31 mei 2018: ASCO 2018
A.s. weekend start ASCO 2018 in Chicago. Hier een selectie van belangrijke abstracten gerelateerd aan borstkanker
Klik op de nummers voor de abstracten zelf. We zullen komende week zeker een aantal abstracten eruit kiezen om die wat uitgebreider te beschrijven maar hier alvast een voorselectie door dr. Lee Schwartzberg en prof. dr. Lillie Shockney die wij hebben overgenomen van ASCO POST:
Session: Breast Cancer—Metastatic
Saturday June 2, 8:00 AM–11:30 AM
1013 Final overall survival (OS) analysis of PHEREXA: A randomized phase III trial of trastuzumab (H) + capecitabine (X) ± pertuzumab (P) in patients with HER2-positive metastatic breast cancer (MBC) who experienced disease progression during or after H-based therapy. A Urruticoechea, M Rizwanullah, S-Ah Im, et al
- Presented is the final prespecified analysis of the PHEREXA trial. The median study time was 23 months in arm A (IV trastuzumab 8 mg/kg→6 mg/kg every 3 weeks plus oral capecitabine 1250 mg/m2 twice daily) and 33 months in arm B (IV pertuzumab 840 mg→420 mg every 3 weeks plus IV trastuzumab per arm A plus oral capecitabine 1000 mg/m2). Patients in arm B had longer survival compared with those in arm A, suggesting that clinical efficacy is maintained on longer follow-up. A small increase in adverse events was reported on longer follow-up.
- These results show that capecitabine plus trastuzumab and pertuzumab increased overall survival after taxane plus trastuzumab, which gives weight to using pertuzumab either in the second line, if it was not used in the first line, or after early adjuvant failure to taxane plus trastuzumab–based combinations.
Session: Breast Cancer—Metastatic
Sunday June 3, 8:00 AM–11:00 AM
1000 Ribociclib (RIB) + fulvestrant (FUL) in postmenopausal women with hormone receptor-positive (HR+), HER2-negative (HER2–) advanced breast cancer (ABC): Results from MONALEESA-3. DJ Slamon, P Neven, SKL Chia, et al
- This study included 726 postmenopausal women with HR+/HER2− advanced breast cancer who had received no or up to one line of prior endocrine therapy for advanced breast cancer and who were randomized to receive ribociclib plus fulvestrant or placebo plus fulvestrant. Patients treated with ribociclib exhibited significantly prolonged progression-free survival compared with patients who received placebo. Both the overall response rate and clinical benefit rate were significantly higher in patients who received ribociclib. Grade 3 neutropenia, increased ALT, and increased AST were more common in patients treated with ribociclib.
- These results are similar to those reported with other CDK4/6 inhibitors in this setting. Second-line CDK4/6 plus letrozole is associated with similar hazard ratios, confirming benefit of the doublet in either line.
1001 Genetic landscape of resistance to CDK4/6 inhibition in circulating tumor DNA (ctDNA) analysis of the PALOMA3 trial of palbociclib and fulvestrant versus placebo and fulvestrant. NC Turner, B O'Leary, R Cutts, et al
- This study assessed mechanisms of resistance to CDK4/6 inhibitors in the PALOMA-3 trial using ctDNA analysis. Paired ctDNA analysis was performed in 125 patients treated with palbociclib plus fulvestrant and 68 patients treated with fulvestrant alone. At the end of treatment, RB1 mutations were found in 6 patients treated with palbociclib plus fulvestrant. New driver mutations in PIK3CA and ESR1 were reported at the end of treatment in both groups.
- ctDNA identified acquired resistance mechanisms after palbociclib plus fulvestrant, including ESR1 mutations, PI3KCA mutations, and, in a small minority of patients, RB mutations. There is still a long way to go to determine why these drugs fail.
1002 Abemaciclib for pre/perimenopausal women with HR+, HER2- advanced breast cancer. P Neven, HS Rugo, SM Tolaney, et al
- Abemaciclib plus fulvestrant was compared with placebo plus fulvestrant in terms of safety and efficacy in 114 pre-/perimenopausal women with HR+/HER2− advanced breast cancer. Median progression-free survival was 10.5 months in patients treated with placebo plus fulvestrant and not reached in patients in the abemaciclib group. In 79 patients with measurable disease, the objective response rate was significantly higher in patients treated with abemaciclib plus fulvestrant compared with the placebo group (60.8% vs 28.6%). Frequently reported adverse events included diarrhea, neutropenia, and leukopenia.
