Search

Background: Triple negative breast cancer (TNBC) is well known for its more aggressive course and poorer prognosis compared to other BC subtypes. RegistEM study provides real world data to understand the distribution of BC subtypes in the advanced setting, being its primary objective. Biological samples collection is part of its procedures. This is a non-interventional cohort study and 1,907 patients (pts) have been enrolled up to now (females and males) with advanced BC (ABC), diagnosed from Jan-2016 to Dec-2019, either after recurrence or as first BC diagnosis, in 38 Spanish sites. These pts will be followed for at least 5 years. Methods: In the current analysis (cut-off date 08/April/2022, database ongoing), we describe characteristics, treatment patterns and outcomes, including comparison between recurrent and de novo disease, of 157 pts with advanced TNBC included in the RegistEM study. Those pts represent the 10% of pts available in the database at the cut-off date and with ABC diagnosis up to December 2018 (n=1559). The BC clinical subtypes were histologically confirmed on the most recent tumor lesion (metastatic [M] or primary BC) before starting with the 1st-line therapy. Results: At first ABC diagnosis, 73% pts had recurrent early BC (EBC), 26% de novo MBC and 1% unresectable locally ABC (ULABC). Median age was 57 years (range 30-88), all pts were women, 98% Caucasian and 65% postmenopausal. Family history of BC and/or ovarian cancer was reported in 37% pts, and a hereditary-risk genetic test was performed in 59 of 147 pts. Germline BRCA1/2 and TP53 were the most frequently mutated genes, 21% (6/28) and 47% (8/17) pts, respectively. Visceral involvement was present in 69% pts (similar between recurrent EBC and de novo ABC, although brain metastases were only present in the recurrent EBC group), and ≤ 2 metastatic locations in 59%. In 61% (70/115) pts with recurrent EBC, the subtype was assessed in metastatic lesions, and 39 pts of them also had TN subtype in primary BC. In terms of the most frequent therapies by line: 1) 1st-line: chemotherapy (CT) (60%) and CT/biological therapy (BT) (39%). Of the 87 pts with CT alone, monotherapy was the preferred option in 57% pts (capecitabine 25%, taxanes 16%, and eribulin or vinorelbine, 5% each). Bevacizumab was the most frequent BT (79%) combined with CT (single agent in 56% pts, mostly taxanes and capecitabine). Progressive disease (PD) was reported in 85% pts (similar in pts with both recurrent and de novo MBC or ULABC); 2) 2nd-line: CT (79%) (monotherapy capecitabine, eribulin, taxanes) and CT/BT (17%) (CT-containing bevacizumab 82%). Progression was reported in 92% pts; 3) 3rd-line: CT (90%) (eribulin 33%, platinum-based 25%) and CT/BT (9%) (CT-containing bevacizumab 67%). Progression was reported in 88% pts. At database cut-off date, death was reported in 133 (85%) pts, mainly because of PD. Overall survival (OS) was similar between both groups, recurrent and de novo MBC. Conclusion: In this population of Spanish TNBC pts with ABC, three quarters had recurrent disease. De novo ABC pts had a higher proportion of non-visceral metastases, with absence of brain involvement at the first diagnosis. Single-agent CT and CT plus bevacizumab were the most frequent therapies, and OS was similar between recurrent and de novo MBC pts, although numerically higher in the later group. Citation Format: Silvia Antolin Novoa, César A Rodríguez, Josefina Cruz, Sara López-Tarruella, Ariadna Tibau, Encarna Adrover, Ana Miguel, Mireia Margelí, Purificación Martínez, María Hernández, Antonio Antón, Álvaro Rodríguez-Lescure, Catalina Falo, Isabel Álvarez, Diego Malón, Raquel Andrés, José L Alonso-Romero, César Gómez, J. José Illaramendi, Ruth Campo, Juan José Miralles, Susana Bezares, Federico Rojo, Angel Guerrero-Zotano. Treatment strategies for advanced triple negative breast cancer patients as per routine clinical practice: analysis from the observational study GEICAM/2014-03 (RegistEM) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-45.

