Mamounas, Eleftherios P.

Abstract Our objective was to validate the NSABP 8-gene trastuzumab-benefit signature, developed and initially validated in NRG Oncology/NSABP B-31 in Alliance/NCCTG N9831. The B-31 and N9831 trials demonstrated the benefit of adding trastuzumab to chemotherapy in the adjuvant setting for HER2+ breast cancer patients. NSABP investigators utilized gene expression profiles of N9831 patients (N = 892) to blindly assign patients to large-, moderate-, or no-trastuzumab benefit groups and then NCCTG investigators assessed the degree of trastuzumab benefit using Cox models adjusted for age, nodes, estrogen receptor/progesterone receptor status, tumor size, and grade. Hazard ratios and 2-sided P values for recurrence-free survival of the predicted large- (n = 387), moderate- (n = 401), and no-benefit (n = 104) groups, based on the 8-gene signature were 0.47 (95% CI = 0.31 to 0.73, P < .001), 0.60 (95% CI = 0.39 to 0.92, P = .02), and 1.54 (95% CI = 0.59 to 4.02, P = .38), respectively (Pinteraction = .02), providing validation of the 8-gene signature in an independent study.

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.

591 Background: Both Cb and Bev demonstrate activity when combined with standard chemotherapy in TNBC. CALGB 40603 is a 2x2 randomized trial that previously demonstrated that adding Cb to NACT significantly increased pathologic complete responses in the breast/axilla (pCR), while adding Bev did not (Sikov, JCO 2015). Here we report 5-year LTOs and assess factors that influenced them. Methods: 443 patients with clinical stage II-III previously untreated TNBC received 12 weeks of paclitaxel (wP) +/- Cb then dose-dense AC, +/- Bev before surgery. The primary endpoint was pCR. Analyses of LTOs (event-free survival (EFS), distant recurrence-free interval (DRFI) and overall survival (OS)), impact of residual cancer burden and other variables were secondary. Results: Median follow-up was 5.7 years (y); 5y EFS was 70.9% (95% CI; 66.7%-75.4%), DRFI 76.3% (72.3%-80.5%) and OS 76.9% (72.9%-81.2%). Pretreatment clinical stage and achieving pCR correlated with LTOs, while age, race, subtype (basal-like vs. not) and tumor grade did not. Among pCR 5y EFS was 86.4% vs. 57.5% for non-pCR (HR 0.28, 0.19-0.43), OS was 88.7% vs 66.5% (HR = 0.28, 0.17-0.44). This relationship was similar in all trial arms. Any residual disease conferred poorer outcome; compared with pCR/Residual Cancer Burden (RCB) 0, EFS HRs were 2.29 (1.32-3.97), 3.01 (1.90-4.74), and 9.67 (5.66-16.51) for RCBI, II and III, respectively. There were no improvements in LTOs with Cb (EFS HR 0.99, 0.70-1.40) or Bev (EFS HR 0.91, 0.64-1.29). In an exploratory analysis, receipt of ≥11 doses of wP was associated with better EFS (HR 1.92, 1.33-2.77); this was particularly notable in Cb-treated arms. Conclusions: As expected, regardless of treatment arm pCR was associated with markedly better LTOs, and pts with any residual disease had significantly worse outcomes. The addition of Cb or Bev to standard NACT for TNBC did not improve LTOs in this trial, although it should be noted that the trial was not powered for this endpoint. Omission of chemotherapy doses may result in poorer outcomes, especially among Cb-treated pts, which may warrant further evaluation. Support: U10CA180821; U10CA180882; Genentech; https://acknowledgments.alliancefound.org ; NCT00861705 Clinical trial information: NCT00861705.

