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1863 First line trastuzumab- or lapatinib-based therapy in her2-positive metastatic breast cancer patients after prior (neo)adjuvant trastuzumab
S286 most popular are the elevated levels of circulating estrogens and the insulin resistance with increased levels of insulin and insulin like-growth factor 1 (IGF1). However, little is known about the role of BMI on clinical outcome of HER2-positive metastatic breast cancer (MBC). MATERIAL AND METHODS This is an ancillary study of a cohort study conducted in 14 Italian centres within the GIM (Gruppo Italiano Mammella) group. We performed a retrospective analysis from 329 consecutive pts with HER2-positive MBC treated with trastuzumab-based regimen as first line treatment. World Health Organization BMI categories were used: normal 18.5–24.9 Kg/m2 , overweight 25–29.9 Kg/m2 , and obese 30 kg/m2 . Given the limited sample size, we carried out the analyses using two categories: BMI <25 (normal/underweight) and BMI 25 (overweight/ obese). Progression Free Survival (PFS) and Overall Survival (OS) curves were estimated using Kaplan–Meier method. Survival univariate and multivariate analyses were performed using the Cox proportional hazards model. Disease response to therapy was analyzed using univariate and multivariate logistic regression. Results: Overall, 176 (53.5%) pts were normal or underweight, 109 (33%) pts were overweight, and 44 (13.4%) pts were obese. Median PFS was 14.8 months in BMI <25 group and 15.7 months in BMI25 group (adjustedHR 0.88; 95% CI 0.66–1.17; p = 0.387). Median OS was 58.6 months in BMI <25 group and 52.6 in BMI25 group (adjusted-HR 0.88; 95% CI 0.59– 1.31; p = 0.525). The Overall Response Rate (ORR) was 71.7% and 65.9% (p = 0.296) and Clinical Benefit Rate was 82.1% and 83.3% (p = 0.781) in BMI <25 and BMI25 groups, respectively. Conclusion: This analysis suggests that BMI is not associated with the outcome of pts with HER2-positive MBC treated with trastuzumab-based regimen. We hypothesize that, in contrast with that observed in EBC, in metastatic setting the mechanisms by which BMI may affect prognosis are less important than tumor biology per se. No conflict of interest.
1862 POSTER Pleomorphic lobular carcinoma of the breast associated with impaired overall survival M.B. Hacioglu1 , T. Babacan2 , O. Diker2 , S. Akin2 , M. Demir2 , O. Dizdar2 , M.A. Sendur3 , S. Kilickap2 , M.K. Altundag2 . 1 Diskapi Yildirim Beyazit Education and Research Hospital, Ankara, Turkey, Medical Oncology, Ankara, Turkey; 2 Hacettepe University Oncology Institute, Ankara, TURKEY, Medical Oncology, Ankara, Turkey; 3 Yıldırım Beyazıt University, Medical Oncology, Ankara, Turkey Background: Invasive pleomorphic lobular carcinoma (IPLC) is a rare and distinct morphological variant of invasive lobular carcinoma (ILC) with aggressive biology and poor prognosis. Multiple studies showed impaired overall survival for patients with IPLC than for patients with classic ILC. The aim of this study was to assess clinical and pathological features and survival outcomes associated with pleomorphic ILC compared to invasive ductal carcinoma (IDC). Material and Methods: The files of patients diagnosed with primary breast cancer between 2006–2015 in Hacettepe University Cancer Institute, Medical Oncology Department were reviewed retrospectively. We compared the clinicopathologic characteristics, treatment modalities, diseasefree survival (DFS) and overall survival (OS) of patients with IPLC, ILC and IDC. Results: A total of 2785 breast cancer patients were reviewed retrospectively. Seventeen (0.6%) were male and 2768 (99.4%) were female. Median age was 49 (range 18−92) years. We identified 165 patients with ILC (5.9%), 2599 with IDC (93.3%) and 21 with IPLC (0.8%) histotypes. Characteristics of patients with IPLC compared with ILC and IDC are shown in Table 1. Patients with IPLC had significantly larger tumor size compared to IDC and ILC (p < 0.001). Axilla involvement and disease stage distribution were similar between the groups. Tumor grade was significantly higher in patients with IPLC (p < 0.001) and tumors were more frequently bilateral and multifocal compared to other subtypes. Three years DFS was %76 in IPLC compared to %87 in IDC and %87 in ILC. Three years OS was % 74 in IPLC compared to %94 in IDC and %93 in ILC. Conclusions: As a result, IPLCs tend to occur in younger age group and more frequently in premenopausal women compared with classical lobular carcinomas. IPLCs are more likely to be bilateral, multifocal, high grade and less likely to have positive hormone receptor. Clinical and pathological features of IPLC resemble ductal cancer rather than lobular cancer. 3-year overall and disease-free survival rates in IPLCs are even shorter than ductal and lobular carcinoma despite having similar clinical stage distribution. Given higher grade and lower rates of DFS and OS, more aggressive treatment is needed in patients with IPLC. No conflict of interest.
