Zoledronic Acid Prevents Bone Loss in Premenopausal Women with Early Breast Cancer Undergoing Adjuvant Chemotherapy: A Phase III Study of Korean Cancer Study Group (KCSG-BR06-01)

Background: Adjuvant chemotherapy results in early menopause in the majority of premenopausal patients due to premature ovarian failure and consequent skeletal morbidity. Zoledronic acid (ZA) is known to prevent bone loss in postmenopausal women. The purpose of this study was to determine whether ZA can prevent bone loss in premenopausal women undergoing adjuvant chemotherapy for breast cancer.Methods: This study is a randomized, open-label, phase III multicenter trial. Premenopausal women older than age 40 were randomly assigned to ZA group (two infusions of 4 mg IV, every 6 months) or observation group after surgery. All patients were treated with the same adjuvant chemotherapy regimen (AC-->T; 4 cycles of AC followed by 4 cycles of paclitaxel or docetaxel). The first infusion of ZA was given on day 1 of the first chemotherapy. All patients received supplementations with oral calcium 600 mg/d and vitamin D 400 IU/d. The bone mineral density (BMD) was measured at the baseline, 6th and 12th months. Bone turnover markers were measured before chemotherapy and in 3, 6, 12 months.Results: Between March 2007 and May 2008, a total of 110 premenopausal women were enrolled in this study and the majority of women (91.8%) developed amenorrhea at 1 year post chemotherapy. The mean percent change of BMD in lumbar spine was +0.5% in the ZA group versus -3.6% in the observation group at 6 months (p<0.01) and, -1.0% versus -7.5%, at 12 months (p<0.01). Differences in percent change of BMD from baseline between two groups were 6.5% (95% CI, 5.2 to 7.9%) for the lumbar spine, and 3.6% (95% CI, 2.2% to 5.1%) for the femoral neck (p<0.01). Type I collagen metabolite PINP levels at 12 months were significantly higher in the observation group than in the ZA group; 72.7 mg/l (range 21.8∼250 mg/l) versus 30.8 mg/l (range 14.7∼62.7 mg/l) (p=0.0001). Changes of other bone turnover markers including urinary N-telopeptide, bone alkaline phosphatase, and serum C-telopeptide were also significantly different between two groups (p<0.01). ZA was generally well tolerated, and adverse event profile was similar between two groups.Conclusion: Adjuvant chemotherapy with AC-->T induced amenorrhea in the majority of patients over 40 years in this study. Treatment with two infusions of ZA 4 mg every 6 months effectively prevented bone loss within the first year of adjuvant chemotherapy for early breast cancer in premenopausal women. Regular BMD measurements and early bisphosphonate therapy should be considered for this population.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2104.

KIT and PDGFRAmutation status and their immunohistochemical (IHC) expression profile of gastrointestinal stromal tumor (GIST) patients treated with imatinib (IMT): Seven-year single-center experience