508 Background: PBI is an alternative to WBI, with potentially greater therapy (tx) compliance, and better integration with chemotherapy (CTX). NSABP B-39/RTOG 0413 clinical outcome results from 2018 did not show equivalence of PBI to WBI in local tumor control; PBI was statistically inferior, but with clinically small differences. PBI may be an acceptable alternative to WBI for some women. Understanding cosmesis and quality of life (QOL) treatment outcomes is important. Methods: B-39/0413 included a prospective QOL substudy with PRO evaluation of breast cancer treatment outcomes (cosmesis, function, pain) and fatigue using BCTOS and SF-36 vitality scales. Secondary QOL parameters included treatment related symptoms, perceived convenience of care, and the BPI pain scale. The study sample was stratified by CTX or not, as CTX is given before WBI but after PBI. PRO assessments occurred before randomization, the last day of adjuvant tx [CTX or radiation], 4 wks later, and 6, 12, 24, and 36 mo later. Primary aims included comparisons of change in fatigue from baseline to end of tx and equivalency of change in cosmesis from baseline to 36 mo for PBI v WBI. Separate analyses were done for CTX and non-CTX pts, controlling for axillary dissection. Each comparison used α=0.0125. Planned sample size was 964. Results: From 3-23-05 to 5-27-09, 975 pts were enrolled in the PRO study; 950 had follow-up data. 504 did not receive CTX and 446 received CTX. In non-CTX pts, PBI had less fatigue (p=0.011) and did not meet criteria for cosmesis equivalence (97.5% CI, -0.02 to 0.22; ∆=0.20). In CTX pts, PBI had worse fatigue (p=0.011) and equivalent cosmesis to WBI (97.5% CI, -0.09 to 0.21; ∆=0.24). In both groups, PBI pts reported less pain at end of tx. In non-CTX pts, PBI had more pain at 36 mo but in CTX pts, there was no difference. Convenience of care and treatment related symptom outcomes will be presented. Conclusions: In non-CTX pts, PBI is more convenient with less fatigue and slightly poorer cosmesis at 36 mo. Cosmesis was equivalent at 36 mo in CTX pts. Support: U10CA180868, -180822, UG1CA189867. Clinical trial information: NCT00103181.

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.

LBA500 Background: The primary endpoint of NSABP B-35, a phase III trial comparing 1 mg/day anastrozole to 20 mg/day tamoxifen, each given for 5 years, was breast cancer-free interval (BCFI), defined as the time from randomization to any breast cancer (BC) event including local, regional, or distant recurrence or contralateral disease, invasive or DCIS. Methods: Postmenopausal women with ER-receptor or PgR-receptor positive (by IHC analysis) DCIS and no invasive BC who had undergone a lumpectomy with clear resection margins were randomly assigned to receive either 20 mg/day tam or 1 mg/day A (blinded) for 5 years. Stratification was by age (<60 v ≥60). Results: From 1/6/2003 to 6/15/2006, 3,104 pts were entered and randomized (1552 in groups tam and A each). As of 2/28/15, follow-up information was available on 3,083 pts for OS and on 3,077 pts for all other disease-free endpoints, with mean time of follow-up of 8.6 years. There were 198 BCFI events, 114 in the tam group and 84 in the A group (HR, 0.73; p=0.03). 10-year point estimates for BCFI were 89.2% for tam and 93.5% for A. A significant time-by-treatment interaction (p=0.02) indicated that the effect was not evident until later in the study. There was a significant interaction between treatment and age group (p=0.04); benefit of A is only in women <60 years old. As to secondary endpoints, there were 495 DFS events, 260 in the tam group and 235 in the A group (HR, 0.89; p=0.21). 10-year point estimates for DFS were 77.9% for tam and 82.7% for A. There were 186 deaths, 88 in the tam group and 98 in the A group (HR, 1.11; p=0.48). 10-year point estimates for OS were 92.1% for tam, 92.5% for A. There were 8 deaths due to breast cancer in the tam group and 5 in the A group. There were 63 cases of invasive breast cancer in the tam group and 39 in the A group (HR, 0.61; p=0.02). There was a non-significant trend for a reduction in breast second primary cancers with A (HR, 0.68; p=0.07). Conclusions: Anastrozole provided a significant improvement compared to tamoxifen for BCFI, which was seen later in the study, primarily in women <60 years. Support: CA12027, 37377, 69651, 69974; 180868, 180822, 189867 196067, 114732; AstraZeneca Pharmaceuticals LP. Clinical trial information: NCT00053898.