Background: HER2-low breast cancer (BC) is a new therapeutic entity, but it is uncertain if this subgroup of BC differs from HER2-negative tumors in clinical characteristics, prognosis, and response to therapy. The objective is to describe the clinical characteristics and outcomes of 422 patients (pts) with HER2-low BC documented before 1st line, having been diagnosed with advanced BC (ABC) before 2019 and included in the RegistEM study (n=1,663). Methods: In this analysis (cut-off date 08/April/2022; database is ongoing), two subgroups of pts have been considered based on HER2 results: HER2-low (n=422) (immunohistochemistry [IHC] 1+ or IHC 2+ and in situ hybridization [ISH] negative) and HER2-IHC 0 (n=590), as reference. Hormone Receptor (HR) expression has also been considered for subgroup analysis. Results: At first ABC diagnosis, < 1% pts had unresectable locally advanced BC (ULABC) in both groups, 31% de novo metastatic BC in HER2-low and 20% in HER2-IHC0 groups. Less than 1% were male, 99% Caucasian and ~71% postmenopausal. Median age was 60 years, being similar between both groups (range 26-96). Family history of BC and/or ovarian cancer was reported in 32% pts in HER2-low and 29% in HER2-IHC0. Germline BRCA1/2 mutation was higher in HER2-low (14/40=35%) in reference to HER2-IHC0 (14/64=22%) (p=0.14). Relevant information summarized by HR expression and HER2 status are detailed in the table below. Visceral disease was similar in both total groups (58% in HER2-low vs HER2-IHC0 56%), but slightly higher in HR- HER2-low pts (81% vs 64%), and 84% and 90% pts had ≤3 metastatic locations, in HER2-low and HER2-IHC0 groups, respectively. Distribution of 1st-line therapies was also similar between both groups, being endocrine therapy (ET) plus biological therapy (BT) (HER2-low 39% vs HER2-IHC0 36%) and ET (HER2-low 30% vs HER2-IHC0 28%), while chemotherapy (CT) (HER2-low 13% vs HER2-IHC0 16%) and CT plus BT (HER2-low 9% vs HER2-IHC0 10%) were more frequent in HR- pts. A 2nd-line therapy was reported in 70% HER2-low pts and 67% HER2-IHC0 pts. The median time to progression (TTP) at 1st-line therapy in HER2-low pts was 11 mo (0-66), being similar in HER2-IHC0 pts, but the higher difference was observed in relation to HR expression. Treatments in 2nd-line were similar in both groups, CT and ET/BT were the most frequent totally. Median duration of 2nd-line therapy was ~6 mo; progressive disease (PD) was reported in 85% pts. A 3rd-line therapy was reported in 74% HER2-low and 69% HER2-IHC0 pts. The median time to progression (TTP) to 3rd-line therapy was 6 mo, being similar in HER2-low and HER2-IHC0 pts .The most frequent 3rd-line therapies were CT and ET/BT in both groups, as in 2nd-line. Median duration of 3rd-line therapy was 4 mo; PD was reported in 84% HER2-low pts and 82% HER2-IHC0 pts. Median (95% confidence interval [CI]) PFS at 1st, 2nd and 3rd lines (mo) were 14 (12-16), 6 (5-7) and 6 (5-6) in HER2-low pts, being similar in HER2-IHC0. OS was comparable in all soubgroups analyzed, however, differences were observed regarding HR status. Conclusions: Our results show that HER2-low BC pts have similar characteristics than HER2-IHC0 BC pts. There are differences in therapy outcomes in terms of survival and prognosis, particularly in HR- tumors, being better in HER2-low BC pts. It could be related to the fact that these tumors have a specific biology, but more evidence is needed. Citation Format: Isabel Álvarez, Angel Guerrero-Zotano, Ariadna Tibau, Catalina Falo, María Hernández, Ana Miguel, Raquel Andrés, Álvaro Rodríguez-Lescure, Miguel Corbellas, Sara López-Tarruella, Purificación Martínez, Cesar A Rodríguez, Diego Malón, María Marin, Mª José Echarri, Antonio Antón, Josefina Cruz, Diana Moreno, J. Ignacio Chacón, Ruth Campo, Andrea Blasco, Susana Bezares, Federico Rojo, Silvia Antolin. Features and survival outcomes of HER2-low patients from a prospective registry of unresectable locally advanced or metastatic breast cancer: GEICAM/2014-03 (RegistEM) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-30.