10558

Background: Previous studies suggested the role of KIT and PDGFRAmutations on treatment outcome of GIST with IMT, but results are heterogeneous. IHC value of PDGFRA and PDGFRB is not established. Methods: We included patients (pts) treated with IMT as a first line therapy for metastastic or relapsed GIST between 2001 and 2008. Tumor DNA was extracted to investigate the mutation status of KITexon 9, exon 11, PDGFRA exon 12 and 18. IHC stain of c-KIT and PDGFRA/B was performed. We assessed the correlation between the treatment outcome, genetic status and IHC results. Results: A total of 85 pts (M:F=49:36, median age 58.4 years) received IMT 400 mg daily. Location of primary disease included stomach (33), small bowel (34), rectum (10), esophagus (1), and omentum/mesentery (7). Complete and partial responses were achieved in 6% and 62% of pts respectively, while 5% of pts had progressive disease. During median follow up of 28.1 months, estimated median PFS was 39.8 months. KIT exon 11 and 9 mutations were detected in 64% and 5% respectively. Exon 11 mutations included 44 deletions, 2 insertions, 5 substitutions and 3 deletion/insertions. PDGFRA exon 12 and 18 mutations were detected in 2% respectively. Positive rate of c-KIT, PDGFRA and PDGFRB using IHC was 96%, 21%, and 26% respectively. PDGFRA and PDGFRB were co-expressed (p=0.001). PDGFRA mutation did not correlate with PDGFRA/B expression. Clinical response was not different according to the mutation status or IHC expression. PFS of KIT exon 11, KITexon 9, PDGFRA mutants and pts without detectable mutations were not different (p=0.397). Pts with KIT exon 11 balanced mutations (substitution or deletion/insertion) showed longer PFS compared with pts with unbalanced mutations (deletion or insertion) (p=0.014) or pts without exon 11 mutations (p=0.033). Median PFS was shorter in pts lacking c-KIT (p=0.001) expression. PDGFRA/B expression did not influence PFS. Conclusions: Balanced mutation of KIT exon 11 predicted longer PFS, while lack of c-KIT protein expression predicted shorter PFS for GIST pts treated with first line IMT. PDGFRA and B were co-expressed without predictive value.

No significant financial relationships to disclose.

The relationship between the responses to prior systemic therapies and the efficacy of subsequent pemetrexed (Pem) therapy in patients (pts) with advanced non-small cell lung cancer (NSCLC)

8061

Background: Pem has been used for pts with previously treated advanced NSCLC. We tried to examine whether the response to prior systemic therapy regimen could predict the efficacy of subsequent Pem therapy. Methods: The medical record of clinical stage IIIB or IV NSCLC pts who received Pem as the second-line or further-line treatment were analyzed retrospectively. Prior systemic therapies were divided into 4 types [gemcitabine based (G), paclitaxel based (P), docetaxel based (D), and EGFR tyrosine kinase inhibitors (I)]. Along with that, patients were classified into two response groups, either responders (partial responses or stable disease for 4 months or more) or non-responders to each type of the prior therapy. Response rate (RR) and progression free survival (PFS) for Pem therapy were analyzed according to the response groups for each type of prior therapies. Results: A total of 247 pts received Pem therapy, and their median PFS was 2.3 months. The number of pts who previously received G, P, D and I, was 159, 120, 110, and 139, respectively. The RR for Pem was higher in responders to G therapy than in non-responders to G (15.0% vs 4.3%, p = 0.02). In addition, median PFS after Pem therapy was longer in responders to G therapy than in non-responders (3.0 vs 1.7 months, p = 0.007). However, the responses to prior P, D, I therapies had no impact on the efficacy of subsequent Pem therapy. By univariate analyses, the variables of the responders to G therapy, female, never-smoker, ECOG performance status 0–1 were good predictive factors for Pem therapy in terms of PFS. By multivariate analysis, only the responders to G therapy had a statistical significance (Hazard ratio = 0.55; 95% CI, 0.37–0.82). Conclusions: The response to the prior gemcitabine based therapy was a predictive factor for subsequent pemetrexed therapy for advanced NSCLC.

No significant financial relationships to disclose.

Prospective evaluation of oral mucositis in solid tumor patients undergoing chemotherapy and its clinical implication

