component Summary (MCS). SX were measured with selected scales from the BCPT symptom-checklist, and other standardized instruments. Stratification was by age (&lt;60 v ≥60) as in the main trial. Study hypotheses and endpoints were examined by comparing PROs in the two treatment arms using a mixed model for repeated measures analysis with adjustment for the baseline scores, time point and age category, using an intention-to-treat principle and including only patients who completed the baseline and at least one follow-up questionnaire. Patients with protocol events were censored. Only data through 60 months are reported here. The accrual goal for the sub-study was 1,150 consecutive patients.

Results

Between January 6, 2003 and June 15, 2006, a total of 3,104 patients were entered and randomly assigned to NSABP Protocol B-35. Accrual to the PRO study of B-35 closed on December 28, 2004, at which time 1,275 patients were entered, with 1,193 patients included in this analysis. There were no medical or demographic differences between patients assigned to A or tam in the PRO sub-study, and they reflected the characteristics of the parent trial. Adherence to data collection across the 60 months was 87%. There were no significant differences in QOL outcomes by treatment for the PCS (p=0.16) or the MCS (p=0.38). SX subscales: hot flash scale was greater in tam group and this difference varied over time (p=0.001); musculoskeletal pain was significantly greater in A group for time points 6-24 months (all p&lt;.001); vaginal problems were greater in A group (p=0.03). Hot flash and vaginal problems were significantly worse in women &lt;60 years. Additional SX outcomes (depression, fatigue, sexual function) will be reported at presentation.

Conclusion

In this large, double-blind, placebo-controlled trial comparing A to tam in patients with DCIS, there was no significant difference in QOL between the two treatments. However, there were important treatment differences in SX outcomes, which should be considered as part of treatment decision-making discussions, along with the clinical breast cancer outcome results.

Support: CA-180868, 180822, 189867, 196067, 114732; AstraZeneca Pharmaceuticals LP.

Citation Format: Ganz PA, Cecchini RS, Julian TB, Margolese RG, Costantino JP, Vallow LA, Albain KS, Whitworth PW, Cianfrocca ME, Brufsky A, Gross HM, Soori GS, Hopkins JO, Fehrenbacher L, Sturtz K, Wozniak TF, Seay TE, Mamounas EP, Wolmark N. Patient-reported outcome (PRO) results, NRG Oncology/NSABP B-35: A clinical trial of anastrozole (A) vs tamoxifen (tam) in postmenopausal patients with DCIS undergoing lumpectomy plus radiotherapy. [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 S6-04.

Abstract ML1: The Contribution of NSABP Clinical Trials to the Management of Early Breast Cancer

For over a half century the NSABP has conducted clinical trials to ascertain optimal therapy in patients with early breast cancer. The trials, performed in chronologic sequential manner, provide a well- documented compilation of evolving biologic theories disclosing both flaws and occasional episodes of perspicacity in a disinterested manner. In the process, this endeavor has contributed to establishing standards of care; a tribute to the 100,000 women who participated.

Two landmark studies started in the 1970s (B04, B06) initiated the retreat from radical mastectomy and established the propriety of breast preserving operations. They convinced the surgeon that treatment failures were not a consequence of inattention to operative detail but were due to the presence of micro-metastatic disease. Thus the decline of the radical mastectomy and the ascent of adjuvant therapy are inextricably intertwined and the latter would not have occurred without the former.

In 1975 the NSABP demonstrated that adjuvant chemotherapy (oral L-PAM) given to N+ patients could significantly prolong disease free survival (DFS). These data were eclipsed in 1976 by the CMF results but taken together these two pivotal trials launched an initiative which is still relevant in the present therapeutic arena. Between 73-05 NSABP consecutive adjuvant therapy trials increased the ten year DFS from 30% to 75% in N+ patients. Perhaps viewed in harsh hindsight, some of these studies might seem banal, however, the incremental gains in DFS and the number of lives saved are incontrovertible.

In 1988 a preoperative chemotherapy program (B18, B27) established the association of pCR and improved survival. The results were instrumental in the FDA considering accelerated approval on the basis of a surrogate end point, such as pCR (2012).

The salutary effect of adding tamoxifen to chemotherapy in N+ patients was first shown in 1981 (B09). A concerted effort was made to define a cut point in quantitative ER that would be both prognostic and predictive. Although this effort was unsuccessful it did serve as the forerunner of and the stimulus for the 21 gene recurrence score panel. Protocol B14 (82-88) confirmed that tamoxifen was beneficial in N- ER+ pre- and post-menopausal women. Protocol B20 further showed that the addition of chemotherapy to tamoxifen was superior to tamoxifen alone. These two trials served as the validation for the 21 gene recurrence score panel (2004) and to date this assay has been performed in 550,000 N- ER+ women to determine whether chemotherapy could be omitted. As a result the overall use of chemotherapy in the United States has been significantly reduced.