Abstracts 1863 POSTER First line trastuzumab- or lapatinib-based therapy in her2-positive metastatic breast cancer patients after prior (neo)adjuvant trastuzumab M. Vaglica1 , M. Lambertini2 , A. Ferreira3 , F. Poggio2 , F. Puglisi4 , F. Sottotetti5 , F. Montemurro6 , E. Poletto4 , E. Pozzi5 , E. Risi7 , A. Lai8 , E. Zanardi9 , V. Sini10 , S. Ziliani11 , G. Minuti12 , S. Mura13 , D. Grasso14 , I. Ferrarini15 , P. Pronzato2 , L. Del Mastro1 . 1 IRCCS AOU San Martino-IST, Medical Oncology, U.O. Sviluppo Terapie Innovative, Genova, Italy; 2 IRCCS AOU San Martino-IST, U.O. Oncologia Medica 2, Genova, Italy; 3 Hospital de Santa Maria, Instituto de Medicina Molecular, Lisboa, Portugal; 4 University Hospital, Oncology, Udine, Italy; 5 Fondazione Maugeri IRCCS-, Medical Oncology, Pavia, Italy; 6 Fondazione del Piemonte per l’Oncologia, Istituto di Candiolo IRCCS, Unit of Investigative Clinical Oncology, Candiolo Torino, Italy; 7 Sapienza University, Radiology, Oncology and Human Pathology, Oncology Unit B, Roma, Italy; 8 Azienda Ospedaliera Universitaria, Medical Oncology, Sassari, Italy; 9 IRCCS AOU San Martino-IST, Medical Oncology, Clinica di Oncologia Medica, Genova, Italy; 10 Sant’Andrea Hospital, Sapienza University, Oncology, Roma, Italy; 11 Ospedale San Paolo, Medical Oncology, SAVONA, Italy; 12 Istituto Tumori Toscano, Civil Hospital, Medical Oncology, Livorno, Italy; 13 Ospedale Santissima Annunziata, Oncology, Sassari, Italy; 14 IRCCS San Matteo University Hospital Foundation, Medical Oncology, Pavia, Italy; 15 Azienda Ospedaliera Universitaria Pisana, Polo Oncologico, Pisa, Italy Background: Approximately 15−20% of patients (pts) with HER2-positive early breast cancer relapse during or after (neo)adjuvant trastuzumab. The optimal first-line treatment in this setting has been poorly investigated so far. We evaluated the clinical outcomes of HER2-positive metastatic breast cancer (MBC) pts with prior exposure to (neo)adjuvant trastuzumab who underwent first-line trastuzumab- or lapatinib-based therapy. Materials and Methods: This is an ancillary study within a retrospective cohort study conducted in 14 Italian centres of the GIM (Gruppo Italiano Mammella) group. Consecutive pts undergoing first-line trastuzumab or lapatinib-based therapy after prior exposure to (neo)adjuvant trastuzumab were included. Analyses were performed according to the type of firstline therapy for metastatic disease (trastuzumab or lapatinib). Dichotomous clinical outcomes were analyzed using logistic regression and time-to-event outcomes using Cox proportional hazards models controlling for relevant demographic, clinicopathologic and therapy characteristics. All data were analyzed using Stata 12.3 (StataCorp LP). Results: Out of 450 MBC pts included in the study, 416 (92%) received trastuzumab and 34 (7.5%) lapatinib. A total of 128 pts relapsed after prior (neo)adjuvant trastuzumab and were included in the present analysis: 101 (24.3%) received first-line trastuzumab and 27 (79.4%) lapatinib. As compared to the trastuzumab cohort, more pts in the lapatinib group had a trastuzumab-free interval <1 month (37% vs 14%) and brain metastasis as first site of relapse (38.2% vs 9.4%). In pts receiving first-line trastuzumab or lapatinib, the following outcomes were observed, respectively: overall response rate (ORR) 61.3% vs 45.5% (p = 0.184), clinical benefit rate (CBR) 72.5% vs 68.2% (p = 0.691), median progression-free survival (PFS) 12 vs 11.4 months (p = 0.814) and median overall survival (OS) 48.2 vs 34.7 months (p = 0.722). In pts who had brain metastasis as first site of relapse receiving first-line trastuzumab or lapatinib, PFS was 9.9 vs 12.2 months (p = 0.093) and OS 28.5 vs 33.7 months(p = 0.280), respectively. Conclusions: In HER2-positive MBC pts relapsing after prior (neo)adjuvant trastuzumab and receiving first-line trastuzumab or lapatinib, no significant differences in their clinical outcomes were observed. Although not significant, a trend favouring the use of lapatinib was observed in pts with brain metastases as first site of relapse. No conflict of interest. 