Purpose Trastuzumab is a humanized monoclonal antibody against the human epidermal growth factor receptor 2 (HER2). The clinical benefits of adjuvant trastuzumab have been demonstrated in interim analyses of four large trials. Initial data of the combined analysis of the North Central Cancer Treatment Group (NCCTG) N9831 Intergroup trial and National Surgical Adjuvant Breast and Bowel Project (NSABP) B-31 trial were reported in 2005. Long-term follow-up results on disease-free survival (DFS) and overall survival (OS) have been awaited. Patients and Methods Patients with HER2-positive operable breast cancer were randomly assigned to doxorubicin plus cyclophosphamide followed by paclitaxel with or without trastuzumab in the NCCTG N9831 and NSABP B-31 trials. The similar design of both trials allowed data from the control and trastuzumab-containing arms to be combined in a joint analysis. Results At 3.9 years of median follow-up, there continues to be a highly statistically significant reduction in DFS event rate in favor of the trastuzumab-containing arm (P < .001). Similarly, there continues to be a statistically significant 39% reduction in death rate in favor of the trastuzumab-containing arm (P < .001). Conclusion These data demonstrate consistent DFS and OS advantages of adjuvant trastuzumab over time, with the longest follow-up reported to date. The clinical benefits continue to outweigh the risks of adverse effects.

Purpose To review the state of the science with respect to diagnostic imaging and locoregional therapy for patients with breast cancer receiving preoperative chemotherapy. Methods Published data relevant to clinical staging, monitoring of tumor response, and locoregional therapy for patients with breast cancer treated with preoperative chemotherapy were reviewed. Results High-quality data from prospective randomized trials are limited. Available data suggest that locoregional therapy decisions should be based on both the pretreatment clinical extent of disease and the pathologic extent of the disease after chemotherapy. Accordingly, physical examination and imaging studies that accurately define the initial extent of disease are required before treatment. Sentinel lymph node biopsy can be performed either before or after preoperative chemotherapy for patients with clinical N0 disease. The success of breast conservation after preoperative chemotherapy depends on careful patient selection and achieving negative surgical margins. Adjuvant breast radiation is indicated for all patients treated with breast conservation. For patients treated with mastectomy, chest-wall and regional nodal radiation should be considered for those who present with clinical stage III disease or have histologically positive lymph nodes after preoperative chemotherapy. Additional prospective studies are needed to determine the value of postmastectomy radiation for patients with stage II breast cancer who have negative lymph nodes after chemotherapy. Conclusion The increased use of preoperative chemotherapy has raised new questions concerning the optimal methods to stage and monitor disease response to treatment and how to optimize locoregional treatment. The available evidence suggests that a multidisciplinary approach improves outcomes.

PURPOSE: This trial was prompted by uncertainty about the need for breast irradiation after lumpectomy in node-negative women with invasive breast cancers of ≤ 1 cm, by speculation that tamoxifen (TAM) might be as or more effective than radiation therapy (XRT) in reducing the rate of ipsilateral breast tumor recurrence (IBTR) in such women, and by the thesis that both modalities might be more effective than either alone. PATIENTS AND METHODS: After lumpectomy, 1,009 women were randomly assigned to TAM (n = 336), XRT and placebo (n = 336), or XRT and TAM (n = 337). Rates of IBTR, distant recurrence, and contralateral breast cancer (CBC) were among the end points for analysis. Cumulative incidence of IBTR and of CBC was computed accounting for competing risks. Results with two-sided P values of .05 or less were statistically significant. RESULTS: XRT and placebo resulted in a 49% lower hazard rate of IBTR than did TAM alone; XRT and TAM resulted in a 63% lower rate than did XRT and placebo. When compared with TAM alone, XRT plus TAM resulted in an 81% reduction in hazard rate of IBTR. Cumulative incidence of IBTR through 8 years was 16.5% with TAM, 9.3% with XRT and placebo, and 2.8% with XRT and TAM. XRT reduced IBTR below the level achieved with TAM alone, regardless of estrogen receptor (ER) status. Distant treatment failures were infrequent and not significantly different among the groups (P = .28). When TAM-treated women were compared with those who received XRT and placebo, there was a significant reduction in CBC (hazard ratio, 0.45; 95% confidence interval, 0.21 to 0.95; P = .039). Survival in the three groups was 93%, 94%, and 93%, respectively (P = .93). CONCLUSION: In women with tumors ≤ 1 cm, IBTR occurs with enough frequency after lumpectomy to justify considering XRT, regardless of tumor ER status, and TAM plus XRT when tumors are ER positive.