Perhaps the most dramatic results in the 50 year history of the group were obtained in NSABP B31 where trastuzumab was added to chemotherapy in N+ Her2+ patients. The initial joint analysis from NSABP B31 and North Central N9831 disclosed a hazard ratio of .48 and an absolute 18% increase in DFS (2005). These results were hailed as the harbinger of a completely altered approach to the treatment of breast cancer by an exuberant editorialist who may yet be proven correct. Symbolically the age of therapy targeting genetic aberrations in the adjuvant setting was initiated.

Citation Format: Wolmark N. The Contribution of NSABP Clinical Trials to the Management of Early Breast Cancer. [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 ML1.

Abstract P5-17-01: A definition of a high-risk early-breast cancer population based on data from the collaborative trials in neoadjuvant breast cancer (CTNeoBC) meta-analysis

Background: Pathological complete response (pCR) is a proposed surrogate endpoint for predicting long-term clinical benefit on endpoints such as event-free survival (EFS) or overall survival (OS). The CTNeoBC meta-analysis did not validate the surrogacy of pCR for EFS or OS, and there is no precedent for its use as a regulatory endpoint in oncology. Use of the accelerated approval pathway has been proposed for neoadjuvant therapies that substantially improve pCR as a means to expedite widespread access to highly effective therapies for high-risk, early breast cancer. Potential risks of this approach include approving an agent that ultimately does not demonstrate clinical benefit and, in the interim, exposing curable patients to the toxicity of therapy without certainty of benefit. To mitigate the risks of this pathway, enrollment to neoadjuvant trials intended to support accelerated approval should be restricted to patients presenting with high-risk early-stage breast cancer. The 5-year EFS rate by breast cancer subtype in the CTNeoBC meta-analysis population is presented. Methods: We identified 12 neoadjuvant randomized trials (N = 12,993) with pCR clearly defined and long-term follow-up available for EFS and OS. Trials included AGO 1 (n = 668), ECTO (n = 1355), EORTC 10994/BIG 1-00 (n = 1856), GeparDuo (n = 907), GeparQuattro (n = 1495), GeparTrio (n = 2072), GeparTrio-Pilot (n = 285), NOAH (n = 234), NSABP B18 (n = 760), NSABP B27 (n = 2411), PREPARE (n = 733), and TECHNO (n = 217). The key objective of this analysis was to establish a definition of “high-risk” based on the Kaplan-Meier estimates of the 5-year EFS rate in the different clinical breast cancer subtypes (hormone receptor-positive, HER2-positive and triple-negative) analyzed by tumor stage and tumor grade at presentation. Results: The 5-year EFS rate was less than 65% in all the breast cancer subtypes with stage III disease. For patients with stage II disease, the impact of tumor grade varied by hormone receptor status. Patients with hormone receptor-negative breast cancer, regardless of HER2 status had a poor prognosis that was independent of tumor grade. For patients with hormone receptor-positive tumors, regardless of HER2 status, high grade histology was associated with an increased risk of recurrence.

5-year Event-Free Survival Rate (EFS) 5-year EFS Rate Estimate (95% confidence interval)TNMStage IIStage III Grade IIGrade IIIGrade IIGrade IIIHormone Receptor + HER2-83% (80%, 85%)71% (65%, 77%)63% (58%, 69%)51% (42%, 59%)HER2+ HR+81% (75%, 86%)69% (60%, 76%)50% (41%, 59%)48% (37%, 59%)HER2+ HR-61% (51%, 70%)66% (57%, 73%)58% (46%, 69%)46% (36%, 55%)Triple Negative66% (58%, 72%)72% (67%, 76%)38% (27%, 48%)37% (29%, 45%)

Conclusions: This analysis estimated the 5-year EFS rate in the breast cancer subtypes from the CTNeoBC meta-analysis population. The HER2-positive population in the meta-analysis was at particularly high risk because most of the patients had locally advanced breast cancer and only 39% of these patients received trastuzumab therapy. We propose defining less than 75% 5-year EFS rate as “high-risk” for the purposes of designing neoadjuvant trials that intend to use pCR to support accelerated approval.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-17-01.

