Citations

Abstract Purpose: We evaluated the prognostic and predictive value of circulating tumor cells (CTCs) hormone receptor–positive (HR+) metastatic breast cancer (MBC) patients randomized to letrozole alone or letrozole plus bevacizumab in the first-line setting (CALGB 40503). Experimental Design: Blood samples were collected at pretreatment and three additional time points during therapy. The presence of ≥5 CTCs per 7.5 mL of blood was considered CTC positive. Association of CTCs with progression-free survival (PFS) and overall survival (OS) was assessed using Cox regression models. Results: Of 343 patients treated, 294 had CTC data and were included in this analysis. Median follow-up was 39 months. In multivariable analysis, CTC-positive patients at baseline (31%) had significantly reduced PFS [HR, 1.49; 95% confidence interval (CI), 1.12–1.97] and OS (HR, 2.08; 95% CI, 1.49–2.93) compared with CTC negative. Failure to clear CTCs during treatment was associated with significantly increased risk of progression (HR, 2.2; 95% CI, 1.58–3.07) and death (HR, 3.4; 95% CI, 2.36–4.88). CTC-positive patients who received only letrozole had the worse PFS (HR, 2.3; 95% CI, 1.54–3.47) and OS (HR, 2.6; 95% CI, 1.59–4.40). Median PFS in CTC-positive patients was significantly longer (18.0 vs. 7.0 months) in letrozole plus bevacizumab versus letrozole arm (P = 0.0009). Restricted mean survival time analysis further revealed that addition of bevacizumab was associated with PFS benefit in both CTC-positive and CTC-negative patients, but OS benefit was only observed in CTC-positive patients. Conclusions: CTCs were highly prognostic for the addition of bevacizumab to first-line letrozole in patients with HR+ MBC in CALGB 40503. Further research to determine the potential predictive value of CTCs in this setting is warranted.

AbstractObjectiveYoung breast cancer patients experience greater psychosocial distress compared with older patients, which raises concern for their risk of posttraumatic stress disorder (PTSD). We sought to characterize the prevalence of clinically significant symptoms of PTSD and associated factors among breast cancer survivors diagnosed at a young age.MethodsThe Young Women's Breast Cancer Study, an ongoing prospective cohort study, enrolled 1302 women diagnosed with breast cancer at age ≤ 40 between 2006 and 2016. Participants complete serial surveys, and we obtained additional information from medical record review. Socio‐demographics, anxiety and depression, social support, and psychiatric co‐morbidities and medications were assessed at study baseline (median, 5 months post‐diagnosis). We defined a participant as having clinically significant posttraumatic stress symptoms (PTSS) by scoring ≥50 on the PTSD Checklist‐Specific Version, administered on the 30‐month survey.ResultsAmong 700 women with stage 1‐3 disease, the prevalence of PTSS was 6.3% (95%CI = 4.5‐8.1). In multivariable analyses, PTSS was significantly associated with anxiety (OR 12.43, 95%CI = 5.81‐26.59, P < .0001) and stage 2 vs 1 disease (OR 2.26, 95%CI = 1.04‐4.93, P = .04). PTSS was inversely associated with having a college degree (OR 0.29, 95%CI = 0.13‐0.62, P = .002) and greater social support (OR 0.44, 95%CI = 0.21‐0.94, P = .03).ConclusionsWe found similar rates of cancer‐related PTSS in breast cancer survivors diagnosed at a young age compared with the general breast cancer population despite their well‐documented increased risk of overall distress. Nevertheless, factors associated with posttraumatic stress should be considered at diagnosis and in survivorship to identify young patients who may benefit from psychosocial resources.