Background: Over the last years, the treatment of HER2-positive (HER2+) breast cancer (BC) patients (pts) has been changing because of the development of new anti-HER2 agents. In the current analysis, we describe the features, treatment patterns, progression-free survivall (PFS) and overall survival (OS) outcomes of BC pts with HER2 + (immunohistochemistry [IHC] 3+ or IHC 2+ and in situ hybridization [ISH]+), following ASCO/CAP 2018 guidelines in the most recent tumor lesion before the 2nd-line. Methods: The RegistEM study is an ongoing BC registry study that is providing prospective data from around 1900 pts diagnosed with advanced BC (ABC) between 01/Jan/2016 and 31/Dec/2019, in 38 Spanish institutions from GEICAM network. In this analysis, 296 HER2+ BC pts have been included, representing the 18% of pts available in the database at the cut-off date (08/Apr/2022), with ABC diagnosis before 2019 (n=1559). Results: At first ABC diagnosis, 58% (n=173) pts had recurrent disease (>36 months [mo] from initial BC diagnosis in 62%), 41% (n=120) de novo metastatic BC and 1% (n=3) unresectable locally ABC (ULABC); the median age was 58 years, 68% were postmenopausal and there was only 1 male pt. From total 296 pts, 66% had hormone receptor expression [HR+]; the BC subtype was assessed in tumor tissue from the breast (58%) or a metastatic lesion (34%), and in 8% pts, HER2 positivity was observed after the 1st-line. Family history of BC and/or ovarian cancer was reported in 28% pts, and a hereditary-risk genetic test was performed in 26% pts (n=74/282). Germline BRCA1/2 and TP53 genetic testing were reported in 14 and 26 pts respectively, being mutated in 3/14 (21%) and 5/26 (19%) pts. Bone (50%), lymph nodes (49%), liver (35%), lung (31%), soft tissue (8%) and central nervous system (CNS), mostly in brain (8%), were the main metastatic sites. One hundred pts were diagnosed with CNS metastases: 24 at baseline, 48 during the 1st-line and 28 in subsequent lines. Additional data according to HR status and type of ABC are detailed in the table below, showing a worse prognosis in absence of HR expression. In HR- pts, bone metastases were less frequent and lymph nodes metastases more frequent compared to HR+ pts. Visceral disease was present in 69% (66% in HR+ and 74% in HR-; non-statistically significant) pts and ≈80% had ≤3 (54%, ≤2) locations involved. The most common therapies by line were: 1) 1st-line: Chemotherapy (CT) + biological therapy (BT) (38%), CT + BT+ endocrine therapy (ET) (35%), and ET + BT [11%]; 2) 2nd-line: BT (55%), CT + BT (20%) and ET + BT (15%); 3) 3rd-line: CT + BT (49%) and BT (31%). The median (95% confidence interval [CI]) progression-free survival (PFS) on 1st, 2nd and 3rd line was 18 (15-22), 8 (7-9) and 6 (5-8) mo, respectively. The median (95% CI) overall survival (OS) from ABC diagnosis was 43 (40-49) mo. These survival outcomes were higher in HR+ pts, however, the differences were only statistically significant in OS (p=0.006; log-rank). At database cut-off date, death was reported in 47% pts. Conclusions: In spite of the anti-HER2 therapies administered in the advanced setting, the HR expression is a relevant prognostic factor, with a clinically and statistically significant impact in OS, improving the outcomes of HR+ pts. Citation Format: Sara López-Tarruella, Angel Guerrero-Zotano, Josefina Cruz, Silvia Antolin Novoa, Purificación Martínez, María Hernández, César A Rodríguez, J. Ignacio Chacón, Ariadna Tibau, Catalina Falo, Álvaro Rodríguez-Lescure, Mireia Margelí, Sonia Servitja, Raquel Andrés, María Galán-Gramaje, Encarna Adrover, Ana Miguel, Rafael Villanueva, Silvia Varela, Ruth Campo, Mª José Escudero, Susana Bezares, Federico Rojo, Isabel Álvarez. Real-world data of Advanced Breast Cancer (ABC) patients with HER2-positivity before the second-line therapy: data from the observational study GEICAM/2014-03 (RegistEM) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-38.

Background: The RegistEM study is a non-interventional study that is providing prospective data from around 1900 ABC pts (females and males) diagnosed with advanced disease between 01/Jan/2016 and 31/Dec/2019, either after recurrence or at 1st diagnosis, in 38 Spanish sites representative of the national territory and whose investigators are GEICAM members. Methods: In the current analysis (cut-off date 10/May/2021, ongoing database), we describe the features of 279 pts included in the RegistEM study, with HER2+ (immunohistochemistry [IHQ] 3+, IHQ 2+ and in situ hybridization [ISH]+) tumors at any time of their ABC (5% after the 1st-line therapy). This subgroup has been evaluated because of the interest from a clinical perspective. Multivariate Cox analysis aiming to identify factors associated