- Abemaciclib plus fulvestrant led to improved progression-free survival and objective response rates, with a tolerable safety profile, in pre/peri-menopausal women.
1004 Efficacy of sacituzumab govitecan (anti-Trop-2-SN-38 antibody-drug conjugate) for treatment-refractory hormone-receptor positive (HR+)/HER2- metastatic breast cancer (mBC). A Bardia, JR Diamond, LT Vahdat, et al
- Here, the authors present the results of a phase I/II basket trial investigating the activity of sacituzumab govitecan, a novel anti-TROP2 ADC, in 54 patients with HR+/HER2− metastatic breast cancer who received a median of three prior hormonal therapies. To date, 16 patients died, 27 are in long-term follow-up, and 11 remain on treatment. Grade 3 or higher adverse events reported in 10% or more patients included leukopenia and neutropenia. The overall response rate was 31%, with 17 partial responses. The clinical benefit rate was 48%. The overall response rate was 24% in patients who previously received CDK inhibitors.
- Sacituzumab yielded a response rate of 31% in patients with heavily pretreated HR+ metastatic breast cancer, including in patients with prior exposure to CDK4/6.
LBA 1006 Phase III study of taselisib (GDC-0032) + fulvestrant (FULV) v FULV in patients (pts) with estrogen receptor (ER)-positive, PIK3CA-mutant (MUT), locally advanced or metastatic breast cancer (MBC): Primary analysis from SANDPIPER. J Baselga, SF Dent, J Cortés, et al
1007 AZD5363 plus paclitaxel versus placebo plus paclitaxel as first-line therapy for metastatic triple-negative breast cancer (PAKT): A randomised, double-blind, placebo-controlled, phase II trial. P Schmid, J Abraham, S Chan, et al
- In this study, 140 patients with previously untreated metastatic triple-negative breast cancer were randomized to receive paclitaxel plus AZD5363 or paclitaxel plus placebo. Median progression-free survival was numerically longer in the patients treated with paclitaxel plus AZD5363 (5.9 vs 4.2 months; one-sided P = .06). Median overall survival was significantly longer in patients treated with paclitaxel plus AZD5363 (19.1 vs 12.6 months). The most frequently reported grade 3 or higher adverse events were diarrhea, infection, neutropenia, rash, and fatigue.
- These results demonstrate improved overall and progression-free survival in patients treated with the AKT inhibitor AZD5363 added to paclitaxel.
1008 Overall survival (OS) update of the double-blind placebo (PBO)-controlled randomized phase 2 LOTUS trial of first-line ipatasertib (IPAT) + paclitaxel (PAC) for locally advanced/metastatic triple-negative breast cancer (mTNBC). R Dent, S-A Im, M Espie, et al
- The authors report updated survival results in the intention-to-treat population following events in approximately 50% of patients. At 23 months of follow-up, patients who received ipatasertib plus paclitaxel exhibited prolonged median overall survival compared with patients who received placebo plus paclitaxel (23.1 vs 18.4 months). The 1-year overall survival rate was 83% in patients in the ipatasertib group compared with 70% in patients in the placebo group. No new safety signals were reported.
- These results demonstrate a trend toward increased overall survival in patients treated with ipatasertib.
Session: The Arrival of Biosimilars
Monday June 4, 9:45 AM–11:15 AM
110 Biosimilar trastuzumab-dkst monotherapy versus trastuzumab monotherapy after combination therapy: Toxicity, efficacy, and immunogenicity from the phase 3 Heritage trial. A Manikhas, EJ Pennella, I Bondarenko, et al
- In this multicenter, double-blind, parallel-group phase III trial, 500 patients with HER2+ metastatic breast cancer were randomized to receive trastuzumab-dkst (biosimilar) or trastuzumab, in combination with taxane in the first line. At 24 weeks, 342 patient continued treatment, and 214 continued through 48 weeks. During monotherapy, treatment-emergent adverse event (TEAE) rates were similar between groups. Grade 3 or higher TEAEs were more frequent with trastuzumab, but severe TEAE rates were similar between groups. At 48 weeks, median progression-free survival was 11.1 months in both groups.