e19132 Background: The Functional Assessment of Cancer Therapy–General has an item about patient tolerability of treatment: “I am bothered by side effects of treatment” (GP5). We examined the predictive value of this single item for early treatment discontinuation in clinical trials. Methods: GP5 level prior to protocol therapy (rated using a 5-point Likert scale) and treatment start/end dates and off treatment reason data at each treatment phase were drawn from five phase III clinical trials conducted by ECOG-ACRIN. In the present analysis, GP5 was dichotomized as 0 = “Not at all”/“A little bit” and 1 = “Somewhat”/“Quite a bit”/“Very Much”. Early treatment discontinuation was defined either as receiving less than protocol specified cycles of treatment when maximum cycles specified in the protocol (E1A06 induction, E1912 induction, E1609 induction, E1105 induction, E5103 adjuvant), analyzed using logistic regression via odds ratio [OR]), or treatment cessation for reasons other than progressive disease or death when treatment continued until progression or intolerability (E1A06 maintenance, E1912 maintenance, E1609 maintenance, E1105 maintenance), analyzed using Cox proportional hazard model via hazard ratio [HR]. Results: GP5 prior to treatment was significantly associated with early discontinuation of E1A06 maintenance, E1609 maintenance, E1912 maintenance, and E1912 induction. No significant association was found for other therapies examined in the study. Conclusions: High GP5 level prior to treatment is associated with higher likelihood of early treatment discontinuation in patients who have received previous treatment. The limited predictive value of GP5 for treatment naïve patients is more limited, serial on-treatment assessment should be considered in this setting. Clinical trial information: NCT00602641 . [Table: see text]

514 Background: The 21- gene Breast Recurrence Score predicts benefit from adjuvant chemotherapy in estrogen receptor positive (ER+), HER-2 negative (-) breast cancer (BC). We aimed to examine whether the 21-gene assay predicts response to neoadjuvant chemotherapy (NAC). Methods: We identified patients with stage I-III ER+/HER2− BC treated with NAC from the Young Women's Breast Cancer Study, a prospective cohort of women diagnosed with BC at age ≤ 40 years. The 21-gene assay was performed on tumor specimens removed prior to NAC either as part of clinical care or retrospectively for research. Pathologic complete response (pCR) was defined as no residual invasive tumor (ypT0/is ypN0). The relationship between Recurrence Score result (RS) and pCR was evaluated using logistic regression modeling. Results: 76 women in the cohort had undergone NAC for ER+, HER2- BC and were eligible for this analysis: 5 had undergone clinical 21-gene assay testing, 71 had banked specimens retrospectively tested. Median age at diagnosis was 36.7 (24.3-40). Most tumors were of ductal histology (78%), high grade (51%), progesterone receptor (PgR) positive (86%), ≥T2 (88%), clinically node positive (74%), and anthracycline and taxane containing protocols were administered in 86% of cases. RS ranged between 5-75 with 50% > 25 and only 4 < 11. Mean RS was significantly higher among tumors achieving pCR vs. non-pCR response (51.9 vs. 26.6, pwilcoxon= 0.0005). pCR rate in patients with RS > 25 was 21% (8/38) vs. 5% in patients with RS < 25 (2/38), with both pCRs in the <25 group in patients with RS 21-25. In univariable analysis, PgR negativity (odds ratio (OR) 5.62, 95% confidence interval (CI) 1.27-24.89, p = 0.02), high grade (OR 9.03, 95%CI 1.07-76.32, p = 0.04) and higher RS as a continuous variable (OR 1.08, 95%CI 1.04-1.13, p = 0.0003) were associated with a greater likelihood of pCR. In multivariable analysis only RS remained significantly associated with pCR (OR: 1.07, 95%CI 1.01-1.12, p = 0.01): a 7% increase in the odds of pCR for every 1-point increase in RS. Conclusions: In young women with ER+, HER2- BC who received NAC, higher pretreatment RS was associated with an increased likelihood of pCR. Genomic expression profiling assays may have a role in decision-making in young women in need of neoadjuvant therapy. For women with low likelihood of benefiting from NAC, alternative approaches are clearly warranted. Given the demonstrated efficacy of neoadjuvant endocrine therapy in post-menopausal women, further evaluation in young women should be pursued.