with overall survival (OS) were built. Results: 279 pts were identified, representing the 15% pts available in the database at the cut-off date. At first ABC diagnosis, 48% pts had recurrent BC (>12 months [mo] from initial BC diagnosis in 93%), 51% de novo metastatic BC and 1% unresectable locally advanced BC (ULABC). The median age was 59 years, 98% were white , 71% postmenopausal and only 1 male was part of this subset. Considering the BC subtype assessed in the most recent tumor lesion before the 1st-line therapy, 264 pts wereHER2 positive (67% with hormone receptor [HR]+). Family history of BC and/or ovarian cancer was reported in 31% pts, and an hereditary-risk genetic test was performed in 25% (66/267 pts). BRCA1/2 and TP53 mutations were reported in 4/20 and 4/19 pts, respectively, and p53 overexpression in 20/46 pts. Lymph nodes (56%), bone (49%), liver (34%), lung (33%), soft tissue (10%) and brain (8%) were the main metastatic sites. Additional data according to HR status and type of ABC are detailed in the table below. In HR- pts, bone metastases were less frequent and lymph nodes metastases more frequent compared to HR+ pts. Visceral disease was present in 68% pts and ≈75% had ≤3 (47% ≤2) locations involved. The most common therapies by line were: 1) 1st-line: CT + dual anti-HER2 blockade (3%), chemotherapy (CT) (almost in all pts taxane-based)+dual anti-HER2 blockade + endocrine therapy (ET) (mainly aromatase inhibitors) (35%), and ET + anti-HER2 blockade or ET + cyclin-dependent kinases 4/6 inhibitors (11%); 2) 2nd-line: anti-HER2 blockade (56%) [mostly an antibody-drug conjugate (90%)], CT + anti-HER2 blockade (18%) and ET + anti-HER2 blockade (14%); 3) 3rd-line: CT + anti-HER2 blockade (55%) and anti-HER2 blockade (22%). The median time-to-progressions to 1st-, 2nd- and 3rd-line were 14, 5, and 4 mo, respectively. A 4th-line therapy was reported in 52% of pts who received a 3rd-line. At database cut-off date, death was reported in 34% of pts. The median OS of this subset of pts was 41 mo (36-49). In a multivariate Cox regression analysis, the following variables were significantly related with worse survival (from ABC diagnosis): Brain (HR=2.62; 95% CI, 1.02-6.73) and Visceral no Brain involvement (HR=2.15; 95% CI, 1.02-4.53) compare to only soft tissue lesions; early stage at first diagnosis (HR=1.77; 95% CI, 1.15-2.73); HR- (HR=1.70; 95% CI, 1.11-2.60) and age (HR=1.04; 95% CI, 1.02-1.07). Conclusions: In this cohort of HER2+ pts with advanced disease, half of them had de novo ABC which was associated with better OS. The median PFS in 1st- and 3rd-line were slightly better in HR+ pts, and in 2nd-line was similar between HR+ and HR- cohorts. HR+181 (67%)HR- 91 (33%)Recurrent EBC134 (48%)ULABC or de novo M1 145 (52%)Time to recurrence >12 mo in EBC pts., n8435125NALocation of metastaticsites, nBoneBrainLiverLungLymph nodesSoft tissue104 10 62 57 90 1829 9 3232 64 1059 15 36 47 51 2278 6 59 46 1056Líne123123123123n180935690492613385521446333Deaths, n211112111161715141584Therapies by line, nET/BT261922101910212100ET12441011022323CT/BT/ET935031038305830CT/BT4017307581552182366924CT3572353711211BT6431373651145143385The most frequent therapies, nCT + dual anti-HER2 blockade + ET8623331551CT + single-agent HER2 blockade + ET522CT + dual anti-HER2 blockade3493644391016252CT + single-agent HER2 blockade4825641588211521CT5573354711411ET*22105212162644ET + HER2 blockade1213411662782Anti-HER2 blockade6431073651145143382Median duration of treatment, mo125585310441064TTP (mo), median (range)15(1-47)5(1-32)5(0-18)11(2-38)5(1-27)4(2-12)12 (1-47)5(1-26)4(0-17)17(2-45)7(1-32)4(1-18)Median PFS, mo14561154------HR: hormone receptor; EBC: early breast cancer; ULABC: unresectable locally advanced breast cancer; M1: metastatic; mo: month; ET: endrocrine therapy; BT: biological therapy; CT: chemotherapy; TTP: time-to-progression; PFS: progression-free survival. *ET includes aromatase inhibitors or selective estrogen receptor degraders, as single-agents or combined with cyclin-dependent kinases 4/6 inhibitors. Citation Format: Isabel Álvarez, Ángel Guerrero-Zotano, Josefina Cruz, Purificación Martínez, María Hernández, César A Rodríguez, Álvaro Rodríguez-Lescure, Silvia Antolín, Encarna Adrover, Raquel Andrés, Catalina Falo, Jose Ignacio Chacón, Ana Miguel, Sonia Servitja, Maria Galán Gramaje, Mireia Margelí Vila, César Gómez Raposo, María Jose Echarri, Rafael Villanueva, Ariadna TIbau Martorell, Silvia Varela Ferreiro, Ruth Campo, Juan Jose Miralles, Susana Bezares, Federico Rojo, Sara López-Tarruella. Features of HER2+ metastasic patients (pts) from a prospective registry of advanced breast cancer (ABC), GEICAM/2014-03 (RegistEM) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-15-04.