1864 POSTER Chemotherapy versus endocrine therapy as first line treatment in patients with luminal-like metastatic breast cancer. Impact on survival M. Bonotto1 , L. Gerratana1 , G. Arpino2 , M. Di Maio3 , C. De Angelis2 , D. Iacono1 , M. Cinausero1 , M. Milano2 , P. Gargiulo2 , C. Fontanella1 , C. Bozza1 , S. Moroso1 , A.M. Minisini1 , M. Mansutti1 , G. Fasola1 , S. De Placido2 , F. Puglisi1,4 . 1 University Hospital of Udine, Department of Oncology, Udine, Italy; 2 University of Naples Federico II, Department of Clinical Medicine, Naples, Italy; 3 University of Torino, Department of Oncology, Turin, Italy; 4 University of Udine, Department of Medical and Biological Sciences, Udine, Italy Background: First line treatment options for patients (pts) with luminal-like metastatic breast cancer (MBC) include chemotherapy (CT) and endocrine
1862 POSTER Pleomorphic lobular carcinoma of the breast associated with impaired overall survival M.B. Hacioglu1 , T. Babacan2 , O. Diker2 , S. Akin2 , M. Demir2 , O. Dizdar2 , M.A. Sendur3 , S. Kilickap2 , M.K. Altundag2 . 1 Diskapi Yildirim Beyazit Education and Research Hospital, Ankara, Turkey, Medical Oncology, Ankara, Turkey; 2 Hacettepe University Oncology Institute, Ankara, TURKEY, Medical Oncology, Ankara, Turkey; 3 Yıldırım Beyazıt University, Medical Oncology, Ankara, Turkey Background: Invasive pleomorphic lobular carcinoma (IPLC) is a rare and distinct morphological variant of invasive lobular carcinoma (ILC) with aggressive biology and poor prognosis. Multiple studies showed impaired overall survival for patients with IPLC than for patients with classic ILC. The aim of this study was to assess clinical and pathological features and survival outcomes associated with pleomorphic ILC compared to invasive ductal carcinoma (IDC). Material and Methods: The files of patients diagnosed with primary breast cancer between 2006–2015 in Hacettepe University Cancer Institute, Medical Oncology Department were reviewed retrospectively. We compared the clinicopathologic characteristics, treatment modalities, diseasefree survival (DFS) and overall survival (OS) of patients with IPLC, ILC and IDC. Results: A total of 2785 breast cancer patients were reviewed retrospectively. Seventeen (0.6%) were male and 2768 (99.4%) were female. Median age was 49 (range 18−92) years. We identified 165 patients with ILC (5.9%), 2599 with IDC (93.3%) and 21 with IPLC (0.8%) histotypes. Characteristics of patients with IPLC compared with ILC and IDC are shown in Table 1. Patients with IPLC had significantly larger tumor size compared to IDC and ILC (p < 0.001). Axilla involvement and disease stage distribution were similar between the groups. Tumor grade was significantly higher in patients with IPLC (p < 0.001) and tumors were more frequently bilateral and multifocal compared to other subtypes. Three years DFS was %76 in IPLC compared to %87 in IDC and %87 in ILC. Three years OS was % 74 in IPLC compared to %94 in IDC and %93 in ILC. Conclusions: As a result, IPLCs tend to occur in younger age group and more frequently in premenopausal women compared with classical lobular carcinomas. IPLCs are more likely to be bilateral, multifocal, high grade and less likely to have positive hormone receptor. Clinical and pathological features of IPLC resemble ductal cancer rather than lobular cancer. 3-year overall and disease-free survival rates in IPLCs are even shorter than ductal and lobular carcinoma despite having similar clinical stage distribution. Given higher grade and lower rates of DFS and OS, more aggressive treatment is needed in patients with IPLC. No conflict of interest.