504 Background: For PM patients (pts) with locally advanced ER+ HER2- BC, NET improves breast conservation surgery (BCS) rates, and modified preoperative endocrine prognostic index (mPEPI) 0, defined as pT1-2 pN0 Ki67< 2.7%, or pathologic complete response (pCR: no invasive disease in breast or lymph node) is associated with low risk of recurrence without adjuvant chemotherapy (CT). The ALTERNATE trial was initiated to assess if the endocrine-sensitive disease rate (ESDR: number of mPEPI 0 pts/number of eligible pts initiating NET) with fulvestrant (F) or F+anastrozole (A) is improved relative to A alone (reported here) and if the 5-year (yr) recurrence-free survival (RFS) rate for pts with mPEPI 0 on A alone without CT is ≥ 95% (awaits further follow-up). Methods: PM pts with clinical stage II/III ER+ HER2- BC were randomized 1:1:1 to 1 mg A po daily, 500 mg F IM every 4 week (wk)s after loading dose, or A+F for 6 months. Ki67 was tested centrally on biopsies acquired prior to NET, wk 4, wk 12 and at surgery. Pts with Ki67 >10% at wk 4 or 12 were recommended to go off protocol-directed ET and switch to CT. Pts with mPEPI 0 at surgery were recommended to continue assigned ET for 1.5 yrs followed by A for a total of 5 yrs ET (and not to receive CT). The primary endpoint of the neoadjuvant phase was ESDR. ESDR of each F arm was compared to that of the A alone arm. With 425 pts per arm, a one-tailed alpha = 0.025 chi-square test of two independent proportions has 84% power to detect an increase of ≥10% in ESDR for F or F+A compared to the A arm, assuming ESDR ≤30% in A. Results: 1362 pts (A 452; F 454; A+F 456) were enrolled Feb 2014 to Nov 2018. 63 pts were excluded (did not start NET). Of the remaining 1299 pts (A 434; F 431, A+F 434), 42% were cN1-3 and 73% were considered candidates for BCS. ESDR was 18.6% (95%CI: 15.1-22.7%) with A, 22.7% (95%CI: 18.9-27.0%) with F, and 20.5% (95%CI: 16.8-24.6%) with A+F. No significant difference in ESDR was found between A and F (p=0.15) or A and A+F (p=0.55). Among the 825 pts with wk 4 Ki67 < 10% who completed NET and surgery, ESDR and the BCS rate were 27.7% and 70.3% with A; 29.6% and 68.1% with F, and 26.8% and 69.9% with A+F, respectively. Conclusion: Neither F nor F+A significantly improved ESDR compared to A alone in PM pts with locally advanced ER+ HER2- BC. RFS data are awaited. Support: U10CA180821, U10CA180882, U24CA196171, https://acknowledgments.alliancefound.org ; NCI BIQSFP, BCRF, Genentech, AstraZeneca. Clinical trial information: NCT01953588 .