- These results demonstrate that the toxicity and efficacy of biosimilar trastuzumab is similar to those of the originator molecule in metastatic breast cancer, providing more evidence that substitution will be cost-effective and beneficial to patients.
Session: Breast Cancer Immunotherapy: Can We Crack the Code?
Monday June 4, 3:00 PM–4:30 PM
1011 TOPACIO/Keynote-162: Niraparib + pembrolizumab in patients (pts) with metastatic triple-negative breast cancer (TNBC), a phase 2 trial. S Vinayak, SM Tolaney, LS Schwartzberg, et al
- In this study, 54 patients with triple-negative breast cancer received niraparib 200 mg orally once daily plus pembrolizumab 200 mg IV on day 1 of each 21-day cycle. Of these patients, 22% had deleterious BRCA mutations, and 17% did not undergo testing or had indeterminate results. Of the 45 evaluable patients, the objective response rate was 29% and the disease control rate was 49%. A total of 3 complete responses, 10 partial responses, 9 cases of stable disease, and 23 cases of progressive disease have been reported. Of the 13 responders, 10 have ongoing responses. Among the 12 patients with BRCA mutations, 1 achieved complete response, 7 achieved partial responses, 1 had stable disease, and 3 had progressive disease. The median progression-free survival in patients with BRCA mutations was 8.1 months. For all patients, the objective response rate was 33% in PD-L1–positive patients and 15% in PD-L1–negative patients.
- Niraparib with pembrolizumab was associated with a good response rate in patients with pretreated triple-negative disease, including in patients with BRCA non–mutated tumors and PD-L1 low expression.
Saturday June 2, 8:00 AM–11:30 AM
Session: Breast Cancer—Metastatic
1019 The impact of circulating tumor cells (CTCs) detection in metastatic breast cancer (MBC): Implications of "indolent" stage IV disease (Stage IVindolent). AA Davis, J-Y Pierga, LY Dirix, et al
- In this combined pooled analysis of 2436 patients, CTC counts were performed and used to stratify patients as Stage IVindolent (<5 CTCs/7.5 mL blood) or Stage IVaggressive (≥5 CTCs/7.5 mL blood). Overall, patients with ≥5 CTCs had a significantly worse outcome, whereas patients with indolent disease had a median overall survival of 36.3 months. Patients with indolent disease exhibited significantly prolonged overall survival across all disease subtypes compared with patients with aggressive disease. Of the matched samples, 65% were discordant.
- These findings demonstrate the ability of CTC counts to identify patients with indolent disease, which may be useful for treatment consideration.
1034 Effect of breast tumor subtype and site of distant metastatic disease on prognostic outcome among patients with brain metastases and stage IV denovo breast cancer. SS Dawood, B Sirohi, P Mainwaring, et al
- SEER registry data from 1025 patients with stage IV de novo breast cancer and brain metastases diagnosed between 2010 and 2014 were analyzed to determine the impact of tumor subtype and metastatic sites on outcomes. Significant differences in median overall survival were reported across subtypes: 5 months for triple-negative disease, 13 months for HER2-negative/HR-positive, 9 months for HER2-positive/HR-negative, and 21 months for HER2-positive/HR-positive. Median overall survival was twice as long in patients who underwent surgery for their primary tumor compared with those who did not (14 months vs 7 months). Of the patients who did not have distant metastasis at presentation, median overall survival was 5 months for triple-negative disease, 10 months for HER2-negative/HR-positive, 14 months for HER2-positive/HR-negative, and 34 months for HER2-positive/HR-positive.
- Patients with stage IV de novo breast cancer and brain metastases who have bone-only or no distant metastatic disease, and those who have the HER2-positive/HR-positive subtype, have a better prognosis.
1041 Maintenance of health-related quality of life in elderly patients treated with ribociclib + letrozole in MONALEESA-2. HA Burris, SM Tolaney, LL Hart, et al
- This analysis of the MONALEESA-2 study included 295 postmenopausal patients aged ≥65 years with HR+/HER2− advanced breast cancer who were randomized to receive first-line ribociclib plus letrozole (n = 150) or placebo plus letrozole (n = 145) and who completed the EORTC QLQ-C30 questionnaire for overall HRQoL/symptom scores and the breast cancer-specific QLQ-BR23 questionnaire for breast symptom scores. No significant differences in HRQoL or median time to 10% deterioration of HRQoL were found between treatment groups. Patients receiving ribociclib exhibited a clinically relevant improvement in mean pain score through the first year of treatment.