e20650

Background: Oral mucositis (OM) induced by chemotherapy is a troublesome and debilitating adverse effect in solid tumor patients. OM might influence the complicated aspects such as the poor oral intake and malnutrition over just oral symptom. Therefore we prospectively evaluated the actual incidence of OM and its clinical significance in solid tumor patients. Methods: From October 16, 2007 to September 3, 2008, we consecutively enrolled 344 patients with solid tumor who initiated new chemotherapy. Each patient was prospectively evaluated for two cycles. The data were collected from physician-to-patient interview. And patients’ diary for OM symptom was used as patient-reported measurement. The visual analog scale (VAS) was used to quantify the degree of adverse effects (VAS: 0 point = no symptoms, 4 point = the worst symptom) and FACT-G was used for assessment of the quality of life (QOL). Results: Finally, 322 patients were analyzed. The median age was 51. Breast cancer was the most common (51%). And, stage IV was 137 (43%). OM was 28% per each cycle and 45% per patient during two cycles. Patient-reported OM symptom had peak in one week and was recovered in 9.14±6.77 days. Oral dryness was the most prevalent symptom out of symptoms related with OM such as oral pain, poor oral intake, dysphagia, oral bleeding, scalloping of tongue and ulceration (VAS score 1≤; 47%, 27%, 39%, 15%, 7%, 14%, 13%, respectively). In QOL measured by FACT-G, physical well-being and emotional well-being were significantly dropped in OM-occurred group than in no-OM group (19.09±6.48 vs 22.47±5.95, p<0.001; 16.74±4.10 vs 17.97±3.38, P<0.001, respectively). In addition, higher VAS score for other adverse effects was showed in OM-occurred group than in no-OM group (activity, nausea, vomiting, fever, myalgia and nervous system; p=0.0038, p<0.0001, p=0.0007, p=0.0062, p<0.0001, p<0.0001, respectively). Conclusions: Forty five percent of patients with solid tumor experience OM during 2 cycles of chemotherapy. In case of patients with OM, QOL is worse and the other adverse effects are more prevalent. OM could be an indicator of QOL and other adverse effects during chemotherapy.

No significant financial relationships to disclose.

Trastuzumab-mediated cardiac dysfunction (CDx) outside of clinical trials: Single Asian center experience

e20732

Background: Trastuzumab is an effective drug for the treatment of HER2 positive breast cancer (BC) and CDx has been reported as a major toxicity. The purpose of our study was to investigate the trastuzumab mediated CDx in practice setting and the treatment outcome at single Asian center. Methods: We retrospectively analyzed 181 HER2-overexpressing BC patients (pts) who were treated with trastuzumab containing regimen between January 2005 and December 2007 at Seoul National University Hospital. We investigated the incidence of CDx and the degree of reversibility using echocardiography (EchoCG) and identify the risk factors to predict CDx. Results: Among 181 patients (pts), 112 were treated for palliative purpose and 139 had previously received anthracycline-based chemotherapy. Baseline EchoCG results were available in 129 pts (median age 47; range 25–79) and median left ventricular ejection fraction (LVEF) was 59% (range 45–70). Median follow-up duration was 21 months. LVEF decreased more than 5% points in 37 out of 129 (28.6%). According to the national cancer institute common terminology criteria for adverse events, grade (G) 2 and G 3/4 CDx developed in 4 (3.1%) and 8 (6.2%) pts respectively. Seven pts experienced symptomatic heart failure (HF). 3 among 5 pts who experienced discontinuation of trastuzumab could resume trastuzumab after median 146 (range 94–163) days of discontinuation. Median LVEF was 54% (range 45–63) at baseline in pts who experienced G2–4 CDx and deceased to 45% (range 30–49) after median 175 (range 65–415) days of trastuzumab treatment. HF treatment was initiated in 9 pts. 4 pts received angiotensin converting enzyme inhibitors (ACEI), 3 pts angiotensin receptor blockers (ARB) and 2 pts ACEI or ARB with diuretics. Occurrence of CDx (G2–4) was associated with higher anthracycline cumulative doses (p=0.039) and lower baseline LVEF (p=0.003). The incidence of symptomatic HF was related with past medical history such as hypertension (p=0.019) and lower baseline LVEF (p=0.005). Among the pts who had G2–4 CDx, LVEF was restored to 54% (range 40–59) which was similar to baseline at median 187 (range 56–477) days after the diagnosis of CDx. Conclusions: The majority pts with trastuzumab-mediated CDx were asymptomatic and LVEF could be reversible.

No significant financial relationships to disclose.