Abstract Background: Endx is a Tam metabolite with promising antitumor activity in Tam and aromatase inhibitor (AI) resistant estrogen receptor (ER) positive (+) metastatic breast cancer (MBC). Methods: This randomized phase II study compared progression-free survival (PFS) and toxicity of Endx 80 mg/day to Tam 20 mg/day in patients (pts) with ER+ MBC. Eligibility included postmenopausal women, ECOG PS 0-2, prior progression on AI but not Tam (unlimited endocrine therapy [ET] lines allowed), and a preregistration biopsy confirming ER+ (&gt;10% nuclear staining) and HER2-negative MBC. Stratified randomization was used balancing prior CDK 4/6 inhibitor (CDK 4/6i) use and/or everolimus (yes/no), measurable disease (yes/no) and endocrine resistance (primary/secondary) between arms. Pts randomized to Tam were allowed to cross over to Endx at progression. Due to short expected median PFS, differences in PFS were assessed using approaches for interval-censored data (ICD). 40 eligible pts were to be randomized to each arm so a one-sided alpha=0.10 generalized log-rank test (GLRT) would have a 90% chance of detecting a 50% decrease in hazard of disease progression with Endx (median: 6 months) relative to Tam (median: 3 months). Secondary endpoints include clinical benefit rate (stable or partial response &gt; 6 cycles) (CBR) for measurable and non-measurable disease. Pharmacokinetic (PK) data were obtained Day (d) 1 (4 hour), end of cycle 2, and at time of progression. Results: From March 2015 to March 2017, 108 women with endocrine refractory recurrent or MBC were preregistered. 27 pts did not register due to: biopsy demonstrating ER-/HER2- (3 pts), ER+/HER2+ (5 pts), cancer other than breast (3 pts), no cancer in specimen (6 pts), brain metastases (2 pts), acute infection (1 pt), progression on or recent use of Tam (2 pts), or pt refusal (5 pts). 4/81 pts who registered were excluded due to ineligibility (3 pts) or refusal to start protocol treatment (1 pt). The study cohort consisted of 40 pts randomized to Endx and 37 pts to Tam. The median (m) number of ETs in the metastatic setting was 2 (range 1-4) for each arm including prior CDK 4/6i (Endx: 42.5%, Tam: 29.7%) and everolimus (Endx: 35.0%, Tam: 40.5%). The m cycle number was 6 for Endx (range: 1-35) and 3 for Tam (range: 1-42). PFS for Endx was not significantly different compared to Tam (HR= 0.77; 95% CI: 0.49-1.22, GLRT p=0.309; mPFS: Endx 130 days [95% CI: 76-138 days] and Tam 42 days [95%CI: 24-129 days]). However, PFS was significantly longer in pts with no prior CDK 4/6i in the Endx arm (GLRT p=0.002; HR(no/yes)=0.31; 95%CI: 0.15-0.65) but not in the Tam arm (GLRT p=0.708) (unplanned analysis). Severe (grade (G) 3+) toxicities included: Endx G3 hypertriglyceridemia (3 pts); Tam: G3 hypertension with G2 stroke (1 pt), G3 thromboembolic event (1 pt), and G3 abdominal, bone and liver pain (1 pt). In Endx arm, d1 m Endx plasma concentration (conc) was 216 ng/ml (n=17; range: 144-400). For Tam arm, d1 m Tam conc was 17 ng/ml (n=17; range:11-23) (Endx not detectable). For the 25 pts that crossed over to Endx, CBR was 28.0% (90% CI: 14.0-46.2%) and 14 pts had pk data at progression. A lower median Endx conc (6 ng/ml range: 3.3-16.3) was observed in Tam patients at progression who then had Endx clinical benefit compared to Tam pts without clinical benefit after Endx crossover (median Endx 12 ng/ml; range 4.4-36.6).Conclusions: In endocrine-resistant breast cancer, Z-Endx was not significantly superior to Tam, but clinical benefit was observed in 28% that crossed over to Endx after Tam progression. In pts with no prior CDK 4/6i, the observation of significantly longer PFS in the Endx arm is hypothesis generating. Support: U10CA180821, U10CA180882, U24CA196171, U10CA180820 (ECOG-ACRIN), https://acknowledgments.alliancefound.org; Clinical Trials.gov Identifier:NCT02311933 Citation Format: Matthew P. Goetz, Vera J Suman, Joel M Reid, Mary Kuffel, Sarah A Buhrow, Renee M McGovern, John Black, Travis Dockter, William F Symmans, Minetta C Liu, John R Hawse, James Doroshow, Anna M Storniolo, Jerry M Collins, Howard Streicher, Matthew M Ames, James N Ingle, Ann Partridge, Lisa Carey. A randomized phase II trial of tamoxifen versus Z-endoxifen HCL in postmenopausal women with metastatic estrogen receptor positive, HER2 negative breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD7-06.