- These findings support results from the full MONALEESA-2 study population, demonstrating that HRQoL was maintained in patients aged ≥65 years who were treated with ribociclib plus letrozole.
1079 Breast cancer stem cell autoantibodies to identify women with advanced breast cancer. SE Stanton, DL Cecil, MM O'Meara, et al
- Autoantibodies of eight breast cancer stem cell proteins that may be used as a marker of disease progression were evaluated in 253 participants (100 with no breast atypia; 124 with stage I/II invasive breast cancer ; 29 with stage III/IV IBC). For six of the eight autoantibodies, the percentage of participants with a positive autoantibody response increased between control (no IBC) and stage I/II IBC and/or stage III/IV IBC. This autoantibody panel significantly predicted stage I/II IBC vs control (AUC = 0.66) and stage III/IV vs control (AUC = 0.84).
- These findings support the development of this autoantibody panel as a biomarker of disease progression.
1081 Racial disparity in breast cancer immune microenvironment. A Elkhanany, E Katsuta, K Takabe
- This study was designed to assess biologic disparities between African Americans (n = 183) and Caucasians (n = 752), which may be explained by TIL composition of the immune microenvironment. After adjusting for age and stage, shorter disease-free survival and cumulative incidence of disease was reported in African Americans compared with Caucasians. After adjusting for race, increased activated NK and γδT cell fractions were predictive of longer disease-free survival, whereas M2 macrophages were associated with shorter disease-free survival. In African American patients, Treg cell counts were higher overall and in basal and triple-negative subtypes. Increased memory B cells, plasma cells, and macrophages were seen in all subtypes except basal.
- These findings suggest that the immune microenvironment is significantly different in patients with breast cancer based on race, which may explain the worse outcome in African American patients.
1082 Overall survival following locoregional surgery of the primary tumor in de novo stage IV breast cancer patients. H Yao, Y Yu, Y Wang, et al
- In this multicenter study, data from 353 Chinese patients were evaluated to investigate the role of locoregional surgery in the treatment of primary de novo stage IV breast cancer. Of these patients, 189 underwent locoregional surgery and 164 did not undergo surgery. No significant difference in 5-year overall survival was reported in patients who underwent and did not undergo surgery (62.4% vs 60.3%, respectively). Patients who had locoregional surgery and had Ki67 expression ≥20% had significantly longer survival. Additional analyses of 42 retrospective studies with 130,153 patients and 5 prospective trials with 857 participants reported significantly longer survival in patients who underwent locoregional surgery and no significant difference in overall survival, respectively.
- These authors determined that locoregional surgery had no significant survival benefit in patients with de novo stage IV breast cancer.
1087 Androgen receptor expression in circulating tumor cells of metastatic breast cancer patients. IE de Kruijff, AM Sieuwerts, W Onstenk, et al
- Androgen receptor (AR) mRNA expression was evaluated in CTCs from 133 patients with metastatic breast cancer who had ≥5 CTCs and in 48 matched FFPE tissues. Overall, 31% of the CTC samples were AR+. Patients with HER2+ disease had significantly more AR+ CTCs than patients with triple-negative disease (50% vs 13%). No significant difference in progression-free survival was reported between patients with AR+ or AR−.
- These findings demonstrate the potential for CTC AR expression in the selection of patients for treatment with AR inhibitors.
1091 Prognosis in young women under 40 with brain metastasis from breast cancer. A Mustillo, J-PM Ayoub, L Yelle, M Florescu
- In this study, 121 patients diagnosed with breast cancer and brain metastasis were identified from patient databases to assess survival. Patients aged <40 years had a significantly longer median overall survival compared with patients aged ≥40 years (18 months vs 4 months).
- Patients who had a first brain metastasis had significantly longer survival compared with patients who developed a brain metastasis during the evolution of the metastatic breast cancer (7 months vs 4 months).