Combination chemotherapy of irinotecan with fluoropyrimidine in taxane, anthracycline, and fluoropyrimidine-pretreated metastatic breast cancer

e12003

Background: Irinotecan (I) has some efficacy in taxane (T) and anthracycline (A)-refractory breast cancer, and combination of I and fluoropyrimidine (F) shows synergistic effects in preclinical model. We conducted this study to reveal the clinical outcomes of I and F combination therapy in T, A, and F-pretreated metastatic breast cancer. Methods: We consecutively enrolled metastatic breast cancer patients treated with I and F combination chemotherapy from 2000 to 2008 in Seoul National University Hospital. They all had been previously heavily treated with T, A, and F. We retrospectively analyzed the clinical outcomes. Results: Twenty-five patients were enrolled. The median age was 38 years (range: 30–56years). The performance status was: ECOG 1 (11 patients), 2 (13), and 3 (1). The most commonly involved site was bone (16 patients), liver (13), and lung (12). The biologic subtype was: hormone receptor (+) 17 patients, HER-2 (+) 2, triple-negative (TNBC) 6. The median time from diagnosis of metastatic breast cancer to the initiation of IF therapy was 34 months (range: 12–97 months). The used regimens were: FOLFIRI (18 patients), TS-1/ irinotecan (6), capecitabine/irinotecan (1). Response was evaluable in 24 patients. There was no CR/PR. Stable disease was shown in 29.2% and 70.8% was PD, that is disease control rate was 29.2% (95% CI:10–45%). The median duration of disease control was 3.9 months (95% CI 3.7–4.2, range 2.4–11). The progression-free survival was 1.4 months (95% CI:0.7–21, range: 0.5–11.4), and overall survival was 6 months (95% CI: 4.2–7.8, range: 1–23). According to the biologic subtypes, the median PFS was 2.0 vs. 1.3 months (p=0.895) and OS was 4 vs. 6 months (p=0.807) respectively in TNBC VS Non-TNBC. In multivariate analysis, patients with good PS showed longer OS (p = 0.035). The Gr 3/4 hematologic toxicity was: neutropenia 18.6%, anemia 1.3%, thrombocytopenia 1.3%. And the major Gr 3/4 non-hematologc toxicity was: diarrhea (4%), hand-foot syndrome (0%), fatigue (0%). No treatment-related death was occurred. Conclusions: Treatment of I combined with F might be an option in metastatic breast cancer patients heavily treated with T, A, and F, irrespective of TNBC. Further prospective studies are warranted.

No significant financial relationships to disclose.

The prognostic factors for the recurred breast cancer patients with isolated, limited number of lung metastasis, and the implication of pulmonary metastasectomy

1112

Background: In recurred breast cancer (BC) with isolated lung metastasis, the role of pulmonary metastasectomy (PM) is not established. Methods: We consecutively enrolled recurred BC patients (pts) with isolated lung metastasis from 1997 to 2007 in Seoul National University Hospital. Among 140 recurred pts with isolated lung metastasis, 45 had metastatic lesions less than 4. We analyzed the clinical outcomes of these 45 pts. Results: The median age was 49.0 (range 32–67) years. The median disease-free interval (DFI, Time from initial BC diagnosis to recur) was 26.1 (range 4.2–168.0) months, and the pts with DFI of less than 24 months were 20 (44%). The pts who had biologic subtypes (BS) of hormone receptor (HR)(+), HER-2(+), triple negative (TN) were 16 (36%), 14 (31%,) and 15 (33%), respectively. Fifteen (33%) had PM then followed by systemic treatment (PM group), and 30 received systemic treatment without PM (no PM group). There was no difference in terms of clinical factors such as DFI and BS between two groups. The median progression-free survival (PFS) and overall survival (OS) were 13.0 months (95% CI, 10.05–15.95) and 41.7 months (95% CI, 23.82–59.58), respectively. In univariate analysis, PFS was significantly longer in pts with PM (p < 0.001), DFI of more than 24 months (p < 0.001), and was marginally significant according to BS (p = 0.084). In multivariate analysis, DFI of less than 24 months (hazard ratio [H], 4.53; 95% CI, 1.72–11.90), no PM (H, 9.52; 95% CI, 3.34–27.18) and BS such as HER-2(+) (H, 3.00; 95% CI, 1.04–8.64) and TN (H, 3.92; 95% CI, 1.32–11.59) were independent prognostic factors for shorter PFS. In univariate analysis, OS was significantly longer in pts with PM (p = 0.011), DFI of more than 24 months (p < 0.001), HR(+) BS (p = 0.009). In multivariate analysis, DFI of less than 24 months (H, 7.67; 95% CI, 2.00–29.43) and BS such as HER-2(+) (H, 3.70; 95% CI, 1.03–13.24) and TN (H, 3.27; 95% CI, 1.02–10.44) were independent prognostic factors for shorter OS. Conclusions: In recurred BC with isolated, limited number (less than 4) of lung metastasis, DFI and BS were prognostic factors for PFS and OS. PM also prolonged PFS, and, for OS, more follow-up is needed. Further prospective studies to define the role of PM are warranted.