Abstract Background: Young women with breast cancer (BC) often receive aggressive local therapy and are more likely to undergo (bilateral) mastectomy and receive postmastectomy radiation (RT) than older women. Our previous work suggested better quality of life (QOL) outcomes among women undergoing breast conserving therapy (BCT) vs. mastectomy, even with reconstruction (recon), although limited data was available regarding recon. In the current analysis, we sought to understand the impact of recon, accounting for RT, on long-term satisfaction and QOL. Methods: Between 10/2016-11/2017, we administered the BREAST-Q, a validated patient-reported outcomes measure designed to evaluate satisfaction and QOL after breast cancer surgery and recon, to 743 women in the Young Women’s Breast Cancer Study, a multi-site prospective cohort that enrolled women diagnosed (dx’d) at age &lt; 40 from 2006-2016. Demographic and treatment information was obtained by surveys and chart review. Recon was defined as autologous, implant or complex (combination of autologous and implant). Mean BREAST-Q scores for each domain (breast satisfaction, physical, psychosocial, and sexual) were compared by recon types and stratified by receipt of RT; higher BREAST-Q scores (range: 0-100) indicate better QOL. Linear regression was used to identify predictors of BREAST-Q scores. Results: 584 women with Stage 0-3 BC completed the Breast-Q at a median of 5.7 [range 2-10] years from dx), 357 (61%) had mastectomy and recon and were included in the analytic sample. Median age at dx was 36 years; 85% had stage 0, 1 or 2 disease; 41% received RT and 76% underwent bilateral mastectomy. 90.5% underwent immediate recon; of which 65.5% were tissue expander placement. Definitive recon included autologous tissue in 16%; implants in 81% and complex recon in 3%. Mean BREAST-Q breast satisfaction, psychosocial, and physical well-being scores differed based on recon type accounting for RT (Table 1). Significantly lower scores for breast satisfaction were seen in women having implant +RT. Scores were not impacted by bilateral procedure, timing of recon, use of tissue expander, extent of axillary surgery, cancer stage or other treatment factors. In multivariate analyses, receipt of RT, lymphedema and implant-based recon were associated with lower breast satisfaction scores. Physical well-being scores were lower for those with complex recon, for non-White women, for women who reported being financially uncomfortable, for those with lymphedema, and for those &lt;5 years from surgery. Psychosocial well-being scores were lower for women who received RT, had BMI &gt;25, and for those who reported being financially uncomfortable. Sexual well-being scores were lower for women with a BMI &gt;25 and for those who reported being financially uncomfortable. Conclusion Type of recon and receipt of radiation among young survivors who undergo mastectomy and recon for early breast cancer appears to have a differential impact on satisfaction and QOL. Our finding of lower breast satisfaction among young women who received RT, particularly after implant recon, underscores the importance of counseling regarding surgical options, especially for women who may receive RT after mastectomy and who are candidates for BCT. Table 1. Unadjusted BREAST-Q scores stratified by RTBREAST-Q DomainAutologous -RT N=29Autologous +RT N=27Implant -RT N=174Implant +RT N=113Complex N=13Global p-valueSatisfaction with Breasts, mean (sd)67 (19)63 (18)64 (18)53 (18)58 (22)&lt;0.01Physical well-being, mean (sd)81 (13)80 (14)80 (15)77 (14)67 (18)0.01Psychosocial well-being, mean (sd)71 (18)64 (18)72 (20)66 (23)62 (20)0.03Sexual well-being, mean (sd)54 (21)50 (24)52 (20)47 (22)48 (27)0.26RT= radiation Citation Format: Laura Dominici, Jiani Hu, Hee Jeong Kim, Tari King, Kathryn Ruddy, Rulla Tamimi, Jeffrey Peppercorn, Lidia Schapira, Virginia Borges, Stephen Come, Ellen Warner, Julia Wong, Ann Partridge, Shoshana Rosenberg. BREAST-Q satisfaction and quality of life outcomes in young women undergoing mastectomy and reconstruction for breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD6-1.