Abstract OT2-3-02: NSABP B-43: A phase III clinical trial to compare trastuzumab (T) given concurrently with radiation therapy (RT) to RT alone for women with HER2+ DCIS resected by lumpectomy (Lx)

Background: A significant amount of DCIS is ER negative and/or overexpresses HER2. This provides an opportunity to test targeted therapy in DCIS. In xenograft models and cell lines, T boosts RT effectiveness. In T-treated HER2+ patients, apoptosis occurs within 1 wk of single agent T use, with T found in ductal aspirates. Ample safety evidence for T exists. T given during whole breast irradiation (WBI) may improve results for lumpectomy (Lx) resected HER2+ DCIS. A trial to examine this question will enhance the understanding of breast tumor biology and the prevention of such tumors and could possibly extend breast-conserving surgery benefits for women with DCIS.

Method: After Lx for pure DCIS, each patient's DCIS lesion is centrally tested for HER2 by IHC analysis. HER2 2+ tumors undergo FISH analysis. HER2 3+ or FISH+ patients can be randomly assigned to 2 doses of T, 3 weeks apart during WBI or to WBI alone.

Women ≥18 yrs. with a margin-clear Lx for pure DCIS, with ECOG status 0/1 who are clinically or pathologically node negative are eligible. Centrally tested DCIS must be HER2 +. ER and/or PR status must be known before randomization.

Primary aims are to determine if T decreases ipsilateral breast cancer recurrence, ipsilateral skin cancer recurrence, or ipsilateral DCIS. Secondary aims are to determine the benefit of T in preventing regional or distant recurrence and contralateral invasive breast cancer or DCIS. NSABP B-43 will determine if DFS, recurrence-free interval, and OS can be improved with the use of T. 2000 patients will be accrued over 7.9 yrs, with a definitive analysis of primary endpoints performed at 163 ipsilateral breast cancer events (7.5 - 8 yrs. after protocol initiation) with an 80% power to detect a hazard reduction of 36%, from 1.73 ipsilateral breast cancer events per 100 pt-yrs to 1.11 events per 100 pt-yrs. The 36% observed reduction in the hazard of IIBCR-SCR-DCIS on the T arm is based on a projection of 40% hazard reduction if the compliance were perfect, with a 10% noncompliance rate. As of 5-31-13, 1,349 patients have been randomized.

NCT00769379

Support: PHS NCI-U10-CA-69651, -12027; NCI P30-CA-14599; Genentech, Inc.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT2-3-02.

Abstract OT1-1-12: NSABP FB-7 Trial: A Phase II Randomized Clinical Trial Evaluating Neoadjuvant Therapy Regimens with Weekly Paclitaxel and Neratinib or Trastuzumab or Neratinib and Trastuzumab Followed by Doxorubicin and Cyclophosphamide with Postoperative Trastuzumab in Women with Locally Advanced HER2-Positive Breast Cancer

Neratinib is an oral, small molecule which acts as an irreversible inhibitor of the pan ErbB receptor tyrosine kinase. Dual ErbB blockade combined with chemotherapy improves efficacy in Her-2 positive breast cancer. Both NeoALTTO (Lancet 2012) and Neosphere (Lancet Oncol 2012) trials demonstrated higher pCR for Her-2 positive breast cancer receiving dual anti-Her-2 neoadjuvant blockade therapy. The purpose of this trial is to determine the activity and safety profile of Neratinib as mono-blockade or in combination with Trastuzumab as dual blockade in neoadjuvant therapy of locally advanced breast cancer (stage IIB, III A, B and C).

Methods: This NSABP Foundation Research Program study (FB-7) is designed as a Phase II, multi-center, three arm clinical trial for patients with Her-2 positive locally advanced breast cancer. 126 patients will be enrolled. The initial two- arm study of Neratinib or Trastuzumab in combination with Paclitaxel began in December 2010. 30 patients were enrolled by December of 2011 at which time the study was placed on hold awaiting the recommended phase II dose of the three drug combination, Neratinib, Trastuzamab and Paclitaxel (NSABP FB-8 trial), which is a Phase I dose-escalation study in women with metastatic Her-2 positive breast cancer. The amended FB −7 trial is now a three arm trial of weekly Paclitaxel and Neratinib or Trastuzumab or Neratinib and Trastuzumab for 4 cycles followed by Doxorubicin and Cyclophosphamide for 4 cycles prior to surgical resection. Patients will then receive postoperative Trastuzumb to complete one total year of Her-2 blockade therapy. The primary goal of this study is to determine the pathologic complete response in breast and axillary lymph nodes following completion of neoadjuvant therapy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT1-1-12.