No significant financial relationships to disclose.

Prognostic implication of the maximum standardized uptake value (mSUV) on 18F FDG-PET in patients with metastatic hepatocellular carcinoma

e15531

Background: The role of 18F-fluorodeoxyglucose-positron emission tomography (18F FDG- PET) in hepatocelluar carcinoma (HCC) has not been firmly established. We conduct this study to investigate the value of mSUV on 18F FDG-PET as a prognostic factor in HCC, especially in metastatic setting. Methods: We consecutively enrolled HCC patients with extrahepatic metastatic lesions, who have been evaluated with 18F FDG-PET before palliative anticancer treatment, between January 2000 and June 2008 at the Seoul National University Hospital. We retrospectively analyzed the clinical outcome and the value of mSUV as a prognostic factor. Results: A total of 57 patients (male, 86.0%) were enrolled. Median age was 57 years (range, 36–78). Hepatitis B was the predominant cause of HCC (82.5%), followed by non-viral hepatitis (14.0%) and hepatitis C (3.5%). Most patients (94.7%) were Child-Pugh A and 3 patients (5.3%) were Child-Pugh B. The most commonly involved site was lung (47%), bone (26%), and LN (33%). Median serum AFP level was 68ng/ml (range, 2–48000) and the median mSUV was 4.1 (range, 0.5–57.0). Forty patients (70.2%) received systemic chemotherapy, 14 patients (24.6%) received palliative radiotherapy, 23 patients (40.4%) received palliative surgery, and 7 patients (12.3%) received TACE. In univariate analysis of overall survival (OS), patients with mSUV over 4.0, AFP over 400ng/ml, and presence of intrahepatic viable lesion, and no palliative surgery showed significantly shorter OS (p=0.007, p=0.006, p<0.001, p=0.02, respectively). In multivariate analysis of OS, mSUV over 4.0, AFP over 400ng/ml, and presence of intrahepatic viable lesion were independent prognostic factors (p=0.01, p=0.01, p<0.001, respectively). In patients with mSUV > VS <4.0 or AFP > VS <400ng/ml, there was no difference of palliative anticancer treatment pattern. When combined mSUV with AFP, the OS of patients with mSUV >4.0 and AFP>400ng/ml VS mSUV <4.0 or AFP<400ng/ml VS mSUV <4.0 and AFP<400ng/ml was 11.0 months vs 16.0 months vs 35.7 months, respectively (p=0.006). Conclusions: The mSUV on 18F FDG-PET is a prognostic factor for OS in patients with metastatic HCC. The combined analysis of mSUV with AFP can have a more potent prognostic impact.

No significant financial relationships to disclose.