Abstract Background: Breast cancer arising in young women is more likely to have higher risk features than in older women and more likely to be associated with germline BRCA1 or BRCA2 mutations. We previously reported a higher distribution of luminal B-like tumors among young women. Here we present the clinical and pathologic features of invasive disease in a large prospective cohort of young women with breast cancer, and associations between surrogate molecular subtype and BRCA 1/2 mutation status. Methods: Among 1,297 young women (aged ≤40 years) with breast cancer enrolled from 2006-2016, tumor histopathological features were examined by central review, and biomarker status was extracted from pathology reports. Based on histologic grade and biomarker expression, invasive tumors were categorized as luminal A-like (LA=ER/PR+ and HER2-, histologic grade 1 or 2), luminal B-like (LB=ER/PR+ and HER2+, or ER/PR+, HER2-, and grade 3), HER2 enriched (E) (ER/PR- and HER2+) or triple negative (TN=ER-, PR- and HER2-). Tumor stage, clinical characteristics, and BRCA status were retrieved by medical record review (and patient survey for BRCA status if not in medical record). Results: The majority of women presented with early stage invasive disease (8% stage 0, 32% stage 1, 40% stage 2, 15% stage 3; 5% stage 4). Among invasive tumors with evaluable molecular phenotype (n=1,136), 57% were high grade and the distribution of subtypes was: 33% LA, 42% LB, 8% HER2E, and 16% TN (Table 1). Among different age groups (≤ 30, 31-35, and 36-40 years), there were no significant differences in molecular phenotype, tumor stage, tumor grade or histopathological features including presence of tumor necrosis, lymphocytic infiltration, and central fibrotic focus. 96% of women were tested for BRCA1 and BRCA2 germline mutations, and 127 (11%) tested positive: 65% were BRCA1+, and 35% were BRCA2+ (table 2). Among BRCA1+ patients, 2% of cancers were LA, 30% LB, 5% HER2E, and 62% TN; among BRCA2+, 29% were LA, 56% LB, 2% HER2E, and 13% TN. These proportions were relatively consistent across age groups. BRCA1+ patients’ tumors were proportionately more TN and BRCA2+ patients’ tumors more likely to be LB/HER2 negative (p&lt;0.0001), irrespective of age category. Conclusion: In a large cohort of women diagnosed with breast cancer at age ≤40, there was no association between age group (≤ 30, 31-35, vs. 36-40 years) and tumor stage, grade, or tumor molecular phenotype among women with invasive disease. As in older women, tumor molecular phenotype does vary by BRCA1 or BRCA2 mutation status, which has implications for prevention and treatment. Table 1. Subtype by age groupTotal (n=1136)≤30 yrs (n=144)31-35 yrs (n=314)36-40 yrs (n=678)p=0.42Luminal A-like377 (33%)48 (33%)99 (32%)230 (34%)Luminal B-like477 (42%)59 (41%)137 (44%)281 (41%)• ER/PR+, HER2-, grade 3245 (22%)27 (19%)68 (22%)150 (22%)• ER/PR+, HER2+232 (20%)32 (22%)69 (22%)131 (19%)HER2E95 (8%)13 (9%)34 (11%)48 (7%)Triple Negative187 (16%)24 (17%)44 (14%)119 (18%) Table 2. Subtype by BRCA statusTotal(n=1136)BRCA1+(n=82)BRCA2+(n=45)No mutation/not tested(n=1009)p&lt;0.0001Luminal A-like377 (33%)2 (2%)13 (29%)362 (36%)Luminal B-like477 (42%)25 (30%)25 (56%)427 (42%)• ER/PR+, HER2-, grade 3245 (22%)21 (26%)18 (40%)206 (20%)• ER/PR+, HER2+232 (20%)4 (5%)7 (16%)221 (22%)HER2E95 (8%)4 (5%)1 (2%)90 (9%)Triple Negative187 (16%)51 (62%)6 (13%)130 (13%) Citation Format: Yaileen D Guzman-Arocho, Shoshana M. Rosenberg, Philip Poorvu, Kathryn J. Ruddy, Greg Kirkner, Craig Snow, Rulla M. Tamimi, Jeffrey Peppercorn, Lidia Schapira, Virginia F. Borges, Steven E. Come, Elena F. Brachtel, Ellen Warner, Ann H. Partridge, Laura C. Collins. Clinicopathological features and BRCA 1/2 status in a large prospective cohort of young women with breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-07-02.