Background: There is limited prospective data for advanced breast cancer (ABC) patients (pts), both unresectable locally (ULABC) or metastatic (MBC) treated as per clinical practice. RegistEM study will provide epidemiological, pathological and clinical data, including treatments for different disease settings. Understanding the real distribution of BC subtypes is the primary objective. This is a non-interventional cohort study that will enroll around 1,867 pts (males or females) with ABC diagnosed from January 2016 to December 2019, either after recurrence or as first diagnosis, in 38 Spanish sites. Triple negative (TN) subtype histologically confirmed in the primary tumor (PT) and/or in a metastatic tumor lesion (M1) and recurrent disease from early stage, has been identified as an interesting group from a clinical perspective for detailed analysis. Methods: In this analysis, we describe the characteristics of 131 pts with TN subtype by local evaluation at any disease stage [in PT only (PT group), in M1 only (M1 group) and in both PT and M1 (group PT/M1)] until progressive disease (PD) at first-line and data of therapeutic options at second-line. Results: Distribution of 131 pts within the groups; PT, M1 and PT/M1, was 45.8%, 27.5% and 26.7%, respectively. To date, 32.1% pts have shown a change of subtype along their BC evolution, >50% of those changes was between TN and Luminal B HER2-. Median time from early BC (EBC) diagnosis until recurrent disease in terms of MBC or ULABC was 33.4 months (mo) (PT and PT/M1-26.0 mo; M1-60.2 mo), with the majority of pts recurring >12 mo (91.6%). Median age at diagnosis of ABC was 58 years (range 31-84), most pts were Caucasian (96.9%), female (99.2%) and postmenopausal (65.6%). Family history of BC and/or ovarian cancer was reported in 41.2% pts, a hereditary-risk genetic test was performed in 21.4% pts (8 pts with BRCA1/2 mutation). Lung (40.5%), lymph nodes (35.9%), bone (35.9%) and liver (20.6%) were the most frequent metastatic locations; central nervous system metastases were developed by 12.2% pts. The rate of visceral involment (60-70% pts) was similar among the 3 subgroups. The most frequent first-line therapies were chemotherapy (CT) (51.1%) and CT/biological therapy (BT) (32.8%). Most pts (68.7%) received CT in monotherapy (capecitabine 50%, taxanes 26.1%). Bevacizumab was the most frequent BT within the CT/BT combination (76.7%). Median duration of first line therapy was 4 mo (range 0.2-20.0). Progression to the first-line CT +/- bevacizumab was reported in 51.1% pts with a median time to progression (TTP) of 4.7 mo (range 0.8-19.0) in the whole group, being similar in pts with TN in and PT and PT/M1 (4.4 mo), and higher in pts with TN in M1 (7.1 mo), no statistically significant difference (p=0.38). A second-line therapy was reported in 57.3% pts and the most frequent therapies were CT (78.7%) (eribulin 33.9%, capecitabine 22.0%, platinum-based 22.0%) and CT/BT (12.0%) (CT-containing bevacizumab 77.8%). Median duration of second-line therapy was 3 mo (range 0.03-15.8) and PD has been reported in 80.0% pts. Third-line therapy was reported in 35.9% pts of this subset. Conclusion: In this subset of pts with TN ABC due to recurrent disease, lung, lymph nodes and bone are the most frequent metastatic locations. The main first- and second-line therapies were CT in monotherapy. Progression to the first-line conventional therapy (CT +/- bevacizumab) was reported in 51.1% pts with a median TTP of 4.7 mo (range 0.8-19.0) in the whole group, being similar in pts with TN in PT and PT/M1 (4.4 mo), and higher in pts with TN in M1 (7.1 mo), no statistically significant difference. 36% of the initial subset of pts reported to be treated in the third-line setting. Pts with TN only in M1 seem to have a longer time to progression from EBC. Citation Format: Carlos Jara, César A. Rodríguez, Isabel Alvarez, Catalina Falo, Purificación Martínez, Raquel Andrés, Josefina Cruz, Marta Mori, Encarna Adrover, Ariadna Tibau, Silvia Antolin, Mireia Margeli, Jose L. Alonso, Bella I. Pajares, M. Carmen Camara, J. Jose Miralles, Susana Bezares, Federico Rojo, Sara López-Tarruella, Angel Guerrero- Zotano. Geicam/2014-03 (RegisTEM): A prospective registry of unresectable locally advanced or metastatic breast cancer: Characteristics of a subset of patients with triple negative subtype [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-25.