P1-06-15: A Genomic Predictor Developed from Breast Cancer Cell Lines Predicts Both Disease-Free Survival and Overall Survival in Breast Cancer Patients Treated with Doxorubicin and Cyclophosphamide: A Collaborative Project of the NSABP and Precision Therapeutics

Background: A cell line-derived multigene predictor of tumor response to doxorubicin + cyclophosphamide (MGP-AC) has been shown to predict the pathological complete response (pCR) in breast cancer patients from the National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol B-27. However, a cell line-derived MPG for doxorubicin + cyclophosphamide + docetaxel (MGP-ACT) was not predictive in patients from B-27. The purpose of this study was to further assess the performance of these predictors on disease-free survival (DFS) and overall survival (OS) in the same patient populations.

Methods: NSABP B-27 was a 3-arm trial of 2411 early-stage breast cancer patients randomized to receive 4 cycles of preoperative doxorubicin+cyclophosphamide (AC) or 4 cycles of AC followed by 4 cycles of docetaxel either pre-op (AC+T) or post-op (AC→T). MGPs for AC and ACT were developed based on the in vitro assay and microarray genomic profiles of 40 breast cancer cell lines. A higher MGP score indicates lower chemoresponse sensitivity.

Results: 322 patients with available microarray data were included for this analysis (103 treated with AC, 102 with AC+T, and 117 with AC→T). For patients treated with AC, a higher MGP-AC score was significantly associated with increased risk of disease progression (standardized hazard ratio [HR] [SD set to 1]=1.48, 95% confidence interval [CI]=1.02−2.15, p=0.043) or death (standardized HR=1.66, 95% CI=1.06−2.62, p=0.028) after adjusting for clinical covariates (ER status, clinical tumor size, lymph node status, and age). The addition of MGP-AC to the clinical model improves the accuracy in predicting five-year DFS: the area under the ROC curve improved from 63% to 72%. For patients treated with AC+T or AC→T, MGP-ACT was not predictive of either DFS (standardized HR=1.03, 95% CI=0.78−1.37, p=0.818) or OS (standardized HR=1.05, 95% CI=0.73−1.51, p=0.8).

Conclusions: A cell line-derived MGP for AC that was predictive of pCR was also predictive of DFS and OS in breast cancer patients treated with neoadjuvant AC. The MGP for ACT, which was not predictive for pCR, was not predictive of either DFS or OS in patients who received docetaxel after AC.

The B-27 study was funded by NCI PHS grants U10-CA-37377, U10-CA-69974, U10-CA-12027, U10-CA-69651, and U24-CA-114732, and received additional support from sanofi-aventis.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-06-15.

OT1-02-05: A Phase III Clinical Trial Comparing Trastuzumab Given Concurrently with Radiation Therapy to Radiation Therapy (RT) Alone for Women with HER2−Positive DCIS Resected by Lumpectomy: NSABP B-43

Background

Because a substantial portion of DCIS is ER negative and overexpresses HER2, therapy targeting this protein is a promising strategy for HER2−overexpressing DCIS.

Preclinical studies have shown that trastuzumab (T) boosts the effectiveness of RT in xenograft models and in cell lines with no detrimental effect on irradiated HER2−normal cells. Studies correlating clinical response with molecular markers in T-treated patients show that apoptosis occurs within 1 wk of starting singleagent T, with little effect on proliferation. Shorter duration treatments with this agent require investigation. Adjuvant trials using T during breast irradiation have already provided ample safety evidence. Will T administered during WBI improve lumpectomy + WBI results in women with HER2−positive DCIS? This trial will allow us to better understand the biology of breast cancer and its prevention and will extend the benefits of breast-conserving surgery for women with DCIS.

Trial Design: Post lumpectomy for DCIS without evidence of an invasive component, a central review of each patient's pure DCIS lesion is carried out for HER2 by IHC analysis. If the HER2 is 2+, FISH analysis is done, and patients whose tumors are HER2 3+ or FISH positive can be randomly assigned to receive 2 doses of T 3 wk apart during WBI or to receive WBI alone.

Eligibility criteria: Women 18 years or older with an ECOG status of 0 or 1 who have undergone a margin-clear lumpectomy for DCIS and whose tumors are clinically or pathologically node negative are eligible. DCIS must be HER2 positive by central testing. ER and/or PR status must be known before random assignment.