Abstract BACKGROUND Fertility can be diminished by adjuvant chemotherapy or by age-related decline in ovarian reserve in young women with breast cancer (BC). We sought to better understand the burden of concern about fertility, utilization of fertility preservation strategies, and the impact of fertility concerns on treatment decision-making among young women newly diagnosed with BC enrolled in a large multi-site study. METHODS The Young and Strong study was a cluster-randomized study that tested the effect of an educational and supportive care intervention for young women with BC (≤45) and their oncologists, at community and academic sites across the US. Patients were surveyed following diagnosis at enrollment (within 3 months of diagnosis), and at 3, 6 and 12 months thereafter. The surveys included sociodemographic and psychosocial measures (HADS anxiety and depression; Perceived Stress Scale), as well as a modified Fertility Issues Survey, which assessed fertility concerns and preservation. Treatment and tumor pathology data were abstracted from the medical record. Logistic regression was used to identify sociodemographic, clinical, and psychosocial factors that were associated with fertility concern. Variables with p ≤ 0.20 in univariable analyses were evaluated in the multivariable model using stepwise selection; variables achieving significance at p &lt; 0.05 were included in the final model. RESULTS Of 467 women enrolled from 54 sites (14 academic, 40 community), 419 had evaluable data regarding treatment decision-making. Median age of participants at diagnosis was 40 yrs (range 22-45), 11% were African American, 80% were married/lived with a partner, and 75% had children. 35% of tumors were stage I, 51% stage II, and 14% stage III; 82% of women were treated with chemotherapy. At the time of treatment decision-making, 133 (32%) were concerned about fertility, varying by age, with fertility concern reported by 73%, 28% and 13% of those age ≤35, 36-40 and &gt;40 (p&lt;.01), respectively. 67 (16%) said their treatment decisions had been affected by fertility concerns, including 62 of the 133 (47%) with fertility concern. 12/419 (3%) chose one chemotherapy regimen over another, 4 (1%) chose not to take hormonal medication, and 32 (8%) chose or may choose to take it for less than 5 years. 251 (60%) reported having discussed fertility issues with their physician before starting therapy, including 117/133 (88%) of women with fertility concern. 29 (7%), including 27/133 (20%) of the concerned, took special steps to lessen the chance of infertility: 14 underwent cryopreservation of embryos, 14 cryopreservation of eggs and 12 took GnRH agonist or pursued other strategies. In the multivariable model, history of difficulty becoming pregnant (versus none, OR=3.86, 95%CI: 1.84-8.1) was associated with greater concern about fertility. Older age (OR=.75 per 1-year increase, 95%CI: 0.69-0.81) and having more than one child at diagnosis (versus never delivered, OR=0.14, 95%CI: 0.05-0.40) were associated with less concern about fertility. Race, being partnered, high-education, income, symptoms of depression, stress or anxiety at diagnosis, tumor stage, hormone receptor status and receipt of chemotherapy were not independently associated with concern about fertility in the multivariable model. CONCLUSION In a geographically and ethnically diverse study of young women with newly diagnosed BC in the U.S., many were concerned about fertility, with potential impact on their treatment decisions. For the majority of women, these concerns were discussed with their providers, though only a minority underwent fertility preservation strategies prior to treatment. Citation Format: Elisabeth Etaix, Yue Zheng, Shoshana Rosenberg, Kathryn J Ruddy, J Russel Hoverman, Karen M Emmons, Ann H Partridge. Fertility concerns and treatment decision-making among young women with breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-13-17.