Background: The RegistEM study is a non-interventional cohort study that will provide prospective data from >1,800 advanced breast cancer (ABC) patients (pts), either after recurrence or as first diagnosis in 38 Spanish sites. Primary objective is the distribution of BC subtypes. A new nomenclature has been proposed for those cases with immunohistochemistry (IHC) 1+ or 2+ and negative in situ hybridization (ISH), HER2-low BC. In clinical practice these tumors are reported as HER2 negative. This subpopulation has been identified as an interesting group from a clinical perspective. Methods: In this analysis (cut-off date 01/April/2020; database is ongoing) we describe the characteristics of 229 pts with hormone receptor (HR)+/HER2-low BC documented in a metastatic lesion after early disease recurrence and who received adjuvant endocrine therapy (ET). Three subgroups of pts have been considered for this analysis based on HER2 results: HER2 IHC 0, HER2-low, and HER2 ISH- (without IHC). Biological samples collection is part of study procedures. Results: The distribution of HER2 IHC 0, HER2-low, and HER2 ISH- subgroups was 52.4%, 42.8% and 4.8%, respectively. The median time to advance disease was 98.6, 88.8 and 106.9 mo in each group. Almost all pts were female and Caucasian (99%), and at ABC diagnosis, 75.5% were postmenopausal. Median age was 59 years (range 33-88). Fourteen (6.1%) pts had HER2+ (IHC 3+ or ISH amplified) BC subtype during their disease. Family history of BC and/or ovarian cancer was reported in 31.4% pts, an hereditary-risk genetic test was performed in 11.4% (n=26) pts in total and BRCA2 gene mutation (n=6) was the only one reported. The most frequent metastases are included in Table 1. Visceral disease was present in 63.3% pts and 76% pts had ≤2 locations. The most frequent 1st-line therapies were ET/biological therapy (BT) (46.7%) and ET (28.8%), and were equal distributed in the 3 subgroups. The most common ET/BT regimens were aromatase inhibitor (AI)/cyclin-dependent kinase 4/6 inhibitor (CDKi) (49.1%/48.9%/42.9% in each subgroup) and fulvestrant (FUL)/CDKi (35.8%/27.7%/28.6%); AIs (50%/64%/66.7%) and FUL (31.6%/20%/0%) were also the most common drugs for monotherapy ET. A 2nd-line therapy was reported in ~53% pts in HER2 IHC 0 and HER2-low, and in 36% pts in HER2 ISH-. The median time to progression (TTP) to 1st-line therapy was 11.4 mo (1.2-37.0), being similar in pts with HER2 IHC 0 and HER2-low (~11 mo), and higher in pts with HER2 ISH- (16 mo). The most frequent 2nd-line therapies were ET/BT (~34% in HER2 IHC 0 and HER2-low, and 25% in HER2 ISH-) [FUL/CDKi (36.4%/47.1%/100%), AI/CDKi (36.4%/23.5%/0%)], chemotherapy as monotherapy (17 pts out of 63 in HER2 IHC 0, 17 pts out of 53 in HER2-low and 1 pt (capecitabine) out of 4 in HER2 FISH-) (capecitabine 29.4%/52.9% in HER2 IHC 0 and HER2-low). Median duration of 2nd-line therapy was ~5 mo in HER2 IHC 0 and ~8 mo in HER2-low and HER2 ISH-; disease progression was reported in 52.4%/62.3%/50% pts, respectively. Conclusions: In this population of HR+ tumors, the proportion of HER2 IHC 0 and HER2-low groups was similar. Time to advance relapse and the distribution of distant metastases were similar among the groups. The most common first- and second-line therapy was the ET/BT combination, with AI/CDKi and FUL/CDKi, respectively. Table 1Location of metastatic lesionsIHC 0HER2-lowISH- non IHCN=120 N (%)N=98 N (%)N=11 N (%)Bone74 (61.7)55 (56.1)6 (54.5)Liver36 (30.0)37 (37.8)3 (27.3)Lung27 (22.5)21 (21.4)5 (45.5)Lymph Node27 (22.5)21 (21.4)2 (18.2)Soft Tissue6 (5.0)11 (11.2)0CNS3 (2.5)4 (4.1)0Other43 (35.8)31 (31.6)5 (45.5) Citation Format: Isabel Álvarez, Angel Guerrero, Sara López-Tarruella, Purificación Martínez, Marta Mori, Catalina Falo, Silvia Antolín, César A Rodríguez, Mireia Margeli, Isabel Garau, Ariadna Tibau, Diana Moreno, Josefina Cruz, María José Echarri, Antonio Antón, Álvaro Rodríguez-Lescure, María José Escudero, Susana Bezares, Federico Rojo, Carlos Jara. Characteristics of HR+/HER2- patients with recurrent disease by HER2 expression from a prospective registry of unresectable locally advanced or metastatic breast cancer: GEICAM/2014-03 (RegistEM) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-24.