Specific aims: The primary aim is to determine if T given concurrently with WBI is more beneficial in preventing IBC recurrence, ipsilateral skin cancer recurrence, or ipsilateral DCIS compared with WBI alone for HER2−positive DCIS resected by lumpectomy. Secondary aims are to compare the possible benefit of T given during WBI to that of WBI alone in preventing regional or distant recurrence and contralateral invasive or DCIS breast cancer. B-43 will determine if invasive or DCIS DFS, recurrence-free interval, and OS can be improved with the addition of T to WBI. The effects of T on ovarian function in premenopausal women will also be assessed.

Statistical methods and accrual: Our design calls for accrual of 2000 patients during a 7.9-year period. As of May 31, 2011, 578 patients have been entered. A definitive analysis of primary endpoints will be performed when 163 ipsilateral breast cancer events occur (7.5 and 8 years after protocol initiation). This number of events affords 80% power to detect a hazard reduction of 36%, from 1.73 ipsilateral breast cancer events per 100 patient-years to 1.11 events per 100 patient-years. The 36% observed reduction in the hazard of IIBCR-SCR-DCIS on the T arm is based on a projection of 40% hazard reduction if the compliance were perfect, with a 10% noncompliance rate.

Supported by PHS grants NCI-U10-CA-69651, NCI-U10-CA-12027, and NCI P30-CA-14599 from the US NCI and Genentech, Inc.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT1-02-05.

OT1-02-07: NSABP B-47: A Randomized Phase III Trial of Adjuvant Therapy Comparing Chemotherapy Alone (Six Cycles of Docetaxel Plus Cyclophosphamide or Four Cycles of Doxorubicin Plus Cyclophosphamide Followed by Weekly Paclitaxel) to Chemotherapy Plus Trastuzumab in Women with Node-Positive or High-Risk Node-Negative HER2−Low Invasive Breast Cancer

Adjuvant studies utilizing trastuzumab in early HER2+ breast cancer demonstrated a large reduction in recurrence and death. Post-enrollment central testing showed HER2 non-amplified participants derived similar benefit. Among HER2−amplified patients, multiple studies showed no effect on benefit by degree of amplification. Extensive testing including blinded external review confirmed the non-amplified nature of the HER2 normal group. Detailed relevant background and confirmatory studies will be provided. As a result of these findings, NSABP study B-47, sponsored by the NCI, was activated January 2011. The study is NCI central IRB approved, open in the CTSU, and endorsed by SWOG as of April 2011.

Study: Selection of one of the two chemotherapy regimens is by physician choice: The non-anthracycline regimen is TC (docetaxel 75 mg/m2, cyclophosphamide 600 mg/m2) administered IV every 3 weeks for 6 cycles; the anthracycline regimen is AC followed by WP (doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 administered IV either every 3 weeks or every 2 weeks [per investigator discretion] for 4 cycles followed by paclitaxel 80 mg/m2 IV weekly for 12 doses). Patients will be randomly assigned to receive chemotherapy with or without trastuzumab therapy. For patients receiving the TC chemotherapy regimen, trastuzumab will be given every 3 weeks during and following chemotherapy until 1 year after the first trastuzumab dose (8 mg/kg loading dose; 6 mg/kg for the remaining doses). For patients receiving the AC followed by WP chemotherapy regimen, trastuzumab will begin with the first dose of weekly paclitaxel and will be given weekly for 12 doses (4 mg/kg loading dose; 2 mg/kg for the remaining weekly doses). Following completion of WP, trastuzumab therapy will continue with 6 mg/kg doses given every 3 weeks for a total of 1 year. Patients will also receive adjuvant radiation therapy and endocrine therapy, as clinically indicated.

Detailed menstrual history, concurrent medications, weight changes, and biomarkers (estrogen, stress, inflammation status) will be collected throughout the study. Collection of circulating tumor cells as an ancillary study is planned.

Eligibility: Eligibility includes: node positive or high risk node negative female breast cancer patients; HER2 IHC 1+ or 2+ scores, but non amplified by FISH; normal cardiac, renal, and liver function. Detailed eligibility will be provided.

Statistical: The primary aim is to determine whether the addition of trastuzumab to chemotherapy improves invasive disease-free survival (IDFS). 3260 patients will be enrolled to provide statistical power of 0.9 to detect a 33% reduction in the hazard rate of IDFS using a one-sided alpha level of 0.025. Projected accrual time is approximately 3 years.

Progress: Protocol was activated in January 2011. First patient was entered in February 2011. As of June 16, 2011, 115 of 3260 patients have been enrolled. Supported by NCI U10-12027, -37377, 69651, 69974, and Genentech, Inc.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT1-02-07.