1092 What are the drivers of healthcare cost among patients with metastatic breast cancer (mBC)? Total cost of care analysis to inform value-based reimbursement. C Burudpakdee, A Seetasith, CM Reyes, et al
- This study was designed to assess costs of care and key drivers of cost using data from 7032 patients with metastatic breast cancer identified from IQVIA’s claims database. The average total cost per patient per month for 703 high-cost patients was 3.7-fold higher than for the overall population of 7032. Outpatient drugs, including 76% related to breast cancer medications, contributed to the largest cost difference between overall and high-cost patients. Hospitalization, pharmacy services, and radiology procedures also contributed to increased costs in high-cost patients. In high-cost patients, the proportion of total costs related to office visits, ED visits, lab services, and outpatient surgery was lower than in the overall population.
- These results suggest that increased costs in patients with metastatic breast cancer are due to medications, radiology services, and hospitalizations.
E12565 The prognostic significance of breast cancer stem cells in patients with metastatic breast cancer. K Farag, SSA Shamaa
- This study examined the prognostic and predictive potential of breast cancer stem cells in 60 patients with metastatic breast cancer. Tumor tissues were classified according to CD44 and CD24 expression. Breast stem cells were noted in 7% of tissue classified as CD44+/CD24−. Of these CD44+/CD24− tumors, 64% were of IDC histology, 84% were grade 3, 88% were stage III, 56% were luminal subtype, and 68% developed bone and visceral metastasis. Patients with tumors with breast cancer stem cells had significantly shorter overall survival compared with other CD44/CD24 groups (19 vs 44 months).
- These results demonstrate the feasibility of detecting breast cancer stem cells in tumor tissue according to CD44 and CD24 status and their potential use as a prognostic marker.
E12613 Palliative radiotherapy (RT) to the breast using a novel hypofractionated radiotherapy regime: Results of the HYPORT phase I/II study (CTRI/2015/12/006407). S Chatterjee, R Ahmed, S Chakraborty, et al
- In this study, 30 patients with metastatic breast cancer and symptomatic breast lesions underwent regional FDG PET/CT before and within 6 hours after novel hypofractionated radiation therapy. At baseline, pain and ulceration were reported by 40% and 60% of patients, respectively. At 3 months, ulceration had healed in 42% of patients. The pain score was reduced by at least 2 points in 92% of patients at 1 month. At treatment completion, 32% of responders exhibited a clinically meaningful improvement in the FACT-TOI score. Following radiation, 55% of patients with moderate to severe psychological distress at presentation reported an improvement in the PHQ4. No local metabolic progression was reported at 3 months.
- The findings suggest that this novel radiation therapy regimen is safe and effective in patients with metastatic breast cancer and local symptoms.
E13007 Assessment of cardiac effects of ado-trastuzumab emtansine through strain rate imaging in metastatic breast cancer. V Michalaki, G Koutroulis, I Kontis, et al
- The goal of this study was to see if sensitive measures of left ventricular dysfunction could be used to detect cardiovascular side effects of T-DM1 at an early point. The researchers used Doppler to follow 36 patients with pretreated HER2-positive metastatic breast cancer who were treated with T-DM1 3.6 mg/kg once every 3 weeks until progression. No overall change in left ventricular dimensions, ejection fraction, and peak systolic velocity were reported after a median treatment duration of 7 months, although, after nine cycles, significant reductions in longitudinal and radial strain were noted. Changes in radial strain were reported earlier and were more pronounced compared with changes in longitudinal strain.
- These results demonstrate the ability of tissue Doppler myocardial imaging to detect T-DM1–mediated cardiac dysfunction earlier than conventional methods.
E13022 Genomic testing for HER2 mutation in patients with metastatic lobular carcinoma of the breast. DL Citrin, AK Syriac, V Doctor, et al
- The authors used next-generation sequencing to identify HER2 mutations in 16 patients with metastatic CDH1-mutated lobular carcinoma. Next-generation sequencing showed HER2 mutations in 4 patients, in only 1 of whom was HER2 amplified. All 4 patients were treated with HER2-directed therapy and achieved durable responses.
- These findings support the importance of next-generation sequencing in identifying HER2 mutations in patients with metastatic lobular carcinoma who may be responsive to directed therapy.