Background: The RegistEM study will provide prospective data from advanced breast cancer (ABC) patients (pts). Understanding the real distribution of BC subtypes is its primary objective. A new nomenclature has been proposed for those cases with HER2 1+ or 2+ by immunohistochemistry and negative in situ hybridization, HER2-low BC. In clinical practice, these tumors are reported as HER2 negative. Methods: This is a non-interventional study that will enroll approximately 1,867 pts with ABC diagnosed from January 2016 to December 2019, either after recurrence or as 1st diagnosis, in 38 Spanish sites. Biological samples (primary and/or metastatic tumor lesions, and blood) collection is part of its procedures. In this analysis (cut-off date 01/April/2020, database ongoing), we describe the characteristics of pts with Triple Negative (TN) subtype and HER2-low expression (as mentioned above). Biomarkers, including HER2, were determined in either primary tumor (PT), M1 or in both, PT and M1. Results: This subset of pts make up 37.4% (n=49) of TN pts considered for this analysis (n=131). Their distribution within the three groups (PT, M1 and PT/M1), was 46.9% (n=23), 42.9% (n=21) and 10.2% (n=5), respectively. These pts were diagnosed with early BC (EBC) and at recurrence, 91.7% presented distant metastases. Median time from EBC diagnosis until recurrent disease in terms of ABC was 29.8 months (mo), with the majority of pts recurring at >12 mo (95.9%), similar to the whole TN subset. Most pts were Caucasian (98%), and at diagnosis of ABC, the median age was 60 years (range 31-84) and 65.3% were postmenopausal. A change of BC subtype was documented in 15/49 (30.6%) pts, with the higher rate in M1 group (52.4%); as opposed to the TN subset, a change to HER2+ disease was reported in 6/15 (40.0%) pts and just after the TN subtype in all cases. Family history of BC and/or ovarian cancer was reported in 42.9% pts and any genetic test to assess the hereditary risk was performed in 30.6% pts. Similarly to TN subset, lung (36.7%), lymph nodes and bone (34.7% each) and liver (24.5%) were the most frequent metastatic locations; central nervous system metastases were developed by 14.3% pts. Visceral involvement was present in 66.7% pts, being this rate lower in M1 compared to PT and PT/M1 groups. The most frequent 1st-line therapies were chemotherapy (CT) (44.9%) and CT/biological therapy (BT) (36.7%). Type of CT mainly included capecitabine (36.4%), taxanes (27.3%), eribulin (13.6%) and platinum-based combinations (13.6%). Most pts received CT as monotherapy (86.4%). Bevacizumab (BVZ) was the most frequent BT associated to CT (77.8%), mainly with capecitabine and/or paclitaxel (72.2%). Progressive disease to 1st-line therapy in the whole group was reported in 73.5% pts (higher than in TN subset), with a median time to progression (TTP) of 5.7 mo (range 1.7-15.0); PT was the group with a higher PD rate. A 2nd-line therapy was reported in 63.3% pts. Similarly to 1st-line setting, the most frequent 2nd-line therapies were CT (74.2%) and CT/BT (12.9%) (with BVZ in 75.0% pts). CT in monotherapy was reported in 69.6% pts (capecitabine 31.3%, eribulin 25.0%). Median duration of this line therapy was 3.0 mo (range 0.6-15.8), PD has been reported in 96.8% pts (similar between groups), and 3rd-line therapy in 25/49 (51.0%) pts. Conclusions: In TN/HER2-low ABC pts, lung, lymph nodes and bone were the most frequent metastatic locations. As opposed to TN subset, HER2+ disease is part of the subtype changes reported. Although the main 1st- and 2nd-line therapies were CT and CT/BT, similarly to TN subset, the rate of pts with PD to 1st- and 2nd-line therapies is higher, and also those pts treated in the 3rd-line setting. Citation Format: Carlos Jara, Isabel Álvarez, César A Rodríguez, Purificación Martínez, Raquel Andrés, Álvaro Rodríguez-Lescure, Diego Malón, Jose Luis Alonso, Encarna Adrover, María José Echarri, Mireia Margeli, Ariadna Tibau, Judith Ramírez, Silvia Antolín, Ruth Campo, Juan José Miralles, Susana Bezares, Federico Rojo, Sara López-Tarruella, Angel Guerrero-Zotano. Geicam/2014-03 (registem): A prospective registry of advanced breast cancer: A subset of triple negative breast cancer patients with her2 low expression [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-35.