P3-13-01: Boost Radiation Therapy Not of Value in Reducing IBTR of Invasive or Noninvasive Breast Cancers for Patients with DCIS: Results from the NSABP B-24 Trial

Background: Whole breast irradiation therapy following lumpectomy for invasive breast cancer (IBC) or noninvasive breast cancer (DCIS) significantly reduces the risk of local recurrence. Boost radiation therapy to the tumor bed has been proven to additionally lower the risk of recurrence for IBC. The benefit of boost therapy in patients with DCIS is less certain. We carried out a review of the NSABP B-24 trial to assess the benefit of boost therapy.

Methods: After lumpectomy and radiation therapy, 1804 women with DCIS were randomly assigned to placebo (902) or tamoxifen (902). Whole breast irradiation therapy (50 Gy) was mandatory. Boost radiation therapy was optional, and boost status was known for 1,569 patients. Of these, 1392 patients (86.97%) were identified as having all data sufficient for multivariate analysis. Of these, 613 received boost therapy ranging from 1 Gy −20 Gy, with 81.5% receiving 10 Gy. Mean time of follow-up was 161 months.

Results: Patients who received boost radiation therapy were more likely to be younger (p=0.04), have positive margins (p=0.007), and be more likely to have comedo necrosis (p=0.03). Multivariate analysis identified only treatment (tamoxifen vs placebo) (HR=0.74, 95% CI=0.57−0.98, p=0.034), age (≥ 50 verses &lt; 50) (HR=0.47, 95% CI=0.36−0.61, p&lt;0.0001), and margin status (positive vs negative) (HR: 1.79, 95% CI= 1.31−2.43, p&lt;0.001) as significant predictors for ipsilateral breast tumor recurrence (IBTR). Boost had no significant effect on IBTR (HR=0.87, 95% CI=0.66−1.15, p=0.33). The lack of boost effect applied to both invasive (HR=0.86, 95% CI=0.58−1.27, p=0.44) and noninvasive IBTR (HR=0.89, 95% CI=0.60−1.33, p=0.56).

No interaction was seen between boost and treatment, age, margin status, or comedo necrosis.

Conclusion: In NSABP B-24, the addition of boost radiation therapy was not found to be of value in reducing IBTR of invasive or noninvasive breast cancers for patients with DCIS.

Supported by PHS grants NCI-U10-CA-69651, NCI-U10-CA-12027, and NCI P30-CA-14599 from the US NCI and AstraZeneca.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-13-01.

Effect of serial sectioning and immunohistochemistry (IHC) on sentinel lymph nodes (SLNs) on the false-negative rate (FNR) of SLN biopsy (SLNB): Results from NSABP B-32

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Background: In NSABP B-32 5611 women with invasive breast cancer were randomly assigned to SLNB plus axillary dissection or SLNB alone. Permanent pathologic assessment of SLNs at participating sites was designed to identify all macrometastases >2 mm (slicing SLNs at approximately 2.0 mm intervals, embedding all slices in paraffin tissue blocks, and examining one H&E-stained slide from each block). Routine use of IHC or deeper sectioning was prohibited. SLN paraffin tissue blocks from negative SLNs were later evaluated centrally for occult metastases deeper in the blocks. In this report we examine the effect of this detailed assessment on the FNR of SLNB.

Methods: Routine and cytokeratin IHC stains were used at two widely spaced additional levels. Occult metastases were detected in 616 of 3884 pts (15.9%) with initially negative SLNs; 69.8% had isolated tumor-cells, 27.9% micrometastases, and 2.3% macrometastases (Weaver D, et al: N Engl J Med, 2011).

Results: Previously reported FNR in B-32 was 9.8% (75 of 766 pts). Information on additional pathologic assessment was available on 72 of these 75 pts and revealed occult metastases in 23 pts (31.9%). Of those 23 pts, 14 had isolated tumor cells (61%), 7 had micrometastases (30%), and 2 had macrometastases (9%) in the SLN. Including the information from the additional pathologic assessment, the FNR of SLNB in B-32 was reduced to 6.4% (49 of 763 cases). This 35% reduction in FNR was statistically significant (p< 0.001). Among the 23 FN SLNs with occult metastases, the number of positive non-SLNs was 1 in 16 pts, 2 in 2 pts, 3 in 2 pts, 4 in 2 pts, and 6 in 1 pt.

Conclusions: In the B-32 trial, more detailed assessment of the SLNs with deeper sectioning and IHC staining would have significantly reduced the FNR of SLNB by about one-third. However, this reduction would have come at the expense of a 16% increase in the rate of axillary dissection by taking occult metastases into account. Supported by NCI: U10-CA-12027, U10-CA-37377, U10-CA-69974, U10-CA-69651; and ARRA ROI CA 74137.