E13040 Efficacy of CDK 4/6 inhibitors in ER positive metastatic breast cancer: Systematic review and meta-analysis of randomized clinical trials. A Gennari, C Saggia, V Rossi, et al
- This systematic review and meta-analysis was designed to determine the effect of CDK4/6 inhibitors on progression-free and overall survival in patients with ER-positive metastatic breast cancer, and it included 7 randomized trials and 3854 patients. A significant improvement in progression-free survival was reported in patients who received CDK4/6 inhibitors in addition to endocrine therapy. A slight improvement in overall survival was reported in 2 trials of first-line therapy. No differences were reported among subgroups based on age, disease-free interval, or metastatic site.
- These results demonstrate a consistent 50% reduced rate of progression in first and subsequent lines of treatment in patients with ER-positive metastatic breast cancer who receive CDK4/6 inhibitors in addition to endocrine therapy.
E13062 Establishment and characterization of a circulating tumor cell line from a breast cancer patient. P Zhao, C Zou, H Hu, et al
- In this study, a CTC cell line (CTC-3) was established from the peripheral blood of a patient with metastatic ER+ breast cancer via negative enrichment. Using FISH, cytokeratin was positively stained in CTC-3 cells. Flow cytometry analysis determined that approximately 1% of cells were CD133-positive. Compared with the breast cancer cell line MCF-7, CTC-3 cells had higher colony and spheroid formation capacities, a larger nuclear/cytoplasm ratio, and had a faster replication rate. Using short tandem repeat analysis, CTC-3 and MCF-7 cells were found to have less than 20% alignment, suggesting that CTC-3 may be a new cell line.
- The CTC-3 cell line may provide an improved source for monitoring progression and determining individualized treatments for patients with breast cancer.
E13065 Long-term responders with metastatic breast cancer (MBC) receiving eribulin: Real life experience. V Gorbunova, L Manzyuk, E Kovalenko, et al
- Data from 168 Russian patients with metastatic breast cancer treated with eribulin were assessed for duration of response in this study. Among them, 32 had a long duration (≥8 months). In 97% of cases, ECOG performance status was 0–1. Visceral metastases were present in 78%, with two median metastatic sites. A total of 18 patients were ER+/PR+, 7 were triple-negative, and 7 were HER2+. Eribulin was given in the second and third lines (47%) or the fourth or later lines (53%). Based on RECIST v.1.1, complete responses were achieved in 17 patients and stable disease was reported in 15 patients, with a median progression-free survival of 9.56 months. The most frequently reported adverse events were grade 2 neutropenia (19%), grade 3/4 neutropenia (16%), and grade 2 peripheral neuropathy (6%).
- These results demonstrate real-world characteristics of Russian patients with metastatic breast cancer who achieved long duration of response with eribulin.
E13074 Features associated with long-term survival in metastatic breast cancer. N Klar, MQ Rosenzweig, B Diergaarde, A Brufsky
- In this study, the authors included data from 122 long-term (≥5 years) and 191 short-term (≤2 years) survivors of metastatic breast cancer to determine features associated with survival. Compared with short-term survivors, long-term survivors were significantly younger; had more HER2+, ER+, and PR+ disease; and had lower Charlson Comorbidity Index scores, lower rates of visceral metastasis, higher household income, and positive partner status. Furthermore, long-term survivors were diagnosed significantly more often with de novo metastatic breast cancer and less often with early-stage breast cancer compared with short-term survivors.
- These findings report that de novo metastatic breast cancer diagnosis, primary tumor subtype, higher household income, younger age, and having a partner are associated with long-term survival.
E13083 Restaging de novo metastatic breast cancer to refine prognostic estimates. JK Plichta, SM Thomas, AR Sergesketter, et al
- Data from 16,187 patients with de novo metastatic breast cancer from the National Cancer Data Base were examined to determine the association of anatomic and biologic factors with overall survival using recursive partitioning analysis to create a model for prognostic stratification. The number of metastatic sites was the first stratification point, and ER status was the second stratification point. HER2 status, PR status, tumor grade, cT stage, and presence of bone-only metastases were also used for divisions.
- Anatomic staging, biologic factors, and metastatic disease extent may be used to predict survival outcomes in patients with de novo metastatic breast cancer.