A phase II study of imatinib mesylate as adjuvant treatment for curatively resected high-risk localized gastrointestinal stromal tumors

e21515

Background: In our previous study, the presence of c-kit mutation as well as tumor size and mitotic count was an independent poor risk factor for relapse after curative resection of primary localized GIST. The patients with all the 3 poor risk factors had only 30% of 2 year relapse free survival rate (RFSR). (Kim, et al. Clin Cancer Res, 2004) It is also well known that c-kit exon 11 mutant GISTs respond better to imatinib treatment than the other mutant or wild type GISTs. Therefore, the patients who have primary localized GISTs with large size, high mitotic count, and c-kit exon 11 mutation may be the best candidate of adjuvant imatinib treatment. In this phase II study, we have evaluated the efficacy and safety of adjuvant imatinib for this patient group. Methods: Patients who underwent complete resection of a primary GIST with 1) c-kit exon 11 mutation, and 2) ≥10 mitoses/50 HPF, or tumor size ≥10 cm, or ≥5 mitoses/50 HPF and tumor size ≥5 cm were eligible. Patients received imatinib 400mg p.o. daily until recurrence of disease, intolerable toxicities, or for 2 years. The primary end point was relapse-free survival (RFS). Results: A total of 47 patients from 4 centers in Korea were enrolled. The median age was 57.0 years. Stomach was the most common primary site (n=31). Median primary tumor size was 7.5cm and median mitoses index was 12/50 HPF. With a median follow-up of 26.9 months, the median RFS and overall survival (OS) have not yet been reached. RFSR was 97.7% at 1-year and 92.7% at 2-years. Six relapses (12.8%) were documented among the 47 patients. The treatments were generally well tolerated. Grade 3–4 toxicities included neutropenia 27.7%, rash 8.5%, constipation 4.3%, anorexia 2.1%, vomiting 2.1%, and pruritis 2.1%. There were no episode of febrile neutropenia and treatment-related death. Conclusions: Postoperative adjuvant imatinib for 2 years were safe and could prolong the RFS in patients with high-risk of recurrence following complete surgical resection of the primary GIST. However, it remains unknown if this benefit in RFS can be translated into OS benefit. So, further follow-up is needed with comparison of OS with historical controls who could be use imatinib after recurrence.

[Table: see text]

Metaplastic breast carcinoma: clinicopathologic features and prognostic value of triple-negativity

Abstract #1085

Backgroud Metaplastic breast carcinomas (MBC) are a rare type of breast cancer comprising &lt;1% of all invasive breast cancers and are generally characterized by hormone receptor and human epidermal growth factor receptor 2 (HER2) negativity. There is a paucity of information on prognosis according to hormone receptor and HER2 expression for these rare tumors. The aim of this study was to compare the clinical features and prognosis, between triple negative metaplastic carcinoma (TNMC) and non-triple negative metaplastic carcinoma (NTNMC).&#x2028; Material and Methods We retrospectively analyzed MBC patients treated at Seoul National University Hospital between 1996 and 2006. Pathologic, immunohistochemical findings and clinical outcome information were reviewed.&#x2028; Results fifty-one patients were identified. The median age at presentation was 45.8 years (range: 27.3-83.8). Median tumor size at diagnosis was 3.0 cm (range: 0.8-12.0). 34 cases (66.7%) were node-negative, 16 (31.4%) node-positive, and 1 (2.0%) were missing. Estrogen receptor (ER)/progesterone receptor (PR) yielded negative results in 49 cases (96.1%) and 48 cases (94.1%), respectively. HER2 overexpression by immunohistochemistry was negative in 41 of 51 (80.4%). At median follow-up of 40.8 months, the 5-year overall survival rate and disease free survival were 73.9% and 64.9%, respectively. Non-triple negativity (p=0.031) correlated significant with overall survival in multivariate analysis.&#x2028; Of the 51 patients, 39 (76.5%) were TNMC, and 12 (23.5%) were NTNMC. In TNMC and NTNMC group, median ages were 45.6 and 51.5 years and tumor sizes were 3.0 cm and 3.0 cm, respectively. There were 12 patients (30.8%) in TNMC and 4 patients (33.3%) in NTNMC for lymph node metastasis. Two groups did not differ significantly by age, tumor size, or nodal status. Positive rates for ER, PR and HER2 were 16.7%, 25% and 83.3% in NTNMC. The 3-year overall survival rates in TNMC and NTNMC were 91.4% and 61.9%, respectively (p=0.029). As regards to 3-years disease-free survival, there was no statistically significant difference between TNMC and NTNMC (p=0.694, 75.8% versus 75.0%).&#x2028; Discussion MBC mainly has triple negative features. However, in subgroup analysis of MBC, non-triple negative group displayed a poor prognosis compared with triple negative group, which is contrary to the case of invasive ductal carcinoma of breast. Further research exploring mechanism of this result.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1085.