Effect of axillary dissection for occult detected sentinel nodes metastases on survival: NSABP B-32

80

Background: In NSABP B-32 trial 5,611 women with invasive breast cancer were randomly assigned to sentinel lymph node biopsy (SLNB) plus axillary dissection (Group [Grp] 1) or SLNB alone (Grp 2). There was no significant difference in OS or DFS reported between the two groups. Initial permanent pathologic assessment of the SLNs at participating sites was designed to identify all macrometastases >2 mm and consisted of slicing the SLNs at approximately 2.0 mm intervals, embedding all slices in paraffin tissue blocks, and examining one hematoxylin and eosin stained slide from each block. Routine use of IHC or sectioning of deeper levels was prohibited. SLN paraffin tissue blocks from cases with pathologically negative SLNs were later evaluated centrally for occult metastases deeper in the blocks. This study evaluates group outcomes related to occult metastases.

Methods: Routine and cytokeratin IHC stains were used at two widely spaced additional levels. Using this technique, occult metastases were detected in 15.9% of the patients (pts) with initially negative SLNs (616 / 3884 cases). Of the 616 cases, 431 (69.8%) had isolated tumor-cell clusters, 171 (27.9%) had micrometastases, and 14 (2.3%) had macrometastases (Weaver D, et al: N Engl J Med, 2011).

Results: 316 (16.4%) of 1924 pts had occult metastases in Grp 1 and 300 (15.3%) of 1960 in Grp 2. Non-sentinel node status was available in 312/316 pts in Grp 1; 23 (7.4%) had positive non-sentinel nodes. In pts with occult metastases, there were no significant differences in OS or DFS between groups (Grp 2 vs. Grp 1 OS HR: 0.89, p=0.62; DFS HR: 0.79, p=0.16). There were no significant differences in OS or DFS between the groups in pts who were negative for occult metastases (Grp 2 vs. 1 OS HR:1.25, p=0.07; DFS HR: 1.11, p=0.22).

Conclusions: A more detailed assessment of the SLNs with deeper sectioning and IHC staining detected a significant level of occult metastases in clinically node negative pts. However, no benefit was seen by the addition of axillary dissection in pts with occult SLN metastases. Supported by NCI: U10-CA-12027, U10-CA-37377, U10-CA-69974, U10-CA-69651, and ARRA ROI CA 74137

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.

Two or three year disease-free survival (DFS) as a primary end-point in stage III adjuvant colon cancer trials with fluoropyrimidines with or without oxaliplatin or irinotecan: data from 12,676 patients from MOSAIC, X-ACT, PETACC-3, C-06, C-07 and C89803

BACKGROUND

The ACCENT group previously established disease-free survival (DFS) with 2 or 3 years median follow-up to predict 5 year overall survival (5 year OS) in stage II and III colon cancer. ACCENT further proposed (1) a stronger association between DFS and OS in stage III than II, and (2) 6 or 7 years necessary to demonstrate DFS/OS surrogacy in recent trials. The relationship between end-points in trials with oral fluoropyrimidines, oxaliplatin and irinotecan is unknown.

METHODS

Associations between the treatment effect hazard ratios (HRs) on 2 and 3 years DFS, and 5 and 6 years OS were examined in 6 phase III trials not included in prior analyses from 1997 to 2002. Individual data for 12,676 patients were analysed; two trials each tested oxaliplatin, irinotecan and oral treatment versus 5-FU/LV.

FINDINGS

Overall association between 2/3 year DFS and 5/6 year OS HRs was modest to poor (simple R² measures: 0.58-0.76, model-based R²: 0.17-0.49). In stage III patients, the association increased (model-based R² ≥ 0.79). Observed treatment effects on 2 year DFS accurately 5/6 year OS effects overall and in stage III patients.

INTERPRETATION

In recent trials of cytotoxic chemotherapy, 2 or 3 years DFS HRs are highly predictive of 5 and 6 years OS HRs in stage III but not stage II patients. In all patients the DFS/OS association is stronger for 6 year OS, thus at least 6 year follow-up is recommended to assess OS benefit. These data support DFS as the primary end-point for stage III colon cancer trials testing cytotoxic agents.

Abstract S5-1: Prospective Outcomes for Patients with Micro-Metastases and Macro-Metastases In Sentinel Nodes: NSABP B-32 Sentinel Node Trial

Background: Sentinel node biopsy (SNB) allows for a more detailed analysis of axillary nodes, increasing the detection of nodal metastatic disease. Prospective outcome results related to patients with micro-and macro-metastases in sentinel nodes from the NSABP B-32 trial are presented here.