Abstracts 1863 POSTER First line trastuzumab- or lapatinib-based therapy in her2-positive metastatic breast cancer patients after prior (neo)adjuvant trastuzumab M. Vaglica1 , M. Lambertini2 , A. Ferreira3 , F. Poggio2 , F. Puglisi4 , F. Sottotetti5 , F. Montemurro6 , E. Poletto4 , E. Pozzi5 , E. Risi7 , A. Lai8 , E. Zanardi9 , V. Sini10 , S. Ziliani11 , G. Minuti12 , S. Mura13 , D. Grasso14 , I. Ferrarini15 , P. Pronzato2 , L. Del Mastro1 . 1 IRCCS AOU San Martino-IST, Medical Oncology, U.O. Sviluppo Terapie Innovative, Genova, Italy; 2 IRCCS AOU San Martino-IST, U.O. Oncologia Medica 2, Genova, Italy; 3 Hospital de Santa Maria, Instituto de Medicina Molecular, Lisboa, Portugal; 4 University Hospital, Oncology, Udine, Italy; 5 Fondazione Maugeri IRCCS-, Medical Oncology, Pavia, Italy; 6 Fondazione del Piemonte per l’Oncologia, Istituto di Candiolo IRCCS, Unit of Investigative Clinical Oncology, Candiolo Torino, Italy; 7 Sapienza University, Radiology, Oncology and Human Pathology, Oncology Unit B, Roma, Italy; 8 Azienda Ospedaliera Universitaria, Medical Oncology, Sassari, Italy; 9 IRCCS AOU San Martino-IST, Medical Oncology, Clinica di Oncologia Medica, Genova, Italy; 10 Sant’Andrea Hospital, Sapienza University, Oncology, Roma, Italy; 11 Ospedale San Paolo, Medical Oncology, SAVONA, Italy; 12 Istituto Tumori Toscano, Civil Hospital, Medical Oncology, Livorno, Italy; 13 Ospedale Santissima Annunziata, Oncology, Sassari, Italy; 14 IRCCS San Matteo University Hospital Foundation, Medical Oncology, Pavia, Italy; 15 Azienda Ospedaliera Universitaria Pisana, Polo Oncologico, Pisa, Italy Background: Approximately 15−20% of patients (pts) with HER2-positive early breast cancer relapse during or after (neo)adjuvant trastuzumab. The optimal first-line treatment in this setting has been poorly investigated so far. We evaluated the clinical outcomes of HER2-positive metastatic breast cancer (MBC) pts with prior exposure to (neo)adjuvant trastuzumab who underwent first-line trastuzumab- or lapatinib-based therapy. Materials and Methods: This is an ancillary study within a retrospective cohort study conducted in 14 Italian centres of the GIM (Gruppo Italiano Mammella) group. Consecutive pts undergoing first-line trastuzumab or lapatinib-based therapy after prior exposure to (neo)adjuvant trastuzumab were included. Analyses were performed according to the type of firstline therapy for metastatic disease (trastuzumab or lapatinib). Dichotomous clinical outcomes were analyzed using logistic regression and time-to-event outcomes using Cox proportional hazards models controlling for relevant demographic, clinicopathologic and therapy characteristics. All data were analyzed using Stata 12.3 (StataCorp LP). Results: Out of 450 MBC pts included in the study, 416 (92%) received trastuzumab and 34 (7.5%) lapatinib. A total of 128 pts relapsed after prior (neo)adjuvant trastuzumab and were included in the present analysis: 101 (24.3%) received first-line trastuzumab and 27 (79.4%) lapatinib. As compared to the trastuzumab cohort, more pts in the lapatinib group had a trastuzumab-free interval <1 month (37% vs 14%) and brain metastasis as first site of relapse (38.2% vs 9.4%). In pts receiving first-line trastuzumab or lapatinib, the following outcomes were observed, respectively: overall response rate (ORR) 61.3% vs 45.5% (p = 0.184), clinical benefit rate (CBR) 72.5% vs 68.2% (p = 0.691), median progression-free survival (PFS) 12 vs 11.4 months (p = 0.814) and median overall survival (OS) 48.2 vs 34.7 months (p = 0.722). In pts who had brain metastasis as first site of relapse receiving first-line trastuzumab or lapatinib, PFS was 9.9 vs 12.2 months (p = 0.093) and OS 28.5 vs 33.7 months(p = 0.280), respectively. Conclusions: In HER2-positive MBC pts relapsing after prior (neo)adjuvant trastuzumab and receiving first-line trastuzumab or lapatinib, no significant differences in their clinical outcomes were observed. Although not significant, a trend favouring the use of lapatinib was observed in pts with brain metastases as first site of relapse. No conflict of interest. 1864 POSTER Chemotherapy versus endocrine therapy as first line treatment in patients with luminal-like metastatic breast cancer. Impact on survival M. Bonotto1 , L. Gerratana1 , G. Arpino2 , M. Di Maio3 , C. De Angelis2 , D. Iacono1 , M. Cinausero1 , M. Milano2 , P. Gargiulo2 , C. Fontanella1 , C. Bozza1 , S. Moroso1 , A.M. Minisini1 , M. Mansutti1 , G. Fasola1 , S. De Placido2 , F. Puglisi1,4 . 1 University Hospital of Udine, Department of Oncology, Udine, Italy; 2 University of Naples Federico II, Department of Clinical Medicine, Naples, Italy; 3 University of Torino, Department of Oncology, Turin, Italy; 4 University of Udine, Department of Medical and Biological Sciences, Udine, Italy Background: First line treatment options for patients (pts) with luminal-like metastatic breast cancer (MBC) include chemotherapy (CT) and endocrine