E13095 Estrogen receptor (ER), progesterone receptor (PR) and Her2neu receptor expression: Change from baseline to first metastasis in breast cancer—Single center experience from developing country. M Sharma, A Gogia, SVS Deo, et al
- In this study, the authors assessed biomarker discordance, metastatic sites, and progression-free survival in 97 patients with metastatic breast cancer. Discrepancies in biomarker status at baseline and at first metastasis were reported in ER (23.7%), PR (28.9%), and HER2/neu (14.7%) disease. Single-site metastasis was reported in 37.2%. The most common metastatic sites were bone, lung, non-regional lymph node, liver, skin, and brain. The overall median progression-free survival was 26 months.
- These findings suggest that evolution of metastatic disease may be associated with changes in hormone receptor status.
E13116 Understanding real-world treatment and outcomes in patients diagnosed with metastatic triple negative breast cancer (mTNBC). KE Skinner, MS Walker, A Haiderali, et al
- This retrospective chart review included 608 patients with metastatic breast cancer and was designed to assess outcomes. Of these patients, 505 received systemic treatment following diagnosis. Those who received systemic treatment were younger and more likely to stage IV disease and less likely to have comorbidities, impaired performance status, or brain metastasis compared with untreated patients. Patients were more likely to progress if they had more than one metastatic site, a greater comorbidity burden, and were non-white. Patients had significantly longer overall survival if they received treatment (12.8 months vs 4.8 months).
- Approximately 20% of patients do not receive systemic treatment and overall outcomes are poor, highlighting an unmet need in this patient population.
E18617 Comparison of clinical characteristics and survival of metastatic breast cancer patients in United States according to insurance status as compared to outcomes in Canada. ARB Matutino, AAL Pereira, E Kornaga, et al
- This study included data from 10,927 patients from SEER and 392 patients from the Breast Data Mart (Alberta, Canada) to investigate clinical characteristics and survival of patients with metastatic breast cancer based on insurance status. In Canada, the median overall survival was shorter than in insured (27.4 months vs 36 months), similar to Medicaid patients (27.4 months vs 24 months), with all groups exhibiting longer overall survival compared with uninsured patients (18 months). The shortest median overall survival in Canadians was in patients with triple-negative disease, followed by HR+/HER2−, HR+/HER2+, and HR−/HER2+. The shortest median overall survival in Americans was in patients with triple-negative disease, followed by HR−/HER2+, HR+/HER2−, and HR+/HER2+.
- Survival outcomes in Canadian patients with metastatic breast cancer are similar to those in the US Medicaid group. Compared with insured Americans, Medicaid and uninsured patients had shorter survival.
E18817 Screening for new primary cancers in patients with metastatic breast cancer: A provincial analysis of the Choosing Wisely Canada recommendations. ME Tesch, KE Laing
- This retrospective study included data from 305 patient medical records to assess screening for new primary cancers in patients with metastatic breast cancer and compliance with the Choosing Wisely Canada recommendations. Of these patients, 37.4% underwent at least one screening, with 70% ordered by primary care providers, 14% by oncologists, and 12% by other specialists.
- A significant proportion of patients with metastatic breast cancer in Newfoundland and Labrador undergo screening for new primary cancers, highlighting increased educational strategies aimed at clinicians to promote adherence to Choosing Wisely guidelines.
Session: Breast Cancer—Local/Regional/Adjuvant
Monday June 4, 8:00 AM–11:00 AM
500 Adjuvant denosumab in early breast cancer: Disease-free survival analysis of 3,425 postmenopausal patients in the ABCSG-18 trial. M Gnant, G Pfeiler, GG Steger, et al
- In this double-blind phase III trial, 3425 postmenopausal patients with early HR-positive breast cancer receiving adjuvant aromatase inhibitors were randomized to receive denosumab 60 mg subcutaneously or placebo every 6 months. Patients receiving denosumab exhibited significantly improved disease-free survival compared with patients receiving placebo at 5 years (89.2% vs 87.3%) and 8 years (80.6% vs 77.5%). No osteonecrosis of the jaw and a single potential atypical femur fracture was reported in the denosumab arm.
- Based on these results, adjuvant denosumab should be offered to postmenopausal patients with HR-positive breast cancer who are receiving aromatase inhibitors.