Methods: After stratification, women with operable invasive breast cancer and clinically negative nodes were randomly assigned to sentinel node resection (SNR) with immediate conventional axillary dissection (AD) [Group 1] or to SNR without AD [Group 2]. Group 2 patients with positive SNs underwent AD. Sentinel nodes underwent analysis by hematoxylin and eosin. Systemic therapy was at the discretion of the physician. Regional nodal irradiation for node positive lumpectomy patients and chest wall/regional node irradiation for node positive mastectomy patients was permitted. Univariate and multivariate analyses were carried out via Cox PH models to identify predictors of overall survival (OS) and disease-free survival (DFS).

Results: From May 1999 through February 2004, 5,611 patients were entered into NSABP B-32. A total 1,390 patients with positive SN were identified; 1,389 of these patients had follow-up data. There were 422 patients with macro-metastases (&gt;2mm), 312 with micro-metastases (&gt;0.2, ≥2.0mm), and 626 with unknown status. Median time in study was 94 months. 97% of SN-positive patients received systemic adjuvant therapy. Significant univariate predictors of OS and DFS were age, receptor status, clinical tumor size, histologic grade, number of positive SNs, SN metastasis size, number of positive nodes, lymphovascular invasion, and systemic therapy. Multivariate analysis identified histologic grade (HR: 2.30, P&lt;0.0001), SN macrometastasis (HR: 2.44, p=0.0003), systemic therapy (HR: 0.22, P&lt;0.0001), age, and clinical tumor size (CTS) as significant predictors of OS (Table 1) with similar predictors for DFS. For DFS, a significant quadratic effect due to age (p=0.015) was observed where younger and older women had higher risk of having an event than did middle aged women.

Conclusion: The most striking factors associated with poor OS and DFS were poor histologic tumor grade and macro-versus micro-SN metastases. Patients with micro-or macro-SN metastases who received systemic therapy had a 78% reduction in mortality and a 76% improvement of DFS.

Supported by: NCI U10-CA-69651, -12027, -37377, -69974.

Primary outcome results of NSABP B-32, a randomized phase III clinical trial to compare sentinel node resection (SNR) to conventional axillary dissection (AD) in clinically node-negative breast cancer patients

LBA505

Background: NSABP B-32 is the largest prospective randomized phase III trial designed to determine in SN negative patients that SNR alone results in the same survival and regional control as SNR + AD while reducing morbidity. It was designed to detect a survival difference of 2% between the 2 groups at 5 years.

Methods: 5,611 women with operable, clinically N0, invasive breast cancer were randomized to SNR + AD (Group 1) or to SNR alone with AD only if SNs were positive (Group 2). 3,989 (71.1%) of the 5,611 patients were SN negative and followed for events. 99.9% of these SN negative patients had follow-up information: 1,975 in Group 1 and 2,011 in Group 2. Median time on study was 95.3 months. Patients were well balanced across clinical strata. Log-rank tests for unadjusted analyses and Cox proportional hazard models adjusting for study stratification variables were used to compare overall survival (OS) and disease-free survival (DFS) between the two groups. Two-sided p-values were used. HR values > 1 indicate a more favorable outcome in Group 1 (SNR + AD).

Results: Comparisons of OS (Group 1 vs. Group 2) yielded an unadjusted HR of 1.20 (p = 0.12) and an adjusted HR of 1.19 (p=0.13). Five-year Kaplan-Meier estimates for OS are 96.4% in Group 1 and 95.0% in Group 2 and the 8-year estimates are 91.8% and 90.3%, respectively. Comparisons of DFS (Group 1 vs. Group 2) yielded an unadjusted HR of 1.05 (p=0.54) and an adjusted HR of1.07 (p=0.57). No substantial differences could be seen across sites for first treatment failure. Five-year Kaplan-Meier estimates for DFS are 89.0% in Group 1, and 88.6% in Group 2 and the 8-year estimates are 82.4% and 81.5%, respectively. Local and Regional Recurrences: There were 54 local recurrences in Group 1 and 49 in Group 2 (p=0.55). There were 8 regional node recurrences as first events in Group 1 and 14 in Group 2 (p=0.22).

Conclusions: No significant differences were observed in OS, DFS, or regional control between the trial groups. Within the limits of this trial, SNR without AD is validated as a safe and effective method for regional node treatment of SN negative breast cancer patients.

[Table: see text]