Abstract Background: Fear of cancer recurrence (FCR) is prevalent among breast cancer survivors and more intense in younger women. Given that FCR is a powerful determinant of quality of life and is associated with healthcare utilization, identifying who may be at risk for experiencing elevated FCR without resolution can inform the timing and targeting of interventions. Methods: Participants included women diagnosed (dx’d) at age ≤40 enrolled in the Young Women’s Breast Cancer Study, a multi-site prospective cohort surveyed at baseline and regularly in follow-up. Surveys include the 3-item Lasry Fear of Recurrence Index which measures the degree of concern about recurrence and current health using 4-point Likert response options that provide a score ranging from 3-12; higher scores indicate greater concern. Group-based trajectory modeling was used to classify distinct FCR patterns from baseline (median of 5 months from dx) through 3 years post-dx. Multinomial logistic regression was used to identify the associated patient (socio-demographics and BRCA status), disease (stage, ER/PR/HER2) and treatment (surgery, chemotherapy) characteristics associated with each trajectory. Variables significant at p&lt;0.05 in univariable models were entered into the final multivariable model. Results: 965 women with Stages 0-III breast cancer were included in the analysis, with a median age at dx of 37. Participants were predominantly non-Hispanic White (85%), partnered (76%) and had completed college (84%). There was a significant decrease in median FCR scores from baseline to year 3 (9 vs. 8, Wilcoxon signed-rank test P&lt;0.01). Five FCR trajectories (Table) were identified: 1) 10.5% of participants reported low/stable FCR from baseline over follow-up; 2) 33.1% had moderate FCR that improved over time; 3) 5.5% had moderate FCR scores at baseline that worsened over time; 4) 30% had high FCR scores at baseline that improved over time; 5) 20.8% had high FCR at baseline that remained high at all time points. In the fully adjusted multinomial model, younger age at dx and Stage 3 and 2 (vs. 1) disease were associated with higher odds of being in the high/stable trajectory. Having a lumpectomy (vs. mastectomy) was associated with higher odds of being in a high/stable as well as moderate/improving trajectory while White (vs. non-White) women had higher odds of being in a trajectory of improving FCR. Receipt of chemotherapy and financial discomfort were significantly associated with assignment to specific FCR trajectories in univariate analyses, however did not remain significant in the adjusted model. Being partnered, BRCA mutation status, and ER/PR/HER2 status were not significantly associated with any FCR trajectory classification in univariate or multivariate analyses. Conclusion: While FCR improves over time for many young women with breast cancer, a substantial minority (26%) had FCR that was severe and did not improve or worsened over time. Younger women with higher stage disease who are at risk for high levels of unresolved FCR may benefit from intervention including early referral to mental health professionals. Ongoing monitoring of women at risk for developing FCR following active treatment is warranted. Table Mean FCR score for each trajectoryBaselineYear 1Year 2Year 3TrajectoriesLow/Stable (N=103)5.725.605.545.45Moderate/Improving (N=331)7.907.487.287.09Moderate/Worsening (N=34)6.748.329.6410.54High/Improving (N=294)9.889.419.088.67High/Stable (N=203)11.0211.0811.0310.88 Citation Format: Lidia Schapira, Yue Zheng, Shari Gelber, Philip Poorvu, Kathryn J Ruddy, Rulla Tamini, Jeffrey Peppercorn, Steve Come, Virginia Borges, Ann Partridge, Shoshana Rosenberg. Trajectories of fear of cancer recurrence in young breast cancer survivors [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-13-09.