Remarkable complete pathologic response rate after preoperative paclitaxel, gemcitabine, and trastuzumab chemotherapy in HER2 positive stage II/III breast cancer: a phase II multicenter study

Abstract #5105

Background: Preoperative paclitaxel (P) and gemcitabine (G) combination therapy given on D1/D8 every 3 weeks (wks) for 4 cycles was well tolerated and effective in stage II/III breast cancer (BC) in our previous phase II study, with an 18% pathological complete response (pCR) rate. Adding trastuzumab (H) to the preoperative chemotherapy increases both of the clinical and pathological response rates in HER2 positive BC patients (pts). Thus far, the highest pCR rate reported in the literature was obtained with anthracycline-based regimens in combination with trastuzumab. This study evaluated whether non-anthracycline combination chemotherapy with PGH could improve the pCR rate in HER2 positive BC. Methods: HER2 positive, stage II/III BC pts with cytologically confirmed axillary lymph node (LN), ≥ 18 years of age, with adequate organ function, and good performance status were eligible. No prior therapy was allowed. Pts received H intravenously (iv) at 4 mg/kg on D1 of the first cycle with subsequent weekly doses of 2 mg/kg in combination with P 80 mg/m2 and G 1,200 mg/m2, iv, on D1/D8 every 3 wks for 6 cycles. Within 2 wks postoperatively, patients received H 6 mg/kg every 3 wks for 11 cycles with tamoxifen or an aromatase inhibitor for 5 years if indicated. All pts received postoperative radiation therapy. Initial evaluation included sonogram and MRI of the breast, MUGA scan, or echocardiogram, and PET-CT. Results: All 53 planned pts were enrolled between April 2007 and February 2008. The median age was 43 years (range, 26–61 years), the median primary tumor size by sonogram was 5.3 cm (range, 2.0 to &gt; 12 cm) with 89 % ≥ stage IIIA, 42% T3/T4, and 28% N3. Twenty four tumors (45%) were multiple and 20 tumors (38%) were ER positive. By May 2008, 47 patients completed surgery with a 74% breast conservation rate. Twenty-eight of 47 (60%; 95% CI, 45-72) patients achieved pCR in both the tumor and lymph node, with 68% (32/47; 95% CI, 54-80) pCR in the primary tumor, and 77% (36/47; 95% CI, 63-86) pCR in the axillary LN. Median metastatic focus in 21 positive LNs (n=11 pts) was 1 mm (range, &lt;1–13mm). Grade III/IV adverse events (AE) were neutropenia (53%), febrile neutropenia (4%), and transient elevation of AST/ALT (9%). After 6 cycles of PGH chemotherapy, all patients maintained above normal LVEF. Conclusions: A remarkably high pCR was obtained by non-anthracyline based PGH combination therapy for HER2 positive stage II/III breast cancer. This combination is well tolerated with mild degree of AEs.&#x2028; Supported by NCC Grant No 0610240-3. Trastuzumab, paclitaxel, and gemcitabine were supplied by Roche, CJ Cheiljedang CO., and Eli Lilly and CO., respectively.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5105.