Background: There is limited prospective data for advanced breast cancer (ABC) patients (pts), unresectable locally or metastatic, treated as per clinical practice. RegistEM, an academic study conducted by a non-profit collaborative group, will provide epidemiological, pathological and clinical data as per routine practice, including treatments for different disease settings, collected from pts’ medical records. Understanding the real distribution of BC subtypes is the primary objective. This is a non-interventional cohort study that will enroll approximately 1,867 pts with advanced disease diagnosed from January 2016 to December 2019, either after recurrence or as first diagnosis (de novo), in 38 Spanish sites representative of the whole country geography and whose investigators are GEICAM members. Biological samples (primary and/or metastatic tumor tissue, and blood) collection is part of study procedures. Methods: In this analysis we describe the characteristics of 229 pts with HR+/HER2- BC documented in a metastatic tumor lesion after disease recurrence and who received adjuvant endocrine therapy (ET). This subpopulation has been identify as an interesting group from a clinical perspective for detailed analysis. Three subgroups of pts have been considered for this analysis based on their disease-free interval (DFI) since the diagnosis of early disease: 50% pts recurring at ≥84 mo and only 1.3% pts at ≤12 mo. Most pts were Caucasian (99.1%) and female (99.6%), and at ABC diagnosis, 75.5% were postmenopausal and their median age was 59 years (33-88); median age was higher in pts with DFI ≥60 mo. Family history of BC and/or ovarian cancer was reported in 31.4% pts, with a slightly higher percentage in pts with DFI 50% pts recurred at ≥84 mo. Bone is the most frequent metastatic location in all DFI subgroups. The most common 1st- and 2nd-line therapies were the ET/BT combination, with AI/CDKi and FUL/CDKi, respectively. The median TTP to 1st-line therapy was superior in pts with DFI ≥60 mo. Citation Format: Isabel Alvarez, Angel Guerrero- Zotano, Sara López-Tarruella, Purificación Martínez, Marta Mori, Catalina Falo, Silvia Antolin, Cesar A. Rodríguez, Mireia Margeli, Isabel Garau, Ariadna Tibau, Diana Moreno, Josefina Cruz, M. Jose Echarri, Juan Lao, Alvaro Rodríguez-Lescure, Juan Jose Miralles, Susana Bezares, Federico Rojo, Carlos Jara. Characteristics of HR+/HER2- patients with recurrent disease from a prospective registry of unresectable locally advanced or metastatic breast cancer: GEICAM/2014-03 (RegistEM) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-08.

Background: The addition of trastuzumab (T) to neoadjuvant chemotherapy increases pCR rate in patients with HER2 + breast cancer. Lapatinib (L) in combination with chemotherapy is also an active drug in breast cancer patients. This study investigates the efficacy of trastuzumab or lapatinib added to chemotherapy in the neoadjuvant setting. Methods: Patients (Pt) with tumors greater than 2 cm (or less with positive axilla) and HER2+ (Herceptest 3+ or 2+ with FISH+) that have not received any prior treatment for breast cancer were recruited. Pts were randomized to receive epirubicin 90 mg/m2 plus cyclophosphamide 600 mg/m2 × 4 cycles (cy) followed by docetaxel 100 mg/m2 (with growth colony stimulating factor support) plus either T 8 mg/kg loading dose and then 6 mg/Kg intravenous (EC-DT) or L 1250 mg orally (EC-DL). Patients were stratified according to tumor size (T1-2 vs T3-4), and estrogen receptor status (positive vs negative). The primary end-point was pathological complete response (pCR) in the breast measured by Miller and Payne criteria. Secondary end-points were clinical response (by imaging test), toxicity and correlation between pCR and tumor biomarkers. Results: From February-09 to October-10, 102 pts were randomized (50 EC-DT, 52 EC-DL). Pts characteristics were well balanced between arms. Median age was 48 years (30-79), 56% of pts were premenopausal, 7% grade I, 45% grade III. 14/59/12/15% were T1/T2/T3/T4 and 69% N+. 58% were estrogen receptor positive and 44% progesterone receptor positive. Three patients were FISH negative after central assessment and were not considered evaluable for efficacy. pCR rate in the breast was 52% (95% CI: 38–66) for EC-DT and 25% (95% CI: 13.5−37.5) for EC-DL (p-value=0.0065). pCR—pN0 was 48% (95% CI: 34–62) for EC-DT and 24% (95% CI: 12 - 35) for EC-DL (p-value=0.01). Clinical response was 77% with EC-DT and 65% with EC-DL (p-value=0.176). Grade III-IV toxicity was similar between arms except for diarrhea that was more frequent in EC-DL 14% than in EC-DT 2% (p-value=0.03); more patients discontinue treatment due to toxicity with EC-DL (1 vs 6; p-value=0.055). Conclusions: Our study shows that EC-DT was more efficacious and less toxic than EC-DL in the neoadjuvant treatment of HER2+ pts. Biomarker profiling in the tumors, including activation levels of tyrosine-kinase receptors, signaling pathways and surrogate markers (proliferation and apoptosis) is ongoing; their correlation with pCR will be presented at the meeting. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD07-04.